Refacing/resurfacing the ME Engine Cylinder Head???

[thomas m]

Page 3-45 of my Bentley (VG92) manual under IV. Camshaft, Valve, and Cylinder Head Specifications that my ME engine cylinder head "cannot be refaced".

Yet the Aluminum Head Rebuilders, Inc. in Portland, OR says it can be refaced.

Yes or No??? Can the ME engine head be refaced?? I had an over-heat and it might be warped.

I guess I might have to find another or buy a Chinese knock-off??

[vanbcguy]

It can be resurfaced, with caveats.

The prechamber inserts should be removed for resurfacing - they are usually made from iconnel or steel and are therefore considerably harder than the surrounding aluminum. They are also supposed to stick out of the head a bit, there's a spec in the Bentley I believe.

If the head is warped it needs to be straightened before being milled or you'll have cam alignment issues later on. If the shop does lots of overhead cam aluminum heads then they should know what they are doing. The process involves clamping the head to a jig and heating it in an oven until it relaxes and straightens up.

When the factory manual was printed there weren't a lot of places that could deal with aluminum heads at all, hence the "cannot be resurfaced" text. These days OHC aluminum heads are pretty much the standard.

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[thomas m]

I casually asked about heating the head in the oven.
The tech said that it was not cost effective to do that.
I think they have the equipment, but refrain from using it. ?

I might be able to have them do it if I pursue this after pulling the head for inspection.
If I'm lucky it may not be warped. Fingers crossed !!!

I could also find another shop or just buy a Chinese head.
Any comments on the Chinese heads?

I'll use the cam alignment issue on my next conversations with a shop. Thanks.
This shop is well known in the Portland area and is supposed to reliable.

PS:  For what it's worth>>>
Aluminum Head Rebuilders, Inc. in Portland, Or
"Aluminum Head Rebuilders, Inc - Portland, Oregon brings 30 years of experience in remanufacture of aluminum cylinder heads and welding - in addition to more than 50 years of experience in the automotive industry. Our innovative welding and line-boring techniques save time and cores – which results in higher profits for your shop. Our exchange program takes the guesswork out of estimating repairs – which ensures accurate estimates."

[vanbcguy]

If the head was overheated it is probably warped. Pretty common with these unfortunately.

If they have the skill / ability to line bore the cam journals after surfacing then that's an option too.

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[thomas m]

If the head is warped it needs to be straightened before being milled or you'll have cam alignment issues later on. If the shop does lots of overhead cam aluminum heads then they should know what they are doing. The process involves clamping the head to a jig and heating it in an oven until it relaxes and straightens up.

How does milling the head surface affect the gasket selection???

It seems that milling drops the valves closer to the piston head sort of adding to the piston height. So the amount of milling would have to be added to the piston height to get the right thickness gasket?? Does this make sense???
I ask this so I can have a more informed discussion with the shop.

[vanbcguy]

The gasket height is all about how far the pistons stick out of the block. Head milling doesn't change that.

The valves should be ground at the same time as you mill the head which will minimize any excessive valve protrusion.

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[thomas m]

I guess an expedient shop could just put the 3-hole gasket on and not do any of that measuring stuff ??

Mine has the 3-hole as indicated by the gasket tab sticking out under #2 glow plug.
The head was remove in a shop once many years ago.

[air-cooled or diesel]

you can find even a cheapie, crude plastic depth tool, usually like calipers, whether metric or std, you can convert. it takes just a few minutes to get a crude measurement. all 4 piston heights. it will also tell you if there are any problems there, before you just guess, and perhaps just throw in a 3-hole gasket. of course use reference table in book.