Popped my headgaskets again
 

Setup 1:

1.6mm EJ25 (NA) laminated steel gaskets, P1 heads, EJ257, CR about 8.0-8.2:1, ARP head studs. Headgaskets leaked under boost. Running 24 PSI when it first happened, was doing very high speed so it was hot. Was running methanol, lambda 0.80, lots of timing - in the 20s. A retorque didn't help. Mileage - about 7000. So setup 2 was put in place.

Setup 2:

0.8mm EJ257 laminated steel gaskets, P1 heads, EJ257, CR about 8.7:1, Subaru head bolts. Using Redline Water Wetter as surfactant to prevent hot spots. Fine for about 7000 miles running up to 23 PSI on plain pump fuel, about half of that on larger GT30R/P20 iON turbo. Tried running 24-25 PSI with methanol and octane booster, again took good timing 20-25 degrees, lambda 0.80. Again used at very high speed and the gaskets appear to have failed again. The oil temp and coolant temp have not got too hot.

Setup 3:

Tempted to just rebuild it, can't decide on studs or bolts this time, I have a new block and CP pistons available, but I will probably just rebuild it as setup 2 but run under 20 PSI.

Last time the heads were checked and flat, no cracks.

Thoughts?

You need heat treated bolts or studs that won't stretch, no question, ring RCM.

Water wetter only makes things worse so don't use it next time.

Check for cracks between plug and valves.

And lambda 0.8 could be too lean imho what were your egt's?

Or you could weld the heads to the block .... lol (don't tell David)


bob

Thanks Bob.

EGTs are in the low to mid 900s when measured before - not a gauge I use continually, maybe I'll need to review this. I thought the pistons would cop it first though so I gave up worrying about it LOL.

Water wetter worse because it reduces the heat carrying capacity?

Will recheck for cracks again.

Maybe I'll need to run it leaner even with methanol.

Are the RCM studs different to ARP ones? I'll give them a call.

Ditto the above, whilst building mine this could be interesting to know.... Got ARP studs here.....

John

of the topic I was looking through my old posts and you were asking about office 97 and nhs staff, sorry I must have missed it

it will be free unless you want the disks then its about £17 but this will only before office 2k onwards

if you have any problems send me a Pm and I will give you a hand

John

Can you machine the block top faces to accept "Wills Rings" or similar ( I think they are called ) but not sure if these suit scoobies, and you'd still need some head gasket for the oil and waterways ...

But there should be a suitable gasket / method - look to the world of silly power yanks or skylines.

As Bob said, if the head bolt / stud stretches it could allow the heads to lift or the head gasket to blow.

Where are they failing John?

Last time they were all around the circumference of all the bores. This time I'll have to see when they come out.

I'm 95% sure that is what we are dealing with again.

It worth checking the torque on the head bolts during the strip John, just see if they will take any more turning at the corect torque as that may give you a clue to what is going wrong.

If you havnt seen any change in the bolt retention then it may be worth looking at using some wire ringing on the gas seal. How is the clamped area size in reference to the 2.0L engine? is it narrower?

Thanks John.

I think the clamped area is similar, but will check.

Tempted fate by speaking to me on Thursday !
I would be interested if you find a cause and also what shape your engine is in.

Mark

Present plan is probably heat-treated Roger Clark 14mm head studs, wire ring the block, fit the CP pistons and try again.

Is this due to problems with block stiffness in the EJ257, do you think?

Could be.

Plan has changed, having had six engine removals from this car, I'm going to just fix the problem and run lower boost and see how others manage to sort it as they come across the problem. I really think a lot will. I just can't be sure that it will be fixed with the o-rings and 14mm studs, everyone I ask says that I am the first one really doing this sort of power on this engine over this period of time.