Refitting M20 head

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SilverShadow
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Post Tue Feb 11, 2014 8:04 pm

I'm at the stage of refitting my newly built head to my reworked block.

Whats the best approach to take when placing the head on the block.

I assumed all you had to do is set the head and block at TDC (prior to fitting) place the head on the block and tighten the new head bolts to specification.

However searching for some old threads some people recommend not to do this as you can bend a valve etc?

What's people opinion on this?
Last edited by SilverShadow on Tue Feb 11, 2014 8:16 pm, edited 1 time in total.
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Brianmoooore
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Post Tue Feb 11, 2014 8:16 pm

Set the cam pulley to the timing mark, and the crank pulley to 10 - 15 degrees before the timing mark. That way, all the pistons are down way below deck level, and won't make contact with any valves if the cam pulley gets moved at all.
Once everything is bolted down, check the cam pulley is dead on the mark, then advance the crank to the mark and put the belt on.
SilverShadow
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Post Wed Feb 12, 2014 7:20 pm

Thanks Brian!

Makes logical sense! :cool:
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Brianmoooore
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Post Wed Feb 12, 2014 8:19 pm

Don't forget the locating dowels!
Tighten the bolts to their initial torque, then mark a line at 12 o'clock on each bolt head with a permanent marker. Then, after angle torquing them twice, the lines should all be at 6 o'clock. If one isn't, you know that you missed one!
SilverShadow
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Post Wed Feb 12, 2014 9:16 pm

When angle tightening them the second time round should it be after normal temp running condition?
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Brianmoooore
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Post Wed Feb 12, 2014 10:00 pm

90 degrees is 90 degrees, whatever temperature the engine is at, and however long the engine has run. Do it cold, before start up.
SilverShadow
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Post Fri Feb 14, 2014 2:58 pm

Thanks Brian!

1 final question before I attempt the work this weekend, is the intermediate shaft "timing specific"?

Taking in account that this is a late motronic engine and the distributor located on the head.

I think I know the answer to this question however would be good to get confirmation.
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Brianmoooore
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Post Fri Feb 14, 2014 8:13 pm

Only on ancient M20s with the distributor on the side of the block.