tanman Posted October 2, 2021 Share Posted October 2, 2021 Maiden voyage after installing all my new parts and oil was literally pouring down the back of the engine from the valve cover. I used the expensive $30 gasket. Torqued to 7 ft-lb, I verified all the holes were nice and flush when I painted the valve cover… I’m at a loss, I can see the oil just puddle around the cover. Pulling my hair out … Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 2, 2021 Share Posted October 2, 2021 Could the gasket have gotten folded? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 2, 2021 Share Posted October 2, 2021 Is the PCV functioning properly? Do you have excessive blow by? Is the valve cover flange distorted around the bolts from previous over tightening? There should be a constant slight negative pressure in the block and valve cover. If not, then many (if not all ) seals and gaskets are going to leak. I use a super soft silicone valve cover gasket from Original Gasket Company in Tennessee. If I had cork or rubber gaskets and stamped valve covers I would glue them to the tin. Link to comment Share on other sites More sharing options...
tanman Posted October 2, 2021 Author Share Posted October 2, 2021 Is the PCV functioning properly? Do you have excessive blow by? Is the valve cover flange distorted around the bolts from previous over tightening? There should be a constant slight negative pressure in the block and valve cover. If not, then many (if not all ) seals and gaskets are going to leak. I use a super soft silicone valve cover gasket from Original Gasket Company in Tennessee. If I had cork or rubber gaskets and stamped valve covers I would glue them to the tin. There is no pcv valve. I put two breather caps on. The valve cover is not bent. I will have to google “ excessive blow by” Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 2, 2021 Share Posted October 2, 2021 There is no pcv valve. I put two breather caps on. The valve cover is not bent. I will have to google “ excessive blow by” I think you've already found the problem.. Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 2, 2021 Share Posted October 2, 2021 I think you've already found the problem.. Sounds like you need a can of compression. Had a friend's Corvair years ago, had a plume coming out of the breather tube, put my thumb on it and the dipstick lifted up and oil started coming out. Worst I ever saw was a Mercedes-Benz 220D that one of the salesmen had the lube rack boy help him plug the inside the valve cover oil separator tube. The gasket on these engines is a U shaped cross section that the cast aluminum valve cover goes into. The pressure built up so high it actually bowed the valve cover and blew the gasket off on the manifold (straight) side, 7 of the 9 quarts of nice black Diesel lube oil went everywhere, including out onto the fenders and windshield. Link to comment Share on other sites More sharing options...
tanman Posted October 2, 2021 Author Share Posted October 2, 2021 Sounds like you need a can of compression. Had a friend's Corvair years ago, had a plume coming out of the breather tube, put my thumb on it and the dipstick lifted up and oil started coming out. Worst I ever saw was a Mercedes-Benz 220D that one of the salesmen had the lube rack boy help him plug the inside the valve cover oil separator tube. The gasket on these engines is a U shaped cross section that the cast aluminum valve cover goes into. The pressure built up so high it actually bowed the valve cover and blew the gasket off on the manifold (straight) side, 7 of the 9 quarts of nice black Diesel lube oil went everywhere, including out onto the fenders and windshield. Wouldn’t the breather caps actually prevent the pressure from building up? Wouldn’t I just have low power. I’m gonna swap the cork gasket for the rubber one and see if that does the trick. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 2, 2021 Share Posted October 2, 2021 Wouldn’t the breather caps actually prevent the pressure from building up? Wouldn’t I just have low power. I’m gonna swap the cork gasket for the rubber one and see if that does the trick. There's a reason it's called a positive crankcase ventilation system.... Even if you had an incredibly tiny leakdown, like 4-5%, you're still going to see pressure building up. Things like front and rear main seals are designed to work with negative crankcase pressure. But if I were in your shoes I would definitely do a leakdown with the pistons at various points in the bore. (This requires the crankshaft to be locked in place) If you decide to investigate blow by you will understand how this testing is accomplished. Link to comment Share on other sites More sharing options...
tanman Posted October 2, 2021 Author Share Posted October 2, 2021 There's a reason it's called a positive crankcase ventilation system.... Even if you had an incredibly tiny leakdown, like 4-5%, you're still going to see pressure building up. Things like front and rear main seals are designed to work with negative crankcase pressure. But if I were in your shoes I would definitely do a leakdown with the pistons at various points in the bore. (This requires the crankshaft to be locked in place) If you decide to investigate blow by you will understand how this testing is accomplished. I think I have found the culprit. I don’t think these rubber gaskets are a good fit for the older trucks. Not sure why, it was a suggestion from the Facebook groups. Anyway, I happen to have a new cork gasket so I will try that. This also explains why the oil was leaking from the back. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted October 2, 2021 Share Posted October 2, 2021 I think I have found the culprit. I don’t think these rubber gaskets are a good fit for the older trucks. Not sure why, it was a suggestion from the Facebook groups. Anyway, I happen to have a new cork gasket so I will try that. This also explains why the oil was leaking from the back. If you've going to try making a cork gasket seal I'm going to suggest (again) firmly gluing it to the tin cover with gasket shellac, like old school Indian Head before assembling. I usually leave a thin film of grease on the head itself so I can get the cover off without a chisel. Link to comment Share on other sites More sharing options...
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