PCM 351W fresh water cooling (FWC)
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=47357
Printed Date: April-27-2024 at 9:59am
Topic: PCM 351W fresh water cooling (FWC)
Posted By: Wilhelm Hertzog
Subject: PCM 351W fresh water cooling (FWC)
Date Posted: April-14-2019 at 6:40pm
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Hi there. I have a 1982 Ski Nautique with the PCM Ford 351W motor. I use the boat in a variety of fresh/brackish/salt water locations. I am in the process of an engine rebuild (including getting a new block - original one bored out to its limits), and am considering converting to fresh water cooling while I'm at it. Can anyone offer some advice/guidance? I take it that since PCM ceased production of the OEM FWC kit in 2016, it is a matter of building a custom setup? Has anyone attempted to fit the Indmar kit (http://catalog.orcamarine.com/item/marine-cooling-system-kits/conventional-marine-cooling-system-kits/400800) to this motor? I saw some reference to that kit in the forums in the context of converting a PCM 351. Thanks for any help! ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Replies:
Posted By: 8122pbrainard
Date Posted: April-14-2019 at 7:04pm
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Wilhelm, There are several companies that make generic fresh water cooling kits so check what's available in your area. I'm sure some fabrication of bracketry would be needed as well as some custom hose/plumbing work. The alternate that many do here is add a means of flushing with fresh water after each outing. Is that possible as I have heard that there is a major water shortage in your area. Is the shortage still a concern? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Gary S
Date Posted: April-14-2019 at 7:07pm
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I realize your overseas but a call to PCM might be worth your time,they might just have a few limited parts on hand. You need R024002 the Y fitting, RB025009 upper thermostat cover,R025004 lower thermostat cover. Surge tank RA147009 and heat exchanger RA147008 could be sourced from other vendors. Front heat exchanger bracket R090039 and rear bracket R090038 and surge tank bracket R090040 would be nice but if not available you could fabricate your own. Everything else in the kit are hoses clamps and bolts which you could get on your own. Keep in mind that the PCM kit only cools the block,what ever water your in goes through te manifolds and risers. In saltwater they roughly last about 5 years. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Wilhelm Hertzog
Date Posted: April-14-2019 at 7:42pm
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I have installed flushing connections, so I do flush after salt water trips, but my boat may sometimes be moored in salt water for e.g. a week or two in places where flushing on the water is difficult. And yes, we did have some severe water restrictions in place, which made flushing a bit tricky, but our water situation is much better currently, so flushing is less of a problem from that point of view currently. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: Wilhelm Hertzog
Date Posted: April-14-2019 at 7:47pm
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Thanks a lot Gary, that parts list is hugely helpful. As you say, the heat exchanger and surge tank I can get from generic suppliers - I guess it's the first three parts that you mention that are mission critical for my application. I'll get in touch with PCM. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: rosconole
Date Posted: April-14-2019 at 7:52pm
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Might check if crusader has something similar... ------------- 1989 ski nautique ,1991 barefoot nautique, 1993 Mustang Cobra 1998 5.0 Magazine shootout invitee |
Posted By: Wilhelm Hertzog
Date Posted: April-17-2019 at 5:16am
I tracked down an installation manual with parts list for the FWC kit. Any idea why the parts with Reference Number 'N.I.' at the bottom are included in the list? Other than R045029A (overflow hose for the surge tank) it looks to me like these parts have nothing to do with the cooling system?  ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Gary S wrote:Posted By: Gary S
Date Posted: April-17-2019 at 11:40am
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Do you have the actual instructions or just the parts list? I obviously cannot speak for them but if you follow their instructions they want you to remove the risers from the manifolds to move the water inlets from the front to the back. You then need to change the gaskets. PCV valve hose needs to be longer and I suspect the valve it's self may be one with a 90 degree bend built in. Either way you would think they should be included but who knows.... If you need the instructions I have them but have no scanner,maybe I could take a picture of them and post if you need them. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Gary S
Date Posted: April-17-2019 at 12:00pm
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I just want to add don’t sweat the small stuff, get the Y and the thermostat upper and lower those will be the hard to find items. The expansion tank and heat exchanger will be available from other sources, but if PCM has them get them but the system will revolve around those first 3 parts. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Wilhelm Hertzog
Date Posted: April-17-2019 at 12:25pm
Thanks Gary. I do have the full instruction manual, and upon paying closer attention I realised why they include the riser gaskets, pcv hose, etc. in the kit - as you explained. I also found the full PCM parts manual here, which is very helpful: https://www.marinepartsguys.com/product-tag/pcm-marine-engines/ . I contacted PCM as you suggested. They referred me to Trans Pacific Distributors (www.transpacificdist.com or www.marinegate.com). These guys seem to have almost all of the parts in the FWC kit parts list available, except for what looks like a few generic pieces of hose. Not sure why PCM discontinued the conversion kit if all the components are still available. Be that as it may, I also enquired from Marine Parts Guys (www.marinepartsguys.com) about the six parts you mentioned in your first post, and they informed me that they are all available. So it looks like I'll get the parts I need from one of those two sources. Thanks again for the help! ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: Gary S
Date Posted: April-17-2019 at 1:42pm
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I know marine parts guys do not stock those parts they are dropped shipped from PCM, I suspect the others are the same. Nautique Parts seems to be cheaper on normal parts than them plus you can get 10% off by using planet Nautique as a discount. Might be worth your time to contact them and see if they will ship overseas. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Fl Inboards
Date Posted: April-17-2019 at 5:58pm
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I actually have new old stock R025002 the Y pipe. it is a NLA part. And I have the thermostat housing that is NLA part also New. I also have a complete 351 with fresh water on it for sale. not going to seperate it but if one wants a fresh water set up one can get a complete running engine package.[URL= https://panamacity.craigslist.org/bpo/d/panama-city-marine-ford-351-and/6857320127.html i see you are in South Africa could be a stretch with any parts.. ------------- Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise. 1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
Posted By: Wilhelm Hertzog
Date Posted: April-17-2019 at 6:16pm
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Is that the upper (RB025009) or lower (R025004) thermostat housing that you have available? ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: 91nautique
Date Posted: April-19-2019 at 11:31pm
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Wilhelm, I have a few of parts that you need, they are located in Western Australia,$300 US for everything in the pics.   
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Posted By: Wilhelm Hertzog
Date Posted: December-18-2019 at 11:21am
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So I eventually got all the parts together except the rear heat exchanger bracket (R090038). Also, the part number that I needed to order for the upper thermostat housing assembly (RB025009) was changed to RA025009. Something to do with the separate seal on the RB025009 (part number R047011) having given problems, so the design changed to incorporate a seal in the housing itself, which negates the need for R047011. Be that as it may, I had a rear bracket fabricated to fit the heat exchanger, and my motor is now FWC. However, the guys who did the installation work for me commented that the size of the heat exchanger is surprisingly small. They are more used to working on Mercruiser motors, where heat exchangers for smaller capacity motors than mine are apparently typically about 50% larger. And subsequent to the FWC conversion, I am now having issues with the motor getting too hot after running at high RPM for a while and then pulling back to idle. Has anyone else had similar issues? I'm thinking that I may need a larger heat exchanger... ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: 8122pbrainard
Date Posted: December-18-2019 at 11:30am
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Wilhelm, How hot is "too hot"? Regarding the size of the heat exchanger, you can't go totally by physical size. It's all about internal surface area and fluid flow rates. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Wilhelm Hertzog
Date Posted: December-18-2019 at 11:33am
Touching 220 degrees Fahrenheit. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: outerbanked
Date Posted: December-18-2019 at 1:33pm
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Pics of your engine would help. I would want to know if they included your exhaust risers (the stock system did not). Have you done the bucket test with the raw water pump to ensure you are getting correct flow? Have you verified the temps with a infrared temp gun? Checked for kinks? Made sure the hoses are not collapsing under load? Coolant is at proper level? |
Posted By: tryathlete
Date Posted: December-18-2019 at 4:36pm
Gary—if you replaced your iPhone since it took a drink on Deep Lake, there’s a built in scan feature in the camera function. Might be worth a look see. You are really helpful. |
Posted By: Wilhelm Hertzog
Date Posted: December-18-2019 at 4:49pm
None of the above explicitly, no. I'm reasonably confident the hoses aren't collapsing, and I haven't noticed kinks, but I'll double-check. We replaced the heat exchanger inlet hose with a transparent hose, and there appears to be a good flow of water into the heat exchanger, but I haven't checked the actual flow rate. How does one do the bucket test? And no, my exhaust risers aren't included - it's just the stock FWC system. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: 8122pbrainard
Date Posted: December-18-2019 at 4:55pm
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Wilhelm, Is the exchanger used or new? If used, has it been cleaned? They will "plate" ( a build up of impurities on the heat transfer surfaces) out over time loosing their efficiency. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Wilhelm Hertzog
Date Posted: December-18-2019 at 5:05pm
Brand new. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: 8122pbrainard
Date Posted: December-18-2019 at 5:26pm
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http://correctcraftfan.com/forum/forum_posts.asp?TID=32564&KW=bucket+test&PID=417883&title=bucket-test#417883" rel="nofollow - Here's a link to a thread on the bucket test It's testing if the RWP is doing it's job. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Gary S
Date Posted: December-18-2019 at 7:25pm
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I happen to have in my stash 2 new heat exchangers,1 for a regular PCM engine and 1 for a GT40. They both measure approx 2" in diameter and 2' long but have different inlets and outlets. The GT 40 one looks to have more tubes inside it. Curious if yours has the same dimensions? GT40 on the right-    ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: sport1999
Date Posted: December-19-2019 at 1:52pm
| May be wrong, but I believe the GT40 is a double pass. Where as, the 351w would be a single pass. |
Posted By: Wilhelm Hertzog
Date Posted: December-19-2019 at 4:42pm
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Exactly the same as your one on the left. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: Wilhelm Hertzog
Date Posted: December-19-2019 at 5:35pm
   ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: KENO
Date Posted: December-19-2019 at 6:48pm
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The things that people notice when you put pictures up Maybe somebody will notice the Chinese HEI distributor with the vacuum advance canister peeking out and say something about it. Or they may question whether the carburetor is marine or automotive. Just tell them that you're in South Africa and USCG regs don't apply to you, even if it's a good safety thing. Sparks and explosions/fires don't really know any borders though, so I tend to think an African spark and an American spark can have the same end result in a fuel leak situation. 
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Posted By: TRBenj
Date Posted: December-19-2019 at 7:02pm
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How is the exhaust cooled? Dry risers? |
Posted By: Gary S
Date Posted: December-19-2019 at 8:10pm
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Last picture shows the the heat exchanger at the top of the picture.The 1" hose coming down in the middle of the picture with the T is the feed to the manifolds, the green striped hoses are going to the rear of each exhaust manifold. The only differences to PCM's setup is that their heat exchanger is usually mounted along side of the block right behind the raw water pump and the manifolds look more like Crusaders. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Gary S
Date Posted: December-19-2019 at 11:33pm
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Wilhelm where does is hose that feeds the T come from? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Wilhelm Hertzog
Date Posted: December-20-2019 at 5:23am
Points taken, thanks! It is indeed an automotive carb, but it has been fitted with J shaped float bowl vents. Not always simple/cost effective to get OEM marine parts for old engines in South Africa... As to the distributor: does that unconnected vacuum advance canister potentially cause ignition timing issues? ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: KENO
Date Posted: December-20-2019 at 8:05am
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As far as the distributor, it more a matter of spark protection. Where the advance mechanism goes through the distributor there's an opening that gas fumes can pass through and get into the distributor if you have a fuel leak. The fumes meet the spark in the distributor and you have an explosion that is not contained in the distributor because of that open unprotected path. The marine version has no vacuum advance and the opening is blocked off but there are a couple of vent holes in the body of a DUI HEI marine distributor that have brass screens in them which keep the explosion contained inside the distributor. The gas fumes can still get in if you have a leak but like mentioned above the screens prevent the internal explosion from getting outside the distributor so it keeps the fumes in the engine compartment from exploding. The distributor may be damaged internally, but you won't be in an exploding boat. It works on the same principle as an old miners lamp Here's a link down below to a thread by somebody who "converted" his Chinese distributor. In his mind it meets USCG requirements The typical factory job has 2 layers of screen per vent hole, not 1 like he did. I think there's a reason for that Lots of people have survived for a long time without USCG approved stuff on their boat, but it just takes that one bad day to change all that. http://www.correctcraftfan.com/forum/forum_posts.asp?TID=38635&title=marine-distributor" rel="nofollow - link Some later marine certified distrihbutors are well sealed with no openings for fumes to get into the distributor. By the way, is your engine normal automotive rotation or if it's reverse rotation, did you have some machine work done to adapt a reverse rotation gear to that distributor? |
Posted By: TRBenj
Date Posted: December-20-2019 at 9:00am
Just 1 connection, rather than in/out? Risers are dry? |
Posted By: KENO
Date Posted: December-20-2019 at 9:09am
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It seems to me that the manifolds and risers are raw water cooled. Instead of the raw water going in the front of the manifold, it goes in the rear and up through the riser and out the back of the boat. |
Posted By: Wilhelm Hertzog
Date Posted: December-20-2019 at 9:21am
Correct. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: Wilhelm Hertzog
Date Posted: December-20-2019 at 9:24am
Reverse rotation. I can't recall if the PO installed the distributor or if it was done by the guys who rebuilt the motor for me. I suspect there was some machine work involved, yes. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: KENO
Date Posted: December-20-2019 at 9:33am
That would be a FWC half system or a closed cooling half system 
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Posted By: TRBenj
Date Posted: December-20-2019 at 9:48am
I’d like to see how the cooling passages line up on those risers. Never seen that style before, though they are handsome. Manifolds look like normal PCM. Gasket for reference: https://www.skidim.com/images/RM0002.jpg" rel="nofollow - https://www.skidim.com/images/RM0002.jpg 
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Posted By: Wilhelm Hertzog
Date Posted: December-20-2019 at 10:28am
No, neither the risers nor the manifolds are the standard PCM Ford ones. Off a GM motor IIRC, with a bit of adaptation to fit them to the Ford block, and custom cut gaskets. I have had this setup since buying the boat - seemingly no issues. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: GottaSki
Date Posted: December-20-2019 at 10:45am
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I don't see any gazintas ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: 8122pbrainard
Date Posted: December-20-2019 at 10:51am
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Wilhelm, Getting back to the high temp issue, if your bucket test proves the RWP is doing the job AND if your manifolds are running cool, I'd see if a raw water restriction to the manifolds will do anything. The restriction may put more raw water through the heat exchanger to make a difference. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Gary S
Date Posted: December-20-2019 at 11:32am
Tim the raw water from the hull pickup follows the normal PCM path until it exits out of the Sherwood pump. Instead of running to the thermostat housing it goes to the heat exchanger cooling the block coolant then exits out of exchanger via 1 outlet into that T and then like a raw water cooled engine into each exhaust manifold through the risers and out. They put the water in the back of the manifolds only because the way the exchanger is mounted its outlet is near the bellhousing thus keeping the hose length short. The only real difference here is that he has the exchanger mounted across the rear of the engine rather than PCM's length wise mount behind the Sherwood pump. This is why it is called a half system in the sence that only the block is protected- the manifolds still being raw water. I'm not sure but I think a full system has the manifolds cooled by the block water with block off plates at the manifold to riser joint but the risers are still cooled by the exit of the raw water ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Gary S
Date Posted: December-20-2019 at 11:36am
I'd like to know where the water comes from before that T to the manifolds i.e. Is the raw water making a full pass through the exchanger not tapped off half way down it or something. I just cannot see where it is coming from in the pictures ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: GottaSki
Date Posted: December-20-2019 at 11:45am
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I think the vacuum advance is inhibiting water flow What happens if you remove the statat? that could tell you if you have a enough heat transfer available in the system, and suggest which water circuit the problem is. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: TRBenj
Date Posted: December-20-2019 at 11:45am
I know how it’s supposed to be plumbed, I’m asking how he has it plumbed since there appear to be a number of inconsistencies to go along with the described cooling problem.
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Posted By: Gary S
Date Posted: December-20-2019 at 11:59am
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Oh - never mind. According to the Shamrock guys these parts can be mounted just about anywhere but they are not to concerned at how anything looks,just that it does the job. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: JoeinNY
Date Posted: December-20-2019 at 1:20pm
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So if it is reverse rotation it may actually need a bidirectional circulation pump to work correctly, Something has to move that water through the heat exchanger. Considering the number of automotive parts needed to make things work over there I would check to make sure a standard rotation automotive pump wasn't used. It is important that the heat exchanger is plumbed in the correct location to get full capacity out of the heat exchanger but near as I can tell it is. I would love to see how they got a chevy manifold to fit a ford. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: KENO
Date Posted: December-21-2019 at 1:04pm
I figure if you start with a marine manifold for a 5.3 or 6.0 Chevy, a sandwich type adapter plate that would probably have to be "home grown" would make this halfway easy Here'a a picture of a 6.0 Chevy exhaust gasket and a 351w exhaust gasket, you'll have to visualize the adapter plate. I think a machinist in South Africa or anywhere else could whip up a couple of those adapters fairly easily 
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Posted By: Wilhelm Hertzog
Date Posted: December-29-2019 at 6:32pm
The pictures below shows the detail. Raw water leaves the heat exchanger to the T circled in blue. From there I assume it is supposed to flow to the next T circled in green (more clearly visible in the second photo). This T sends water to the exhaust manifolds and the trans oil cooler. From the trans oil cooler, water is sent to a heater I have mounted in the front of the boat. Water from the heater comes back to the blue T via the red elbow connector. Upon looking at this setup, a few things here don't make sense to me the way the guys who did the installation for me did things: 1. Water coming out the heat exchanger and water coming back from the heater will be 'fighting' each other at the blue T, not so? Surely this will create flow issues somewhere? The heater never heated up properly despite the engine running hot - a symptom of this perhaps? 2. Having raw water pass through the heat exchanger before going to the trans oil cooler must surely mean the trans oil cooler is not getting particularly cool water? The standard placement would be before the heat exchanger, right? Even though this means the trans oil cooler is putting some heat into the water going into the heat exchanger? Thanks for any help here!   ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: KENO
Date Posted: December-29-2019 at 7:47pm
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#1 Why not keep it simple till you get things figured out and disconnect the heater or at least isolate it? #2 The transmission cooler is usually the first place the cool water goes. Some setups have the cooler before the raw water pump and others have it after the raw water pump but in either case, the first thing to get cooled is the transmission fluid. In the link is a "typical closed water cooling half system" like yours. It's for an inboard outboard and shows the raw water going through a power steering cooler after the transmission cooler, but you'll see the typical flow path. https://www.cpperformance.com/t-marine-closed-cooling-systems.aspx" rel="nofollow - link |
Posted By: outerbanked
Date Posted: December-30-2019 at 2:00am
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I know you have a few issues you are working on. Agree with KENO to simplify what you have until it is working. Get an infrared temp gun. 1. Create a block diagram of your system. 2. Your heater should be on the antifreeze circuit. (Warmer heat, ability to help cool your engine using it). 3. Have you been able to verify both of your pumps are working? a. Part number for your engine mount water pump is a bi-directional marine pump? b. Raw water pump has sufficient flow. 4. Your path should be water inlet, strainer, trans cooler, raw water pump, heat exchanger, tee, exhaust manifolds. Pg55. https://www.marinepartsguys.com/wp-content/uploads/ILLUSTRATED-PARTS-MANUAL-PCMcompressed.pdf" rel="nofollow - https://www.marinepartsguys.com/wp-content/uploads/ILLUSTRATED-PARTS-MANUAL-PCMcompressed.pdf |
Posted By: Wilhelm Hertzog
Date Posted: January-02-2020 at 1:22am
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Should I replace the plastic tees and elbows in the system with brass while I'm at it? Or is plastic fine? ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: Gary S
Date Posted: January-02-2020 at 1:59am
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Up to you if you change them Correct Craft seems that now days they only use that grey plastic. If your in salt,which I think the reason you have the fresh water cooling, and you want to change you don't want brass you'll want bronze ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Wilhelm Hertzog
Date Posted: January-10-2020 at 5:40pm
I have a dripless shaft seal. Where in this path should the water feed to the shaft seal ideally be located? And is it okay to run the engine in gear on a flushing connection with a dripless seal (bearing is lubricated with the water feed?) or will that destroy the cutlass bearing? ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: Wilhelm Hertzog
Date Posted: May-19-2020 at 7:13am
Finally figured out what manifolds and risers I have: http://www.easeintegration.co.nz/iboatspage/products.htm" rel="nofollow - link . They are the Chevy ones though, hence the adapter plate as mentioned in some of the later posts. Interesting mix I have here: New Zealand manifolds on an American boat in South Africa.  ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: Wilhelm Hertzog
Date Posted: November-12-2020 at 3:47am
Okay, so a follow up after doing the following over the past few months:
Engine temps were fine on a hose in the garage (I could not run it for extended periods on the hose though), but when I took it out for its first water test a few days ago, engine temperatures were still running up (to about 190 - and rising - on my IR temp gun) when the motor is at idle for long periods of time and when coming down to idle rpm after running at speed. At speed, and also when revving the motor in neutral to about 2,000 rpm the engine temp drops quickly back to normal (170 and below - I have a 170 deg. thermostat). So it seems to me the raw water pump is not circulating enough raw water through the heat exchanger at idle speeds. Is this a common problem with fresh water cooled setups like mine? I imagine not. Other than replacing the impeller and seeing if that gives me (even) better results on a bucket test, I can't think of anything else to improve the situation. Any suggestions? ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: 8122pbrainard
Date Posted: November-12-2020 at 7:58am
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Wilhelm, Did you ever investigate potential issue with the size of the heat exchanger?
------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Wilhelm Hertzog
Date Posted: November-12-2020 at 8:25am
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No, I didn't. It is the OEM heat exchanger from PCM, and as best I can tell nothing in my engine should make it need a larger heat exchanger. So I figured I'll revisit that as a last resort if I've exhausted all other troubleshooting options. At the moment I'm leaning towards replacing the impeller to see if that makes a difference. The impeller looks fine when inspected through the pump outlet, but I'm not sure how old it is (which probably means it's quite old), and maybe it's bucket test performance is not quite as good as it should be, which just may be enough to tip the engine into overheating and not maintaining a stable temperature? If replacing the impeller doesn't help, then maybe there's an issue with my circulation pump not circulating water through the engine well enough? ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: KENO
Date Posted: November-12-2020 at 1:50pm
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Logically, if you have no idea what the Raw Water Pump impeller or the inside of the pump looks like or how old it is, that would be a good place to start. You have a bunch of money invested in new cooling system parts, why not spend a little more on a new impeller? The worst thing that can happen is that you'll have a spare impeller and that's not exactly a bad thing. Here's a link to a Sherwood catalog that has impeller performance curves on page 10. Your G20 or 21 pump with a 9959K impeller should empty a 5 gallon bucket in under a minute at about 1000 rpm if you want to compare your test results to their graph. If you have a different Sherwood pump, you should be able to find it's info in the same catalog. http://inetmarine.com/DataSheets/Sherwood/Sherwood_Catalog_ENGLISH.pdf" rel="nofollow - link Then you could figure out what you have for an engine circulating pump as the next step if necessary
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Posted By: Wilhelm Hertzog
Date Posted: November-12-2020 at 6:35pm
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Before realising there were air leaks in the raw water circuit I was thinking the impeller was to blame for my issues, so I ordered a new one. Because my bucket test results were far better after the air leaks were fixed (definitely emptied a 5 gallon bucket in less than a minute at idle) I never installed the new impeller. But I'll install it and see if that makes a difference. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: Wilhelm Hertzog
Date Posted: November-16-2020 at 4:03am
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As I noted in https://www.correctcraftfan.com/forum/forum_posts.asp?TID=49390" rel="nofollow - this thread, my boat's ventilation system was totally butchered at some point. As part of this process, the front vents were sealed off, so it seems to me there is very limited flow of fresh air getting to the engine under normal operating conditions. Could improving engine ventilation improve engine temperatures in any meaningful way? ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: 8122pbrainard
Date Posted: November-16-2020 at 5:19am
I really don't feel it would help the cooling problem. Have you double checked how you have the engine plumbed? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Wilhelm Hertzog
Date Posted: November-16-2020 at 6:35am
Yes, I'm confident the plumbing is correct. I'll change the impeller and report back. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: Wilhelm Hertzog
Date Posted: November-24-2020 at 2:01am
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Below are pictures of my disassembled raw water pump. The impeller clearly is not in the best of shape anymore, so hopefully changing that will improve water flow/priming at low engine speeds. Three questions I'd really appreciate some help with:
        ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: KENO
Date Posted: November-24-2020 at 7:55am
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To me, the cam looks good, it's symmetrical and can go in either way. The O ring goes on one side of the plate and gasket on the other just like the diagram shows. Pete will probably say that impeller is good for another quarter of a century or so...........I'd replace it anyways since you're having cooling issues
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Posted By: SNobsessed
Date Posted: November-24-2020 at 1:11pm
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The housing only goes together 1 way, as the holes are not exactly 120 deg apart. I would just scrape off the crud, put a new PCM impeller in it, & not look back. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: KENO
Date Posted: November-24-2020 at 5:54pm
I think what you really mean to say is that the holes are indeed 120 degrees apart and the housing can go on 3 different ways but only one way works to have the suction and discharge facing straight up and down on a PCM pump bracket Wilhelm took some really good, clear pictures and you could measure the distance between the 3 holes and see that they're 120 degrees apart on the bearing housing, the impeller housing and the gasket.. Or I could mention that I just put one together 3 different ways
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Posted By: SNobsessed
Date Posted: November-24-2020 at 9:28pm
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OK sorry for bad info, it must be a different pump than I had. Mine would only go together 1 way. Maybe it was machined wrong but it is a fact. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: Singlespeedy
Date Posted: May-23-2021 at 11:36am
| Do you still have the lower thermostat housing R025004? Mine is cracked and I'm searching! |
Posted By: Wilhelm Hertzog
Date Posted: May-23-2021 at 3:01pm
Yes I do - it is installed on my engine. It took quite a bit of searching around to get everything together for the fresh water cooling conversion I did in 2019. Rudy Solares at Marine Parts Guys eventually managed to get everything together for me (after a lot of to and fro with PCM from his side). Bottom line: I could not order R025004 as an individual part. PCM (via Rudy) eventually gave me one part number (RA025009) to order which included (or replaced) all of the following items:  My understanding at the time was that there had been a problem with the sealing of the thermostat in the thermostat housing, so the thermostat housing was redesigned and the old one (R025004) discontinued. I'm not sure of the part number for just the lower housing that was included in my RA025009, and whether the lower housing included with RA025009 will work with the old upper housing (R025009 or RB025009). I guess SkiDim or someone like Marine Parts Guys should be able to get the answer out of PCM for you (PCM doesn't like dealing directly with the public - they told me as much via Rudy). ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |
Posted By: Wilhelm Hertzog
Date Posted: December-31-2021 at 9:31am
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Wrapping up this thread: the impeller change did not change much as far as engine temps or bucket test results go. I've decided to live with the slightly high (by marine standards - but seemingly acceptable by automotive standards) operating temps. ------------- 1982 Ski Nautique PCM351W RR II Velvet Drive 10-17-003 1:1 II PerfectPass Stargazer Do not go gentle into that good night. Rage, rage against the dying of the light. |