Outer Limits 4x4 Board

Just finished putting the head back on my TD42 with genuine gasket, new bolts etc.

Checked the manuals (OEM and Gregory's) and no mention of re-torqueing the head after the first run etc.

Is there any need to re-torque or is the initial torque procedure just fine and dandy?

depending on the boost your running and other mods to the engine, i always re-torque after the head gasket has settled, usually back off and re-tighten to spec or for modified "1 flat" extra.

good luck

the head bolts are a torque to yield ie used them once and then bin them so no you don't need to re torque them
steve

Hate to disagree Steve but you should always retorque. The head expands more than the bolts so the gasket becomes more crushed when the engine is heated and cooled. Torque to standard specs one bolt at a time from the middle working out in the correct order making sure to fully loosen each bolt first. I mark each bolt with a white texta against the casting to check the amount of additional bolt rotation.
Torque to yeild bolts can be reused if you have the luxury of a bolt stretch gauge, torque to yeild bolts have a maximum lenght as a general rule.

Cheers

Joel

Thanks for the replies.
In the case of the TD42 what would be a time / kms to retorque?

1/2 a dozen warm up cycyles is sufficient. I have also retorqued heads on vehicles that have been overheated and often before installing turbo kits. I have even saved the odd engine where loose heads have been lifting and pressure gets into the cooling system without removing the heads, it will work if you get onto it quickly before the gasket becomes damaged.

Joel

Nice info, thanks.
Coincidentally the reason I just did the head was a previous owner had done the head not long back and half the head bolts were loose ( mainly around the cylinders). It was blowing into the water jacket on no.5, but sealing enough to not let water into the sump.
Lucky I pulled the head though as it was warped considerably and the gasket wasnt looking too good

Thanks again

An unfortunate problem is that some engine machinists cut to quickly causing less than flat surfacing, the same goes with the block deck. Some surfacers are better in design than others too.

Joel

Interesting, i never thought about it that way.
I guess a long skinny head would tend to be more susceptible than a shorter one too.
Might explain some of the reason why mine was like a banana (up at the ends - looking from the top)

Clanky wrote:Interesting, i never thought about it that way.
I guess a long skinny head would tend to be more susceptible than a shorter one too.
Might explain some of the reason why mine was like a banana (up at the ends - looking from the top)

Yes and alloy expands at a different rate to steel.

PGS 4WD wrote:Hate to disagree Steve but you should always retorque. The head expands more than the bolts so the gasket becomes more crushed when the engine is heated and cooled. Torque to standard specs one bolt at a time from the middle working out in the correct order making sure to fully loosen each bolt first. I mark each bolt with a white texta against the casting to check the amount of additional bolt rotation.
Torque to yeild bolts can be reused if you have the luxury of a bolt stretch gauge, torque to yeild bolts have a maximum lenght as a general rule.

Cheers

Joel

Joel,

do you recomend using factory head bolts for hi power td42t's or would aftermarket head bolts be fine?

Cheers