gemellocattivo.com

30 minutes so no gross leaks

Hylomar on a head gasket? Is that a thing? Would RTV be an option too? The max temp for both are above what you're likely to get on your head but I've just never considered using something that or anything like that on a head gasket. I realize you have your spacer too but I guess I would have assumed you'd use a head gasket sealant like Permatex 80697 Copper Spray-A-Gasket.

Obviously, it seems to be sealing so congratulations!

Nope, strike 3. It was 2psi this morning, I recharged it and it lost 5 psi in under 20 minutes so it blew out the hylomer somewhere. Luckily this is more like t-ball and I can swing until I get a hit. I'll need to think about what to try next but the spray stuff is on the list, I think its just copper spray paint so I worry it won't have enough thickness.

What about embossing the plate around the coolant passages to help it seal? Like a MLG.
I don't see sealant lasting over the long haul. I see it as a helper but it this case, it is the main ingredient.

_________________
Wade Williams
Master Ferrari Tech
Restoration Tech
Engine Machinist
Fabricator
Racecar Driver

Embossing works with MLS because they are like leaf springs, the thin layer can flex quite a bit without yielding

In general I trust a lot of sealing trust to sealant, engine to trans, the intakes to the heads and such so sealant deosn't scare me. But while I was stacking 20k+lbs of patio stones I don't need but my wife got for a great price the last couple days it occurred to me that in my new design there is nothing supporting the o-rings between the cylinders so when I get it to pass the bench test and installed in the car, it will blow out the orings when it starts. Then I though I could make the copper rings taller and yield them on assembly to mostly seal, but then the hoop stress will be 6-8 times their yield stress so getting this setup to pass a bench leak test is a pointless exercise I think. I'm not yet sure what it the3 next attempt will be.

In happier news, the trans shaft now has threads so the ring nut fits, thank you Sean.

I was wondering what was holding the o rings in place. I have never seen o rings for a combustion seal. Why are you not using copper and stainless fire ring machined into the head? It seems to me the stainless fire ring would be the way. Then you could also dry deck it and AN hose bypass it.

_________________
Wade Williams
Master Ferrari Tech
Restoration Tech
Engine Machinist
Fabricator
Racecar Driver

I think the next attempt I will remake the 0.05" think alum shim to butt right up to the copper flame rings and remake those with 0.063" material so they are crush washers and forgetthe rubber orings. If I leave them 0.08" wide like they are they should crush at around 9k lbs. the WOT combustion load on the head is going to be 10k-13k lbs maybe and the bolts usually deliver about triple that. so the rings should crush down to the shim.

I requested a couple quotes for gas filled metal orings having no idea what they cost but possibly a good solution.  Just got a budgetary quote of 16-20 weeks, $3500-$5000 to get 10-20 seals.  At that price I don't think I'd be willing to test them as both the seal and flame ring which is which is what I'd end up with using the existing liners and/or piston so this thought will go on the back burner until I win the lottery.

I have a note into the cometic engineer and I have a second head gasket specialist (thanks Wade) I will reach out to today to get some more thoughts and a 308 buddy shared copper crush ring/alum shim design he is currently using on a 308 which is a little different form what I was thinking.....one of these paths should work.

Wade's guy Murray, who Wade has been trying to get me to call for some time now, says no problem making gaskets that work but is on holiday so now I go back to working on brakes I guess.

Edit: I mentioned I would be rechecking the cylinder/deck height relationships and as I was typing this got an "oh that's critical..." response so so I may be doing more engine work as Brian suggested. I guess I'll make some kind of tool to push down on the liners and see if they are moving before touching brakes.

Heads off and everything clean again. The hylomer extruded with enough pressure to force the copper flame rings into the bore so they are scrap.


I made a simple fixture to put pressure on the liners and measured to the protrusion. The highest is +0.0004", the lowest -0.0008". Have to wait to see what Murry says about that.