ARP Bolt Torque Settings

[jimbob]

Hi,

This might have been covered, but I've searched and never found a correct reply.

Ive a 3.9 EFI Disco, around 65,000K's ago i replaced the head gaskets, with composite ones, new cam etc. Now i've slight leak of coolant behind piston 7 near the bulkhead. I torqued all the nuts down to 70 NM was this correct, the studs i just nipped up, no torque applied.

Could i get away with away re-torque? if so what is the correct torque for RV8 ARP nuts on studs. I just don't want to go over board and strip the block.

Ive no worries if i have to replace, but wanted to know the correct torque value's.

Just pulled my old info from ARP it states 100 ft lb (135Nm) for the nuts with their own lube.

Cheers

James

[garrycol]

I torqued all the bolts down to 70 NM was this correct, the studs i just nipped up, no torque applied.

Sorry I am confused - so you used a mix of bolts and studs You should be using either all bolts or all studs.

The OEM bolts are one use stretch bolts and not torqued up as such but used a specific tightening sequence by using angles of degrees not torque. I cannot recall the sequence but it is in the engine rebuild handbook.

For ARP studs - the studs are lubed and go in basically finger tight. The nuts are then tightened in three torque steps - I have a 4.6 and it is three steps up to 100 ft lbs but many consider this is too high and I did mine to 80 - 30 in the first step, 60 in the second and 80 in the last - seems OK.

The instructions with your ARP studs should have the required torque.

See here http://arp-bolts.com/kits/ARPkit-detail ... ordID=4560

Specific instructions (actually if you have the right kit the same as the 4.6) http://arpinstructions.com/instructions/157-4301.pdf

Garry

[jimbob]

Sorry my typo, just fixed it.

Ok, that's whats in my kit, i hear so much about stripping threads. Just wanted the general opinion in all honesty.

At the back of the block is the main water way so i feel its weeping out of the composite, then running down the back, unless the manifold is leaking where it joins the heads.

[sidecar]

70 Nm is about 52 ftlbs which is not enough! I use ARP studs on my 4.6, I torqued them to 75 ftlbs, I use the proper ARP lube on the threads and the nuts and washers. (This was with comp gaskets). Even with the comp gaskets I ran a thin smear of silicon around the water and oil holes on both sides of the gasket

[garrycol]

Ok understand - I had the same issue as yourself about torque etc - and I did pull a stud out of the spot you have trouble with at 90 ft lbs but it was already damaged and had a helicoil in it. Some said 100 ft lbs was Ok others no.

So I had the hole repaired with a metal insert and went to 80 and all is good.

Also, I always put sealant around that water hole when doing head gaskets just as an extra precaution - it is a bit away from the combustion and the coolant moderates the heat so the sealant is an extra insurance against coolant leaks.

Hmm - my conversion indicates that 70nm is only about 52 ft lbs so that is way to low so that is maybe why you have the leak.

[DaveEFI]

The BL SD1 workshop manual gives 70 ft.lb as the torque for the 'main' bolts.
Perhaps that's where the confusion arose. 70 ft.lb or 95 Nm in that manual.

[sidecar]

The problem is that when you stray away from standard components then to a degree the manual goes out of the window! I torqued all the nuts up to 75 ftlbs because that was the device given to me by V8 Developments.

[unstable load]

I have found that a coating of Indian Head Shellac on the gasket/s before fitting has a very positive effect on stopping drips and weeping.
I cover the whole gasket surface except the fire rings with it, and it has served me well... even better than the copper gasket spray.

https://www.permatex.com/products/gaske ... -compound/

[bigaldart]

With ARP studs we have always used 70 ft/lbs and have had zero issues, this is with up to 20 lbs of boost and almost 12-1 compression so I doubt you need more than that on a street application. Of course the bottom row is only torqued to around 25 ft/lbs if you are using them.

Alan

[DaveEFI]

Do the studs stick with UNC threads at the nut end? If using a finer thread like UNF, the actual clamping force will be higher with the same torque setting.
And also less friction than a longer UNC thread into ally - as with the bolts.

My first Rover V8 factory manual - for a P6 - insisted you use ScotchClad thread sealer as a sealer/lubricant on the head bolts. This also prevented them corroding. So I still do. It is well worth it on the water pump bolts. Which will almost certainly shear without, some years down the line.

[sidecar]

Do the studs stick with UNC threads at the nut end? If using a finer thread like UNF, the actual clamping force will be higher with the same torque setting.
And also less friction than a longer UNC thread into ally - as with the bolts.

My first Rover V8 factory manual - for a P6 - insisted you use ScotchClad thread sealer as a sealer/lubricant on the head bolts. This also prevented them corroding. So I still do. It is well worth it on the water pump bolts. Which will almost certainly shear without, some years down the line.

Its a finer thread at the nut end, maybe UNF. You are right it does increase the clamping force whilst at the same time hopefully not pulling the ali thread out of the block due to the fact that that stud is already fully screwed into the block.

[jimbob]

Gents,

Thank you for the advice, greatly appreciated!

I'm going to give the RHD side bank a re-torque to the torque as indicated, to see if that gets me over the issue, until i have the time to overhaul both heads.

Same time, order in some composite gaskets, should i stick with LR OEM, or Victor Reniz, i know LR don't make much all sub-suppliers etc.

Also get some of that permatex shellac, i suppose it all helps!

[SimpleSimon]

Composite in Elring are OE fit but Reinz are still an OE quality supplier too, the Elrings are a known quantity however and cheap too about 30 squids a pair