I've been out of the honda scene for a while and have gotten into the toyota thing. I don't know of any real knowledgable forums other than this one as far as motor problems are concerned so here is my problem.

I had my iron block 4AGE motor rebuilt. While the block was at the machine shop, they found out there was slight pitting on the deck of the block. I had them mill off 1mm off the deck to take care of the pitting. To compensate for this I tried running a 1mm thicker, 2mm cometic head gasket to bring the compression back to stock.

When I was running the motor NA I had no problems with the headgasket leaking but once I went turbo I blew through headgaskets left and right. Each headgasket would blow after a few miles into use.

My question is since the block was milled down that extra 1mm and the pistons would protrude that much further out of the block, would this cause more strain on the head gasket. I've also heard of many people having troubles with the metal cometic headgaskets sealing.

Here are a couple pictures of my setup.

 

Hve you taken a look at club4ag.com? they would have a better answer as they have a section specifically for this engine.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by smoovy &raquo;</TD></TR><TR><TD CLASS="quote">Hve you taken a look at club4ag.com? they would have a better answer as they have a section specifically for this engine.</TD></TR></TABLE>

Yeah, I'm a member of that forum aswell as mr2oc and both don't seem half as knowledgable as this forum. I think this questions pretty broad too so hopefully somone may be able to give some good answers/guesses.

 

What head studs? How many times have they been used/reused? Sounds as if you're lifting the head

 

It can be your tune doing this.

Do you have any tools to check the flatness yourself? Don't trust machines shops after they've done work for you.

AND

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

 

1mm is roughtly .040 that you had shaved off the block.......that is quite a bit of material......i dont know how safe that is but it may be part of your problem.

also there are numerous issues/reports of guys running into problems with cometic headgaakets. (for honda's) they seem to be a hit and miss with reliability.

 

I checked both the deck of the block and the head surface with a flat edge and mechanics shims both in a cross pattern and across. Both surfaces were flat. I'm running new ARP studs.

I know 1mm sounds like a lot thats why I used a 2mm headgasket to make up for the milled off material. My question was if having the gasket make up for the milled block cause weakness in the gasket seal.

 

Combustion may be happening too close to the gasket since the block was decked.

But I doubt it.

Are you torquing the studs to arp's specs ?
if so. GO HIGHER.

I blew HG's on my sohc for a couple years repeatedly. Been torquing to 90 ftlbs and NO problems since.

 

What are you tuning with?

 

I've been torqueing the studs to the recommended settings by arp (I think it was 65 or 75 ftlbs off the top of my head). Would taking it up to 90 be safe both for the block and the studs?

I've been tuning with megasquirt. Megasquirts been pretty big in the 4AGE world. It's basically a diy fuel and ignition standalone system.

 

Id go 90. Just make sure all the threads in your block are good.

Good luck dude.

 

i would try a stock gasket and compensate with the tune, mostly to test theory. but god 1mm is a lot just for pitting, unless that was some nasty pitting. i would guess its a problem with the gasket if the surfaces are as great as you say. the ARP's should be holding but you might go a little more on the tq.

 

maby a thicker headgasket? i usually torque mine down to spec start the car and let it get up to temp, then take the cams out and re torque them again, then put it back together and drive it. i also use copper spray on my headgaskets,both sides. this seems to work for me

 

if the surfaces are flat, then it's a fastening issue.

The torque values provided by ARP are with specified lubricants on the threads. Also, is your torque wrench accurate. What torque value were you using.

Is the leak in the same spot every time?

Check the studs to make sure they aren't bent. they could also be stretched.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aw1234dude &raquo;</TD></TR><TR><TD CLASS="quote">\ Would taking it up to 90 be safe both for the block and the studs? .</TD></TR></TABLE>

I wouldn't be as concerned with stripping an iron block's threads as I would if the block was aluminum like honda's. .. . .

 

The torque specs may be for a stock headgasket instead of a thicker one. Your quench on the gasket changes when you increase the thickness. You might want to up your torque a little.


Are your torqueing in the correct sequence?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Speed Industry &raquo;</TD></TR><TR><TD CLASS="quote">if the surfaces are flat, then it's a fastening issue.

</TD></TR></TABLE>

How did you know his tuning is on point ?

Don't over torque ARP studs.

 

Any pictures of the pistons or internals?

Back in my Toyota days (non-turbo) the biggest problem with blown gaskets was warped heads.
Despite the warnings, I would torque those studs a bit higher. Just make sure you put the lube on the threads.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XSIintegra &raquo;</TD></TR><TR><TD CLASS="quote">Any pictures of the pistons or internals?

Back in my Toyota days (non-turbo) the biggest problem with blown gaskets was warped heads.
Despite the warnings, I would torque those studs a bit higher. Just make sure you put the lube on the threads. </TD></TR></TABLE>


i run an extra 10 ft pounds using the moly lube on mine...