alerdale

I'm changing the crankshaft seal on a 307 from a 1988 custom cruiser. All the videos I'm finding about crankshaft seals show the seal going into the timing chain cover very snug (needing to use a big socket to tap it in. I'm easily fitting my new seal in by hand and there's room to move it around. Is this right?(no wonder it was leaking!) Should I use RTV? The old one is the same size and I double checked the part #.

Any help is much appreciated!

69HO43

What's the part number you're using? And how tough was it to remove the old one? 552711 is the GM p/n for basically all Olds 307 gas and 350 Olds diesel engines of the era. SKF19887, Timken/National 472082 are just a couple aftermarket part numbers, among others.

You should not be able to move it around. If the seal is the exact same size as one you took out, I'm betting some goober that had the engine apart before reamed out the cover plate hole for whatever reason. Couldn't have been a good reason.
RTV probably won't help you here.

If you need a new front cover, you would need GM p/n 22525282 or an aftermarket equivalent. I have no idea of the quality of the front covers from aftermarket. Heck, the one you have may be one of those Chinesium ones and that could be one of the problem areas?

alerdale

Thanks for the info! I have both the National p/n 472082 and skf 19887 seals and both just slide into the plate with room to move. The old one stayed with the harmonic balancer as I pulled it out. I think I'll look into a new plate, you might be right that that could be the issue, it looks a little beat up.

67OAI

Recently in the "Big Blocks" forum a similar issue was posted; see https://classicoldsmobile.com/forums...ay-put-158028/. As 69HO43 posted above, there may be fitment issues with some of the current aftermarket replacements.

BillK

I just finished doing a 425 and the Fel Pro seal that came in the gasket set pressed in fine. This was also a new timing cover that my customer supplied.

The fact that your old seal came out with the damper tells me that there might be a problem with the cover. I have the original 425 cover at the shop and can measure it if you want.

alerdale

Yeah, if you don't mind measuring the one you have at the shop, it would help me make my next move. I'm weary of the new covers out there as I've read those can have fitment issues as well. First, I'll check the cover I have and see if that's the issue. Thank you, I appreciate the help.

BillK

The original 65 425 cover I have here measures 2.878" Its not perfect but that should be a good number to go by. The seal that came out of it measures 2.884 or so and it has been compressed so take that number with a grain of salt.

I have an old National seal catalog and it says the 472082 measures 2.884 od and the housing should be 2.880 so that pretty closely matches what I measured.

What does your 472082 seal measure ?

alerdale

First, I want to thank this amazing community. I'm new to this forum and you all helped so much. With the measurements BillK provided I was able to determine that it was, in fact, the timing cover that was the issue. I found one on ebay and the seal fit perfectly snug like it should. I can't wait to get this wagon back on the road.

BillK

Thanks for the update ! Always nice to know when a problem is solved