blowing head gaskets too often

[autronicDSM]

i'm lost at why am i blowing a head gasket so often. car lasts maybe a week on a new HG. i have ported big 16g runing 17psi and recently installed standalone. as of now i'm left with only 2 possibilities. head or block is warped although last time i did HG i checked the head and it was straight. 2nd possibility is that it's runing rich. i doubt that's the cause but i just want to make sure. when i tuned my car i started rich and left it there until i can get it on a dyno and figure out a way to monitor for knock. at idle/cruise i have ~13:1, 1/2 to WOT i get anywhere from 10.8:1 to 10.0:1 AFR. timing is conservative. EGT are stable but could be higher, i get about 1400F at WOT at 7000 rpm.

anyone with standalone experience let me know if it's my tuning or do i have a mechanical problem. thanks

 

[mclaren55]

I also blew a few head gaskets, not as often as you. However my head was warped slightly, and I got it decked. I suggest you do the same, as I can't see why a rich A/F ratio would cause blown head gaskets. By the way, 10.0-10.8 is very very rich, you should lean it out, its hurting your performance, and you might realize some gains by taking it up to 11.8-12.0 or there abouts. I run mine at 11.6 ish.

 

[Tevenor]

When you checked the head ahd block, what did you use? Did a machine shop check for flatness?

 

[GRNDSM]

Machine shop usually uses a calibrated straight edge with a filler gauge.

I highly recommend doing EVERY time you install a head. I just did in my head, but forgot to check the block... Now I am pushing coolant at high boost .

So even though it is pretty rare, it looks like I have warped block.

Leon
RR

 

[Big Woo]

Have the block deck surface, and the cylinder head checked by a qualified machinest. If there is any question have them milled.

Also are you using the stock head bolts, or studs, and what are you torqueing them to?

What are the maximum coolent tempatures your engine has seen?

What head gaskets have you been using?

 

[autronicDSM]

i did it myself and used a straight edge so it wasn't as accurate as machine shop's. i guess i will have to wait until semester is over till i get to it

btw, i suggested rich AFR because it's the only thing that isn't right with my car. i thought maybe it was rich knock but i didn't hear any pinging

 

[autronicDSM]

max coolant temp is 90*C that's about 195*F. i'm using arp studs torqued to 100lbs/ft but still a stock head gasket. i will have a machine shop inspect my head when it comes off and buy metal head gasket. i didn't think i would need it for 17psi out of big 16g but looks like i might have to try it for safety sake. thanks for all replies!