head gasket replacment

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k10
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Sat Feb 02, 2008 10:39 pm

Anyone done a head gasket before. We need to change one on our track car. 325 (M20).
Haynes doesnt appear to be much use.
Anyone got any info on how long this takes, new bits needed and a step by step guide for dummies would also be useful !

Also what has happended to ther zone shop there is no longher a link??
march109
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Sat Feb 02, 2008 10:46 pm

Zone shop is now the Evolve link!

Can't help on the other, sorry never done it myself.
325i Tech 1 Touring, breaking.

2.5 high comp. M20, 3.64 LSD, Fully undersealed, Spax springs & Bilstein shocks, s/s exhaust, Alpina rep wheels and more.
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Brianmoooore
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Sat Feb 02, 2008 11:14 pm

New bits required are a gasket set and a set of bolts.
New bits to be considered are cam belt and idler, thermostat, water pump, and exhaust studs.
The head should be lightly skimmed while it's off, even if just to get a professional to give an opinion on it.
Tools required are a torque wrench with a torx bit to suit the head bolts, and an angle torque gauge.
Head bolts must be undone and torqued up in the correct order. Mark a line on the head of each bolt with a marker after the initial tightening with a torque wrench. That way you can check if you've remembered to angle torque all the bolts properly when you've finished.
Take the inlet manifold off before removing the head, leave the exhaust on. DON'T break the exhaust studs when you do remove it.
bmwe30mtech
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Sun Feb 03, 2008 1:05 am

Brianmoooore wrote:Mark a line on the head of each bolt with a marker after the initial tightening with a torque wrench. That way you can check if you've remembered to angle torque all the bolts properly when you've finished.
Just to emphasise this point. Its vital you turn all the bolts this extra 90 degree turn. I forgot when i did mine and the engine kept overheating.

The main thing with a head gasket it to make sure the surfaces are very very clean. Get the head skimmed, and sand the block with wet and dry paper yourself to remove mess.
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k10
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Sun Feb 03, 2008 1:05 am

Thanks again, we'll let you know how this goes over the next few saturdays !
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Brianmoooore
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Sun Feb 03, 2008 1:09 am

bmwe30mtech wrote: Its vital you turn all the bolts this extra 90 degree turn.
Vital you do it twice, in fact!
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WerkdE30
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Sun Feb 03, 2008 6:49 am

id get the head checked for cracks while its off. in fact you should get it reco'd with new stem seals and a valve re-grind.

"DON'T break the exhaust studs when you do remove it."

i always spray them with a lot of wd40 or rost off or what ever u can get. they are a pain.
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k10
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Sun Feb 10, 2008 12:32 am

Okay cheers all
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