Head bolt retorque - warm or cold?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Godwin

Godwin

Resident Herpetologist
SILVER Star
10 Year 15 Year 20 Year
Joined
Dec 4, 2004
Threads
378
Messages
7,777
Location
Alabama
Situation is that I have a freshly rebuilt 2f that's gone through a few heating and cooling cycles and a recheck of the valves would be a good idea. So I warm up the engine to do the valve check. Now after the valves I dedicide to retorque the head bolts, does it matter if the engine is warm or cold?
 
Just as you want to set valves while the engine is at operating temp, so it goes for retorquing the head bolts. Usually, it isn't necessary to retorque until 15K to 20K miles later.
 
Godwin said:
Situation is that I have a freshly rebuilt 2f that's gone through a few heating and cooling cycles and a recheck of the valves would be a good idea. So I warm up the engine to do the valve check. Now after the valves I dedicide to retorque the head bolts, does it matter if the engine is warm or cold?
Click to expand...

I know this is a somewhat dead post, but I thought it would be nice to set straight the miss information that was given.

Head bolts should NEVER be torqued warm/hot! They should be done stone cold.;)
 
Pighead said:
Hmmmm...why?
Click to expand...

Easy to tweak the bolts and under torque the head. I've heard more than once about broken bolts when torque hot. Plus, some of the best machine shops I know of all state cold! as in first thing in the morning.;)
 
Yet, one of the best LandCruiser mechanics says (said) do them warm, before adjusting valves, which I have always done because I take the rocker shaft off to get to the middle bolt...
 
Pighead said:
Yet, one of the best LandCruiser mechanics says (said) do them warm, before adjusting valves, which I have always done because I take the rocker shaft off to get to the middle bolt...
Click to expand...

Do what you want! Machinist know more than mechanics, and every machinist I've ever asked, always stated cold.

I would think it makes less of a difference on our cast iron/cast iron engines.

Next time your at a machine shop, ask them.

Also, I've done well over 100 heads over the last 30 years and never had one come back.
 
Way to revive an old thread.

As recommended by Jim C. I retorqued the head bolts while the engine was warm. That's been about 100k miles ago and have had no head/head gasket issues.

Just out of curiosity how many of the >100 heads you've done were 2Fs?
 
I seriously doubt that it makes a lot of difference. But I have to disagree with the comment that machinist know more than mechanics. Really? Perhaps about... well... machine work? But I am pretty sure than non of the machinists in town here have as broad a background in overall vehicle repairs as any of the comparably skilled and experieneced mechanics do.

And simply being called a "Machinist" does not mean anything about a persons abilities or experience.

I am sure that Jim can also say that he has done 100s of head and not had any come back in the last 30 years. for that matter so can I.


While I am here... Steve's comment about not needing retorque until 15K or more is not accurate. Cruiser heads need to be checked after a few warm up/cool down cycles.


Mark...
 
Godwin said:
Way to revive an old thread.

As recommended by Jim C. I retorqued the head bolts while the engine was warm. That's been about 100k miles ago and have had no head/head gasket issues.

Just out of curiosity how many of the >100 heads you've done were 2Fs?
Click to expand...

zero!:D
 
Mark W said:
I seriously doubt that it makes a lot of difference. But I have to disagree with the comment that machinist know more than mechanics. Really? Perhaps about... well... machine work? But I am pretty sure than non of the machinists in town here have as broad a background in overall vehicle repairs as any of the comparably skilled and experieneced mechanics do.

And simply being called a "Machinist" does not mean anything about a persons abilities or experience.

I am sure that Jim can also say that he has done 100s of head and not had any come back in the last 30 years. for that matter so can I.


While I am here... Steve's comment about not needing retorque until 15K or more is not accurate. Cruiser heads need to be checked after a few warm up/cool down cycles.


Mark...
Click to expand...

I was speaking in general terms, as in all things being equal, a mechanic is (for the most part) someone that works on cars, and nothing in the way of training is mandatory. A Machinist will often require in excess of 3 years training.
A good machinist could build an engine from scratch, as a mechanic could only assemble the engine. I should know, as I'm a mechanic that works hand in hand with machinist at a local refinery.:)
 
I'm with "Head bolts should NEVER be torqued warm/hot! They should be done stone cold".
Because , for the Engines that did require re-torquing , they were retorqued as they were assembled COLD. From many engine manufacturers manuals.
Now TTY (Torque to yield ) bolts are only to be torqued once by the manufacturers manuals.

Any overheating normally kills the head bolts strength. Measuring bolt length cold of all bolts , reuse them , and now measure them again , you will find that they have grown , and will "NECK" causing a second head gasket failure and head warp-age.

Some head bolts are special cut / made and can be reused , others ask for replacement.

On re-torques that I have done , same order as the original sequence , But remove bolt , clean hole well , light lube , and back to the set torque, next bolt and hole, If your not going to clean the threads , and the lube , your not going to get an acurate crush / torque. You must undo a bolt to do a retorque.
Just re-tighting it is false also , and one sweep up to the torque.

VT
 
Are we still talking about 2Fs here?



VTCDN said:
I'm with "Head bolts should NEVER be torqued warm/hot! They should be done stone cold".
Because , for the Engines that did require re-torquing , they were retorqued as they were assembled COLD. From many engine manufacturers manuals.
Now TTY (Torque to yield ) bolts are only to be torqued once by the manufacturers manuals.

Any overheating normally kills the head bolts strength. Measuring bolt length cold of all bolts , reuse them , and now measure them again , you will find that they have grown , and will "NECK" causing a second head gasket failure and head warp-age.

Some head bolts are special cut / made and can be reused , others ask for replacement.

On re-torques that I have done , same order as the original sequence , But remove bolt , clean hole well , light lube , and back to the set torque, next bolt and hole, If your not going to clean the threads , and the lube , your not going to get an acurate crush / torque. You must undo a bolt to do a retorque.
Just re-tighting it is false also , and one sweep up to the torque.

VT
Click to expand...
 
Benjaman said:
I was speaking in general terms, as in all things being equal, a mechanic is (for the most part) someone that works on cars, and nothing in the way of training is mandatory. A Machinist will often require in excess of 3 years training.
A good machinist could build an engine from scratch, as a mechanic could only assemble the engine. I should know, as I'm a mechanic that works hand in hand with machinist at a local refinery.:)
Click to expand...



Making broad definitive statements based on "generalities" is a good way to make some pretty inaccurate statements.


Mark...
 
cwwfj60 said:
To be a little more simple here, as a mechanic, don't RE-torque your head bolts, after a rebuild I torque them to spec and send it down the road. Never heard of anybody heating up an engine then re-torqueing the heads, that just sounds stupid.
Click to expand...



I am guessing that you do not work on many F series engines, or talk with many who do. There may be stupid here but it is NOT the advice to recheck the torque the head of this engine.

Do all F series head wind up needing retorque? Nope. But plenty of them do. And ignore it will lead to failed head gaskets in those engines.


Mark...
 
Mark W said:
<snip>

While I am here... Steve's comment about not needing retorque until 15K or more is not accurate. Cruiser heads need to be checked after a few warm up/cool down cycles.


Mark...
Click to expand...

This is rich as I defer to guys like Mark and Jim C as they know what they are talking about, their knowledge having been learned through years of hard work and experience, while I am mostly just repeating what I have heard, read and learned from folks like Mark and Jim. My statement that Mark is refuting was learned from another experienced pro that I place in the echelon of M and J, someone who is highly regarded in the Toyota community. He built the 3FE in my 62 and re-torqued the head at 20K miles after the rebuild. This rebuilt engine has 60K on it now and still runs as strong as it did when it was rebuilt. I think it all boils down to the fact that our tractor motors aren't all that picky when it comes to being maintained to the degree being discussed here. Should we adjust valves when hot or cold? Torque head when hot or cold? When to re-torque head? How many F engine heads have never been re-torqued after leaving the factory and are still going strong hundreds of thousand miles later? It would seen it isn't super critical with the F engine and it's all good. Or maybe I'm missing something.
:cheers:
 
overhanger said:
This is rich as I defer to guys like Mark and Jim C as they know what they are talking about, their knowledge having been learned through years of hard work and experience, while I am mostly just repeating what I have heard, read and learned from folks like Mark and Jim. My statement that Mark is refuting was learned from another experienced pro that I place in the echelon of M and J, someone who is highly regarded in the Toyota community. He built the 3FE in my 62 and re-torqued the head at 20K miles after the rebuild. This rebuilt engine has 60K on it now and still runs as strong as it did when it was rebuilt. I think it all boils down to the fact that our tractor motors aren't all that picky when it comes to being maintained to the degree being discussed here. Should we adjust valves when hot or cold? Torque head when hot or cold? When to re-torque head? How many F engine heads have never been re-torqued after leaving the factory and are still going strong hundreds of thousand miles later? It would seen it isn't super critical with the F engine and it's all good. Or maybe I'm missing something.
:cheers:
Click to expand...

You just had to ruin the tread with common sense.:D
 
I won't say that you are going to loose your motor if you do not retorque quickly. As I mentioned I have seen some that did not need it at all. And I have seen several the needed it within a week or less. Since it can not hurt to check and engine that does not need it... and it can hurt to ignore one that does... well... seems to be a simple choice to me. :)


Mark...
 
You must log in or register to reply here.

Share this page

Back
Top Bottom