I turbo'd my 94 si (115k miles) about 8 months ago. It ran fine until about a month ago. After it overheated a few times, I figured out that the head was lifting and that air was escaping into the coolant (coolant was bubbling in overflow container).

I had the head machined a few thousandths of an inch, and I used a new OEM headgasket and ARP head studs. When I got the head back from the machine shop, it looked perfectly flat, but it looked like it had been ground with ~80 grit sandpaper instead of having a smooth finish like I thought it would. I talked with a mechanic who said that was fine. After putting it all back together and letting it run for a few minutes, it started leaking coolant from the headgasket.

I am guessing my problem is one of the following:

1. The head is too rough and is not sealing.
2. The block is warped (can the block even warp?)
3. The copper spray I used messed up the seal (has anyone had this happen?)

#1 is my main suspect, has anyone had their head machined to where it looked like you ran 80 grit (or so) sandpaper across it? Any ideas?

 

how much boost?? maybe a cracked sleeve?

 

copper spray is supposed to give u a better seal, not damage it, so I would cound it out. #'s 1 and 2 are good possibilities, I'd say go and machine the head again, and if that doesn't work, then could be a warped clock, but then again, could be a cracked sleeve as well...

 

hrm, I guess it could be a cracked sleeve, but I'm only running 5 lbs of boost (greddy kit). A cracked sleeve doesn't explain the coolant coming out of the headgasket though Anyone else?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aphelion &raquo;</TD></TR><TR><TD CLASS="quote">hrm, I guess it could be a cracked sleeve, but I'm only running 5 lbs of boost (greddy kit). A cracked sleeve doesn't explain the coolant coming out of the headgasket though Anyone else?</TD></TR></TABLE>

true, get the head machined again, also, was there any gasket left over that you forgot to scrape of the block?

 

Did you over-torque the head? Was it an OEM paper gasket or the metal layered one? Did you have the head pressure checked? Did you have it inspected for hairline fissures or cracks? Even a few low-temp overheats can cause severe damage to a cylinder head.

 

Torque the head??
there is supposed to be some swirl marks on the head when it gets machined but no deep scratches. Torque the head down properly?
Never used copper spray never will.
Don't reuse the headgasket if you will redo it.

You can measure if the block is warped with a straight edge and feelergauge, shouldn't cost over $30. And yes block can warm especially on boost with overheating problems.

 

The head was torque'd down to arp's spec very carefully. I am using a metal OEM gasket (three-layered) I had the head pressure checked as well. I really don't think I have a problem with cracks, as the coolant is leaking from the headgasket.

 

It sounds like you did everything correctly. I always use copper spray and have never had problems, I doubt that it your problem. Even if your head had little imperfections in it the copper spray should make up for that.

Someone else asked if you cleaned the old gasket off the deck (if there was any) I'm assuming you made sure it was clean?

You torqued the studs to ARP specs, did you make sure to bottom them out in the block? Did you use ARP assembly lube or motor oil?

It is possible to warp the head, but it wouldn't just warp itself unless you have overheated recently.

So I think your problem (given you installed the ARPs and did everything correctly) is either:
1. Machine shop screwed up resurfacing your head
2. Block is warped

 

thanks JZ, that's pretty much the conclusion I have come to. The deck was cleaned and studs bottomed out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aphelion &raquo;</TD></TR><TR><TD CLASS="quote">thanks JZ, that's pretty much the conclusion I have come to. The deck was cleaned and studs bottomed out.</TD></TR></TABLE>

go back to the machine shop and eithe A) have them redo it at no extra charge, or B) get your money back and go to another shop...

i'd be pissed if I were you

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by egcoupe94 &raquo;</TD></TR><TR><TD CLASS="quote">

go back to the machine shop and eithe A) have them redo it at no extra charge, or B) get your money back and go to another shop...

i'd be pissed if I were you</TD></TR></TABLE>

Or there is an easy way to do this is just measure it your self. The problem of milling the head so many times (especially on the boosted set up) you are increasing the compression.

 

when i get my heads resurfaced they look like they have been polished. they are so smooth theyre shiny. you said 80 grit? damn thats bad. 80 grit is rough.. they definetly fucked your head up. id get a different head because you dont want to be milling it too many times.

 

just keeping it simple when you take the head off check to see if gasket is upside down not trying to insult your intelligence or however you spell that just **** happens

 

it cant go on upside down