Rear Main Seal Advice

[jrstock]

I have observed a leak from my rear main seal. The leak is occurring ,not at the seal split line, but at the bottom 6 o'clock position. Currently using a Fel Pro 2090 seal.

I've pulled the seal and it does not look worn or damaged.

Is there a way to shim between the seal to tighten the clearance to the crank? Is there a better SBC main seal to use?

Is there a tool to locate the 2pc rear main seal adaptor on the crank that I should be using?

Any other tricks to stop the leak?

Thanks in advance for the advice.

[FED 387]

Put a thin film of rtv between the block and cap before installing the 2 halfs also rotate the seal splits about a 1/4 from horizontal and put a little dab there too--make sure the oil pan rail is FLAT so it's not pinching the seal and is making proper contact with the seal.maybe wipe a light film of oil on the seal to help on start up

[ss3011]

What is the year of the block ? Is it a 2 pc or a 1 pc seal . Has the block been line honed ?

[jrstock]

The block is a late model bowtie block with an adaptor to run 2 piece seal. It has been line honed.

[Alan Nyhus]

One block I used had been line bored and the rear seal was leakage prone. Shortened the half of the seal that fits in the block until it fit normally. No offset and a dab of Valco aluminum silicone on the back of the seal and the parting lines.

We've seen a rash of rear main seal leaks lately with both the brown and blue seals.

[SSDiv6]

Originally Posted by jrstock

The block is a late model bowtie block with an adaptor to run 2 piece seal. It has been line honed.

I have seen this happen a few times with the Bowtie block using the adapter. If the block has been align bored or honed, I remove the locating dowel and use the Allstar Performance rear seal adapter alignment tool P/N ALL26127.

https://allstarperformance.com/align...pter-all26127/

[carl hinkson]

Originally Posted by jrstock

I have observed a leak from my rear main seal. The leak is occurring ,not at the seal split line, but at the bottom 6 o'clock position. Currently using a Fel Pro 2090 seal.

I've pulled the seal and it does not look worn or damaged.

Is there a way to shim between the seal to tighten the clearance to the crank? Is there a better SBC main seal to use?

Is there a tool to locate the 2pc rear main seal adaptor on the crank that I should be using?

Any other tricks to stop the leak?

Thanks in advance for the advice.

2090 seal is not a good number

[Nmbr1GMfan]

My issue was the crankshaft wasn't perfect where the seal would normally ride, this seal fixed it. Fel-Pro BS 11829-1 Rubber 2 piece offset double lip seal

[FED 387]

I think he means 2909

[carl hinkson]

Originally Posted by SSDiv6

I have seen this happen a few times with the Bowtie block using the adapter. If the block has been align bored or honed, I remove the locating dowel and use the Allstar Performance rear seal adapter alignment tool P/N ALL26127.

https://allstarperformance.com/align...pter-all26127/

That does not work with a 400 main