While chasing some oil leaks on my motor I discovered that the O-ring used between the tube and the valve cover were undersized. The ID seemed OK but they were too thin and did not seal with the valve cover at all. I found a bag of O-rings that came with some spare tubes and they appear to fit much nicer, problem is that there were only 7 in the bag. I will try to match them up at a local supply place but does anyone have an actual size reference for these? The undersized ones were .132" thick and the better fitting ones are .182" thick. I measured the tube OD to be 1.250" and the opening in the valve cover to be 1.560"
While we are on the O-ring topic, anyone know the size needed for the Milodon #27500 tube seals that are pressed into the heads?

Jim

The closest I can find in the Parker O-ring handbook is a #5-297 with an ID of 1.230 and a cross-sectional diameter of .197". I normally spec the 2-series o-rings on things I design which are commonly available. The cross-sectional diameter of the o-rings in the 2-series jump from .139" to .210". A #2-322 has an ID of 1.225" and a CS of .210".

It looks like the bag of O-rings I had were metric. Best cross we could do was 30mm ID and 5mm thick(1.181" x .196"). The #322 fits well over the tube but not sure how well it will fit in the valve cover. I also got a few smaller ones to test fit by stretching then over the tube to get a slightly smaller OD. I'll test them tonight and post results.

Jim

Well as it turns out the #322 O-ring fit well over the tube, but was not a good fit (big) in the valve cover. The metric one fit easy over the tube and fits OK in the valve cover and would probably work OK. There is very little crush and pretty much drops in place with little effort. At the suggestion of the counter dude I also tried a #318 O-ring which has a 1.0" ID. This is obviously a snug fit over the 1.25" tube but it has a nice tight fit into the valve cover. I think that unless there are issues where the stretched O-ring will break quickly then I will go with this size.

Anyone have the Milodon seals not installed on the heads and could provide the O-ring thickness?

By the way, the installed O-rings were size #218 - they fit fine over the tube but come up way short to sealing against the valve cover...learning as I go...

Jim

I got some from Arrizzi or something like that and they worked great.

The proper spelling is Aruzza Performance

(336) 475-0426

Great product, but not cheap.

Thanks for the reference. I asked the counter guy about potential breakage using the smaller O-ring and since it is just in a static environment we should have no issues. Problem would be if it was used with a moving part. I plan on installing them over the weekend.

Jim