Head bolt replacement/retorque

JimS · Sep 22, 2019

I am replacing the head gasket on an Isuzu Rodeo with a 2.6 4 cylinder (The same engine is in Honda Passports.). There is nothing in any manual I have or anything online that says the head bolts should be replaced. In fact, everyone has instructions on cleaning them up and reusing them, just keep them in order. Also, none of the resources says anything about retorquing the head bolts after getting some heat on the head after running it. If I remember correctly (I've done this before), there are two or more bolts under a cam, that I would need to remove to retorque.

My question is, how unusual is it to not replace head bolts or retorque them after running the engine? Should I go against the instructions and replace and retorque? Thanks.

fixerupper · Sep 22, 2019

I have done head work on a tractor where the head bolts were reused and the bolts were not re-torqued. I forget what specific brand it was. Maybe Allis?

Sprint 6 · Sep 22, 2019

While technically reusable, probably not that expensive for cheap insurance. Most Asian makes allow re-use of head bolts if they pass a stretch measurement. Honda and Toyota usually publish a maximum length for their head bolts. Without that info, re-use is a crapshoot.

No retorque is needed. That is probably an angle torque spec. Meaning a certain foot pound torque, then so many degrees rotation beyond that.

Mutt and Jeff · Sep 22, 2019

I put up the link to headbolts for you a while ago.
find it click on it order bolts and torque per spec
do not retorque
do the job once do it well and move on
did you surface the block?
the head? replace the head?
gaskets factory or felpro?
some other?

Oregon Tractor Jack · Sep 22, 2019

Here is a You Tube video showing a shade tree mechanic replacing the head on a Isuzu 2.6. He just torques the bolts down with no mention of torque to yield.

https://www.youtube.com/watch?v=zi-OQSydhyo

As with any You Tube video you should proceed with caution on the information provided. This was the first result of my search, there are many others out there.

OTJ

T in NE · Sep 22, 2019

If you're on facebook, look up the group "isuzu trader"

jimg.allentown · Sep 22, 2019

As a general rule, head bolts that are NOT torque to yield can be re-used safely. TTY bolts cannot.

To the best of my knowledge, there are no automotive engines (those used in passenger cars) that require or even recommend re-torqueing after warm up. Mostly because of access problems. Bolts under cam shafts, valve covers under intake plenums, and the like. Re-torqueing is simply not practical.

4play · Sep 22, 2019

I thought you already asked this a couple weeks ago? Anyway these bolts are reusable. Lightly coat threads and contact surfaces on cyl head and bolts with engine oil, Re-torque is not needed. The multi-step torque sequence is all that is needed for the gasket to compress and stay sealed.

The only head bolts I know that must be replaced are torque to yield bolts. These bolts have multiple torque steps, then a final step being a degree/angle measurement.

Head bolt replacement/retorque

JimS

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fixerupper

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Sprint 6

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Mutt and Jeff

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Oregon Tractor Jack

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T in NE

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jimg.allentown

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4play

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