Im getting ready to put heads back on my motor w/ ARP studs vs. bolts.

An older guy (lt1 corvette guru) has warned me about water jacket leaks up-thru-the-threads of ARP studs.

He says its not an issue so much with bolts because the bolt top provides an additional sealing surface in addition to the threads.

He claim's he's still had issues with leaks even when using ARP's special sealer on the threads.

In fact, he swears loc-tite PST 567 works much better for sealing heads studs vs. ARP's special sealer.

Have any of you had any issues with head-stud-leak-up when using ARP head studs?
id like to get any advice so I can avoid this pitfall.

 

Can I guess you are looking to swap from bolts to studs with just this topend work?

I would not use studs if the block was bored and hones with bolts. Bolts and studs distort the cylinders differently and the machining should be done with whatever fastener you intend to use at the torque value you intend to use.

Studs are harder to seal everyone has an idea of what works, some prefer specific brands of thread sealer, others actually prefer RTV.
I do not believe the reason bolts seal better is because of the bolt head, probably has something to do with more deformation of the threads in the block or something like that. If we relied on the heads of the bolts to seal rather than thread sealant then heads would be grooved for a small o-ring that would be compressed under the bolt head. I have seen some heads come off motors pretty chewed up at the head bolt holes due to using washerless bolts and they sealed just fine. Which brings up another reason that is just silly, with aluminum heads you really should use a washered head bolt, in which case how would that seal any better than a washered stud and if leakage through the top stud threads was the issue then you would use sealant on top stud threads.

I know that is rambling a bit, I was thinking it through more as I typed.

 

yes, you guessed pretty good.

Im about to switch from bolts to studs, but only because the guy that sold me the heads also threw in a complete ARP stud set as well. So I figure why not use it to bolt these heads to my stock bottom end.

Also, the gentleman who warned me about studs said the same thing you did. The tougher ARP threads dont distort/ bend?/ seal-the-hole? as well as the stock stuff.

In fact, he recommended I just find a stock bolt set for my 'modest' HP goals of app. 525 rwhp.

I hate the idea of paying money for stock bolts when I already have ARP studs, but Im on the fence that maybe thats what I should do..

 

I personally prefer Permatex's High Temp Thread sealer(not high performance).

http://www.permatex.com/products/Aut...ad_Sealant.htm

I've never had any problems using this stuff(water pump bolts and head bolts). However, I have never tried to seal studs. I expect it would work just fine. I know it's not always possible, but I recommend to let the sealant dry 24 hours before using the parts. I also make sure the parts are dry(except for the sealant of course) and are not going to be soaked in water until the sealant has set for 24 hours. Using these methods have served me well.

 

Yep. The ARP studs leaked on me when I first started up 7 years ago.

I didn't know about the sealing issues at the time, so I originally just used some high-temp non-hardening pipe thread sealant (non automotive brand I had laying around). It always worked well on the waterpump bolts, but it didn't work too well on the head studs -- think it was perhaps a little too thick for the tighter thread clearance, causing too much of it to be squished out of the threads upon installation of the stud. Eventually got them to stop leaking, but it was quite annoying.

Most here will recommend using Permatex thread sealant, which I'd recommend if you're going to use a non-hardening thread compound. Never tried it on the head studs, but it's good stuff, and some here have mentioned having good luck with it on studs. Be sure to chase the threads in the block with a thread chaser (NOT a thread tap) and clean it out with some brake parts cleaner / carb cleaner. When you install the studs, you don't torque the stud itself down -- tighten them finger tight, then back off like 1/4 turn.

Alternatively, my heads are currently off the car getting some work done (engine is out as well), so this time around, I'll be red-loctiting the studs to the block (torquing the heads down quickly after application to ensure proper thread contact). Not my idea -- someone posted the idea here years ago at the recommendation of their engine builder, and it entirely fixed the problem, as you're essentially fusing the studs to the block. Some say this will force you to remove the engine to pull the heads, others say it doesn't, but I don't mind either way. I'm more concerned about having a 100% fail-proof seal.

I wouldn't personally recommend using RTV, as a piece of it could theoretically break off and clog one of your steam pipes. If you go that route, don't go hog wild with the amount you use.

HTH

 

I used ARP studs with their teflon sealer which looked a lot like the pipe dope I always use. I put it on the threads and also qtipped some into the holes before turning them in. I also use the GM veggie tabs in the cooling system, and you don't get the hassle of steam and water leaks. The tabs don't seem to clog anything up or affect radiator performance.

 

I used the ARP studs at first with the sealant they suggested and they leaked on me but then I switched to their bolts and never had the issue.

 

I use Permatex with teflon...NEVER had a leak..It will work with studs or bolts..

 

I second that as well. I use them each time I empty the system(GM F-Body manual recommends it too).

 

what is a 'veggie-tab'?

BTW.. thanks guys you are really helping me out w/ your past experiences!

 

Click for big:



I assume Kevin was joking about how they look like big vegetable tablets (dietary supplements). Don't eat 'em though!


--

 

On the back of the package refers to a vegetable formula(ginger is one of the ingredients). I think that is what he is referring, but certainly don't consume for food.

 

Hmm, I didn't know that. Looks like they're made from ginger root, almond shells, turmeric, and vegetable oil byproducts as a binder. They literally are veggie tabs -- Kevin wasn't kidding.

But yeah, still don't eat 'em.

 

I bet those are real good for the heater core.

 

I was always to believe head bolts where torque to yield, that's why you would want new bolts when rebuilding. My guess is the studs are not torque to yield so there would be less distortion in the threads? (takes off engineering hat) RTV worked for me with studs on 2 builds... just my .02