Head torque procedure

[Bandit1200]

I have read and understood the manuals and watched the Rimmer's video on how to replace a head gasket.

To me the act of tightening the first head nut to 55ftlbf seems brutal and I'm considering 2 or 3 passes at the torqueing down procedure.

What advice would you give on this and how many passes would you recommend/or not?

Thanks in advance.

Steve

[flying farmer]

I always start with a light hand torque (wrench doesn't start till 40lbft), then again at 40, 50 and 55lbft.
I have never known anything come to harm by gentle torqueing, but I have seen a few things buggered by whacking the first nut tight before doing the rest!

Neil

[Motorsport Micky]

I've not seen the Rimmers Video but are you sure that's what it says ? If so that's an excellent way to "ripple "a headgasket or contort a head !
I always tighten it in 3 passes, you can apply the amounts of torque you want, you obviously end up with the final figures being at what you decide is correct (in my case Studs 65, long set bolts 55, short set bolts 35), but it's the act of applying the torque evenly and smoothly in increments that helps give you the correct headgasket seal.

Micky

[davidf]

I always do mine progressively in a number of passes. I can't remember what figures but I think something like hand tight then 30 ft-lb then 40, then 55 then round again at 55.

[mole42]

Yep, tighten the studs and bolts progressively.
And tighten 'em again after 500, 1000 and 1500 miles.

[GDPR]

I do the 55 torque at least 3 times in sequence, slackening 1/8 turn each time. You would be surprised the difference on angular movement when comparing first and last

[davidf]

Yep, tighten the studs and bolts progressively.
And tighten 'em again after 500, 1000 and 1500 miles.

And at least once every year for ever after!

[GDPR]

And at least once every year for ever after!

Why? Haven't touched mine in the nine plus years I've had it...

[davidf]

Why? Haven't touched mine in the nine plus years I've had it...

I always used to check mine regularly, and it would always take up a little on one or two studs or bolts. Then it got left for about 7 or 8 years.
Then I had a HGF, annoyingly, while on holiday in France with the caravan. Not a massive failure, but pressurising the water and ejecting some. After recovery home, when I went to strip it, the bolts and studs were nowhere near 55; in fact, the ones at the rear of the left head were barely hand tight. At first, I could not see where the HG was damaged, but on closer inspection, I could see a stain from one cylinder to the adjacent water jacket. And guess where it was stained - left hand head, at the rear, where the bolts and studs were loose.
So, now, I am back to my annual check.
I don't know whether the gaskets compress, or the bolts/studs stretch, or whether they simply work loose with heat and vibration, but there are always a few that take up a little slack.

[KOY 23]

Why? Haven't touched mine in the nine plus years I've had it...

Russ.
I love your Avatar.

[len]

I was told by a respected stag specialist to torque my heads to 65lb...I didn't ...I stuck to the 55lb........65lb just seemed too much to me...
Len

[Motorsport Micky]

I was told by a respected stag specialist to torque my heads to 65lb...I didn't ...I stuck to the 55lb........65lb just seemed too much to me...
Len

That's it then Les, you've decided you know better than "a respected Stag specialist" who's done dozens of these engines and earns a living out of standing by his work.
Who knows ? maybe "it seemed too much to me" expressed as a gut feeling is correct, it's your car and decision.

Micky

[len]

i didnt say i knew better than a specialist ....i just said what one told me.....yes 65lb does seem too much to me and i also said that to the specialist.....sorry for mentioning it
Len

[davidf]

Another anecdote - I built my new engine in 1984, and, having had a HGF on the old engine, and knowing the Snag's reputation for HGF, I thought a bit of extra welly on the bolts/studs might be a good idea, and took them up to 65. All seemed Ok, but when I stripped it 8 years (and 40,000 miles) later, I found that on one cylinder, the reinforcing ring of the gasket had been squeezed into the combustion chamber at one point, and had slightly marked the piston crown. There was an area of corrosion (erosion?) on the cylinder head face where the combustion products had got behind the ring.
So, since then, always use 55 ft-lb.

[Motorsport Micky]

Thats why I only use 65 on the studs, they stretch more than the long set bolts whichI set at 55, and the short set bolts are at 35. Because they stretch even less.

Micky