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My car is a weekend cruiser and no performance mod. Got a l82 in it (1976 stingray). What's the difference between the two and which one would be best suited for my car?
The offset double lit moves the lip of the seal a bit in case you have a groove in the crank surface. It's impossible to tell if you have a groove until you look at it.
I normally just use the felpro 2900 and put a super thin coat of right-stuff on the cap next to the seal groove. Grease the the lip of the seal before installing and the crank surface so it doesn't burn before it gets oil.
Some notes I kept when researching SBC rear main seals.
Just read an interesting article in the current Corvette Restorer by John Bissell regarding the two different rear main seals available for the SBC - Fel-Pro parts 2900 (silicone, blue) and 2912 (fluoroelastomer, red), wherein the author espouses the superiority of the red 2912. Basically the 2900 is old technology and the new 2912 does the job.
You use the anaerobic sealant on the top metal surface of the main cap. NOT on the end of the rubber seal itself which is pretreated to bond together.
The GM rear main seal is GM 10121044 and is constructed of fluroelastomer. This seal GM lists for $45.
The best Fel-Pro seal, also constructed of fluroelastomer is Fel-Pro BS40013. This seal sells for about $9.
Once-upon-a-time I was installing the above referenced Fel-Pro BS40013 seal and I noticed it had the GM 10121044 part number embossed on it. I presume this means that this was the part that Fel-Pro supplied to GM since they could not otherwise place this GM part number on their product.
Thank you all for the assistance. I installed the BS 40013 (double lip) seal and it's leaking again I am absolutely frustrated with this. Everything was done according to specs. Offset, sealer, torqued 80 ft etc. I also noticed oil on the starter bolt.
I place on tackling this again, would the Felpro 2912 be best? I was also advised by a local mechanic to try a high-vacuum seal which I am not sure what that is.
Thank you all for the assistance. I installed the BS 40013 (double lip) seal and it's leaking again I am absolutely frustrated with this. Everything was done according to specs. Offset, sealer, torqued 80 ft etc. I also noticed oil on the starter bolt.
I place on tackling this again, would the Felpro 2912 be best? I was also advised by a local mechanic to try a high-vacuum seal which I am not sure what that is.
I see oil on my starter bolt when the valve cover gasket fails. Are you sure the leak is from the main seal? Not coming from the cam seal above it?
The cam plug above the crank is an area known to leak. I was able to replace this with the engine and cam still installed. Was where my 72 was leaking.
I used 2912 first go around. Installed it by the book. Leaked. Very frustrating I had a minor and I mean minor groove from wear that I didn’t notice first go around. Installed offset seal. No leaks. If I had to do this on another SBC again I’d probably just go straight to the offset seal.
I used 2912 first go around. Installed it by the book. Leaked. Very frustrating I had a minor and I mean minor groove from wear that I didn’t notice first go around. Installed offset seal. No leaks. If I had to do this on another SBC again I’d probably just go straight to the offset seal.
Interesting. Did you notice a groove on the crank. I'm undecided but I can try the offset seal first before going to the expensive one
Interesting. Did you notice a groove on the crank. I'm undecided but I can try the offset seal first before going to the expensive one
Here is a pic the first time I pulled the cap off. You can see where the seal was running but upon running my fingernail over that area I could barely feel any groove. The picture shows the residue upon pulling the cap so looks worse than it actually was. So I Figured I’d be ok. I think if you can feel any groove at all, I would go offset to be safe. I also installed the seals both times with the seal clocked, and only used sealant on the cap as per instructions.
Old original seal upon pulling the cap first time. I don’t think I cleaned the crank bearing surface much when I took the pic. When I redid the seal I inspected it even further. Very very hairline groove. Enough to cause a problem obviously. Actually the leak ended up worse than with old seal. Don’t know why. 2nd install I used the offset seal. It sealed. Good so far.
The cam plug above the crank is an area known to leak. I was able to replace this with the engine and cam still installed. Was where my 72 was leaking.
Use the high-tack permatex and it will not leak. I do the same for the freeze plugs.
Here is a pic the first time I pulled the cap off. You can see where the seal was running but upon running my fingernail over that area I could barely feel any groove. The picture shows the residue upon pulling the cap so looks worse than it actually was. So I Figured I’d be ok. I think if you can feel any groove at all, I would go offset to be safe. I also installed the seals both times with the seal clocked, and only used sealant on the cap as per instructions.
Old original seal upon pulling the cap first time. I don’t think I cleaned the crank bearing surface much when I took the pic. When I redid the seal I inspected it even further. Very very hairline groove. Enough to cause a problem obviously. Actually the leak ended up worse than with old seal. Don’t know why. 2nd install I used the offset seal. It sealed. Good so far.
That looks like a huge worn gap on the crank. That area should be perfectly smooth, no visible marks.
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Felpro Rear Main seal
I am absolutely frustrated with this. Everything was done according to specs. Offset, sealer, torqued 80 ft etc. I also noticed oil on the starter bolt.
