I know there’s a lotta experienced guys around here.

Anybody have any experience resurfacing their cylinder heads below minimum thickness?? My head is at about 84.2 mm thick. Research indicates that min is 84 mm. That leaves my machine shop about 9 thou to resurface off. Might not be enough.

Do I risk thinning the head to the point of causing a leak in one of the passageways?? Better yet, if I trim a few thou under minimum, what do I do about the timing? Can’t exactly shorten the timing chain...

I'd have him take the limit and see where you are. You may be able to get a thicker head gasket too.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

How much is your cylinder head warped?

You will also likely need to adjust the pre-chamber protrusion.

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84 300D, 82 Volvo 244Gl Diesel

Its probably not warped. It is cast iron for pete's sake. Just a little clean up like the kiss of a baby.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

You should have him check the block too for twist and deck if there is any.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I’ve considered all of the above.

If the block is warped or tweaked, there’s not much that I can do about that, short of tearing it out of the car and getting it decked. Haven’t even checked it because of this. Suppose I should though just to know

As for the HG, where would I get a thicker gasket??

Head shouldn’t be warped. I only have it off for an external oil leak. On the rear of the head is what looks like a pressurized oil galley. The HG has what looks like a mini fire ring for it. Literally is a ~1/2” metal ring built into the gasket. I think oil started to slip past this ring,
then head bolts in the area saw oil, thus loosened them a bit over time

That said, I couldn’t get a really consistent read on the head thickness last night. It’s somewhere around 84.1-84.2. Might be because of old gasket, poor measurement technique, or flat out because I was too cheap to buy a set of Mitutoyo calipers. Wouldn’t trust HF calipers with this amount of precision.

Now, do you guys think I can get away with cutting a few thou, under min? Perhaps cut to 83.9mm if I must? I’m going to spray the HG with some copper spray if that means anything

Or, should I just abandon this head and rebuild the one on my spare motor? I certain that has more thickness than the aforementioned.

No thoughts on using copper spray on the HG?

I rebuilt heads at the Fuel Injection Shop and a lot more when I worked at the Naval Ship Yard. I have seen lots of warped Cylinder heads and they were all some form of Cast Iron Heads.

I have also seen quite a few cracked cylinder heads.

In short my question was entirely valid.

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84 300D, 82 Volvo 244Gl Diesel

Think copper spray will add a thou or two of gasket thickness?

The head “should” be straight, as it never got overheated or catastrophically blown, but I could envision running for thousands of miles with a slipping corner could cause it to be tweaked a little

I used it on mine including the Volvo Diesel. I don't think any manual recommends it. (Copper Kote or is it Copper Coat?)

What it does is it helps seal the water passages and oil passages. I started using it on head gaskets when I was rebuilding a Dodge Slant 6 engine and the Head Gasket that came in the set was just a piece of stamped steel. Again I sprayed it to make sure the passages got sealed.

Also I don't buy that that oil loosened the head bolts because they are supposed to be lubed when they are installed.

On US Gassers some gaskets are coated with kind of a colored kind of tefolony stuff. If you don't know if it is good to spray them. When I faced that at work I used the Copper Kote in a can and dabbed it on around the passages so the passages for sure would get sealed.

Concerning the cylinder head call a machine shop and ask how much it would cost for them to check to see if it is warped or if you intend to do more then average amount of removing cylinder heads invest in a precision straight edge so that you can check it yourself.

In my experience for ever one warped block there is like 100 warped cylinder heads. It is not something that happens often as the cylinder head gets the bulk of the heat due to the exhaust ports.

I never took the Cylinder head off of my Mercedes but I did take the Manifolds off and the Exhaust Manifold was warmed.

I glued a bunch of course sand paper down to a straight board and worked it back and forth till it was a lot better and used in like that with no issues. Again Copper Koat on the Manifold Gasket which I reused.

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84 300D, 82 Volvo 244Gl Diesel

I got Permatex Copper Spray a Gasket. Others on Amzn used it for HGs so I figured I’d give it a whirl

If this head is salvageable, it’ll need to be cut to the min thickness or a hair under.

Should I just abandon this head and get the spare rebuilt?? It is certainly thicker?

My main concern would be clearance. The only way to know that is to mill it, then bolt it together with some clay and turn it over by hand to check for interference. If you're good there then everything else should be fine. Yes it will increase compression but probably not significantly. It will also retard the timing, but probably not even a degree. You likely wouldn't even have to do anything to compensate.

I mean, some people over-mill a head on purpose for more power, so there's that.

Skim it and measure it. It may be perfectly good to go.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Just got back from the machine shop. As expected, this head is right on the verge of minimum thickness. Resurfacing it would put me a few thou under 84mm. There is a 5 thou deep valley along the length of the head. Plus, the head was milled crooked - one side is thicker than the other. Machine shop refused the head because he didn’t want to go under min. Suggested rebuilding the spare head or potentially running the current one the way it is.

I guess I’ll rebuild the spare head.

Any suggestion as to what to do with the current head?? Bolt it up to the spare motor even though it’s not “right”? Pull/reset the prechambers and find another shop to skim it, then run it on the spare motor one day? Dump it??

Dump it. Why ask for trouble?

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now