Problems during m30 head rebuild.

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winx
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Post Mon Apr 27, 2009 10:41 pm

I have been rebuilding my head tonight and dropped it onto the block. One of the rocker shafts is being pressed out of place by the springs, only the rear part of the inlet side is being affected...

This may not have been such a problem with the oem headbolts as tthe shaft would have been kept in place. However I am using headstuds which I think have a smaller diameter.
It would be nice to compare them but the originals are 200 miles away :roll:

Can any one tell me if putting a spacer behind the rocker shaft to hold it in place would be a really bad idea?

This shows the problem:
Image

I could really do with putting the engine back in the car this weekend as I am running out of time quickly for a ring trip next month, so any help/ideas would be great and much appreciated!
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E30Mark
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Post Mon Apr 27, 2009 10:52 pm

I have no knowledge of M30's but that looks very wrong to me!

Don't go bodging a block in there, their is obviously a technical reason for this, is the shaft the correct orientation? Is there not a plate / seal on the end of the head sealing the shaft hole?
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winx
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Post Mon Apr 27, 2009 10:58 pm

Yup I took the plate off to turn the shaft and line it up for the headstuds.
Even with the shaft aligned so that the headstuds should hold it in place it moves, hence why I think the studs are too smaller a diameter...
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E30Mark
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Post Mon Apr 27, 2009 11:03 pm

Now I see how it's supposed to work, the head studs / bolts align with a groove in the shaft assume. Any reason for not using the OEM head bolts?
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winx
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Post Mon Apr 27, 2009 11:06 pm

I want to go turbo in the not too distant future and after some research decided I would be safer to go with headstuds for future power upgrades. Hence putting these in whilst rebuilding :)
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gareth
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Post Wed Apr 29, 2009 12:26 am

could you not get some steel sleeves made up to drop into the holes and locate the rocker shaft properly again?
would be a quick and easy job for someone with a lathe
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e21Jason
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Post Wed Apr 29, 2009 1:45 am

Common M30 problem the ARP head studs do not have the shoulders the bolts have, so you need to make sleeves as above

Jason
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winx
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Post Wed Apr 29, 2009 11:24 pm

well with so much on at work I just don't have time to make anything up so the engine is going back together again with standard bolts.
I'll revisit this when I swap heads later in the year when I go turbo.

Thanks for the ideas so far guys, all good stuff and will be following them up :)
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