Isuzu Trooper Owners Club UK™

jbaker · * Joined: 10 Sep 2005 Posts: 28

Good luck RSB. I will be watching with interest, as it is likely that I'll also to have to go down the same path (http://www.itocuk.co.uk/forums/viewtopic.php?t=2194 and http://www.itocuk.co.uk/forums/viewtopic.php?t=2333). The last time I took a head off an engine was 20 years ago - it was the somewhat smaller engined Chevette 1300.
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RSB · * Joined: 27 Sep 2005 Posts: 37 Location: Carlisle

Any suggestins where I might get the head bolts from? - Presume isuzu dealer can get them, but I suspect at silly price.

NickP · **** Joined: 07 Jan 2005 Posts: 281 Location: South East

Wherever you get the head gasket from should do the head bolts as well. if not your local Vauxhall dealer will have them for a monterey.

NickP · **** Joined: 07 Jan 2005 Posts: 281 Location: South East

NickP · **** Joined: 07 Jan 2005 Posts: 281 Location: South East

Just looked them up and the GM part no for the bolts is: 94455667 you need 18 of them.

jon willy · Posted: Sat Oct 08, 2005 18:55 Post subject:

Nick ..... Where ever you are gleaning the info from does it not give any re-use / replace tolerances for the head bolts Question

Jon.
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NickP · **** Joined: 07 Jan 2005 Posts: 281 Location: South East

There's no spec on them on my disc! Perhaps Suzu can advise Question

RSB · * Joined: 27 Sep 2005 Posts: 37 Location: Carlisle

thanks for all the advice.

However, I spoke to the service dept at my local isuzu main dealer, who told me that the head bolts on the early 3.1td are not 'stretch' bolts and there is no recommendation to change them when changing the head gasket. Also there is no guidance for checking their length or anything.

As these bolts are £3.77 each plus VAT (£80!) this sounds good to me. But was the guy I spoke to talking sense?

Does the fact that final tightening figures in the manual are in degrees rather than torque settings give any clues?

The manual is for 98 onwards. Is it possible that these figures could be wrong for an older engine?

Really sorry to drag this one out, but I want to get this right - I don't want to do the job twice.

thanks

lotustower · Posted: Mon Oct 10, 2005 11:59 Post subject:

If you're not sure change them. It's better safe than sorry, especially as it will be in bits.

All bolts stretch and swan neck when done up tight, and the tighter they are the tougher it gets hence thicker bolts when there is more load. Particularly in the horrible environment of the engine, as all the different metals expand and contract around them at different rates. The mroe they are undone done up the worse it gets, but the older they are the greater the chance of metal fatigue.
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jon willy · Posted: Mon Oct 10, 2005 12:53 Post subject:

Hello RSB .... I'm not convinced the term as referred to here as stretch bolts is applicable .. they are a different concept.

We are discussing the re-use of bolts that having seen service may have stretched .......... I have searched without success for some data I had when I replaced a head gasket on a Mercedes Commercial Truck last year ......... it gave an acceptable length measurement of the head bolts in this instance for re-use when comparing against new ..... the tolerance was in mm's as opposed to fractions of mm's so it was a tape measure indication and not a micrometer .......... I found the used bolts to be exactly the same length as a new bolt, on the advice of the dealer in your case I would re-use the bolts, ensuring they are clean and the tapped hole is free fom any debris.

Jon.
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Hard1 · Posted: Mon Oct 10, 2005 14:02 Post subject:

I'd throw the damned things away and use studs anyway. Far more accurate torque figures, that's if they are available. If they ever did any competition, I'll bet there's some out there somewhere!
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Hard1 · Posted: Mon Oct 10, 2005 14:03 Post subject:

In the meantime - it's always better to replace the bolts, especially if you have had an unexplained head gasket failure.
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jon willy · Posted: Mon Oct 10, 2005 14:16 Post subject:

lotustower · Posted: Mon Oct 10, 2005 14:24 Post subject:

Not sure the temp issues are the same on the wheel studs and nuts. I guess it is personal choice, and whether the true cause of failure is known, rarely I guess on a head gasket unless you spend more than the cost of the bolts and a new gasket having it all checked/machined, and then it was probably a duff gasket which was damaged on installation!
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Hard1 · Posted: Mon Oct 10, 2005 14:25 Post subject:

You're probably right for road use, but having replaced bolts with studs on high compression competition engines, I found they torque up far more evenly and accurately without binding and you're not straining or distorting the block around the cylinders as head bolts do.

It is fun trying to get the head sitting on about 18 studs though!
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