19J Cylinder Head Rebuild

So my 19J is showing the signs of an impending head gasket failure- excess pressure in the coolant after sitting overnight, along with an abnormally high coolant level in the expansion tank. I believe combustion gases are leaking into the system under load and collecting in the heater matrix, which is displacing coolant and so raising the apparent level in the tank.

I guess the head will be coming off to investigate/fix it fairly soon, but is it worth doing some other work on the head while I'm at it? Disassembly and valve grinding wouldn't be too much of a hassle to do. Is there anything significant to be gained from just a top-end rebuild?

Have you tested the coolant to see if it is oil getting into the coolant?

If I was taking the head off and had the time/money and tools I would do all the other bits whilst in the area but that's just me

There's no discernible oil in the coolant or vice versa, but something's pressurising the coolant and raising the level in the expansion tank.

I guess it's worth grinding the valves and replacing the springs and oil seals while the head's off. It doesn't look too hard with the right tools. It might be an idea to fit reconditioned injectors while I'm at it.

Valve spring compressor from halfrauds, grinding stick n paste, head gaskets set should come with new valve oil seals a couple of hours job done.

FlyingPete said:

There's no discernible oil in the coolant or vice versa, but something's pressurising the coolant and raising the level in the expansion tank.

I guess it's worth grinding the valves and replacing the springs and oil seals while the head's off. It doesn't look too hard with the right tools. It might be an idea to fit reconditioned injectors while I'm at it.

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You will probably need to replace some of the swirl chambers. Good to grind the valves and renew springs and seals.
Get your injectors tested at a fuel injection place. They will service them if needed.

you can buy new guides if old are worn, not expensive with new valves ,but main part is to closley look for cracks in the scallop between the valves

Yes, notorious for cracked heads! And if it is, changing the gasket wont help!

The head has been off before with some slight pitting in the top of the combustion chamber, but no apparent cracks and otherwise seemed in good condition. I guess there could be a hairline fracture that only opens up when the head gets hot, but not sure how you'd identify that from a visual inspection. Hopefully a new head won't be on the cards...

FlyingPete said:

The head has been off before with some slight pitting in the top of the combustion chamber, but no apparent cracks and otherwise seemed in good condition. I guess there could be a hairline fracture that only opens up when the head gets hot, but not sure how you'd identify that from a visual inspection. Hopefully a new head won't be on the cards...

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if you clean the areas ,cracks will be visible ,ive never found one that wasnt

Can cracks be welded up?

nobber said:

Can cracks be welded up?

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Cast iron heads can be repaired, the actual process often involves pinning as well as welding. It is quite a specialized and expensive process, which I have only seen used on high value marine and vintage engines.
Here is a specialist that does it

http://www.castironwelding.co.uk/

I doubt it would be worth it with a cheap and plentiful head like a 2.5, though. More economical to get another.

Two deliveries today. The postman wasn't particularly happy at having to lug this out of his van

One replacement cylinder head with valves, in pretty good condition. Certainly better than the one currently fitted. Going to regrind the valve seats and replace the oil seals before installing it on the engine.


The other parcel was just a bit lighter.

Top end gaskets and rebuilt kit, including oil seals and various sized washers.

Not sure what the two rubber parts on the right are for?

Cylinder head rebuild is underway Made a start on the valves for no. 1 cylinder this evening. So far everything seems to be within specs and can be reused which is good news. There is only a small amount of pitting in the valve seats, which I've got rid of by grinding in the valve seats to get a good seal. My valve spring compressor isn't quite the right size to fit the valves, but with a bit of fiddling I managed to get it working.

There's something slightly therapeutic about dismantling, inspecting and rebuilding mechanical things

Have you taken a good, close look at your pistons? 19Js are notorious for cracking them.

Have a really good look at the block when the head is off. You may be able to see where the leak into the cooling system from the cylinder or exhaust port was. A leak of this kind will often discolour the coolant - is it a bit "dirty" looking?

I notice you seem to be using the dining table - you must have a patient missus!

zeaphod said:

I notice you seem to be using the dining table - you must have a patient missus!

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Was just using the dining table to check all the parts (hence the cardboard under the head!) Now migrated to the workbench in the garage

Got the cylinder head back together Also gave it a quick coat of satin black engine paint I had lying around to smarten it up. Going to decapitate the engine over the next couple of days and swap the heads over.

Well it's on Had to swap over the lifting brackets and coolant sensor adapter from the old head. Still need to refit injectors, glow plugs and thermostat, plus set up valve clearances. Getting there slowly.

Nearly there, Pete!

Careful as you refit the injector pipes, spin on the unions and then wiggle the pipes around to settle them in the spigots before tightening the ends. It is quite easy to lock a stress into the pipes during tightening, which sometimes causes them to snap later.

General condition and underbonnet view is better than a lot of the 2.5 tds I see. Nice to see!
I would get rid of the Bearmach filter and get a Delphi, and clean up the turbo actuator a bit, but that is just being a pedantic old git!