ARP Studs versus Head Bolts?
 

Not to start a debate but...

If given the choice between head bolts and ARP studs which would you install?
(without using the price argument... I know the ARPs will run an extra $70-80)
Think as if someone else was paying the invoice...

1. Ease of installation?
Which would be best for a do-it-yourself job?
2. Accuracy in torquing?
Seems studs would be more accurate at first glance.
3. Long term results?
Do either require a "re-torque" after a 1000 miles of replacing the head gaskets?

Any opinions on either...good or bad?
I imagine that a majority of us have used the stretch bolts from Atlantic British.

With all the block problems some people have, I like the idea of the studs.

However, arp's recommeded torque is too much. I've read people who recommend 60 ft/lbs in three equal steps (20-40-60). I think arp recommends 80 ft/lbs, which can apparently pull the studs out.

I havent run it yet, but I have re-installed the heads on an '04 4.6 with ARP studs using ARP ultra lube.

The specs for the old kit say 80lb/ft.

The new kit says 100 lb/ft.

The people who say spec torque is too much say 65lb/ft. I got them from Lucky8 (not sure which set he sells, but I think it is the old based on the price), who recommended torquing 20-40-80.

I compromised at 25-50-75, and it didnt seem close to overstressing anything. Torquing in this general range also seems very close to the stretch bolt procedure. My last 2 turns were right about 90*.

So before flex or stretch bolts were plain old ARP normal studs.

Why did Rover go to stretch bolts in the first place?
Must have been a good reason.

Well then read this:

The stretch bolt will automatically compensate and keep a degree of clamping force.
ARP stud will not.

Using the torque-angle method, the variations in bolt clamping force lie in a range of ±10%. Using the simple torquing method with several steps, the variations will be within ±30% of the calculated bolt clamping force. The reasons for this lie in the dispersion range of torque values and the overall coefficient of friction, i.e. the friction occurring under the bolt head and in the threads.

Cylinder-head Bolts - Dana

After trading emails with one of the engineers and trainers from boltscience.com I decided to stick with the bolts.

I have used the ARP on many HG jobs that I have done and will only use them now. I tend use a 3 torque sequnence and final torque I always torque to 70 lbs feet. I have used them both on 4.0 and 4.6 engines with out any problems and would rather trust to the ARP studs than stretch bolts.
Longevity has not been a problem either and I seem to get a more reliable torque over all the bolts including the shorter length ones.

Just did mine with the AB TTY bolts. Torqued 25-50-75-80. They started to yield at 75. At 80 the felt just right.

Land Rover head bolts suck, the clamping force is way to low. I have not used ARP studs on Land Rovers. BUT I can tell you that the aftermarket bolts Rovers north sell are the best. The way stretch bolts work is by only applying x amount of clamping force then stretching to keep the clamping force between all the bolts uniform. ARP studs are way stronger and are able to apply a greater clamping force and are also re-useable. But you really don't need them unless you are worried about lifting the heads under 30lbs of boost at 9k RPM - Go with the aftermarket stretch bolts.

By using ARP studs you eliminate the torsional pressure on the stud/bolt. by using studs which are already installed in the block when you tighten the nuts you are only putting clamping pressure on the studs, all of the torsional stress is relieved. Thus less likely to crack a bolt hole behind a liner.

This is why I would use them.