Headgasket recommendation please gents ...............

[Kevin B]

I am not trying to put you off the idea of removing the cylinder for an inspection and valve job etc...

But, I did a very similar thing a long time ago on a high milage BX19 RD, upon removing the head the bores were found to be in excellent condition(so the bottom end was left alone). I fitted new guides, ground the valves and fitted new valve stem seals, reshimmed the head, had it lightly skimmed, recon injectors, etc etc, then put it all back together.

It ran well after this, but the oil consumption had increased significantly upon what it was before I gave it a head job. I can only assume that grinding the valves increased the compression pressure sufficiently to cause increased piston ring blow by, hence the increased oil consumption. As there were no external oil leaks, I can think of no other explanation.

[Linegeist]

I did a very similar thing a long time ago on a high milage BX19 RD, upon removing the head the bores were found to be in excellent condition(so the bottom end was left alone). I fitted new guides, ground the valves and fitted new valve stem seals, reshimmed the head, had it lightly skimmed, recon injectors, etc etc, then put it all back together.

It ran well after this, but the oil consumption had increased significantly upon what it was before I gave it a head job. I can only assume that grinding the valves increased the compression pressure sufficiently to cause increased piston ring blow by, hence the increased oil consumption. As there were no external oil leaks, I can think of no other explanation.

I've rebuilt one or two engines, and I've never found skimming a head has led to increased oil consumption. I have to say, given the very high compression ratios found in diesels, I rather doubt that piston ring blowby would be a cause of significantly increased oil consumption. In any event, you'd notice the clouds of smoke from improper combustion of the engine oil (it doesn't burn cleanly).

I've fitted gasket sets with stem seals before now, that have allowed engine oil to flow into the port throats. That'd have been my first suspicion ...... closely followed by worn guides and then oil seal leakage.

[Kevin B]

I can only assume that grinding the valves increased the compression pressure sufficiently to cause increased piston ring blow by,

I have to say, given the very high compression ratios found in diesels, I rather doubt that piston ring blowby would be a cause of significantly increased oil consumption. In any event, you'd notice the clouds of smoke from improper combustion of the engine oil (it doesn't burn cleanly).

I was thinking more along the lines of grinding the valves in had eliminated any loss of compression via the valves, hence it sought out the next easiest leak path, past the piston rings.

When I had this car on the road, you could not see any exhaust smoke from burning oil (nor could you smell it), all in all it was most puzzling. The gasket set fitted was a Payen item (before it became Curty / Payen).

If I ever encounted a similar situation again I would be tempted to pull the pistons out at the same time and re-ring them.