Gen3 LS1 head bolt threads in block pulling

[VX L67 Getrag]

Howdy all,

As the topic suggests I went to go pull a head down on a LS1 it started pulling some of the threads on the first 90degree torque down, let alone the 2nd lot of 90 degs it's supposed to get too!

There's 3 in 1 area & another not far away from them but thinking if 4 on 1 bank are doing it there all going to need some sort of helicoil, but not sure if that's even going to be strong enough or if there's a better not too expensive option.

I'm guessing stud kit could be an option but don't really want to go to that much trouble.

If anyone's had a similar experience or any ideas that would be great!

[HQ355]

Not knowing the cause of your problem is a bit hard but helicoils are stronger than original alloy threads in block. In saying that though from memory the LS head bolts are some strange thread like 11mm with 1mm pitch ? Can u get a helicoil in that size ?

[Gareth]

Yeah, been there on the last LS I built, ended up using a purpose made kit to replace the threads with like a nut sert, I think it's call thread sert? Anyway, still have the kit with some inserts left, pm me if your keen.

[vs ss]

Yep I use time serts.

[VX L67 Getrag]

The car was actually driving fine, but was loosing water out of the side of the head & getting worse over the last year (my brothers car).

Eventually got that bad you couldn't drive more than 30mins without it loosing water & getting hot, so I said I'd take a look & actually drove it into the workshop myself (over 40 minute drive) which it barely went too far over 1/4 on temp gauge.

Anyway it all came apart fine but as soon as I went to do new bolts up the thread just started falling apart without tension!

But yeah the thread pitch is 2.0 so really wide & the book said 11mm for diameter when looking at tension settings, which I thought was weird & thought they would have been 12.

I would take you up on your threadsert set Biggvl but I'm guessing I'll end up needing more than what you have left in your set.

[vlad01]

Yep I use time serts.

I reckon this is the only proper way to do it. They should come with inserts from factory.

[immortality]

From a manufacturers point of view where the bolt will only be fitted and tensioned once it would just be an added expense to use thread serts for every thread in an alloy block. How many engines are rebuilt rather than scrapped at the end of there service lives? A decent quality alloy should hold a thread well enough.

[Jayme]

what was the first torque that your book said?
xx nm, then 90 deg, then another 90 deg?

[VX L67 Getrag]

Yeah I'll have to look into thread serts fleebay didn't show them in Aus!

Book said 40nm then 90 & another 90!

Edit; that's from memory first stage could have been 30nm just thinking again?

[Gareth]

I would take you up on your threadsert set Biggvl but I'm guessing I'll end up needing more than what you have left in your set.

I recon that theres enough left to do one side of the motor, they can be brought seperate from the installation kit, the high cost comes from the kit to install, the time serts are worth very little on their own.