Headgasket issues?

[alpinaseeone]

Thanks Panici - can confirm that trigger angle was checked with fixed timing first and then altered by 2 deg (1 tooth) to align timing marks on the crankshaft pulley and timing cover. Then altered the tooth #1 angle to increase by 2 deg.

I'll check on tunerstudio over the weekend and update exact numbers & settings when I get time.

Also, an ARP stud tip: if the washers aren't the type which are textured on the bottom in some way, sand the bottoms of the washers a bit on some coarse sandpaper, I think I used 100grit. It textures the bottom of the washer and keeps it from spinning on the head mating surface, which will alter your torque values. Clean the mating surfaces before dropping the washers in sanded side down and do not lubricate both sides. I've yielded and stretched an ARP stud mistakenly because when the washer slips, the torque drops, and I was in a hurry and kept pulling on the torque wrench even though I should have known better when the torque plateaued. Luckily I had the presence of mind to realize what I had done right after.

Wow I think maybe this is what I was doing wrong. I tried to look into how to use the ARP lube as it was my first time but ended up lubricating both sides of the washer and under the nut. No lube on the bottom of stud threads.

I'll try the 100 grit sanding and make sure next time to only lube the bottom of the nut and top of the washer! Thanks for the advice.

[varg]

I should have specified this when I made the post but since it's quoted now and can't be edited, sand linearly. https://www.enginelabs.com/engine-te...ng-head-bolts/ when the washers slip you put more load on the stud for the same torque, it's possible to yield them doing this, so with yours pulled compare the lengths and if there's much variation you'll need new studs. I compared my yielded one and it was a few mm longer than a good one.

[alpinaseeone]

varg I remember reading this article a while back but was given conflicting advice from people with turbo M20's so decided to (perhaps naively) trust their opinion.

I'll measure all studs before reinstalling to see if they're any good!

Side note - The machine shop just called and the head was warped. He skimmed 6thou off the surface and hot tanked it. Will hopefully get some time over the next week or so to reassemble and try again!

[bangn]

I would say head/block surface issue or under torqued. 10psi is nothing, I ran 19-22 on a stock gasket and studs for while before the elring gasket eventually started to push, and even then it was a tiny bit nothing like that.

[MrBurgundy]

every slap it back together?

[digger]

You have to periodically retorque arps with composite gasket. To do this properly you need to back it off some not just turn until it clicks statically

[alpinaseeone]

every slap it back together?

Been so busy didn't get time to update the thread - Got the head skimmed and it was off by 6thou.
Pressure tested too and all okay although the PO had beat on the rocker shaft so much that it had to be milled at the end to clear the holes getting back in.

Now running an OEM gasket and measured all ARPs were within stretch spec for what I could find online. Sanded the washers using 80 grit and only applied lube between nut and head.
Motor seems to be holding well under new setup, although was having overboosting problems with the internal wastegate not actuating and accidentally saw 20psi for a couple of seconds when testing. Strangely enough, this ended up cooking the tired China turbo I got with the manifold from PO - I wonder why
Waiting for my Maxpeedingrods replacement now - will see how it holds up for sub $200, read somewhat good reviews online and am keen to try one for myself.

Hopefully once back together with turbo I can see how the HG holds up. Planning on keeping 15-16psi, running stock HG, ARP's, wasted spark and have bigger injectors + pump.


digger I've retorqued a few times (periodically) since first re-assembly but didn't know to back the nut off first. Is it as simple as just breaking the nut's torque back so it's not completely torqued and then without removing, just torquing back to spec? I'm also assuming it's good practice to follow torque sequence?

[digger]

Yes, one at a time following the sequence. Back it off so that you break the static friction then tighten in a continuous motion under dynamic friction