cylinder head torque

[ceedub]

I am ready to re-torque the head after my rebuild but cannot find if the torque setting for the head is for a warm or cold engine. The valve settings appear to be for a warm engine. So do I set the head cold and then the valves warm?

 

[tony barnhill]

Torque the head cold & retorque again after about 500 miles.

 

[Steve_S]

I always re-torque with the engine warm, but not hot.

 

[billspohn]

He didn't say if he had a stock or alloy head and the techniques are a bit different.

The cast iron head gets torqued cold, then run until at operating temperature and retorqued.

The alloy heads are torqued cold, run up to heat and then allowed to cool completely and rechecked. Seems to work best.

 

[Scott_Hower]

Good info.

When retorquing... is the protocol to loosen each in the tightening order and then retighten? Or loosen all then tighten in order. or does it not matter?

For example, loosen only #1 in the sequence, then retorque. Loosen #2, then retorque. And so on.

Or loosen all slightly then torque in order according to sequence.

I'd imagine it's the former, but I dont remember the manual being specific.

 

[jlaird]

I have never loosened head nuts unless I was takeing the head off. Just check what you got.

 

[Kuz]

Just retorque the bolts,don't loosen anything. Start at 5 footpounds below max, then max twice all in sequence.Keith

 

[Bugeye58]

/bcforum/images/%%GRAEMLIN_URL%%/iagree.gif
I've been doing it the same way for a lot of years, and that method works for me.
Jeff

 

[DrEntropy]

I assumed cast iron (MGB). But Bill brings up a good point: alloy vs iron.

The collection of rolling stock in my .sig file has all-sorts as combos of iron and alloy. Each requires its own different proceedure if re-torqued. The Alfa (alloy head, wet-liners in an alloy block) is the biggest PITA: torque, heat to "normal operating temp", cool to ambient, retorque... "wash, rinse, repeat."

And don't EVEN think of rolling off in "winter" climes until the temp gauge at least twitches off the peg.
When I lived in western PA I used to buy Alfa head gaskets by the ~six-pack~!! /bcforum/images/%%GRAEMLIN_URL%%/jester.gif

 

[Steve_S]

There is much debate on the subject, but I always loosen a tiny bit to eliminate stickiness while torquing. This way there is no false reading due to a nut not breaking loose before the torque wrench reaches it's maximum setting. I'm talking 1/8 of a turn or so, and I do them one at a time.

 

[DrEntropy]

Yup. "crack" it loose then give it the tweak... and in order.

 

[billspohn]

Yup. "crack" it loose then give it the tweak... and in order.

Agree - only way to get a reliable torque figure - otherwise they can 'stick'

 

[Kuz]

If you used anti seize they won't stick. If you didn't your torque is probably inaccurate

 

[Steve_S]

If you used anti seize they won't stick. If you didn't your torque is probably inaccurate

That depends on what studs you use. Some require lubrication and some require no lubrication be used. You need to check the manufacturer's specs before torquing.

 

[DrEntropy]

Makers' spaec's can call for either. "Dry" or "lubricated". It's a RTFM deal.

 

[tony barnhill]

Never thought about backing them off a bit before retorquing! Guess it wouldn't hurt...don't know what it gains....

 

[Scott_Hower]

Yup. "crack" it loose then give it the tweak... and in order.

Thanks Doc, and Steve.

 

[DrEntropy]

It breaks the corrosion/rust/electrolysis and gives you a more accurate torque. If you just tug on it without "breaking" the resistance you can overtighten or not get a smooth turn to proper torque. Even with a bit of "goose-grease" on the threads it's a good idea to back 'em off a bit first.

 

[tony barnhill]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]It breaks the corrosion/rust/electrolysis and gives you a more accurate torque.[/QUOTE]
After 500 miles?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]If you just tug on it without "breaking" the resistance you can overtighten or not get a smooth turn to proper torque. [/QUOTE]
If you back them off before using your 'click' torque wrench, you'll never know if there was a problem with the initial torque 500 miles earlier.

 

[Scott_Hower]

If you used anti seize they won't stick. If you didn't your torque is probably inaccurate

Welcome to BCF and thanks for the input; I use antiseize on any stud/bolt that may gall from dissimilar materials and/or come in contact with water.

I've never seen a factory spec for using antisieze paste on head studs. The spec (as stated in my copy of B-Series Engine Data) is usually engine oil or dry. Most specs list wet torque w/engine oil. Copaslip, et al, was widely available at the time.