i don't think i have enough cylinder pressure. i only distorted three of four cylinders on the driver's side. i haven't torn the passenger side off yet. have a slight bolt issue to take care of.

this was on the 250 shot from sunday's race.



i keep blowing the gasket at the service notch in the head on the passenger side. here's some pics to show that.




here's how deep the notch is. would have to weld it up and then resurface the head.

 

Looks like your going to need to try a little harder next time. Go for all 8!

 

maybe time to drop the compression a little with a thicker hg?

 

What compression , what gasket ,and what thickness? what deck hight for the pistons

 

11.3 compression
.057" head gasket
felpro 9199PT

got more good news. broke a valve spring on the #8 exhaust. good thing they are duals.

 

I could be off base here, so if I am, just correct me instead of flaming, but here I go....

When I was looking for head gaskets, I found out about 2 different heads for the ls1's, one's like you have there with the notch and ones without. I think there's 2 different gaskets out there too, one for the notches and ones for heads without notches. maybe you have the correct ones and I'm totaly off base here, just something to check into....

Ever tried MLS gaskets?

 

Put cometics on it.

 

Get the "notches welded and the heads re-trued. I have heard good things on the felpro's but atv and i have never had a head gasket issue with cometics so thats what we recomend.

 

what timing? what power level and what fuel?

 

cannot use any type of MLS gasket with a notch in the head that i'm aware of. it will not seal at the notch and water comes out. the MLS is the first one i out on. when i put water in the radiator, it came pouring out the notch. here's a pic of the MLS gasket.


here's pic of the head and how the MLS gasket seals.

black = sealing area
blue = water
white cylinder sealing ring

 

25* ( i've done 21* with same result)

on old cam i made 663 rwhp

93 octane

 

springs were over a year old and most likely nearing 15,000 miles. tested them today, pressures are supposed to be 137 seat and 370 open. they were 94 seat and 320 open. here's pic of the spring. large diameter one is the outer. the smaller diameter is the inner spring.

 

god damn dude, why dont you pull some timing out of that thing and get some good gas in it? no wonder youre having issues!

I'd run 15* and some form of race gas.

 

No **** !

I didnt see that was on a 250 shot.

15*, race gas and some ngk 10 spark plugs would be a good start.

 

What they said and
get the notches welded / epoxied up.

 

on the dyno, at 21*, it had no knock. AFR 12.5ish so i don't see why i need to drop 6* of timing. but hey if that's what it'll take.
autolite 103 plugs = ngk bp7efs plugs have looked fine.

you guys run these times more than i do.

 

Dont tune to knock retard. That can be very misleading. You need to be reading the spark plug at that HP level for more acccurate results. I aggree with the advice up top You have to mutch timming. What plugs are you using as well?

Dave

 

And I'd also tune the AF down to 11.5 or so, also, a colder plug wouldnt hurt

 

autolite 103 plugs = ngk bp7efs no signs of anything going on.


when i look at my PLX wideband on the street, it showed 11.9 on the bottle. dynojet showed 12.5ish. so, which one would be correct?

either way, i'm changing to autolite AR-94 plugs and i'll drop the timing some more.

 

Cool. Number 8s may be a better hoice but I would not say the 7s are a no no. The combination you had though with timming, octain, plug and possible airfuel is not good.

I am not familiar with the PLX wideband. However I have found that most dyno wide bands if in good shape are sclser. The key would have been to look at the plugs and see which wide band complimentsed what the plugs were telling you.
Dave