Evening all, long term lurker here...

I know there is a lot of conjecture about this and I've searched the forum without finding the specific answer I'm looking for.

Long story short I have a colleague who has a newly built engine which has experienced head lift despite a low boost tune and reliable fuelling. The suspicion is the head-studs. He wants to rebuild the motor with an aftermarket stud but doesn't want another full engine strip down to machine the cases to accept bigger studs. Therefore he's stuck with 10mm studs as his only option.

Without getting drawn into the whys and wherefore's of why the heads lifted, does the collective have an opinion on which 10mm stud is best and why?

Searching the www shows up a few possibilities - Racewear, ARP and EVOMS. Are there any others?

Anyone got any definite experience with any of these and care to give a recommendation please?

Cheers!

 

For 10mm the Evoms are the strongest. I run ARP 2000's in 12mm. Some say the 10mm studs need a re torque after heat cycling but I think you can do without as long as you use an angle torque install method.

 

Thats really interesting dude, many thanks. Do you happen to have the angle torque specs, or are they as prescribed by EVOMS?

I know the OE studs are torqued up in stages to about 15/20ft lbs and then a 120 degree swing.

Reading the Sharkwerks site for the same studs seems to hint at a few different torque settings depending on yield but they don't specify exactly.

 

I don't have specs. I developed my own specs for my install. Here is how I did it:


If you know they need to be 80 ft lb torqued down, then you torque the studs down in stages to 60 ft lb or so. Loosen them up a bit and then do it again to 60 ft lb. Then torque one stud down to 80, and measure the degree angle you used to get there from 60. Then use that same angle on all the other studs. The important thing is that all the studs are stretched the same. The studs are able to better distribute the load across the parts if they are all even, making the whole setup stronger. The problem with the torque wrench is that at higher torques it starts to lose accuracy because of differences in the threads or nut surface and whatever else. You can use the torque wrench accurately up to a point though, that's why angle methods use it but then switch to the angle for the very high torque.

 

Great, thanks! I read your build thread - impressive work indeed!!

One thing that I'm curious about with the EVOMS 'hellfire' gaskets - are they proprietary or are they rebranded Cometic ones? They look identical in design and description...

 

They are the same head gasket. They are also a little bit thicker than the stock piece so you lose a slight amount of compression. The stock head gasket is excellent quality so the Cometic isn't really an upgrade. They are both good. I used the Cometic from SRM (best price) because it has larger holes for the 12mm studs. Otherwise I probably would have just used a stock set.

 

Such a pain to re-tourqe. I've seen systems to heat cycle while on a stand, wonder if someone has used them here in our application.

 

 

Care to share your install method?

 

Sounds like I'll be recommending the evoms studs to him then!
Whats the deal with O-ringing, are there rings you can just drop in without having to machine the heads? If so where do you source them?

 

You won't need O ringing unless you are doing a really insane build, in which case you should go to 12mm. You have to groove the heads for the O ring.

 

So some movement on this - We contacted EVOMS and they no longer make their own studs. Instead the studs used in the engine builds are now Raceware...

Anyone have any experience with these, most importantly do they need a re-torque? If so then that would be a disaster...

 

The racewears are decent. They are better than stock. They have held on some big builds and have also failed. I wouldn't run them past 800 hp wheel but you can try your luck. Most have gone to 12mm, it is the end all solution. Proto, Bray, and SRM big builds are all 12mm.

I saw the Evoms available on Amazon. Maybe try that.

 

A1 technology makes the evoms studs, check into that.

 

Cheers brnrdtns, I've had a look and it appears that A1 are no longer in business? Their FB page hasn't been updated since 2013 and their website is no longer active.

Its all getting frustrating now because there doesn't appear to be a stud which doesn't require a re-torque unless you go 12mm which my guy doesn't want to do. The EVOMS solution appeared to be the best but they have split with their manufacturing arm and now just use the Raceware studs.

He's currently waiting for EVOMS to contact to inform whether they will be ok without a re-torque.

Looking around another thread on here, there's a guy running a lovely yellow 996 turbo and it appears that there was no re-torquing with his Raceware studs.. Fingers crossed.