Thread: Headstud comparison

i popped headgaskets twice on my vet. the car was sitting at around 470whp at 24lbs. the first time i thought it was the cometic hg. but couldnt find anything that showed where it blew out. never did i think about what was really happening. the second time i used a stock 20V steel hg. it held but then it happened again. pulled the head and it appeared that nothing blew the gasket into a water passage. just there was water everywhere. after seeing matt's greddy bolts in person, i then realized on why the arp's are ****, and that under hard boost the head was actually lifting, that since the arp's only lockon to the first two threads in the block,... that when a great amount of psi is in the combustion chamber... those two threads give a little.... a little enough for the headgasket not to seal.

ill say it again. the arps are a ****ty disign. there is no in between..there is no right in saying ill use them since im staying under a level of horsepower. they were not engineered properly.

at this point ill take my chance with 1/2 inch head studs, or the old school...factory head bolts.

here is another expierence i have had to back up that they are designed wrong. when you install arp's they tell you to install them, but not at all to tighten them. this means that when you go to take them out (one of a few reasons)... they should just screw out. nope they dont. not at all. you damn near have to vice-grip them to get them out. why? becuase they are now locked onto the top few threads in the block, from tightening the nuts when the head was installed.

You're saying you've got a secret stash? Wish I had your number on speed dial. Phone was wiped.

Seriously the headstuds are different, I believe. Or did i have the wrong headstuds originally? The "new" design head studs are undercut and maybe 1.5 threads longer. Part #102-4701. Were any of you that have the old design ARP's undercut???? Here is ARP's take on undercut studs, "You will also note that ARP offers specially undercut studs for several engines. This procedure (done only to the shorter studs) more equalizes the "stretch" of both studs, which makes for a more consistent clamping force - and one that compensates for head gasket compression when the cylinder heads are installed. This helps prevent blown head gaskets, and assures optimum engine sealing!" Alright great but every stud I have of the new design is undercut.

So do any of you carrying the old studs, are they undercut?
My second issue is with the torque specifications: The paper that comes in the new box specifies that these are for the sr20det engine and should be torqued to 105 ft/lbs!!!!!!!!! Seriously?!?!? And the old ones list they should torqued to only 65-70ft/lbs..... That is a massive difference and 105 is a serious amount going into an aluminum block!!!! Does anyone have some insight????

screw ARP's! Im gonna try and return these and Im getting greddy head studs.......Im guessing my originals were wrong and the new ones are no different than the old ones anyways....And the greddy's are only $300.....don't care anymore and going with something good.......

$300?? where??

x 2...........^LINK^..........

http://phase2motorsports.stores.yahoo.net/grsrhestkit.html

335 there

It might have something to do with the lube. I remember something about it changing depending on if you used the stuff included or if you used a certain weight oil. I think that may be an issue a lot of people may have and not realized. There are too many variables to getting "proper torque", which takes in the fact that the ARPs studs turn some when the nuts get torqued.

A separate issue I think is the lack of threads and length. To show how just much less thread and bolt the ARPs have compared to OE (not very scientific but so everyone has an idea) Both were screwed into the block as much as possible with the same lube to show where they stop. The top one is OE bottom is old ARP
And Lance said the threads in the block don't run all the way down to the bottom of the hole only FEW catch :o

Always follow the directions that come on APR stubs. Every build that I have done we have followed this and have had no problem...not one!

Lance, how do you feel about the product from link #97? I have followed a lot of your SR work and you do AMAZING work. I would think that you would have good judgement along with the tast that you present.



^I know they worked great your car..........How is the design on the ones you used compared to the design used on our cars?