Oil Seal Material

[Barnburner]

Just purchased a 77 spider recently started doing maintenance items - timing belt and water pump first on the list. Knowing it was going to be easier to do seals while I was in there, I ordered a seal kit from Midwest Bayless that contained oil seals for the cams, auxiliary gear and front and rear crank. Not doing the rear seal but I figured I could handle the rest.

I pulled the seals for the cams using a blunt screw only to find what was sent to me didn’t match the stock size. Replacement size was too large by a couple MM. I assume either it was labeled wrong or my 77 engine is early enough in the run to be compatible with the earlier engines (head reads 132AC2C).

Not wanting to delay the work too long, I went to a local auto parts chain supplier and found out they carried oil seals in the exact size I needed. Picked up a few and when I got home I realized they aren’t the same material. Stock and replacements had a metal jacket whereas the new seal I bought seems to be entirely a plastic compound (maybe polyacrylate?). See photo below comparing the two.



Is there an issue running this new seal without the metal jacket? Is it actually an improvement since it’s a modern compound? Thanks in advance for any insight!

[Nut124]

Interesting.

I had never heard of a plastic bodied seal. I have used metal and metal with rubbery coating.

I would worry about it popping out if it were not as rigid as a metal seal.

Try another parts store?

[Barnburner]

Thanks for the response! It's a firm but still somewhat pliable compound. I looked up the part from another source and it says it's nitrile, which I understand is a synthetic rubber compound. It's also a spring-energized seal like OEM. Hard to tell if there's any metal encased by the compound - if there is it would be really thin. For the record, this is what was listed in the parts store database as the seal for my car, not just something they grabbed off the shelf.

Can anyone confirm if the oil seal sizes went up in late 77?

[18Fiatsandcounting]

Can anyone confirm if the oil seal sizes went up in late 77?

Weird, because the camshaft and aux. shaft seals were the same for the entire production run from 1966 to 1985. I would give M-B a call as maybe they have an explanation, but if you give me the ID of your camshaft box opening (or the OD of the old seal), I can compare with some spare parts that I have. Just in case there's something weird like your seal opening was machined larger for whatever strange reason.

-Bryan

[Barnburner]

On closer inspection in the light of day, it looks like there's metal on the inside of the seal



I'll call MB and check on the seal and get measurements off my engine and report back. Thanks for the help.