Don Terrill’s Speed-Talk

Hey guys, I have an old school 468 BBC race engine built many moons ago. 12.7:1 CR, stainless o-rings in block deck, copper head gaskets. It currently uses 049 iron oval port heads. I have been contemplating switching to some aftermarket aluminum heads, but I was unsure if the current o-ring set up would work with the aluminum heads. People's opinion's seem to vary from "Only use MLS gaskets with aluminum heads" to "You have the have the o-ring in the head, not the block, for an aluminum head" to "You'll need a receiver groove in the aluminum head for the current set up". What are some of your experiences with this? I tried searching this forum, but there were no direct answers that I could find, and mostly stuff that dealt with import motors. Will the aluminum heads work with o-rings in the block and a copper head gasket? If not, what would you do? Thanks for your time.

The last couple of years, I've been running copper head gaskets with aluminum heads on my BBC and I only have the block O-ringed. It's worked fine in sealing the combustion and I was running upper 15's in compression. You may need to add some stop leak in the motor in the beginning. You also will need to pull the heads after the season and reseal. Copper is really a pain if you bracket race. My new motor has Cometic head gaskets. No more copper for me now that Cometic is available. Jim

Get some copper wire and hammer it in place of the stainless o-rings. Hammer it in the groove, file it flat with a file, then put the MLS on, problem solved. I have done it more than once on some 1200Plus hp engines and it works fine.

I agree with Mr. Kenneth Abbott on the suggestions of the copper wire in place of the SS O-ring wire. He suggested this to me earlier in the year and we coverted a BBC NOS engine to the MLS gasket utilizing the copper wire and it has worked great. The motor makes about 920 hp and then is sprayed with another 200-225.

Absolutely no problems what so ever with the copper wire and Fel-Pro MLS gaskets.

Thanks guys. I appreciate the feedback.

I have used copper head gaskets and there is no problem with sealing the combustion chamber. Sealing the water passages has allways been a problem. Almost every engine builder that has used copper head gaskets will have their preference of what to use, silicone (in many colors),hylomar(brush or spray),copper coat and permatex brown sealer. No matter what you use water will seep out somewhere. They also have copper gaskets that have sealing inserts to seal the water jackets. If you have a block with o-rings you can either keep the copper gaskets and contend with seepage problem. Or can have the block milled. I have milled quite a few blocks with the o-rings to accomodate a Cometic or MLS gasket. If the groove has been machined at the proper depth for the thickness of the wire, the block can be milled with the o-rings. I have a Peterson segmented grinder and with light cuts and a slow feed the o-rings can be milled flush with a minor effect on the block hgt. I have also pulled the wire out of(while milling) the groove and have had to mill the block to remove the groove. I have also filled grooves with "Marine Tex" in desperation when a wire pulled out after reinstalling the wire and was spit out a second time. It held up, but that was last result. If the block was o-ringed, I woud advise a receiver groove. Copper head gaskets were the only option before Cometic or MLS and are still a viable alternative. If you have Aluminum heads the o-ring should be install the head, but that is not the case. If you are contemplating the cost. The price of the gaskets are probably comparable. If the stainless wire was removed and copper wire reinstalled and filed to accomodate the MLS gasket, machining a receiver groove might be comparable. You can not cancel out what has worked for so long. I agree ,if you were starting from scratch - use aCometic or MLS. You have a block with o-rings, receiver grooves are a suggestion - not a necessity.This was batted about on earlier posts and it was stated by a credible source, The only problem Cometic or MLS is if there is a detonation problem the "block might burn through before the gasket". The gasket becomes the fuse. You now have to weigh the alternatives,torch the gasket or the block.