arp head stud torque

Seight-V8 · Post by **Seight-V8** » Mon Aug 18, 2014 8:38 pm

hello all,

the sheet supplied with my 7/16" arp head studs says torque up to 80ft lbs.

is this ok to use or too much...as other posts say 65ft lbs...

cheers

scott

mgbv8 · Post by **mgbv8** » Mon Aug 18, 2014 10:18 pm

I use ARP lube between nuts and washers and 70 ft/lbs on my engines.

DEVONMAN · Post by **DEVONMAN** » Mon Aug 18, 2014 10:24 pm

My understanding of the ARP sheet is that for an aluminium engine the torque is 65 ft/lbs when using ARP moly assembly lubricant.
I have pulled 2 ARP studs out of the block in the past but now I extend the UNC threads by 1d before fitting. The studs are hard so a very good quality die is needed for this.

Regards Denis

mgbv8 · Post by **mgbv8** » Mon Aug 18, 2014 11:00 pm

I've never pulled a head stud. But on my new engine I have helicoils in the block to full depth just to be sure I never have a problem

DEVONMAN · Post by **DEVONMAN** » Tue Aug 19, 2014 7:00 pm

mgbv8 wrote:I've never pulled a head stud. But on my new engine I have helicoils in the block to full depth just to be sure I never have a problem

Hi Perry,
The longest helicoils I have found are 2.5d long. Did you manage to find some longer than this? (I think 2.5d would be adequate in any case.)

Regards Denis

mgbv8 · Post by **mgbv8** » Tue Aug 19, 2014 7:50 pm

DEVONMAN wrote:
mgbv8 wrote:I've never pulled a head stud. But on my new engine I have helicoils in the block to full depth just to be sure I never have a problem
Hi Perry,
The longest helicoils I have found are 2.5d long. Did you manage to find some longer than this? (I think 2.5d would be adequate in any case.)

Regards Denis

Thats what I meant Denis !!
I didnt explain myself properly. They were the longest coils in the it I had. Some of them were about 1 D long and the others were about 2.5d long.
If those buggers pull out I'll be in big trouble

Pel

DEVONMAN · Post by **DEVONMAN** » Mon Feb 02, 2015 7:15 pm

If you reads the link below, apparently ARP have said that the head studs are not meant for a modern Rover V8..
It relates to this thread but is it true?

http://forums.lr4x4.com/index.php?showtopic=72718

SimpleSimon · Post by **SimpleSimon** » Tue Feb 03, 2015 10:48 am

mgbv8 wrote:I use ARP lube between nuts and washers and 70 ft/lbs on my engines.

I reckon so, 65/70 is plenty considering when using the grease the clamping force is greater

its not like the RV8 has HG issues anyway apart from the old 14 bolters when using all 14 bolts

mgbv8 · Post by **mgbv8** » Tue Feb 03, 2015 9:20 pm

To add some confusion to this debate. When I last bolted my heads on I let my mate do one head. He was using the latest electronic Snap On wrench which has all the bells and whistles on it. When i got the wrench to do the passenger side head I checked it and found it set to 90 ft/lbs ??

He had been pressing some buttons while fiddling with the wrench which he didnt realise he was doing. I torqued up the other head to 70 ft/lbs and went racing. No pulled studs or HG leaks ??

Both heads have been off since then and both went back on at 70 ft/lbs with no problems. This was the last build just before I did the stupid wheelie and spun some bearings. Both heads came off 10 days ago and there is no evidence of leaky HG's.

DEVONMAN · Post by **DEVONMAN** » Tue Feb 03, 2015 11:35 pm

I think this debate is related to the standard UNC thread in the RV8 block.
I believe yours are heli coiled and therefore much more less lightly to pull given the greater outside thread diameter.

Regards Denis

mgbv8 · Post by **mgbv8** » Wed Feb 04, 2015 9:50 am

Yes mate!
This block is helicoiled but all the other blocks have not been. During the several years of testing I've pulled heads down to 85 ft/lbs with and without
sealant just to see how far I could go to stop the gasket blowing out of the side. I never pulled a thread on any of the 4.6 blocks. BUT I pulled a few threads on the early 3500's that we started with back in 2004. I think this was 3 different blocks and possibly 7 threads pulled between those blocks? All head bolt threads.