ARP Heads Studs - Power before you change to them?
 

Using these myself at the moment.

What power would you guys use these upto? Meaning the standard ones? 400bhp/400lb-s torque or?

Cheers
Jon

Make myself clearer what would you use the standard ARP Head Studs power upto?

It depends on how old your studs are. Although it's hard to confirm, it seems there are a couple different generations of ARP studs about.

I have several engines seeing over 500hp to the wheels using the latest versions with no problems. One person is Singapore is right at 700hp to the tires and still no problems.

Ron

Hello

How much Newtonmeter you tight the 190.000 PSi ARP Headstuds?

Same tightening procedure as original?

reg

Markus

when you say the latest version is there any way to tell which ones you have,brought a set of these from Mark A along with my stage 3 engine which came from you any way ,so hoping i have the latest stud kit
Ron could you explain the procedure you use when fitting these please :)
Gary

Do you actually need to have them at all?

Will they stop the head gasket from going? - or just delay the death.

Looks like I'm now going to be on my 3rd set of cylinder heads - means the last ones lasted about 15k miles............ Is there any way top stop them from cracking around the spark plugs at high boost!! - i.e no point in getting the bolts if the weak link is the cylinder heads - Unless people are putting Phase 1 heads and inlet manifolds on in place of the inferior phase 2 heads

Will find out for sure next week - if that is the case then I'll have to keep the boost down....... still should be ok I'd hope for at least 450-470bhp and 400lbs on a 2 litre

Steve,

Do you really need new heads? Given that I have done about 9000miles with your old ones, at 450+hp levels, I would question the need to replace so often.

Yes they are both cracked, but I have put them back on with the new block and they seem fine.

Paul

Well I think we know that Roger Clark were playing at silly buggers last time

This time though I think they have cracked - but will find out next week - if its just the head gasket I will be happy!

good luck steve :)

Steve its not a question of them having cracked or not ... they nearly all crack in that area, its a question of wether any crack is the cause of your overheating problem, could just as well be the head gasket.

When my engine was firest rebuilt the original heads were cracked there, I had no coolant problem but considered it prudent to replace the castings, that set lasted just about 30k miles b4 I had the coolant problem. How long the original cracked heads would have lasted is anyones bet though, risk analysis led me to replace knowing the new ones would crack but last longer than the originals at that. The set that are on now have been skimmed to ensure flatness and the plug thread interface with the combustion chamber radiused and de-fraized to minimise stress crack propogation, I'll let you know if it's worked in due time. I'm still running the same boost levels as I always have on it.

Bob

it does seem to be a problem with v5/6 heads. A few people are using v4 heads, but it requires and inlet manifold change, and then an idle control valve fix (ie use a non plug&play ECU). As such it's often not worth the trouble. I would like to look at new age heads as they seem okay, and will be a straight swap in terms of manifold fitment.

Paul

If you received your engine from Mark, then you have the latest version. They have been the same since middle of last year.

Fitting procedure I use is this:

Tighten in the factory sequence(bolt hole order) using 20ft lb increments. I always do about 2-3 rounds of torque at each value until I am satisfied that they are at the correct value. If you torque the first round to 20, then go back and check the center two, you will find that they will actually turn a bit until it reaches 20 again. Follow me?
Do the same for 40, 60, then finish off with 80ft lbs. I know the instructions say 72ft lbs, but that is not enough. You need to go to 80ft lbs. Leave sitting for about an hour or two, then come back and check final torque again.

Two things why I have seen ARP studs fail.
1. Studs are not fully seated into heads. There is a reason they put the allen key in the end. You need to use that to make sure the studs are bottomed out in the head. You don't need much, maybe 5ft lbs or so, but it needs to be somewhat tighter than just hand tight.
2. Heads are not resurfaced before install. Even brand new heads out of the box are not perfectly flat. If you machine the heads flat, torque the studs as instructed, and all surfaces are clean you should not have any problems.

Also, there is no need to torque the center two any tighter than outer 4 studs. I have never done it and see no reason why. For stretch bolts, yes I can see the logic as heat plays a big factor, but not with the ARP studs.

ROn

Thanks for the info Ron
Gary