ChefJ

yea there are some over 700 at 11:1 compression. how long the motors will last boosting at that pressure is still unknown as it is a recent thing. even with a built motor make sure you are running a good fuel and the tuner is checking the knock after every pull to make sure you aren't detonating.

ap1tuner

I almost got the engine torn down to the HG and ill see how it looks. And as for power, I hadn't thought about it, but I made 300 on the dyno before on lowest boost and 450cc injectors. But I had to change the injector driver shortly after I had it tuned and I wonder if that threw the tune off.. also my fuel pump failed and I had to replace it... turns out I had a fake walbro... so maybe all this change and no retune caused this

kimsey

I would have to say that you definitely stood a good chance of damaging your engine when your fake Walbro started going out. It could have easily caused a lean condition and detonation, which would wreck havoc on the head gasket. I'd be interested to see pictures of the piston tops and underside of the cylinder to see if there are any signs of detonation.

Although my experience with MLS gaskets on S2Ks is limited, I have extensive experience with them on BMWs. Regardless of brand used (Cometic or Wiseco), I have found that the biggest factor in their survival is prep work and following the install directions. The head and block really need to be resurfaced by a machine shop to the exact specs of the MLS gasket spec sheet. Also, do not try to rush the installation of the gasket, Being multi-layered, it will settle as pressure is applied when torqueing down the head studs. I've always used ARP fasteners in teh past and they required being torqued in stages. As such, the BMW FI community found it extremely important to torque the first value, wait an hour, come back a retorque to the first value (as the gasket settles the studs are no longer taught to the 1st value and require being turned some more to get to that value), wait another hour or two, retorque to the 1st value, and repeat until all studs are already at the torque value when you go to retorque them. At which point you should loosen them in the correct order by 1/2-3/4 of a turn and torque to the 1st value again. then you can go through all the the torquing stages.

If you're using factory studs and they only require being torqued to one setting, I would recommend dividing that value by 3 or 4 and torque to the value that you come up with and use the method above to get the MLS gasket to settle properly. Also, if the stock studs are a torque to spec and not a torque to yield bolt, you have a great advantage over teh BMWs, as you can wait a couple hour after final torque and go back and check for any more settling of the gasket.

Hopes this helps

ap1tuner

Well I spent over 6 months having the engine built and took it to a reputable machine shop for all the work. Everything was rebuilt, replaced and resurfaced. I used the oem honda gasket and arp head studs. As far as proper torquing, idk if they did it right or not. Ill make sure that I do it myself this time. And I have an aem wideband in the car and as far as I could tell while watching it, I never saw it get grossly out of range... meaning btw 11 and 12 under load and never leaving 11's in WOT. Ill take pictures and post them when I crack it open. I hope all is well. My pistons were cp and the blocked is steel sleeved

ap1tuner

just curious... is the 2mm cometics head gasket any good? just thinking about all options before i start buying parts and put this thing together again.

ap1tuner

ok got the head off today.... heres the scoop. BLOWN! cylinder one is all jacked up... as you can see.

and here is cylinder 2

cylinder 3

and cylinder 4

as for the head gasket.... im pretty sure it was gonzo as well. i noticed that the oem honda head gasket that the engine builder used actually ever so slightly hangs over the edge of the cylinder... (remember its been bored out .50 over) so it looks like my 11:1 cp pistons are finished and ill have to order a set of low compression pistons. and i guess ill need to call cometics to see if they will make me and oem thickness HG thats wider..... BALLS.... this blows.

siadam

Those are CP pistons?

ouch. You've got other issues going on than a headgasket problem.

How much power are you making? Tune?

I'd suggest reevaluating your setup.

As for the gasket, I believe GE bores out OEM gaskets for whatever size you need, I'm not much of a cometic guy myself.

ap1tuner

ALSO... can someone tell me what the stock bore of the oem headgasket is? i called cometic and they said they originally sell their gaskets in 89mm bore and i know my engine is bored out to 87.5.... so is their gasket already large enough to not be a problem?

ap1tuner

well i think that possibly my problem originated when that fake walbro started going out on me. and probably had something to do with my injector driver going bad also.... but next week im ordering a new gasket and some lower compression pistons and we will see how this all pans out i guess. and a retune is top of the list

wadzii

make sure you have the rods and crank checked.. preignition that bad will tear some shit up.