Leaking combustion caps

[mike os]

Discolouration on the head suggests leaking above the clean cylinder

 

[Ubique]

The injector would be clean from a coolant leak - have you 'pop tested' the injectors?
I suspect the area of interest is shown below, it's quite pixelated from the zoom but there is something wrong between the coolant port and the injector port.

You can see the corresponding mark on the gasket here

 

[anto44]

Looks like coolant leaking in by the gasket in this area.

 

[Ubique]

Looks like coolant leaking in by the gasket in this area.
View attachment 316976

I think that's just wet from disassembly, there's nothing on the head gasket in that area, certainly worth cleaning the head up and die testing it though.

ETA - it might just be the photo but the smaller valve on that cylinder seems to be sitting deeper in the head - possible seat issue?

 

[arther dailey]

agree with the fact its coolant leaking in, had a mitsi with cracked head , one cylinder was effectively steam cleaned when taken apart .replacement head cured it , but paul doesnt have that option easily on a p3.

 

[Welderpaul]

Few close ups of that area

 

[Welderpaul]

The cylinder head is quite pitted on the underside on this cylinder whereas the others are not. It would be historical pitting though

 

[8ob]

That head would definitely benefit from a skim.


Bob

 

[Welderpaul]

Not sure what the ‘centre punch dots’ are from

 

[Welderpaul]

There’s some query as to whether the head gasket was torqued correctly and in the correct order. It was properly torqued after, but the problem still persisted.

 

[carbon]

Could one element in the injection pump be stuck up or even broken, so not injecting fuel to that cylinder

 

[Welderpaul]

Injectors and pump were professionally refurbed and tested so I tend to think they will be ok

 

[8ob]

Looking at the top of the block it would appear the head gasket sits well in from the edge of the bore, looking back on your build you used the stepped liners and modified them to parallel. A flanged protruding stepped liner will provide a superior gasket seal , a pound to a pinch of salt there will be a more suitable gasket available for this application.

Bob

 

[Ubique]

There’s some query as to whether the head gasket was torqued correctly and in the correct order. It was properly torqued after, but the problem still persisted.

That would explain it, that whole end looks like it's been under-torqued if you look at the contact area of the gasket. I'd get the head checked for flatness first and skim / grind if needed. the higher resolution pictures don't give me any cause for concern given what you've said above.

 

[Welderpaul]

The photos show that the cylinder head is pitted on the ‘clean’ cylinder. This is historical so could it be a crack? Strange the problem still persists on the same cylinder even after a full rebuild

 

[Welderpaul]

Are sooty cylinders like this normal?

 

[Ubique]

Are sooty cylinders like this normal?

For something that is relatively cool running, yes.

 

[Ubique]

They'll also be compensating for the cyl. that isn't doing much so i'd expect a bit of overfuelling in them too.

 

[brightspark]

That head would definitely benefit from a skim.

Bob

and crack tested at same time. well worth doing

 

[Ubique]

Are sooty cylinders like this normal?

Volvo cyl. head for comparison - I'm sure you can see where the problem is...