"Old wrote:

Seems you kind of jumped the gun pulling the head so soon.
I don't see anything glaringly amiss with the gasket sealing but pictures are not the same as actual witness.
Anyway, things to check:
Liner protrusion should be in the range of 0.002 to 0.005"
Head warpage is not usually a problem but you can check for daylight under a straight edge.
Pre-combustion chamber seals and seal surfaces can be combustion source leaks.
Worn valve guides can be a contributor to engine slobber.
Close check for any cylinder head/block cracks.

By all means replace the head gasket with new and coat both sides with "Permatex 300" gasket sealer.
Ferrules and seals are purchased separately
That head number doesn't match the info I have, Should show a 7B0596 casting number (7B3068 part number)

Couple of parts diagram pictures for the D25Uxxxx head, same as the 933 11A

I will take the head to the machine shop on Monday. I will get it magnafluxed for cracks. I will also have them see if they can resurface the chamber seats and check the valve guides and condition of the valves. The valves appear to be in excellent shape with the combustion surface with the original part number showing like brand new.
The pitting on the pre combustion chamber that you pointed out from the picture also has some very light pitting on the head as well as a bit on the valve faces just in that one cylinder. Don't know if this is a critical issue for the head or the chamber. These chambers, as far as I know are not available. I inspected the seat surface on the chambers and they all look quite nice and shiny. The seal surface for the oring on the chamber is pitted but that was not leaking since the new o rings that I installed this last summer. I will ask the machine shop if they can touch that up without enlarging it too big for the o ring seal to work.

Agree the chambers look ok and the minor pitting won't hurt anything, just an indicator.
True the glow plug chambers for the D311 are no longer available but it is possible to use D4 chambers and have a machine shop turn down the threads from 1-1/8 - 12 tpi to 1"- 12 tpi

When I pulled the head on my 933 found some of the liners had crushed the copper shim allowing a very low protrusion. Bob

"restore49" wrote:

When I pulled the head on my 933 found some of the liners had crushed the copper shim allowing a very low protrusion. Bob

Do you mean that they allowed leakage to the radiator? Pressurizing the coolant system?

Low liner height can result in compression leaks finding path into cooling system or water leaks into cylinders when engine is not running. Depends on path of the leakage.

Thank you all for guiding me thru this project. Liner height is .0038- .004 Right in the middle. Hopefully I can check that one off the list. I am going to rig up a plug system for the pre combustion chambers hopefully pressurize them to check for pin holes. I have the capability to turn down and cut new threads on new precombustion chambers. In your opinion, would you invest in new chambers and the trouble of turning them down? I have that capability. I can also chuck up the existing ones and hone the mating surface. $90 dollar investment plus my time.....I found them online for 21.00 each (d4-1S1970).

In those pictures of you chambers, they didn't look all that bad. Your call on whether to replace them or not.

One more search. I have looked into a part number for the thermostat in my unit. Per the 933 partsbook 11a the part number is listed a 5H957. I thought it would be prudent to replace but can't seem to find a site that recognize that part number. Any thoughts?

Try 5H0957, computerized part number look for four digit numbers.
On checking liner protrusion, did you have the liners clamped down in there bores before measuring?

The 5h0957 is out there $27.00