The V8 Owners Forum -

This old chestnut again.

Im building a 3.5 rover v8. It is originally from an SD1 and had tin head gaskets and sd1 type standard bolts. I was advised to fit composite head gaskets and the heads were gas flowed and skimmed to suit. The sd1 manual said that the bolts can be reused, so that is what i am doing.

I have fitted one of the heads using the original bolts, but following the torque sequence as set out in the later land rover manuals for the composite head gaskets, that being 3 stages:

1) 20Nm
2) 90 degrees
3) then 90 degrees again.

One head is on, but this felt extremely tight and at one point i thought i was going to strip a thread.

Am doing this right? or were the composite gasket heads done with different bolts to the SD1 engines? And should i in fact be doing the standard sd1 tightening torques where it just gives a single torque value?

Any advice greatly appreciated!

I thought the 3 stage torque was only used for the stretch bolts. Older V8s using re-usable bolts were only torqued down to 70lb/ft.

Three stage is for stretch bolts which should not be reused,

So do you think I should remove and then retorque to Sd1 non stretch bolt torque or just leave them?

If using composite gaskets, I would get a new set of non-reusable stretch bolts and torque / angle tighten them accordingly.

You cannot use the old SD1 style bolts and torque / angle tighten them as if they were stretch bolts.

Chris.

I’m starting to think I should invest in some arp studs and nuts.

From my experience, if you managed to tighten non stretch bolts by the stretch bolt method you will have damaged the threads. Definitely check before next time.
It is very frustrating when tightening down a cylinder head for the thread to go. leaves a sickening feeling in the stomach as it all has to be stripped back down for helicoils..
I wish someone had told me this years ago!

All sorted now. Drilled out, helicoiled with a 3D helicoil. ARP studs fitted and head torqued up perfect.

Standard 1D (short) helicoil that comes with kit vs 3D (longer) helicoil

So the helicoils held? That was not my experience - mine just pulled out when the stud was torqued up. I had to go for a metal insert (what were used before helicoil - springs - were made). They worked really well where the helicoil did not.

Garry

garrycol wrote: ↑

Mon Jan 29, 2018 11:51 pm

So the helicoils held? That was not my experience - mine just pulled out when the stud was torqued up. I had to go for a metal insert (what were used before helicoil - springs - were made). They worked really well where the helicoil did not.

Garry

Yeah helicoil was fine. Not sure it would have done if I had just used the standard length helicoil. Found an interesting video on YouTube where they did back to back pull out and torque tests of different thread repair solutions and helicoil out performed some of the more expensive and complicatied methods including timeserts.