Cylinder Head Torques

[gppj25]

Have changed cylinder head gasket 150miles ago - all good no problems. Do you recommend a re-torquing of the head after a few miles, or leave it all be?

Thank you for any comments.

gppj25

[ian-s]

Definitely retorque it ,but make sure to do it when the engine is cold , and check the tappets afterwards.

[KirstMin]

IF you buy a reconditioned A-series engine from an engine builder you will see a big sticker on the head saying: "Torque this head after initial run-up to temprature, DO NOT re-torque after that"

Its because gaskets are no longer asbestos based. Make of this what you will but dont always do what the manual says.

Mine? I did what the engine builder said and have been going just fine for 10,000 miles

[bmcecosse]

Clamp it down after 500 miles !!

[KirstMin]

Clamp it down after 500 miles !!

Other than repeating what is in the manual, do you actually have any solid reason for saying this other than its what you have said for 40 years ?

I re-iterate, when you buy a fully worked engine from a mini tuning specialist - charles ware as well i believe - there is a bl00dy great sticker on the head saying DONT re-torque after 500 miles. Now I wonder why that might be?

[bmcecosse]

Charles Ware !!!!!!!!!!!!!!!!!
I have loads of experience with very fancy A series engines (including 8 port ) - my view is clamp it down after 500 miles. But hey - it's up to each to do their own thing!

[alex_holden]

I don't see how re-torqueing after 500 miles could do any harm, even if it isn't strictly necessary with modern head gaskets.

[Onne]

One thing on the side, modern headgaskets are mentioned. I have always found copper headgaskets on my A (and USHM2) engines, is there asbestos involved in those as well?

[bmcecosse]

There used to be - in a sandwich between the metal layers be they copper or otherwise.

[KirstMin]

apparently it was this layer of asbestos that was the reason why you had to re-torque. Still, unless someone can give a good reason why not to re-torque then I dont suppose it matters if you do! I would be interested to know if there was a reason not too though - otherwsie i dont know why engine builders would bother to tell you not to? if you get my drift?

[minor_hickup]

I know on modrn engines the 'head stretch' bolts that run through the block do not reuire any more than the initial torque. However when I bought a head gasket a few months ago the old boy at the motor factors stressed it will need re torquing after warming and after 500 miles.

[simmitc]

When I bought I fully remanufactured engine last year it came with the instructions that the head MUST be retorqued after 500 miles - which is what I've been doing for 25 years. I last chnaged a head gasket 5 days ago; and have always found that after 500 miles at least a couple of nuts will need a slight tweak, and at least a couple won't need touching. Modern engines may be different but with the good old A-series, then definitely torgque down (a) immediately after initial warm up and (b) after 500 miles. In both cases, done whilst the engine is hot. IF your newly supplied engine says DO NOT torque then follow their advice, but question it first.

[bmcecosse]

I suspect the 'engine suppliers' don't want ham fisted amateurs messing with the head nuts - perhaps applying wrong torque to the rocker pedestal studs etc, and so they may very well have 'overtorqued' the head and then set the valve gaps to suit - and prefer it to be left like that.

[crossword]

This may be a bit simplistic , but if you try to tighten the head bolts after 500 miles running & it is not needed , the torque wrench will 'click ' immediately. If this does not happen, re-torquing was needed . Justbe sure you have a reasonable quality torque wrench , correctly set & use the correct sequence .

[aupickup]

do we re torque with engine hot or cold

[simmitc]

Hot (closest smiley I could find) but then let it cool so that you reset tappet clearances with engine cold.