Rocket block oil pan leaks

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amc fan
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Rocket block oil pan leaks

Post by amc fan »

Dart Iron Eagle block aftermarket steel pan number one: 4" stroke crank rotating assembly hit screen on bottom pan. Whizzer wheel the screen welds take out screen rods hit pan. If you use extra rail gaskets it clears. Pan number two, different brand will not go around rear main. Taking off cap and whittling sides of cap to thin the corners all is fine. Oil leaks from front of pan and rear of pan ...front drips, back drips now back drizzles. Seems like the U-shaped curves at front and back are a tad deep. Trying to figure if putting a shim under the rubber or using "Right Stuff "on the seal will do the trick. Anyone ever have this problem or similar problem and what was the fix? Front timing cover lip seal and rear main seal look ok oil is coming from pan ends. Pan number three would be aluminum... vibration and the manhole cover would its enemy. Thanks in advance.
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Re: Rocket block oil pan leaks

Post by steve cowan »

Not Rocket block but my little M I just done, took me a few goes to get pan to seal properly around jesel front cover,one piece felpro pan gasket and black silicone, I then proceed to put in compressed air into vac pump pick up point and check for air leaks.
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Re: Rocket block oil pan leaks

Post by Tom68 »

Most pans I fit I have to modify for one reason or another so while I'm at it with aftermarket pans I weld and reshape the corners for a better fit.

There's two seal heights available for the back of 2 piece rear main blocks.
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amc fan
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Re: Rocket block oil pan leaks

Post by amc fan »

Steve and Tom thanks, I should have been more general in my engine choice. Could be Holden, Ford, Pontiac, Chevy. Do you think black silicone would stick and stay on top of front and back seals? I was thinking .245mm /.010" shim under end seals might help. I am going to seal off engine and check with smoke before & after I attempt a fix. We ran the engine on a run-in stand and noticed the drips while the engine was idling. I am going to put engine on stand and will drain oil and try to fix it. 4-inch stroke small engine/small oil pan and a lot of air moving and pushing inside that crankcase. Looks like the end seals were the weakest link.
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Re: Rocket block oil pan leaks

Post by dannobee »

Use the gray GM/ACDelco RTV engine sealant. It's thick, skins over fairly fast, is made specifically for oil pans, and surely forgives a lot of sins.

Most of the black rtv that I've tried is too runny.
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Re: Rocket block oil pan leaks

Post by amc fan »

dannobee is this the gray rtv that comes in 1/2 tubes for a caulking gun? PN12378521
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Re: Rocket block oil pan leaks

Post by fabr »

The permatex ultra gray is the best I've found. Been using it for a couple decades,never a leak given a day or 2 at most for full cure. Easier to find as well. Truth be told probably the same stuff as the GM stuff.

https://www.permatex.com/products/gaske ... er-3-5-oz/

On all of my "race" stuff I use it in place of all soft gaskets except for valve covers. Tighten "finger tight" ,let cure overnight and then final torque.
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Re: Rocket block oil pan leaks

Post by dannobee »

amc fan wrote: Sun Jun 19, 2022 6:29 pm dannobee is this the gray rtv that comes in 1/2 tubes for a caulking gun? PN12378521
You can get it in either the squeeze tube or the caulking gun cartridge. Your choice. Works great.

For reference, omit any end seals and substitute the GM RTV after cleaning everything thoroughly with brake cleaner and wiping off. No specks of oil anywhere, you want it clean enough to eat off of. Then apply the sealant and put the pan on. It should ooze out a little everywhere, otherwise you haven't applied enough. Let it start to cure, then go on with other assembly work without touching the sealant for at least a few hours. It'll seal up a 1/4 inch gap, no problem. We've used it on oil pans and china walls for 25+ years now. This sealant is probably the single reason why GM engines quit leaking engine oil from the 90's onward.
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Re: Rocket block oil pan leaks

Post by amc fan »

Well ,I borrowed a smoke generator from an Emissions station. I plumbed it into dipstick hole. I found both pan leaks. Smoke came out of the oil pan ends thin like the thickness of a piece of paper. Smoke also came out of mechanical fuel pump vent, base and shaft of the slip collar MSD, and valve cover breather nipple on both covers and the old front motor mount hole. The smoke generator has a regulator and flow meter and its own air pump. I think I will buy a smoke generator to check for leaks from now on. I detected no smoke from balancer seal or rear main seal just a pin hole leak in front and 1/16"/1.57mm at the 10 O'clock position at rear of pan. I am going to remove and reseal pan and re smoke test it after using the sealing tips I got from this thread. Thanks for the replies and help!
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Re: Rocket block oil pan leaks

Post by steve cowan »

amc fan wrote: Wed Jun 22, 2022 11:19 am Well ,I borrowed a smoke generator from an Emissions station. I plumbed it into dipstick hole. I found both pan leaks. Smoke came out of the oil pan ends thin like the thickness of a piece of paper. Smoke also came out of mechanical fuel pump vent, base and shaft of the slip collar MSD, and valve cover breather nipple on both covers and the old front motor mount hole. The smoke generator has a regulator and flow meter and its own air pump. I think I will buy a smoke generator to check for leaks from now on. I detected no smoke from balancer seal or rear main seal just a pin hole leak in front and 1/16"/1.57mm at the 10 O'clock position at rear of pan. I am going to remove and reseal pan and re smoke test it after using the sealing tips I got from this thread. Thanks for the replies and help!
Yep,I find it takes some effort to seal up properly
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