'80 SN 351w RR performance upgrades
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=39508
Printed Date: April-27-2024 at 11:08am
Topic: '80 SN 351w RR performance upgrades
Posted By: EagleEyedOne
Subject: '80 SN 351w RR performance upgrades
Date Posted: July-28-2016 at 2:29pm
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Hi, (Thanks CCF.com for a great forum) Just bought a refurbed '80 Ski Nautique very nicely redone about 10 years ago with engine overhaul 4 years ago. First owner SN and during first week somehow overheated the engine during normal operation and have a knock now. Raw water impeller is good and 160 deg thermostat also good on the stove test. Jury is still out on root cause of overheating. don't have much history from previous owner, other than I never had any problems... Long and short, need to rebuild or buy long long block. Was considering the following performance upgrades to get more RPM's out of the engine for more top speed for reverse rotation 351w with firing order 18456273 and 1:1 Velvet drive tranny: * roller cam with marine grind * roller rockers * GT40P heads * aluminum intake * already has newer Holley 600 marine carb * already has newer Mallory marine distributor Called a long block supplier and he says can't get too 'radical' with a RR roller cam due to reversion and can't get full benefit of GT40P heads with normal marine cam. The 1:1 tranny and and 4 blade prop tops at roughly 40-42 now. Any thoughts CC Fans!? I want reliable solid running engine with no issues. Need it to idle well and low enough through no wake river I spend a bit of time on. Thanks! |
Replies:
Posted By: phatsat67
Date Posted: July-28-2016 at 2:46pm
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A properly tuned 240 horse in a2 80 ski should be running closer to 48-49 MPH. You don't need a cam big enough you would need to worry about reversion. That comes into play on engines that used collector style headers and huge duration and overlap cam selections. That engine should have a 143 degree thermostat. The dizzy and the carb should be fine. If you don't want to blow a ton of cash on a roller cam a cam research camshaft and the rest of those parts should be good for 325 HP and 51-53 mph or so. Go over the cooling system with a fine tooth comb. Replace all the hoses and confirm all of the fittings aren't smashed or boogered up on the ends. For good measure install a new raw water filter and either have your RWP rebuilt or replace if you don't have a good way to verify operation. |
Posted By: JoeinNY
Date Posted: July-28-2016 at 2:49pm
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There are dozens of threads on it around here, you have found the first limit which is the lack of great cam choices. A roller would be spectacular but in reverse rotation its going to need to be a custom job and it would cost more than most will bite. That being said some 1.7 roller rockers have been known to wake up a stock cam. The gt40p heads are a no brainer they yield actual horsepower and are not much more expensive than rebuilding stock heads. After that an intake helps... that gets you through the easy stuff. A good acme 540 propeller will yield the biggest bang for the buck in terms of performance increase with your boat which was not running real great at n40-42, 45-47 would be more correct for a stock 80. The above should have you in the 50+ range done well. ------------- 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: EagleEyedOne
Date Posted: July-28-2016 at 4:24pm
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Well, this is good news Mr. phatsat67! I've already put a new impeller in RWP and bearings seemed good. Reassembled thermostat housing without thermostat to make sure engine was getting cool unrestricted water which it is. Don't know if fluke stuck thermostat or other issue but certainly will heed advice to nit pick the cooling system and lines. Will reinstall 143 deg tstat with new engine. Appreciate the response and confirmation that my new toy should be able to reach 50... YES! |
Posted By: phatsat67
Date Posted: July-29-2016 at 11:35am
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Good luck with it. It'll be a screamer when re assembled. I am considering the same power upgrade as I have one externally cracked head. Reluctant to pull it apart as it runs so well. |
Posted By: gun-driver
Date Posted: July-29-2016 at 12:18pm
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Since you say you spend a lot of time idle in a no wake zone I would expect an air leak in the suction side of the water pickup. 50+ and 325hp with GT-40p heads is a little tall. With the above performance enhancers I'd say more in the 300-310hp range and 49/50 mph as I have an '85 with that setup. Zach get some JB weld on that head and run it...ask me how I know 
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Posted By: phatsat67
Date Posted: July-29-2016 at 12:28pm
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Paul, Been that way all summer ha. No leaks. Cracked half moon shapes below two exhaust ports. I attribute it to high hours and the heads being used in brackish water for 4 years or so. Castings have somewhere between 1600-1800 hours on them. |
Posted By: TRBenj
Date Posted: July-30-2016 at 8:44am
| Paul, I would bet 310hp is close with your set up. With similar flow and smaller chambers than your do0e's, the P heads should be good for a point of compression and another 15hp. I think that should be good enough to flirt with the 50mph mark on an early 2001. |
Posted By: EagleEyedOne
Date Posted: August-09-2016 at 4:09pm
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Guys, thanks for the responses, finally able to get back to responding. JoeinNY, nice ride and holeshot video!! I've got an ACME 208 13X12.5V RH 1" 4-blade prop. Could this be some of the reason for the lack of top end speed? You're recommending an ACME 540 3-blade. After a little research including your thought, I'm finding that the 3 blade is a better fit for my 1:1 drive setup, although being told that an OJ 4-blade 13X13 is stock for my boat and offers less rooster in the wake and relatively same performance at $120+ bucks more than 540 at $375.... I'm installing 1.7 Scorpion roller rockers on GT40P heads and have PCM exhaust manifolds, any recommendations on taller valve covers that don't interfere with exhaust manifolds? Any thoughts here would be mucho appreciated. Thanks! |
Posted By: TRBenj
Date Posted: August-09-2016 at 4:16pm
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If you went with 1.7 crane/fms rockers, chances are better that they'd it under stock vc's. Zach has reported that the 208 is a pancake acme, and thus a good slalom prop. It's lack of rake plants the nose and flattens the wake a little. It will slow the boat down vs a 540 by a few mph. I have a 3-blade 13x13 OJ around as a spare and it's an ok prop, but I would never buy one new. 540 is superior. |
Posted By: halfnelly
Date Posted: August-09-2016 at 4:23pm
I can confirm the FMS/Crane 1.7s fit under the red PCM aluminum valve covers, but the baffles need to be modified and I used some 5/16" valve cover gaskets for more clearance. I believe the steel ones have more room, my aluminum ones were really low. https://www.summitracing.com/parts/fel-1645/overview/make/ford" rel="nofollow - Gaskets |
EagleEyedOne wrote:Posted By: phatsat67
Date Posted: August-09-2016 at 4:39pm
| 208 is a fabulous slalom prop on a 2001 hull. The wake is noticeable just by watching in the mirror. Performance is much much softer all around than the 540. As an example my boat ran 43.xx with the 208 and 46.xx with the 540. Scrubbed about the same rpm off the tach as well. |
Posted By: EagleEyedOne
Date Posted: September-01-2016 at 12:33am
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Thanks for the great feedback! It's getting real now, just got the short block, GT40P heads, RPM AirGap intake, CRC holeshot cam, and other goodies! Getting ready for assembly. Now that things are being removed, noticed the mufflers look original, any reason to consider upgrading exhaust to either stock new or something a bit higher performing? Recommendations? Will summarize the full project in a future post. Thanks. |
Posted By: phatsat67
Date Posted: September-01-2016 at 4:17pm
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No, Joe runs stock mufflers on his 500ish HP stroker Ford. Coming along nicely. |
Posted By: gun-driver
Date Posted: September-01-2016 at 8:21pm
| The Air Gap is a pretty high intake might have some clearance issues with the engine cover. |
Posted By: Jonny Quest
Date Posted: September-03-2016 at 10:10am
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Could the transmission be indexed to run LH? If so, why not change the engine to run Standard (LH) rotation? New cam anyway, right? Just buy a nice, new DUI distributor for LH rotation. New propeller. Any other components have to be changed out for RH to LH rotation? JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: gun-driver
Date Posted: September-03-2016 at 1:03pm
| 1980 would be 1:1 tranny, it can be indexed to go lefty but doubt you want to do that. Plenty of discussions on here about turning these boats with a lefty prop. |
Posted By: EagleEyedOne
Date Posted: September-04-2016 at 2:54am
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Thx gun-driver: It is a 1:1 Velvet drive tranny and could be swapped but read/was told the reverse rotation torque of the engine counters the drivers weight keeping the wake even and boat level, and am already committed with RR parts purchased. Also, agree with clearance issue with tilt of the engine, may need a lower profile air cleaner. Thx too P67, appreciate the note. Not sure I'll be doling out $400 for new pipes if not really necessary. Does anyone have vehicle cross reference info for these marine 351w blocks, specifically for a new oil pan? After a fair amount of research, I ordered exactly what I thought I'd need based on pics and using 81 Bronco specs, and order got cancelled... It's a mid sump pan and having a hard time finding something and would like a new oil pan with new engine and keep existing for future rebuild. Thx... Happy Labor Day weekend, throttles down! Speaking of which.. my Bro has a 93 Sport Nautique that does full speed powerslides like a champ. Can I expect the same from my 80 SN or expect to be thrown from the boat....? Didn't get a chance to test..... |
Posted By: Blamey
Date Posted: September-04-2016 at 10:50am
It's the prop ration that counters the drivers weight. Engine has minimal effect. That why they were able to switch the Regular Rotation engines in later SN 2001s but kept the prop spinning RH. ------------- 96 Super Sport Previously: 95 Sport Nautique, 1980 Ski Supreme |
Posted By: 8122pbrainard
Date Posted: September-04-2016 at 11:09am
Michael, It just may be a mistake in terminology but FYI, it's not an air cleaner as you have mentioned. It's a flame arrestor, a very important piece of ignition prevention and I'd have to say the very first preventative item used on marine engines I just wanted to bring this up since there are "back yarder's out there who have used automotive air cleaners and unknowingly are driving bombs!!  ------------- /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: mmasariu
Date Posted: September-12-2016 at 12:26am
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When you say CRC Holeshot cam, what are the specs on that cam? Have you got it assembled and running yet? I am looking for a rr cam for my 351W that I have apart right now. Thanks. Matt ------------- Matt Masariu Speedway, Indiana 1987 Dominique |
Posted By: EagleEyedOne
Date Posted: September-12-2016 at 2:13am
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Hey Matt, Here are the notes I took from Scott at Cam Research Corp. He's dubbed it his 'holeshot' cam which has the following specs: * marine grind for reverse rotation * 272 intake * 280 exhaust * 0.460 valve lift * 112 lobe separation He says it should perform with following comments: * gives best of both worlds for improved holeshot and top end speed upgrade from stock * should keep stock fuel economy * He can be reached at 303-762-0022 I just got the short block, cam and other parts about 2 weeks ago and haven't installed anything yet due to work travel. Blamey - Thanks for the clarification update about the prop countering driver weight. 8122.. - Thank you for the correcting my 'mis-write'! I won't have a bomb on my hands... |
Posted By: john b
Date Posted: September-12-2016 at 4:35am
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Sounds interesting. This is a slider not a roller correct? ------------- 1970 Mustang "Theseus' paradox" If everyone else is doing it, you're too late! |
Posted By: Duane in Indy
Date Posted: September-12-2016 at 7:35am
You might check with Comp Cams also. They ground my flat tappet cam for my 302 this spring. They have RR blanks in stock. Takes less than a week. About $250 delivered ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: EagleEyedOne
Date Posted: September-12-2016 at 12:37pm
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JohnB - this is not a roller cam. Duane/Matt - I think I paid $260 for the cam at CRC. |
Posted By: mmasariu
Date Posted: September-12-2016 at 7:49pm
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Thanks EEO and Duane. Mine also will be non-roller. Matt in Speedway.  ------------- Matt Masariu Speedway, Indiana 1987 Dominique |
Posted By: mmasariu
Date Posted: September-14-2016 at 12:05am
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While I have everyone's ear, or hopefully anyone's ear, do recommend a particular dealer or site for a rebuild kit? I have an '87 351w rr, and see several kits out there but not sure which mfg's to avoid. Nothing crazy, .30 over, I assume my crank will get .10, so pretty standard stuff. I will probably be picking up a CRC cam, so that obviously wouldn't be needed with the kit. Thanks in advance for the recommendations. Matt ------------- Matt Masariu Speedway, Indiana 1987 Dominique |
Posted By: MrMcD
Date Posted: September-14-2016 at 2:05am
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I see you are in Indiana. Jasper Engines in Jasper Indiana builds a first class engine. They might be $200. high but I can vouch they build and back a good product. They will work with you for custom changes if needed. They use premium parts and take no shortcuts. I have had guys tell me they are priced a little high but no one ever said they make a bad product. If you want to build this engine yourself it is a good idea to have the Machine Shop order your pistons and bearings. That way if your engine cleans up at .020 over they order the parts, if it cleans at .030 or .040 they are still ordering your parts and responsible to have them there on time and your bore is done to match. Same on the crankshaft. You could order your bearings and find out the crank did not clean up at .010 and needs to be turned to .020. Freight charges for returns can eat up any savings on price really fast. I would stay with known quality brands and avoid some of the low cost import copies that may or may not work. Sealed Power, Mahle, Clevite, Cloyes, Melling, Fel-Pro Speed Pro just to name a few. ------------- |
Posted By: EagleEyedOne
Date Posted: July-07-2017 at 9:27pm
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Hi, Does anyone have a spare prestolite alternator with part number alk 6220Y-1N? I know they're hard to come by and the order I placed earlier today was cancelled. I need something quick if possible. Going on vacation with this boat project finally coming together... thanks for any suggestions! |
Posted By: EagleEyedOne
Date Posted: June-22-2019 at 11:51pm
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Hola, Got this project back together, ran it most of last summer with no issues as I was still breaking it in. Ran it full throttle in the early Fall for the longest time yet, maybe a minute or so and while nothing happened directly after that run, A few weeks later, the engine liquid locked with water in the cylinders. Pumped the cylinders dry, dried the plugs, fired it up, ran it lightly, then two weeks later, found water in the oil. Been trying to figure out what the $%&@ is goin on since. Any thoughts about where failure is? Put new intake gaskets on suspecting it might have been there, but still suckin water in from somewhere while running in driveway with hose feeding RWP. Ugh. |
Posted By: EagleEyedOne
Date Posted: June-23-2019 at 2:49am
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Hola, Got this project back together, ran it most of last summer with no issues as I was still breaking it in. Ran it full throttle in the early Fall for the longest time yet, maybe a minute or so and while nothing happened directly after that run, A few weeks later, the engine liquid locked with water in the cylinders. Pumped the cylinders dry, dried the plugs, fired it up, ran it lightly, then two weeks later, found water in the oil. Been trying to figure out what the $%&@ is goin on since. Any thoughts about where failure is? Put new intake gaskets on suspecting it might have been there, but still suckin water in from somewhere while running in driveway with hose feeding RWP. Ugh. |
Posted By: 8122pbrainard
Date Posted: June-23-2019 at 8:06am
Michael, The exhaust manifolds? ------------- /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: KENO
Date Posted: June-23-2019 at 9:16am
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Did you have water in all 8 cylinders, maybe just one bank of cylinders or just some cylinders? Did you have water in the oil the first time? You only mention it the second time. Is it a lot of water or could it be residual from the first time? Have you changed the oil enough times to be sure any residual water was out after the manifold gasket change? Questions, questions
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Posted By: EagleEyedOne
Date Posted: June-23-2019 at 11:10am
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Morning and thanks for the questions.. PRIOR to the full throttle run I was on my 3rd break-in oil change. Did not notice any water in oil before or after the liquid lock. All eight cyls had varying amounts of water that got cranked out. Did not run it very much over the next 2 weeks after the liquid lock, but when I started and was warming up, I could hear the faintest knock and shut it down to find the water in the oil. Pulled the boat, changed the oil twice, each with one quart of kerosene and 4 qts oil to help flush the water before sitting over winter. Each of the two times had RWP fed by hose. On 3rd change had to stop water flow so could get a 'clean' change.... Fast forward last week, was tough trying to fix this over winter... replace intake gaskets, got boat running, ran for about 5 min after/during getting timing adjusted, shut down changed oil only once but it was way too milky in color to be just residual water. Then starts diagnosing... During compression check, each plug was dry and each cylinder ranged between 125 and 137 psi. Haven't checked exhaust manifolds yet, maybe today.. air pressure tested the water cooling system by adapting an air fitting to the hose that feeds the tstat housing from RWP, blocked the exhaust manifold hoses from the tstat housing, and applied 80ish psi to see where things could be leaking. Sprayed soapy water on front of engine and found a small bubbling leak on one of the timing cover bolts. That's about as far as I have gotten before tearing more stuff apart.. Thx. |
Posted By: MrMcD
Date Posted: June-23-2019 at 2:09pm
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Good effort so far but a little tune up is needed on your effort. Gaskets that seal the cooling system are never exposed to more than 20 PSI in normal use. Blowing 80 PSI can blow out your good gaskets. Even running full water pressure from your garden hose can blow these coolant gaskets. Garden hose can be 60 PSI. I like the air test and have used it a few times but I limit air pressure to 30 PSI and use a shut off valve at the engine with a pressure gauge attached before the valve so I can monitor air pressure to see if it is holding at the 30 PSI I installed. A sealed engine should be like a tire, put 30 PSI in and it should stay. Test the connections with soapy water and wait 30 minutes. Air leaks that are slow will take this long to form a bubble spot you can see. If you have a cracked head or cracked block your leak might not open up till the engine is hot. PS: When you release the air pressure so it slowly. My set up was on a quick disconnect. When I released it 30 PSI of water came blowing out of my engine all over my garage and me. I had forgotten there was water in the water jackets, I expected just air to blow out. It was probably only a quart but under pressure that quart got a lot wet quickly. ------------- |
Posted By: KENO
Date Posted: June-23-2019 at 8:26pm
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If you ask 10 people, half will say manifolds, risers and the other half will say head gaskets, intake gaskets, cracked intake, cracked head etc. Then somebody will mention the timing cover as a sneaky possible path directly to the oil sump, but not into the cylinders. (either a crack or bad gaskets) That would show up on the pressure test. Since you had external leakage fronm a timing cover bolt, maybe there' was internal leakage too It confusing that you had water in the cylinders the first time but not the second time. If you do MrMcD's test at 30 psi and isolate the system the rate of pressure drop will tell you the relative size of the leak if it's going down. If it's steady then the exhaust manifolds would be suspect. You don't know the results of the exhaust manifold pressure test yet ? They're a little harder to test, don't know what your method is. |
Posted By: TRBenj
Date Posted: June-23-2019 at 11:13pm
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Start with a compression test. If that passes, then inspect as you start disassembly. Water in cylinders + passed compression test likely points to exhaust manifold(s)/riser(s). |
Posted By: EagleEyedOne
Date Posted: June-24-2019 at 7:06pm
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Gents, Thanks for the fine tuning comments and feedback. Well, the 80 psi didn't blow anything up, that I can see yet.. Compression results were 125 to 137 on a cold engine with throttle open, and butterflies held open. Exhaust manifold testing on the engine - adapted air fitting with gauge on hose that fit to front of manifold and blocked rear of riser exit with old exhaust hose and a small pint paint can (fit pretty damn well in the hose with a lil electrical tape as a gasket...), added some air and all I got was air leaking at the head mating surface. Testing with manifolds removed from engine - used same air adapter to front of manifold and riser exit blocked as mentioned, then back filled the manifold with water until all 4 ports were full. Added air and water came a gushing out of the ports. Both manifolds exhibit the same result. Is this a proper exhaust manifold test? Thanks! |
Posted By: KENO
Date Posted: June-24-2019 at 8:59pm
| At least the way I read your description of the exhaust manifold testing, neither test was a good test of the manifolds since you put air in the water side and blocked off the combined outlet which then put air back thru the exhaust gas side |
Posted By: EagleEyedOne
Date Posted: June-24-2019 at 9:25pm
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Ken, thanks for confirming I'm a dumbass... It took explaining what I did to realize it wasn't a good test, hence my skeptical question whether it was a proper test... Is there a method or documented way to do this manifold testing? Would appreciate any advice how to isolate the dry and wet sides in a test.. |
Posted By: 8122pbrainard
Date Posted: June-24-2019 at 9:40pm
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Remove the risers from the manifolds and then making a block off plate for the manifold is best for the pressure test. Before you go to the work of making a plate, just fill the water jacket with water. Sometimes a leak into the exhaust cavity will show up. ------------- /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: KENO
Date Posted: June-24-2019 at 10:59pm
You got that dumb ass comment all wrong. A dumb ass wouldn't have asked the question I'd do like Pete said , with a couple of things to watch out for. If these are the original Manifolds and risers and they've maybe never been apart, you can try every concoction under the sun that claims to be the best penetrating oil out there to get the 4 bolts per manifold out without breaking some or.........you can go with Oxygen and Acetylene and have a better chance of getting them all out without any breaking. Some penetrating oil and heating the area with the torches together will be the best chance. The plate would be about 3X5 inches with 4 bolt holes and a rubber gasket sandwiched between the plate and the manifold. Other than doing a water flow test with the riser still on the manifold and off the engine, it's kinda hard to test a riser due to the mixing that takes place between the water and exhaust sections unless you can get a good seal with an expandable rubber plug in the exhaust outlet section to separate the water and exhaust sections. Easy to say, hard to do. For the flow test you would flow water thru with the manifold and riser in a normal position on a workbench (preferably outdoors) and look for water leaking from the exhaust ports onto the bench. |
Posted By: EagleEyedOne
Date Posted: June-26-2019 at 2:42am
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Hola, Ok, exhaust manifold testing... first water test by filling each manifold with riser off. No water flowing out the exhaust ports on both. Next, made plate and pressurized the water side with 50 psi which held for about 10+ minutes each. Gettin a bad feelin here.. possible that a compression test is good on all cyls, but could have a head gasket cooling jacket blowout on both sides? Just don't know how both sides of the engine got liquid locked last Fall..? As mentioned earlier, I put new intake gaskets on and torqued to spec of 24 ft lbs. Upon doing that, I decided to re-torque the head bolts (not mentioned earlier) as well and found that all bolts exterior to the valve covers were at low end of torque spec range at 105 ft lbs. Nearly all bolts under both valve covers required at least 1/4 to 1/2 turn to meet 105 spec. Is there a test for the risers? Thanks for the love boys, vacation count down has started and ends Jul6... :/ |
Posted By: KENO
Date Posted: June-26-2019 at 8:29am
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Earlier on, you tested the cooling side of the engine with air at 80 psi but I don't see where you isolated the air and checked for a pressure drop I'd be nice to the engine and do that test over again with 20 to 30 psi and isolate the air like MrMcD described and see what the pressure gauge does before you decide to start tearing into things. It shouldn't take long to do this test |
Posted By: EagleEyedOne
Date Posted: June-26-2019 at 11:37pm
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Ok, Tested engine through hose feeding tstat housing from RWP with 30psi as instructed by Dr. McD.. and lost 5psi over 60 minutes. Getting lost for what to do next, but if I had to take a stab, remove heads... pls tell me I'm wrong... |
Posted By: TRBenj
Date Posted: June-27-2019 at 12:30am
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Did you only get water in the cylinders every time it makes a milkshake or just the once? Presumably you gave a good look for evidence of water intrusion when you removed the intake? Timing cover would be my next investigation if you’re not getting water in the cylinders consistently. I would expect a cracked head (water jacket to cyl) or head gasket failure (cyl to water passage) to show up in a compression test. If you are indeed getting water into the cylinders consistently, that may implicate the risers since the manifolds tested ok? The slight pressure drop over time during your test may be worth investigating. I always figured that submerging the manifold in water to see where the air leak was coming from would be effective. |
Posted By: EagleEyedOne
Date Posted: June-27-2019 at 1:32am
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Hola, I only realized water in all cyls once last Fall, but didn't remove plugs everytime I did an oil change. This last milkshake change after new intake gaskets did not have water wet plugs, but they're looking black and sooty, not the light brownish electrode. Upon removing intake, we did check for intrusion, saw a little rust at the inside corners but no obvious blown gasketing. The graphite gaskets were replaced with black and blue raised rubber Felpro type with some high tack gasket sealant on the corner water jacket areas. I think with how exh manifolds held 50 psi for 10+ minutes tells me they're ok, UNLESS heating them up opens a crack..? My gut says unlikely but won't rule it out. Submerging them would be interesting if expecting an external crack but if an internal, would be difficult to see where it comes from. As mentioned earlier, one of the timing cover bolts was bubbling with soapy spray, for this test I gave the bolt a turn and the bubbling seemingly stopped but guess it could have been micro leaking over an hour.. Appreciate the late response TRB! Thanks. |
Posted By: KENO
Date Posted: June-27-2019 at 8:46am
What Tim's saying is that you'll see air bubbles in the water, coming from one of the exhaust runner openings You may not know where the crack is but you'll know there's a crack Your's held air real good though so submerging them probably would show nothing. |
Posted By: TRBenj
Date Posted: June-27-2019 at 8:59am
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What ken said. Internal leak = air out the exh manifold runners. On the intake I meant searching for evidence of a leak into the valley from the water passage at the front. Rusty lines or pure water droplets (not mixed with oil yet) may indicate the source. On the timing cover, the concern is an internal leak (water—> oil) as well. The bubbly bolt is curious but likely unrelated. A crack here (like the intake and exh) would not show up on a compression test. |
Posted By: KENO
Date Posted: June-27-2019 at 9:10am
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I mentioned the timing cover earlier, you mentioned a slight external leak from one of it's bolts and TRB mentioned it again. Like he said, I'd go there next Bad gasket seal or cracked cover like he said. 5 psi out of 30 says something's leaking . Some of the 5 psi pressure drop could be from hot compressed air cooling off during that hour but not all of it. |
Posted By: KENO
Date Posted: June-27-2019 at 9:34am
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Did you happen to have the valve covers off when you did the 30 psi air test? An external crack in the water jacket or one of the big allen headed plugs leaking will let water mix with the oil up there. With the covers off you might hear or see some leakage. |
Posted By: EagleEyedOne
Date Posted: June-27-2019 at 3:30pm
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Hi Ken, Valve covers were not off during the last 30 psi test, easy enough to do again with rubber gaskets and give it a more thorough check while in there. Sounds like digging into timing cover is next project to begin this eve. Thanks Gents! |