The Fordson Tractor Pages Forum

When i rebuilt my engine I had hard time getting the covers to seal. My friend and myself were talking last night and he ask why those holes were in the head in the first place?I have no idea, dose anyone here know why they are there?

I can't your question I'm afraid, but I will ask another, did you seal them in the end and how did you do it? is there a special method?

Regards

Ian

Dear Oldcharlie
The combustion chamber covers are in fact pre-combustion chamber caps, as this is an indirect injection diesel engine and the pre-combustion chambers assist in efficient burning of the fuel mix. The covers, or caps are probably there to allow machining operations to take place to form the pre-combustion chamber during engine manufacture. They can also be there to assist in maintenance of the cylinder head if the chambers become fouled up (unlikely if the engine is used correctly). I have heard of problems in sealing them on both these and other tractors that use the P3 Perkins engine. One method is to reuse the old (original) copper gaskets (provided they are in reasonable condition). Firstly they should be annealed by heating to red hot and allowing to cool, this softens them. Ensure the caps themselves are absolutely flat.

An old agricultural engineer I used to know would coat both sides of the copper gasket and the sealing surface of the cap with silver exhaust paint before tightening it down. Why it had to be silver, I don't know, but he was the P3/Dexta engine expert in the machine shop he worked in many years ago.

To quote from the Dexta Workshop Manual "It is not as a rule necessary to remove the covers of the combustion chambers during decarbonising, as carbon rarely forms in these chambers".

Perhaps the message to get out there is do not remove the combustion caps for decoking/maintenance of the cylinder head, unless you really, really have to.

Hope this helps

Tim E

i used a product called copper coat ,which is a very good sealant. But still had to use a trick i found on here in the old postings. I put the sealant on with new copper gaskets . Tighten them down the whack it with a hammer and re tighten. Worked like a charm! This was after several failed attempts.