I have a Mercury 8CM going together at a local machine shop. I gave them a rear main seal retainer I had sitting on the shelf and I received a call saying it was too small. I believe it's from an earlier block (59AB) but it's all I had. Is there a difference between AB style blocks and the last generation when it comes to that metal piece that holds in the rear main? My shop is not too versed in flatheads and I'd hate to spend $50 at Van Pelt's if those pieces are all the same.
'49-53 are different from earlier. Clean what you have carefully and look it over...I believe that all of them have therir PN cast in. Yours should have a late prefix there, probably 8BA for what you want. The earlier ones for 1939-48 apps came in two flavors, early slinger type and late rope seal. Without sneaking home to look at parts and catalogs, I think the slinger ones carry 91A prefix and rope type 29A. Van pelt hast the parts illustrations only, and those show only the root numbers and not the prefixes that identify specific parts.
Thank you very much Mr. Lancaster, I was hoping you would see this thread Looks like I'll be calling Van Pelt.
Out of town til Monday but I saw this post. The 49-53 blocks use the 8BA-6335 seal retainer, which is different than the earlier blocks. Not sure if we have any of the last run in stock, but we've got another run in the works. Check back with us this coming week and I will have more up to date info. Sorry about the price ($45.00) but they were costly to have made, and no one else had stepped up to mfr any.
When I was putting my 8BA together, I found the rear seal housing was cracked. I bought one from Flathead Jack's that was a little deeper to reinforce the seal and it worked out perfectly. Just my 2 cents.
I've taken a lot of engines apart and never have found a cracked retainer. Don't think it is a common problem.
I thought is was pretty odd too. Saw that it was damaged before I pulled it apart. More then likely it was dropped during a prior rebuild. Goes to show there is always something to impede progress!
Don't quite know how that would be done since the cavity the retainer goes in is a fixed size and the seal is a fixed size. Any variation would seem to cause a problem.
Maybe just the metal lips coming a bit closer to crank, likely just a minor manufacturing variant. Did you find one?/ I think I know where my 8BA ones are if not.
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