My inlinePro studs lost torque, blew headgasket (L19)
 

So I have the inlinepro version of the L19s, just bought and ran the car maybe 8 times since and after a cold ass night I let my car cool down and when I started driving again I was pushing coolant just idling/cruising. Took off the cams to check the torque on the head studs and only 3 of them were at the recommended torque (85 ft/lbs), the rest all had some give before they got back to 85, a few even turned a full quarter turn or more. I used ARP Ultra lube and did everything to spec, 30, 60, 85. All in sequence. Are these supposed to be retorqued after a few heat cycles? Got them new. I retorqued back to 85 and stopped blowing coolant at idle/partial throttle but in high boost it is. So I know whatever damage was done is not gonna go away with a retorque but just wanna see if anyone else had this happen? I've had the head shaved the last time it was off as well as new o rings/gasket and did the inline pro studs. Timing was also pulled from my tune since last time we suspected my timing was an issue. Defeated at this point :(

If I remember correctly, FB L19 studs get torqued to 100 or 110 lbft. Wonder if the IP L19's are also supposed to be torqued there and they were just under torqued at 85?

Bingo, 100 ft lbs

95ft/lbs for “race” applications as per inline pro. I assume that goes for all boosted applications.

After they figured out, when going past 85ft distorts the block, and causes more issues, they came out with the M12 studs, and no longer mess with L19s. M12s, which are torqued to 85ft, so there's no more distorting. Also can reuse them again and again. And cheaper lol

"Our F20/22C M-series M12 Extreme Duty head studs are made from a JIS super alloy with high nickel content. We developed these to replace the L19 and H11 head studs which retailed for $549. These are not prone to hydrogen embrittlement like the L19/H11. Also, it can be handled and used over and over without worrying about failures. It's currently being used in the fastest and highest horsepower S2000 in the world. It handles up to 80 pounds of boost making 1800-2000hp. We used a true beam design all the way through the stud (it's not necked down like others) and you get a very positive feel when it's torqued."

Id hit up john and make sure they still want you to torque the L19s to 100ft. OR just get some M12s :D

I'm running the M12 studs, i switched from ARP because I have been going through headgasket woes for some time now due to various reasons and i thought maybe it was the studs.

Well today I finally pulled the head again and noticed the blown area is exactly where it blew last time when I had the ARP as well so this is unrelated to studs although i'm not sure if the loosening contributed or not to a possible imperfection in the head/block.

Situation that happened was I bought the inline pro block used, one of the studs was completely stripped in the block and the threads of the block had to be redone, new headgasket, head resurfaced etc. i blew another headgasket shortly after because I was an idiot and didn't replace the copper o-rings on the block. Re-did everything again minus resurfacing since it was just resurfaced. About 500 miles down the road i blew another headgasket, it was on the 2nd cylinder intake side, figured it was due to timing or o ring installation error, replaced the gasket with new, redid o rings, lowered timing and even installed the M12 studs, and that's where I am at present. Blown on the 2nd cylinder, intake side as before but also the area with the blown gasket material seems to be worse on the block side of the gasket, not sure if that has any value or not. I've also become aware that the surface area of my head when it was resurfaced the first time is an extremely rough RA for a MLS gasket (can see/feel the lines of the milling).

My next plan of action is take the head back to a machine shop and have them check for straightness as well as re-deck with a much smoother surface and also get the block looked at for straightness as well but I really don't want to get the block resurfaced as that calls for removing the o-rings or re-doing them and re-assembling the entire engine but if push comes to shove..

Appreciate the replies. I think i'm going to try 90 ft/lbs on the M12's once I get everything squared and re-check after a heat cycle.

Are the IP studs L19 or M12? I haven't heard anything on the L19 studs warping things or having any issues before.

They're M12 studs.

Which head gasket was used? What machining was done to the head and block surfaces? What prep was done to the head and block surfaces? What torque wrench was used and when was it calibrated?