Re-torquing head bolts as preventative maintenance

[SOHCman]

The googles didn't bring much up unfortunately except don't mess with aluminum heads.

I have an old Allis tractor I am currently doing a valve tappet adjustment on and wondered if it may be a good idea to check the head bolt (most are bolts, but 4 are studs) since I have the valve cover and sheetmetal off the tractor to actually get at the bolts/studs.

This is a 60's all cast iron gasser that has probably never been opened up. My hypothesis is that slightly loosened or fatigued head bolts and the possible warped head could result in a blown head gasket, but retightening almost 60 years into service could prolong its life indefinitely if they had loosened.

Is this sound thinking, or could the old style gaskets eventually go out even with perfect clamping force?

Thank you.

 

[Srt20]

I would let sleeping dogs lie.

If it was 1 yr old, sure. 60? no way

 

[SwampSurvivor]

I wouldn't touch them. There's more potential to actually cause a head gasket / head issue by attempting to retorque the bolts.

 

[CT8]

Leave it be. I would guess rust is holding the bolts in.

 

[gathermewool]

Realistically, they're likely so tight, even if the studs have stretched or they initially backed-off a fraction of a flat, that your torque wrench would click right away, without any movement.

The problem, is that you're likely to inadvertently give it a little extra sumthin, causing problem, as Miller88 mentions.

 

[DuckRyder]

Originally Posted by Miller88
I wouldn't touch them. There's more potential to actually cause a head gasket / head issue by attempting to retorque the bolts.



AGREE!

 

[demarpaint]

Leave well enough alone!

 

[CR94]

Good question! I've wondered the same about engines in general, especially designs known for head gasket failures. Seems to me judicious retorquing couldn't hurt and might help, in case something is loosening, as long as one is careful to stay under the original torque specification. Maybe 80%?

 

[bdcardinal]

The only time I have heard of it was on a new build/rebuild to retorque after initial break-in. Kind of hard to do with torque to yield fasteners though.

 

[Lubener]

I have 1940 fORD 9N that has been in the family since 1961 and the head bolts have never been touched. I don't plan on touching them either.

 

[SOHCman]

Thank you for the advice! I think I will just leave it alone...

If I ever do need to touch the head I'll most likely re stud it with ARP studs along with the new gasket, etc. just for good measure. After a good chase, clean and oiling of the block threads that is...

Thanks again!

 

[ragtoplvr]

It probably has asbestos head gaskets. Leave them alone.Nothing you an buy today is anyway near as good. If this engine is cast bore, not sleeves, as things shifted over time, they wore smooth. You mess with them now and you may force a bore out of round, and then it will burn lots of oil. If it ain't broke.

 

[Mainia]

Leave it alone, why wake up Mike Murphy.

 

[Kira]

In the world of 4 cylinder car engines, how many actually had head bolt re-torquing mentioned in their owners/shop manuals?

I'm thinking very few.

 

[SOHCman]

This series had a wet sleeve engine, which I understand is fine for the Gas, but was problematic in diesel form.

 

[SOHCman]

Originally Posted by Kira
In the world of 4 cylinder car engines, how many actually had head bolt re-torquing mentioned in their owners/shop manuals?

I'm thinking very few.


In the manual for this one it states to re torque the head bolts (after a new gasket is installed) after the first run up to full temperature. The re-torque is done with the engine still hot.

 

[Donald]

I did this with my 1980 VW diesel Rabbit. Blew head gasket the next day.

 

[ragtoplvr]

And the composition head gaskets on my oilhead beemer motorcycle are to be re-torqued once, on that engine doing it over and over runs the risk of pulling a stud out of the block.

Rod

 

[mattd]

Originally Posted by SOHCman
This series had a wet sleeve engine, which I understand is fine for the Gas, but was problematic in diesel form.


Just about all heavy duty diesel applications are wet sleeve engines. The liners are removable with o rings that seal the water jackets around them.

 

[DriveHard]

Aren't there engine designs where you have to add sealant to the head bolt threads to keep the coolant out of the oil (SBC)? Wouldn't trying to re-torque a design like this cause them to leak?