71strokerduster
Active Member
Hello all! I am new to the forum and looking for some help. I am currently rebuilding my dads 1971 duster for his birthday and will be giving it to him as a surprise. It has been in the garage at my rental house for about 3 years (he still thinks it's there).
A little back ground. I took the 318 out, had it tank dipped, and bore 30 over (matched to new pistons). I purchased a 390 stroker kit from scat, SB 63CC Edelbrock aluminum heads, RPM Edelbrock intake, holley 750 carb, 1.6 hughes rocker kit, 228/232 hughes cam(110LSA, lobe lift .565intake .571 exhaust), standard oil pump, high flow water pump, .5inch aluminum spacer, ready to run MSD ignition, Edelbrock 80gph fuel pump, tti long tube headers, kevko baffled oil pan, trick flow oil water seperator, mopar performance valve covers all from hughes engines.
On to the issue. We pressure tested heads, primed the engine, broke in at about 2-3k rpm. Everything looked and sounded great. We used royal purple with lucas break in zinc additive. No leaks, oil pressure was about 40psi when worm and around 70-80 psi at high revs. Once we took it for a drive we started noticing a leak in the rear main. We were not sure if it was the rear main or if it was coming from the rubber gasket on the oil pan that fit around the housing of the rear main. We decided to pull the transmission (3 speed on the floor A-230) and replaced the oil pan gaskets and rear main seal. We made sure to put a lot of silicone on the oil pan to ensure we got all corner areas that fit against rear main mount. Let sit for 48 hours. Took it for a calm drive, everything looked good. no issues. Took it for a second drive and really opened it up. We noticed a few drops coming from the rear again but nothin like before (had about 3 drops after an hour and then nothing after that). We thoroughly cleaned the underside of the car to make sure these drips were not from the past oil leak. Let it sit for a day, checked under the car and had no oil leaks on the ground.We then started the car up, let it get worm and reved it a few times, looked under the car and saw no leaks on the ground. we then did a final tuning for about 30 minutes in the shop with high revs and running constantly for 30 minutes, no leaks. we took it for a ride and did about a 20. minute cruise and had about 3 or 4 heavy pedal bursts to really opened it up (thing is a monster!!). When we came back there was oil on the top of the timing cover and manifold. It wasn't a ton but was confusing and couldn't tell where exactly it was coming from. We also noticed a few drops coming from the rear main area again but still nothing like before. We cleaned everything up. The next day I came back and started it to see where leak was coming from. There was no leaks. I let it get good and warm, reved it up a handful of times, no leaks still. I took it for a ride (maybe all of 10 miles) I hammered down on it pretty hard two times and brought it back to the shop. Opened the hood and there was oil all over the timing chain cover and on the manifold and up under the air cleaner (obviously blown there from the fan). This was much more oil than the day before. It looks like it is coming from the front of the manifold.
What we noticed is anytime it is under heavy load, it pushes out oil. When it is in the shop or on the rack and rev it up high, no oil leaks. Even the rear main area doesn't leak when its on the rack and we start it. But as soon as it is under load and we really step on it, theres oil leaks. It first started at the rear main area, as soon as we fixed that it moved to the front of the manifold area, again only under load. I am puzzled. The only thing i could think of is that it is building up too much crank case pressure. We have the trick flow catch can on the passangers side pulling from passanger side valve cover to back of carb. The drivers side valve cover has a foam breather in the front.
Has anyone had this issue before? Why would it be building up pressure to create these leaks. Rings, pistons, bore/honing is all new and inspected. All checked out. Could the foam breather be not enough flow? Is the trickflow catch can not enough vacume? should I add another breather? We did not use the rubber gaskets for the front and rear of the manifold, instead we were very generous with silicone to avoid any leaks ironically (back of manifold has zero leaks). Whats odd is even after it has leaked, when it is in neutral and revs up there are no leaks until it is under load (driving at high rpms). Any suggestions would help! Thanks!!
A little back ground. I took the 318 out, had it tank dipped, and bore 30 over (matched to new pistons). I purchased a 390 stroker kit from scat, SB 63CC Edelbrock aluminum heads, RPM Edelbrock intake, holley 750 carb, 1.6 hughes rocker kit, 228/232 hughes cam(110LSA, lobe lift .565intake .571 exhaust), standard oil pump, high flow water pump, .5inch aluminum spacer, ready to run MSD ignition, Edelbrock 80gph fuel pump, tti long tube headers, kevko baffled oil pan, trick flow oil water seperator, mopar performance valve covers all from hughes engines.
On to the issue. We pressure tested heads, primed the engine, broke in at about 2-3k rpm. Everything looked and sounded great. We used royal purple with lucas break in zinc additive. No leaks, oil pressure was about 40psi when worm and around 70-80 psi at high revs. Once we took it for a drive we started noticing a leak in the rear main. We were not sure if it was the rear main or if it was coming from the rubber gasket on the oil pan that fit around the housing of the rear main. We decided to pull the transmission (3 speed on the floor A-230) and replaced the oil pan gaskets and rear main seal. We made sure to put a lot of silicone on the oil pan to ensure we got all corner areas that fit against rear main mount. Let sit for 48 hours. Took it for a calm drive, everything looked good. no issues. Took it for a second drive and really opened it up. We noticed a few drops coming from the rear again but nothin like before (had about 3 drops after an hour and then nothing after that). We thoroughly cleaned the underside of the car to make sure these drips were not from the past oil leak. Let it sit for a day, checked under the car and had no oil leaks on the ground.We then started the car up, let it get worm and reved it a few times, looked under the car and saw no leaks on the ground. we then did a final tuning for about 30 minutes in the shop with high revs and running constantly for 30 minutes, no leaks. we took it for a ride and did about a 20. minute cruise and had about 3 or 4 heavy pedal bursts to really opened it up (thing is a monster!!). When we came back there was oil on the top of the timing cover and manifold. It wasn't a ton but was confusing and couldn't tell where exactly it was coming from. We also noticed a few drops coming from the rear main area again but still nothing like before. We cleaned everything up. The next day I came back and started it to see where leak was coming from. There was no leaks. I let it get good and warm, reved it up a handful of times, no leaks still. I took it for a ride (maybe all of 10 miles) I hammered down on it pretty hard two times and brought it back to the shop. Opened the hood and there was oil all over the timing chain cover and on the manifold and up under the air cleaner (obviously blown there from the fan). This was much more oil than the day before. It looks like it is coming from the front of the manifold.
What we noticed is anytime it is under heavy load, it pushes out oil. When it is in the shop or on the rack and rev it up high, no oil leaks. Even the rear main area doesn't leak when its on the rack and we start it. But as soon as it is under load and we really step on it, theres oil leaks. It first started at the rear main area, as soon as we fixed that it moved to the front of the manifold area, again only under load. I am puzzled. The only thing i could think of is that it is building up too much crank case pressure. We have the trick flow catch can on the passangers side pulling from passanger side valve cover to back of carb. The drivers side valve cover has a foam breather in the front.
Has anyone had this issue before? Why would it be building up pressure to create these leaks. Rings, pistons, bore/honing is all new and inspected. All checked out. Could the foam breather be not enough flow? Is the trickflow catch can not enough vacume? should I add another breather? We did not use the rubber gaskets for the front and rear of the manifold, instead we were very generous with silicone to avoid any leaks ironically (back of manifold has zero leaks). Whats odd is even after it has leaked, when it is in neutral and revs up there are no leaks until it is under load (driving at high rpms). Any suggestions would help! Thanks!!
