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-   -   What did you Torque your ARP Head Studs to? (https://www.miataturbo.net/engine-performance-56/what-did-you-torque-your-arp-head-studs-84119/)

patsmx5 04-27-2015 07:02 PM

What did you Torque your ARP Head Studs to?
 
I've read the threads here about them, seems some are going with 48, 50, 55, 60, 65, 70, some follow the directions and go to 80....

What are you running? What is best?

I believe I just lifted the head with stock bolts at 60. I'm thinking put the ARPs in and go to 60 maybe 65. What works best?

albertogti117 04-27-2015 10:30 PM

Curious as well. I just torqued my ARP's to 65 based on previous threads (Savington said he torques his to 65 iirc). My motor is not in my car yet so I can't comment on if it works well or not.

Chooofoojoo 04-27-2015 10:42 PM

Quote:

Originally Posted by Savington (Post 1158317)
Not as curious as you might think. IIRC it was FM who worked with ARP to get those studs made. Their original torque spec was 49ft.lbs, which matched the factory clamp load. When I bought my first set in 2009, the instructions said 65ft.lbs, so that's what I did. I installed several sets at that setting before looking at a fresh set of instructions somewhere around 2011-2012, and to my surprise they said 80ft.lbs. A little forum reading turned up Bob's experiences with cracked heads at 80ft.lbs. Clearly, the engineer at ARP who said 49 is no longer there, and ARP doesn't care enough to put thought into their specs beyond "X diameter + Y thread pitch = Z torque".

I torque ARP studs to 65ft.lbs.

As it be said, as it be done.

Edit : Here's the thread with all the info : ARP Hear Stud Question [sic]

Stealth97 04-27-2015 10:42 PM

Just bolted my head on, I believe I went with 55. Maybee two miles on it so far so don't take my word for it..

nitrodann 04-27-2015 11:28 PM

65

guttedmiata 04-28-2015 09:34 PM

Went 80 the first time. No issues. Chickened out the second time and went 65.

18psi 04-29-2015 09:59 AM

65 here too. no issues

curly 04-29-2015 11:28 AM

There's another sheet in the ARP box that says 60ft/lbs for 10mm IIRC, I went with that. In fact I torque rods, mains, and head studs all to 60ft/lbs.

patsmx5 05-07-2015 02:19 PM

Well thank you guys, looks like 65 seems fairly well accepted. I'll use that.

jmann 05-08-2015 07:42 PM

I torgue mine to 65# also, but I use the OEM washers. I was working with Bob on his engine when the issue happened and we thought the smaller OD washers from ARP was also a contributing factor.

patsmx5 05-08-2015 09:07 PM

Yeap I will definitely use the OEM washers as they are larger than the ones supplied by ARP. I'm also gonna check if I can stack the ARP washers on top of the OEM washer, if that appears any better.

jmann 05-08-2015 10:07 PM

I don't see any reason why you couldn't, but I don't think it is necessary, anyway I haven't.

Joe Perez 05-09-2015 12:10 PM

Quote:

Originally Posted by jmann (Post 1229956)
. I was working with Bob on his engine when the issue happened and we thought the smaller OD washers from ARP was also a contributing factor.

Which issue was this?

olderguy 05-09-2015 12:16 PM

80 psi will dig the ARP washers into the head. Go with 60~65

jmann 05-09-2015 01:13 PM

The issue was that the washers were sucked down into the head and cracked it. I wouldn't use the ARP ones even at 65#.

curly 05-09-2015 01:27 PM

I've done 4 sets now at 60 lbs, no issues so far. Arp washers with their lube on both sides.

patsmx5 05-09-2015 03:46 PM

Question for you guys. If you use the ARPs with their supplied lube, and torque to 60 ft*lbs, how much additional clamping force would you get over using the factory bolts with regular motor oil?

My guess is you probably gain 4-5% from having finer threads, then you probably gain quite a bit from using the low friction lube, my guess would be 20% or more for the same torque. Also the advantage of studs vs bolts, I'm guessing you're looking at probably 25-30% more "clamp force" for the same torque when you add it all up. What do you guys think?

Joe Perez 05-09-2015 06:16 PM

Quote:

Originally Posted by jmann (Post 1230050)
The issue was that the washers were sucked down into the head and cracked it. I wouldn't use the ARP ones even at 65#.

Interesting.

When I changed the head gasket on my '92, I used ARP studs with their lube torqued to their spec, and I'm pretty sure I used their washers.

Never heard of this problem before.

Savington 05-10-2015 11:18 AM

I've lost count of the number of heads I've put on engines with ARP studs and washers at 65ft.lb. No issues

dc2696 05-10-2015 11:29 AM

Quote:

Originally Posted by jmann (Post 1230050)
The issue was that the washers were sucked down into the head and cracked it. I wouldn't use the ARP ones even at 65#.

I've done a couple heads with ARP washers and never seen that happen, seems likely that it might have been an over-torque situation no?


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