Burning oil after re-jetting 454
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=48105
Printed Date: November-27-2024 at 8:00am
Topic: Burning oil after re-jetting 454
Posted By: Crmaverick
Subject: Burning oil after re-jetting 454
Date Posted: October-02-2019 at 5:30pm
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I started to have an issue burning oil on my 454, I noticed blue smoke at idle after stepping up two jet sizes to 74 primary 89 secondary. The smoke smells gassy and not like the typical burning oil smell. The jets in there before were 72/87, and the plug electrodes were white with no color after a few hours of use. The 74/89 started to give the plugs a golden brown color after an hour, but now all the plug electrodes are black. I also replaced the pcv valve to see if that would help. One weird thing is that it doesn’t always smoke it seems to be intermittent. Could stepping up the main jets to much cause fuel to wash oil off the cylinder walls and burn at idle or maybe a high float? |
Replies:
Posted By: TRBenj
Date Posted: October-02-2019 at 5:35pm
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Main jets aren’t in play at idle. Something else is buggered, perhaps when you disassembled/reassembled. Why were you rejetting? Sounds like you are too rich now. I wouldn’t expect to see much coloration with modern fuels when the mixture is proper. Just watch out for splotches of aluminum. |
Posted By: Crmaverick
Date Posted: October-02-2019 at 5:39pm
The plug electrodes were still white/new looking after several hours of run time so I figured it was to lean, It’s running better now to, but smoking at idle. Using aimsoil 10w40 marine oil |
TRBenj wrote:Posted By: Crmaverick
Date Posted: October-02-2019 at 6:05pm
Splotches of aluminum in the oil? I did also go from a 6.5 powervalve to a 4.5 |
Posted By: phatsat67
Date Posted: October-02-2019 at 6:15pm
| Go back to the 6.5. Also, the gasket for the PV is very easy to install incorrectly. That leaking will make it rich all around but most notably at idle. Check that and circle back. A spray paint cap works great under the lower bowl screw to drain most of the fuel out. |
Posted By: Crmaverick
Date Posted: October-02-2019 at 6:30pm
I’ll give that a shot. Is it usually a richness related problem when the burning oil smoke has a fuel smell to it? |
Posted By: TRBenj
Date Posted: October-02-2019 at 7:01pm
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Not sure why you are saying “oil smoke” if it’s dark smoke that smells like fuel. That’s just overly rich. Splotches of aluminum on the plugs = too lean. Clean plugs = happy plugs. I would go back to the old jetting when you have your carb apart again. Agree with zach on the PV too (I’d be going higher, not lower- but 6.5 is fine). What size and model carb is this anyways? Seems like a pretty large difference front to back. Hopefully it’s a holley 800cfm 4150 as those appear to match your original numbers... the 800 and 850 have pretty large spreads. For ref, some stock jetting numbers: QF M750 = 75/83 QF M800 = 78/86 QF M850 = 82/94 Holley marine 4150 750 = 73/81 Holley marine 4150 800 = 72/87 Holley marine 4150 850 = 88/96 |
Posted By: Crmaverick
Date Posted: October-02-2019 at 7:08pm
I say oil smoke since it’s blue smoke and burning oil, but it smells like fuel and not like the typical burning oil smell, if that makes sense I’ll try putting it back to stock |
Posted By: TRBenj
Date Posted: October-02-2019 at 7:14pm
| Any oil burning would be unrelated to carb tuning but rich black smoke might look similar. How are you determining oil burn and have you been monitoring it closely since you bought it? |
Posted By: GottaSki
Date Posted: October-02-2019 at 7:24pm
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Huh Yeah, best put it back just the way you found it, and exine the pv gasket type I find both the methods used and reason to change jets, invalid frankly What exactly were you trying to cure? ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Crmaverick
Date Posted: October-02-2019 at 7:28pm
I do have the Holley 4150 800 marine. It wasn’t burning oil when I got it or smoking blue, I kept an eye on oil level and I’ve put maybe 10 hours on it. I added about 4oz after 1.5 hours of run time to get it back to the same level on the dipstick. Here’s a start video from today after I did the pcv valve you can see it smoking https://drive.google.com/file/d/1IIX8Ltme1X1yHO-kK8zVbuAj6Sh7svSv/view?usp=drivesdk" rel="nofollow - https://drive.google.com/file/d/1IIX8Ltme1X1yHO-kK8zVbuAj6Sh7svSv/view?usp=drivesdk |
Posted By: Crmaverick
Date Posted: October-02-2019 at 7:37pm
Here’s a pic of what I was trying to fix. Spark plugs still looked new after a couple hours of running. I wanted to put some color on the plugs to make sure it wasn’t lean. https://drive.google.com/file/d/1TC25gtOpBFEl_eKO6cmAmtiZK7_qixkH/view?usp=drivesdk" rel="nofollow - https://drive.google.com/file/d/1TC25gtOpBFEl_eKO6cmAmtiZK7_qixkH/view?usp=drivesdk Also PV gasket is a paper one |
Posted By: Gary S
Date Posted: October-02-2019 at 7:43pm
All I see is a platform that needs oiling real bad  ------------- 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: October-02-2019 at 8:40pm
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Well I can't see the picture , maybe something is amiss there But a white insulator is not reason to adjust 3 circuits at once, nor at all. Take a plug out of s fuel injected engine, it will have a white insulator One looks elsewhere on the plug to determine jetting, an has to be done methodically Plugs self clean when at the right temp If you jet to make the plug look a Briggs or Tecumseh, it's the wrong way and loose performance and efficiency I really don't think you will have to go down that road with that carb, if your only symptom was a white insulator ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Crmaverick
Date Posted: October-02-2019 at 9:14pm
Yeah that picture was just showing the plug with the white insulator, I’ll put it all back to stock and see what happens. Another guess on the smoke, I switched to aimsoil from conventional, maybe it started leaking past the valve seals? |
Posted By: 8122pbrainard
Date Posted: October-02-2019 at 9:42pm
Why did you go with the bling oil? ------------- /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: phatsat67
Date Posted: October-02-2019 at 9:59pm
| It’s not related to anything else and it’s not oil smoke. It smells like fuel and you messed with fuel = it’s rich and it’s likely because the PV gasket is off centered on the PV and leaking raw fuel into the intake. Examine what you did before everyone gets you going in other directions. I agree the jet change wasn’t necessary on a stock engine but, as Tim said, that’s not the source of your Smokey idle. |
Posted By: Crmaverick
Date Posted: October-02-2019 at 10:48pm
Makes sense, if I put back to stock and still getting the smoke what else should I check/troubleshoot? |
Posted By: KENO
Date Posted: October-03-2019 at 9:40am
Does this mean better with the richer jets in it? It must be time for a quick or maybe not so quick recap of how the boat's running these days and what changes were made to things If you're looking at the power valve gasket, look at the O rings on both ends of the accelerator pump transfer tube right above the power valve. They'll cause the same richness issues that are most noticeable at low engine speed |
Posted By: Crmaverick
Date Posted: October-03-2019 at 12:43pm
The boat starts easier now and feels like it has more power. It also idles better. This could all be from an orfice that was plugged on the metering block that I cleared at the same time the changes were made. The thermostat was also replaced, with a 170. The old 140 in there was giving me water temps between 110 and 120. The boat overall runs better than ever, except for the burning oil about 4oz every 1.5-2 hours. Here’s a cool running video from last weekend: https://drive.google.com/file/d/1R2xyUL8jhjhyKOoncAI-IXj6kGiBlVI9/view?usp=drivesdk" rel="nofollow - https://drive.google.com/file/d/1R2xyUL8jhjhyKOoncAI-IXj6kGiBlVI9/view?usp=drivesdk |
Posted By: GottaSki
Date Posted: October-03-2019 at 1:09pm
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Hm.. what's the timeline on the oil burn and the tstat? increasing the operating temp just opened the bores a scunch. If that are coincidental, consider putting the old tstat in and give it a romp ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: tryathlete
Date Posted: October-03-2019 at 1:22pm
Hotter temp is gonna use more oil like said above. Put a brand new 140 tstat in just to make sure it’s not sticking open |
Posted By: Crmaverick
Date Posted: October-03-2019 at 1:24pm
The oil burning started with the old 140 t-stat. |
Posted By: Crmaverick
Date Posted: October-03-2019 at 1:25pm
I couldn’t find a new 140 to order, PCM discontinued them and new replacement is 170. The 140 was running to cool my water temps were 110-120ish |
Posted By: tryathlete
Date Posted: October-03-2019 at 1:30pm
| I don’t know if Amsoil is ester based but if it is, and it’s a slightly lower viscosity in particular, this could be a factor in oil consumption. Ester based synthetics like the original M1 formula were known to swell some of the seals and the valve stem seals could be allowing some oil to leak into the combustion chamber and give you the small consumption you’re seeing. Maybe switch back to 15W40 conventional as an experiment while you are replacing the carb gasket. |
Posted By: tryathlete
Date Posted: October-03-2019 at 1:32pm
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You just have to look in the right place https://www.nautiqueparts.com/product/thermostat-kit-pcm-ford-engines-143-degrees-rp026002e/" rel="nofollow - Nautique Parts 140 thermostat |
Posted By: TRBenj
Date Posted: October-03-2019 at 1:41pm
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That’s the ford/universal stat, which isn’t technically recommended for the older Pcm 454 housing. I’m not even sure the 170deg version of that special stat is widely available. I can say that I’ve run a “normal” 140 stat like the Pcm ford in the older Chevy housing and it has worked alright. It may have run a little cool though, IIRC. Personally, I’d experiment with a few different stats before paying for the $100+ specialty one of the higher temp than ideal. I went in a different direction with a newer stat housing instead. |
Posted By: Crmaverick
Date Posted: October-03-2019 at 1:43pm
That’s a ford one mines a Chevy 454, does anyone know where to find a GM one? |
Posted By: Kat Daddy
Date Posted: November-26-2019 at 11:57pm
| is that a left rotation prop? |
Posted By: Kat Daddy
Date Posted: November-27-2019 at 12:05am
| Is it better to change oil before or after a winterization, Im was looking into the oil you stated, the conventional, but would synthetic be an ok choice? Im not sure how much the pcm big block even takes. |
Posted By: Kat Daddy
Date Posted: November-27-2019 at 12:07am
| I have the same engine, and I too thought nautique parts had one for the gm. I wanna say it was like $120, so I cleaned up my old one and it still works, its a 140 also. |
Posted By: MrMcD
Date Posted: November-27-2019 at 2:54am
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Oil change at the end of the season before parking the boat lets your engine sit in clean oil all winter. Sitting a long period with old oil may expose the bearings to whatever build up is in your oil at season end, water, Acid dirt. When I bought my first Nautique the Nautique dealer advised parking it with clean oil every year. I do it most years. Synthetics are great oils, no question. For an old 351 engine that was designed to run on Petroleum based oils I stay with the good old Dino oil. (Dynasaur based Petroleum) Synthetics have more heat protection and can lubricate better for a longer period of time in the right environment. They are also thinner than petroleum based oils when hot so they can leak more than your standard dino oils. When I say leak, that does not mean out of your engine onto the floor. I am referring to how much leaks past the Main, Rod and Cam bearings. Modern engines that require Synthetic are built to run synthetic oil so the Rod and Main clearances are tighter than what was used in the old days. With tighter clearances your synthetics perform to an optimum level. WIth older engine loose clearances this can change. When synthetics first started becoming popular in the late 80s many racers started losing engine bearings when they switched to synthetic oil. No other changes and the engines failed. Many of these race engines ran Main and Rod clearances at .0025 to .0032 and the engines failed. The initial race talk was that Synthetic oil was bad and did not hold up to the demands of racing. That talk all went away as they learned more about synthetics, new engines were assembled with tighter clearances and all the synthetic advantages were now positives but the new bearing clearances were held to about .002 Max for Rod and Main Bearings. If I built a new engine I would use .002 max on rods and mains and then be comfortable running either type oil. In an old engine with clearances unknown I would be more conservative and run Dino based Oil and change it more often. That is my 2 cents. At the time these Race Shops were seeing engine bearing failures I was the engine bearing Rep calling on them, our bearings were blamed and it was front page news trying to get answers for these guys. It was about a year before we had it figured out. Some of these engines had values up to $50,000 each so pressure was on to get answers they could trust. FYI: There are race shops running 0/0 weight oil in drag engines because they figured out they dynoed with a few more horsepower, in a tight engine this worked. This information is nearly 20 years old but the synthetic oil did not change its properties over that period. It is great oil and better but has some limitations. Our old 351W engines were built fairly loose for Marine duty. If your question was about an oil choice in a newer Nautique with a 5.3L or 6.0L I would still check with the Engine Provider to see if they modified the engines for Marine use with extra Main and Rod clearance. I would think they did not based on modern engine knowledge but I would certainly check. Boats get run much harder than Automotive engines so Oil is important. I run the Castrol, Delo or Rotella 15-40W Diesel formula oil in my boat a 1995 351W. It works with old flat tappet Non Roller engines just fine. Use the same in my 1966 327/350 HP Chevy. ------------- |
Posted By: KENO
Date Posted: November-27-2019 at 7:25am
He's got a 390 hp PCM 454 and it's normal automotive rotation so the answer to the above would be yes It's a 13X13 Acme |