Rear main leak take three.Please help.

[Ace66]

After building my first engine.1969 block machined .030 over 383 with a 440 source 440 crank and billet mains.It runs great but leaked oil minutes into 25 minutes brake in.Put 1800 miles on since then, didn’t heal it’s self.So tried it the fun way on my back.Second time instead of using Mancini’s billet kit I tried a stock bearing retainer and Fel Pro black seal.The machinist had line honed the mains to the block.He said he took off about .002 to .003”.A friend machined the factory bearing retainer (from another 383 block)square and removed .003”.I pulled trany,clutch and flywheel.So I could apply silicone to the back side.Ran it for twenty minutes no leaks.First sunny day took it out for 30 minutes.Leaking again.Inspected seals before installation lip toward front of engine Lubed seals. Looking for help.

 

[91r/t]

Did you use silicone sealer around the side seals and where the seal retainer meets the block on the bottom when you initially installed the retainer? Once the oil is in there, it won't seal very well unless its thoroughly cleaned and installed with silicone then. Also when I install the rear main lip seal, I always clock the seal parting line off to one side about 1/8" so it isn't at the same point that the seal retainer split line is. Also, I usually put the side seals in the retainer the night before so they dry good and don't slide out of the retainer while sliding it down into place. Then cut them to length once installed flush with the pain rail sealing surface.

 

[WP29440SE]

and you are positive it isn't coming from the oil pressure sending unit galley or a valve cover?

 

[dadsbee]

https://www.forbbodiesonly.com/mopa...ial-rear-main-seal-replacement-thread.175771/

 

[Beekeeper]

I have done a bunch of reading on this subject and seems the best method of installation
for the rear main seal is as stated above clock the seal half ends where they don’t align with the seal
retainer parting line and install and torque the retainer with out the side seals installed. Seems there’s some offset to the crank centerline(especially when a line bore has been performed) and the seals push the retainer off to one side. Then use a good quality sealer where the side of the retainer meets the block.

 

[Ace66]

I have done a bunch of reading on this subject and seems the best method of installation
for the rear main seal is as stated above clock the seal half ends where they don’t align with the seal
retainer parting line and install and torque the retainer with out the side seals installed. Seems there’s some offset to the crank centerline(especially when a line bore has been performed) and the seals push the retainer off to one side. Then use a good quality sealer where the side of the retainer meets the block.

Thank You Beekeeper.We have two B bodies the 66 and 70 Super Bee.So if I understand correctly delete the side seals and fill the back behind the crank flange.I did that my second try but used the side seals.Have you done this with the factory retainer or the billet type?

 

[Beekeeper]

Ace,
I have yet to do mine but the idea would be to put a bead of sealer on the sides of the retainer
Before you slide it over the crank then torque the bolts and put an additional bead of sealer along the retainer and block on both sides. Yes delete the side seals

 

[Ace66]

Did you use silicone sealer around the side seals and where the seal retainer meets the block on the bottom when you initially installed the retainer? Once the oil is in there, it won't seal very well unless its thoroughly cleaned and installed with silicone then. Also when I install the rear main lip seal, I always clock the seal parting line off to one side about 1/8" so it isn't at the same point that the seal retainer split line is. Also, I usually put the side seals in the retainer the night before so they dry good and don't slide out of the retainer while sliding it down into place. Then cut them to length once installed flush with the pain rail sealing surface.

Thank You 91r/t.Yes I did use silicone where the retainer meets the block. Do you use the factory or the billet retainers.

 

[erickson]

My stroker motor leaked bad. After 3 tries of machining.010 off each time it stopped. Now I take.020 off the new seal block and rotate the seals 20 degrees No leaks

 

[Beekeeper]

My stroker motor leaked bad. After 3 tries of machining.010 off each time it stopped. Now I take.020 off the new seal block and rotate the seals 20 degrees No leaks

yep my engine builder told me they have compared the newer seals with some NORS and found them to be a bit smaller in thickness so taking some off the retainer could help

 

[91r/t]

Thank You 91r/t.Yes I did use silicone where the retainer meets the block. Do you use the factory or the billet retainers.

Factory retainer. I had an issue with the studs on my ARP mains hitting the retainer, but I made clearance for that and had no issues otherwise.

 

[dvw]

Where is it leaking? The seal itself? Or the cap sides. I wouldnt use RTV between the cap and block at the crank centerline. Anaerobic sealer should be used there, sparingly. Open the holes in the retainer by a 1/16". Install the retainer with the seal leave the side seals out. The retainer may not be centered in the block opening. The seal half in the retainer should center on the seal/crank. The side seals can force it out of alignment. Fill the side grooves with RTV instead. Never had a rear main leak doing it by this method.
Doug

 

[Frank Mopar]

http://www.fastfishautoparts.com/Performance-Engine-Seals.html

Did mine in the car a year ago. No leaks

 

[Ace66]

Ace,

Ace,
I have yet to do mine but the idea would be to put a bead of sealer on the sides of the retainer
Before you slide it over the crank then torque the bolts and put an additional bead of sealer along the retainer and block on both sides. Yes delete the side seals

and you are positive it isn't coming from the oil pressure sending unit galley or a valve cover?

Thank You

My stroker motor leaked bad. After 3 tries of machining.010 off each time it stopped. Now I take.020 off the new seal block and rotate the seals 20 degrees No leaks

Thanks Erickson.Wow,I had been concerned about taking .003 off a factory retainer.Did you use billets or factory retainers?

 

[Ace66]

and you are positive it isn't coming from the oil pressure sending unit galley or a valve cover?

 

[Ace66]

Thanks WP, I can watch oil dripping from center of main bearing.

 

[Ace66]

https://www.forbbodiesonly.com/mopa...ial-rear-main-seal-replacement-thread.175771/

Thank you

 

[Ace66]

Thanks WP, I can watch oil dripping from center of main bearing.

Sorry WP I can watch oil dripping from the center of the crank right in front of flywheel.
I cleaned inside of bell housing with brake cleaner first.

 

[Ace66]

https://www.forbbodiesonly.com/mopa...ial-rear-main-seal-replacement-thread.175771/

Thanks dad

 

[Ace66]

Ace,
I have yet to do mine but the idea would be to put a bead of sealer on the sides of the retainer
Before you slide it over the crank then torque the bolts and put an additional bead of sealer along the retainer and block on both sides. Yes delete the side seals

Thank you