[Engine] Is my dw8 cylinder head scrap?

[Kieron G]

Was wondering if someone with more experience of engine rebuilding than me could advise. Have got the head off one of my sisters multispace, everything is remarkably clean for a 190,000 mile engine with the honing marks on bores still visable. When I put a straight edge on the head I can get a . 25mm feeler gauge in the worst gap. This seems a lot to be skimmed off the whole surface? Thanks for any advice

[jj9]

Can I ask why the head is off the engine, what was the problem with it?

Are you sure your straight edge is true, test it on a window with a feeler gauge for accuracy.

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[Sol]

That's a cracker of a tip JJ.

[Kieron G]

Hi. Yes I took the head off because there was oil collecting in the coolant header tank which needed to be washed out every few months. I replaced the oil cooler about a year ago thinking that was the cause but the problem continued. Other than this the engine ran well which says something when I discovered the amount of egr crud blocking the inlet. Temperature was always ok too.

[Kieron G]

Yes top tip with straight edge. I will check it

[jj9]

So the head gasket was obviously gone if the oil was getting into the water.

The Haynes manual gives the spec of 0.03mm for the face distortion of the head which is a lot less than your 0.25mm.

In my experience you can get away being a bit out of spec, especially if it's end to end  (so the head is banana shaped end to end) as the bolts tend to pull the head flat but if it out over the width of the head you have less chance of it pulling flat.

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[Kieron G]

Yes the distortion is end to end not across. I was surprised that it was so far out with engine not overheating

[oilyrag]

Kieron, if the distortion measures as you say, that's a lot! To have that skimmed would be more than one pass, if not 3, so could be expensive. Find a reputable engineering company and a visit with the head would be advisable, but it may be cheaper to pick up a good second-hand one. Their experience will hopefully be able to tell you if there's the risk of breaking through into the water jacket on this type of head.

[Kieron G]

OK thanks. I'll contact an engineering company that specialise in engine repairs next week and see what they say.

[jj9]

A diesel cylinder head is flat and the valves are only recessed very slightly not like on a petrol where the valves are in a combustion chamber so this very much limits the resurfacing process without having to recut valve seats etc, so it would be best to seek the advice of an engine machine shop on the best way to go with it.

Let us know how you get on.

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