D2 Owner's Despair - US Style

[Traco]

Land Rover Valve Jobs - Erik Burrows.com (http://www.erikburrows.com/index.php?node_id=148&expand_comments=1)

This is a long and at times depressing forum to read through. It records a litany of failures, fixes and faithfulness among US Disco owners, especially those with early 4.0 litre V8 D2 models (1999 - 2002): slipped liners, blown head gaskets, dodgy electronics, sticking exhaust valves seem to be the main gripes, along with the high cost of parts and poor dealer service. The earlier pre 1996 3.9 Hotwire D1 doesn't fare too badly though.

Why is sticking exhaust valves such a major affliction there? Is it something in the fuel that causes excessive carbon fouling of the exhaust valve stems?

Seems from what I've read that the problem of sticking valves affected many US spec 4.0 Discos increasingly from about 1996 when I believe they started using the GEMS engine management system. Not sure if it continued with the later 4.6 D2s that had the Thor system fitted from the P38 RR.

Do the local Aussie Discos suffer the same problem?

[tempestv8]

They have "oxygenated" gasoline over there, which atomises slightly differently to normal unleaded petrol.

This problem does occur in Australia if you've fed the engine with 100% Shell Optimax 98 octane from day one, as the fuel does not atomise as well as other high octane petrol from the other vendors. As me how I know. :mad:

Actually, ask any Harley Davidson owner and they will say that the denser Optimax fuel plays havoc on their fuel systems too. :o

[PhilipA]

This problem does occur in Australia if you've fed the engine with 100% Shell Optimax 98 octane from day one
That is one I haven't heard before!
But maybe in some cases.
The general concensus is that the cause of the problem and why it only happens in late engines is that only late engines are fitted with "teflon" seals on the exhaust valves. This restricts oil passing down the exhaust valve stem and coking can occur. The seal was added to reduce emissions.

However when I put new gaskets in my 110Kk 3.9 92 RRC I found 2 exhaust valves coked with one a bit sticky, so it can happen in earlier engines.
I have modded the heads and put no seal on the exhaust and a "teflon" on the inlet and my oil consumption is good and no sign after 40k of sticking.
I have always used 91-92 unleaded.
I also use semi synthetic oil and change regularly.
So while I think there are a variety of causes including, too much slow running, infrequent oil changes, the exhaust seals, and maybe Shell 98, the fix is as I described above.
Regards Philip A