Volvo 275 transom seals

[fishndad]

I have been restoring an 89 Admiral (see post in restoration forum) which included a transom rebuild. I have been ordering new seals in preparation of re-installing the transom yoke/shield and various other engine seals. I had 2 questions, found 1 answer already (apparently the big seal strip that is the primary seal should be glued together with rubber cement into the shield and where the ends meet.

So my problem is that there are also oversized o-ring seals for the bolt holes. The transom holes are countersunk slightly to accommodate these. The thing is, Volvo Penta doesn't carry the part, and most of the places I've found so far are out of stock (with no ability to replace them, since Volvo themselves doesn't have any). Part number is 850418 for reference.

I think I still have the old ones, but after spending over $2K US on the rebuild and another $250 in other seals, I'd rather not re-use old seals if I can help it. But if I do, is there advise to make sure all my hard work is not for naught? Should I add a sealer and use the old rings, toss the rings and use a sealer instead? Or perhaps there is some way to measure the rings and find some generic replacement?

By the way, I ordered some of the parts from iBoats - the price was great and the shipping fast. Seems a good idea to support the company that sponsors this forum!

 

[fishndad]

Re: Volvo 275 transom seals

So far, no luck on finding a dealer that still has any. I did find some nitrile rubber grommets that have the same ID, a smaller OD. Might try to see how close they come.

From looking at the old ones, there is a reason they are so big. The new sealing rubber for the main transom shield seal is a big, thick length of rubber. Looking at the the old one still in the shield, it looks lie when it's compressed it could leave about 1/16" of a gap between the shield and the transom. The old bolt o-rings were squished not only into the countersunk holes, but some of it was squished out into that gap between the sheild and the stransom.

My buddy seems to think that this is important, and actually may act as a dampening system. The engine does not have any mounts in the engine box - it all hangs off the transom shield. Could he be right, that the shield shouldn't actually be solid to the transom?

Worse comes to worse, I may try the grommets and sealant together, then use a sealant like 4200 as a bead around the outside of the transom sheild to help settle it in.

Thoughts?

 

[PiratePast40]

Re: Volvo 275 transom seals

The o-rings provide the seal arond the bolt hole through the transom. Yes, you need these. Those holes are outside of the large rubber seal (If I recall correctly, DonS referred to that as a "Svedish blubber hose"). Getting water in between the bolt and the hole is a leak and also puts water in contact with the raw wood of the transom. Not a good thing!

Here's an alternate online dealer that seems to have many of the dealer items in stock: http://www.marinepartsexpress.com:8080/mpeCart/details.faces?productId=850418&Go.x=13&Go.y=11

Yes - the shield may be tight to the transom. The cantilevered engine is supported and dampered by the clamping ring and seal rings (rubber donuts near the end of the flywheel cover). I know it sounds odd, but they've worked for over 40 years so they must be doing something right.