Finished restoration... and 1 problem left!
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Joined: Sep 2008
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From: Iowa
Finished restoration... and 1 problem left!
I finished my restoration of my 76 L48 last week. It's been a weekend warrior project for about 2 years now. Everything is completed, but I have one problem left to work out...
Under high RPM load (acceleration) there seems to be a "puff" of oil smoke that comes from the front passenger side of the engine. The underbody has a thin film of oil from it and you can smell the oil in the cabin. There appears to be no such incidents under normal non-spirited driving. I used the recommended fel-pro gasket on these forums during the rebuild and can't find any discernible leaks around the oil pan gasket. I've looked in the forums but can't really find a consensus of where to look or start replacing things. Any ideas?
Besides that, the car runs fantastic. Virtually everything has been replaced, rebuilt or reconditioned. Other than the non-stock hood, rear bumper and engine power, everything else is pretty close to OEM specs. The engine is a freshly rebuilt 350 (original block) following the GM 350 H.O. engine's specs. The transmission is one of Summit's take-out TH350 units and works great.
I'm not really one for gobs and gobs of power, but the car looks and has the power now that a '76 should of had in the first place. These forums have been instrumental in the restoration process of this car. Help me figure out this last bug! Thanks guys
Under high RPM load (acceleration) there seems to be a "puff" of oil smoke that comes from the front passenger side of the engine. The underbody has a thin film of oil from it and you can smell the oil in the cabin. There appears to be no such incidents under normal non-spirited driving. I used the recommended fel-pro gasket on these forums during the rebuild and can't find any discernible leaks around the oil pan gasket. I've looked in the forums but can't really find a consensus of where to look or start replacing things. Any ideas?
Besides that, the car runs fantastic. Virtually everything has been replaced, rebuilt or reconditioned. Other than the non-stock hood, rear bumper and engine power, everything else is pretty close to OEM specs. The engine is a freshly rebuilt 350 (original block) following the GM 350 H.O. engine's specs. The transmission is one of Summit's take-out TH350 units and works great.
I'm not really one for gobs and gobs of power, but the car looks and has the power now that a '76 should of had in the first place. These forums have been instrumental in the restoration process of this car. Help me figure out this last bug! Thanks guys
Le Mans Master
Joined: Mar 2008
Posts: 5,948
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From: Oxford MA-----You just lost the game!!!!
On the front of the block, in between the fuel pump and the timing chain cover, there is a bolt hole that goes all the way through the block. If you don't have a bolt in that hole, oil will spill out of it when you get on it hard. I'll bet that is what's going on here. At least, I hope so, because it's pretty easy to fix.......just put a bolt in the bolt hole! Good luck, and if that's not the problem, let us know, we'll take another guess! Good luck,
Keep the shiny side up!
Scott
Keep the shiny side up!
Scott
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
There are two bolt holes directly below the freeze plug, I'm pretty sure it's the top one we are concerned with, can you confirm that, Scott?
Keep the shiny side up!
Scott (not Scott Marzahl, a completely different Scott!)
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Joined: Sep 2008
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From: Iowa
Just checked, there are two bolt holes by the pump. The top one has a bolt in it, the bottom one does not. Should I put some thread sealer on this bolt or is the problem possibly elsewhere? thanks
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Keep the shiny side up!
Scott
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From: loxley alabama
you do have the motor properly ventilated with a PCV fitting in 1 valve cover & maybe a breather in the other valve cover? i built a motor a few yrs. ago & somehow left these off so the pressure in the ehgine blowed oil out of every possible path it could find! just a thought. lonebull
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From: loxley alabama
forgot to mention you did a beautiful job on that car & you sure don't want that mist all over th engine bay & undercarriage. the dust & road debris will cling to it & ruin all your good work. don't stop till you find it for sure. lonebull
Le Mans Master
Joined: Mar 2008
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From: Oxford MA-----You just lost the game!!!!
Keep the shiny side up!
Scott
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Joined: Sep 2008
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From: Iowa
I went ahead and replaced the bolt and put thread sealer on it.
I also went ahead and changed the fuel pump gaskets. (pain in the a**, forgot that its much easier to make sure that the fuel pump rod is up as far as possible by cranking the engine until the camshaft lobe allows it)
I will take it for a test drive tomorrow and see if this solved the problem, since it looks like the oil spray is coming from this general area. It's definitely coming from the bottom half of the motor and on the passenger side. I'll have to pick up some of that aerosol foot spray as recommended and report my results after the test drive.
I also went ahead and changed the fuel pump gaskets. (pain in the a**, forgot that its much easier to make sure that the fuel pump rod is up as far as possible by cranking the engine until the camshaft lobe allows it)
I will take it for a test drive tomorrow and see if this solved the problem, since it looks like the oil spray is coming from this general area. It's definitely coming from the bottom half of the motor and on the passenger side. I'll have to pick up some of that aerosol foot spray as recommended and report my results after the test drive.
Melting Slicks
Joined: Aug 2010
Posts: 2,487
Likes: 10
From: Palm Beach Florida
St. Jude Donor '12
I don't know if this will help or not. I just finished buttoning up my motor. I took her out for a drive to a show last night. My son and I smelled oil when we would come to a stop at lights. Got to the show and looked underneath. No drips! Later on during the show we had another look in the engine bay. We discovered a small puddle of oil on the passenger side center bolts intake manifold. I never put any thread or sealer on them. Just bolted them tight. Under pressure they leaked oil from the vally. Driving home I took it very light and easy. Once home very little oil at all. So I just fixed it with some thread sealer.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
I don't know if this will help or not. I just finished buttoning up my motor. I took her out for a drive to a show last night. My son and I smelled oil when we would come to a stop at lights. Got to the show and looked underneath. No drips! Later on during the show we had another look in the engine bay. We discovered a small puddle of oil on the passenger side center bolts intake manifold. I never put any thread or sealer on them. Just bolted them tight. Under pressure they leaked oil from the vally. Driving home I took it very light and easy. Once home very little oil at all. So I just fixed it with some thread sealer.
Keep the shiny side up!
Scott
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
I went ahead and replaced the bolt and put thread sealer on it.
I also went ahead and changed the fuel pump gaskets. (pain in the a**, forgot that its much easier to make sure that the fuel pump rod is up as far as possible by cranking the engine until the camshaft lobe allows it)
I will take it for a test drive tomorrow and see if this solved the problem, since it looks like the oil spray is coming from this general area. It's definitely coming from the bottom half of the motor and on the passenger side. I'll have to pick up some of that aerosol foot spray as recommended and report my results after the test drive.
I also went ahead and changed the fuel pump gaskets. (pain in the a**, forgot that its much easier to make sure that the fuel pump rod is up as far as possible by cranking the engine until the camshaft lobe allows it)
I will take it for a test drive tomorrow and see if this solved the problem, since it looks like the oil spray is coming from this general area. It's definitely coming from the bottom half of the motor and on the passenger side. I'll have to pick up some of that aerosol foot spray as recommended and report my results after the test drive.
Keep the shiny side up!
Scott
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Joined: Sep 2008
Posts: 57
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From: Iowa
Just got back from my test drive.
Initially I noticed my oil pressure was a little higher than before (~60 PSI rather than about ~52 PSI.) When I got on it on the on ramp and accelerated, for a split second there was no oil "puff" - then just when I thought it was fixed there was a tiny oil "puff" visible in my rear view mirror. This was still better than before though. I drove around the highway to the next exit to turn around. On the next on ramp, I floored it again, only this time the oil "puff" was as large as normal and some of it fumed into the cabin. On the way back I noticed my oil PSI was about 52 like it used to be.
I didn't get the foot spray before test driving, but I did clean the under body. The oil is definitely coming from the passenger side of the engine, lower half.
I'm wondering if I'm developing too much oil pressure and it has to vent somewhere? I have a PCV valve in the passenger valve cover, and an breather in the driver side cover. I checked, and the PCV valve is good, but the breather seems a little dirty for only having 800 miles on it. It's an Edelbrock unit that is chrome and has the vent holes at the bottom. The carburetor is one of Summit's 600 cfm units.
Any ideas from here? Thanks!
Initially I noticed my oil pressure was a little higher than before (~60 PSI rather than about ~52 PSI.) When I got on it on the on ramp and accelerated, for a split second there was no oil "puff" - then just when I thought it was fixed there was a tiny oil "puff" visible in my rear view mirror. This was still better than before though. I drove around the highway to the next exit to turn around. On the next on ramp, I floored it again, only this time the oil "puff" was as large as normal and some of it fumed into the cabin. On the way back I noticed my oil PSI was about 52 like it used to be.
I didn't get the foot spray before test driving, but I did clean the under body. The oil is definitely coming from the passenger side of the engine, lower half.
I'm wondering if I'm developing too much oil pressure and it has to vent somewhere? I have a PCV valve in the passenger valve cover, and an breather in the driver side cover. I checked, and the PCV valve is good, but the breather seems a little dirty for only having 800 miles on it. It's an Edelbrock unit that is chrome and has the vent holes at the bottom. The carburetor is one of Summit's 600 cfm units.
Any ideas from here? Thanks!
Melting Slicks
Joined: Aug 2010
Posts: 2,487
Likes: 10
From: Palm Beach Florida
St. Jude Donor '12
Dizzy leaking down side of motor? Valve cover gasket not sitting right in lower left corner? Hows the front main seal? I had a front main seal leak, and the wind forced the oil all over the lower passenger side. Originally I thought it was my fuel pump, it was so wet. I replaced that gasket, and still had it. Took me awhile to figure it out.
Melting Slicks
Joined: Aug 2010
Posts: 2,487
Likes: 10
From: Palm Beach Florida
St. Jude Donor '12
I've read that people have done it with out taking the timing chain cover off, they remove the harmonic balancer pry the old one out, gently tap in a new one. Or take the cover off. You need to loosen up the front oil pan bolts to remove the cover though. Do you see any oil dripping leaking from there? Behind the balancer?