Inliners International Forums General Discussion Hi Performance O'ring installation

I bought a used Chevy 400 engine block (sorry folks...), fully race prepped, still with some good life left (it's 30 over). It will be used with alky Hilborn injection on a slingshot I'm restoring.

The thing is that the block is o'ringed, copper o'ring! The cylinder #1's o'ring was slightly dented, so I decided to replace it. I bought the .041' copper wire from Isky. However, when removing the old wire from the block, I was surprised to find it fully glued to the o'ring groove with super glue.

Is it common to super glue the copper wire to the bottom of the o'ring groove? Is it really required?

I re-wired this cylinder twice, applying super glue to the o'ring groove, but it have the IMPRESSION that the super glue is hardening faster that I am able to fully seat the wire. In other words, it feels like that hardened super glue is 'lifting' the o'ring, unevenly. I'm going to use the SCE copper head gasket, .043" thick, therefore the o'ring shouldn't protrude more then .010" above the block deck, but I've been measuring as high as .016".

Can you guys share your experience in installing copper o'rings?

Thnaks!

Copper O-rings aren't effective at all, and you will likely be replacing them often. They are just too soft and defeat the purpose of what an o-ring does to begin with. The variation you are measuring is probably the remains of super glue in some places not removed from the o-ring groove. You should remove all of them and use the appropriate wire.

CNC-Dude, thanks for your input.

I agree, copper would not be my choice, but since this engine was setup for copper, I wanted to keep it to save time, just for now.

I also suspected on remains of super glue, but I scraped the groove really well.

This is my first time dealing with copper head (and o'ring). On the installation of the copper head, I'm planning to spray it with K & W Copper Coat... Or should I use Hi Temp RTV sealer instead?

I would use stainless wire, as CNC inferred. Shoot for about .006" stick-out on the deck. I would spray the gasket with Permatex HI-Tack areosol spray gasket sealer. I would also expect to get some seepage anyway, which matters little on the track, but makes it imperative that you drain the block between races to avoid water in the cylinders. That is why I went away from copper.

That, and the fact that a copper head gasket will work harden over time, making it necessary to re-anneal the gasket in an oven or BBQ grill.

when you re-anneal those copper o-rings on the BBQ, which Jack Daniels sauce do you use (the bbq sauce, green or black)?

Ok, back to your original concern. As Greg mentioned, your o-rings should only be about .006 above the deck surface. Sounds like the block was either resurfaced again after if was o-ringed at some point, or they didn't cut the grooves deep enough to start with.

I fry them up with some fava beans and a
nice chianti. slurp, slurp, slurp.

I once had a machinist ruin one of my blocks by machining o-ring grooves on a bridgeport. As he cranked the table the weight of the block tilted the table causind each groove to be slightly askew. Better to get one of those o-ring grooving tools. You can true up your grooves and cut them deeper too.

Like the one Isky sells?

yes

Hi folks.. I finally had a chance to resume this work... and here's the conclusion:

I did some measuring and the o'ring groove does have an uneven depth! Thinking the front of the engine as North, driver side as West, the 'Northwest' side of the o'ring groove is 0.031'' deep (good!), whereas at its 'Southeast' side depth is shallow as 0.025''. It seems like the block was not perfectly leveled when the o'ring groove was cut. Anyway, that makes the o'ring to protrude as much as 0.020'' in the 'Southeast' and 'South' (bordering with cylinder # 3) sides. I was concerned that the excessive protrusion would create problems sealing the cylinder #3 where the o'ring of cylinders #1 and #3 are adjacent. So I took the approach to 'level out' the protrusion of the copper o'ring of cylinder #1 by carefully block sanding it. I'll post final results when the time comes.

I'd have taken a much different approach to start with if I knew the copper o'rings would bring so much trouble. This engine doesn't need the copper gasket and o'ringed block to start with. It's a naturally aspirated alky engine with lousy 12.5:1 compression ratio. If I knew the copper o'rings were super glued to the o'ring grooves, I'd have had the deck machined, cleaned up the minimum necessary just to cut the copper o'rings flat. Then I'd probably use steel multi-layer gasket. A lot less hassle than the copper gasket, for this application.

I know the o'rings can be beneficial/necessity for highly boosted engines. I've seen high-end 250 race engines (4 figure HP) with three stainless steel o'rings per cylinder, two in the head, and one in the block positioned in the middle of the head's o'rings. We don't find machinists with such capability in every corner.

By the way... discussing the risk of potential coolant leaks with the copper gasket... a friend suggested considering the use of those 'coolant stop leaks', like those from Prestone or Bar's Leaks. I'm tempted to try it if I find a leak. Any comment?

Thanks for all the great input.

there is another sealer out that has a Life time to it.Not cheap either really.I had the link now i can't seem to find it.

I've always used sealer from Forcelle and Clark with good results. The copper gasket surface(both sides) and deck surface must be really clean to get the best results. If you were using a steel O-ring wire I would be more concerned about the varying ring height. With copper wire, it will squash flat when the head is torqued and won't even leave an impression in the gasket like steel wire will. You will have no additional sealing benefit around the cylinders with copper wire because it is just too soft the perform the job it is intended to for your satisfaction.

I've run .040" stainless O-rings in an iron head GMC for years with .015" sticking out and never had a problem sealing the compression. The only problem was with the copper gaskets around the water passeges. I've even used the same combo on stock gaskets and did not have a problem. Now using a Best head gasket. This is with 14-1. Our 12 port aluminum head has .050" o-ring stainless wire with a .065" reciever groove in the block. I buy the wire from Mc Master-Carr.

If you still have problems an old racer running a blown Chrysler to me to O-ring the block and head at different diameters and o-ring both with stainless(no reciever grooves)and run copper gaskets. If I ever have any more problems it's what I will do.
Good Luck.

PS: more info on the BBQ annealing...My BBQ will get to 600+ degrees on the front temp guage. How hot and how long. I have been doing in with a rose bud and hi heat bricks....