146 Cylinder sealing + 162 Head Gasket Install / Cut-ring and copper spacers info dump

Hey guys, I wasn't going to bother elaborating on this but figured it would be good to archive the info with the webinars in case other people don't know about the cut-ring gasket option. So I asked in the webinar if you had an opinion on or experience with cut-ring head gaskets - like JE now markets in the USA for around 250usd msrp (more commonly sold by the brand Athena for everyone across the pond). They're also known as COOPER ring (not copper as you thought I meant hehe) or fire ring gaskets in some regions or by different brands.

Oddly enough, a common head spacer used for my BMW application IS in fact a copper head gasket for lowering the compression in a combo with these cut-ring gaskets to reach the common mls .140 thickness IIRC. These are sold as a package with ARP studs by CES motorsport out of the USA if anyone is interested in seeing what I mean. As Andre mentioned in the answer to my webinar question the copper does in fact have fluid sealing issues unless they're layered in an RTV (or whatever it is they recommend) on both sides of the copper spacer. Another oddity is someone in the USA has the copper E36 BMW head gasket pattern patented or at least they own the rights to it, so it costs around double vs a non BMW spacer from the same company. They took the fun right outta that! :(

If others don't know, a Cut-Ring gasket is like an intermediate step to o-ringing IMO. They use cylinder rings designed to dig/cut into the head surface to provide a really tight seal without as much risk of blowing out under higher boost/cylinder pressure. The only problem I've ever heard mentioned is the somewhat fiddly install since the metal cut-rings are loose from the head gasket (which itself is a stock style composite gasket). The rings must obviously be in place correctly before you torque the head down, but they've been known to try to wiggle out of place on a few people during install. This is mostly due to the awkward angle of the BMW I6. Add an rtv slathered copper spacer in there too and it would be even more fiddly to install.

In theory a cut ring should be better than an MLS gasket for cylinder sealing, and doesn't require an MLS level of surface prep which can be expensive if you don't have good machines nearby (canada). From my research most of the BMW crowd using MLS started disassembling and sending out their blocks to be surfaced below RA 50 with the head for serious boost levels due to oil leaks that can otherwise pop up if they didn't prep the block. For my budget M52 turbo build that's just not gonna happen ATM *unless I win JE pistons

I had never heard of these type of gaskets until I got into M50/52 BMW engines and priced out options for boost levels above 14 psi for track use. My bench theory setup is ARP's and a JE Cut-ring @ stock compression since I'm not sold on the extra cost or reliability when using the copper+rtv combo. To deal with 'high' stock compression I'd just mix race gas, spray meth, or better yet run e85. Around 425usd for this combo and no extra surface prep beyond a normal head gasket job, should safely seal over 600whp - long enough to bend my rods at least ;)

Hope this helps someone.

Cheers - Ryan T.

Hey Ryan, I think it's just a case of different names for products in different parts of the world. Apologies for the confusion in the webinar and I now understand what you're talking about I think. IU've always referred to these as W-rings. They were quite common in many of the early turbo race cars used in the ATCC. I haven't personally used them myself. They have proven effective but obviously result in some level of permanent damage to the cylinder head. The way I've seen them used still has involved the W-ring sitting in a machined groove in the top of the bore which obviously fixes the location issue and provides a little more integrity to the seal.

Another product that Cometic came out with was their Phuzion gaskets that were a similar idea but used a gas filled o-ring instead of the cut ring/w-ring.

My Barra is using a copper head gasket with an o'ringed block. With only 2000kms on the fresh engine it is now pushing coolant at around number 3 cylinder (hotside) under boost. The engine is not over heating and there is no water is in the oil. I have re-torqued the head as per the specs for the ARP studs as my engine builder suggested this, understandably.

How much of a problem will this be in the longer term if we can't get the gasket to seal? I understand that the copper head gaskets are problematic for sealing coolant and oil, but I am unsure if I should have the head removed and try and fix this or if this leak is something that I can simply live with?

The engine is performing well from what I can tell although I have not yet really been able to lean on it very much in the short time it has been running.

Your advice is appreciated.

Thanks

Louis

Hey Louis, I'm not 100% sure where exactly you're experiencing the leak and I can't quite tell what that pic is of sorry. Copper gaskets are notorious for being problematic sealing oil and water but this is generally unrelated to boost. If you're leaking combustion pressure into the water jacket then you'll need to fix this or you risk pushing water out the overflow and torching the head. If the leak is external between a water jacket and the outside of the block this is less than ideal but less dramatic. You'll obviously lose water over time and this will depend how bad the leak is. If it's minor then you may get away with trying a 'stop leak' style product in the cooling system. It's a bandaid but then again you're likely to always have trouble. i personally only use/recommend copper gaskets for dedicated drag applications for this very reason.

Andre, when re-torquing the head studs, would I back them off 1/2 a turn first before re-torquing them to spec or can I just put the torque wrench on each stud in sequence and re-torque it that way.

what it the correct way to re-torque head studs/bolts?

thanks

Louis

Sorry for the slow reply. When re-torquing a head you need to back off the stud to the point it becomes loose before applying torque. Don't loosen all the studs though - Loosen and then re-torque each stud one at a time in the normal torque pattern for the head.