Compression test.

[Dougal9887]

The engine is a standard 500. 54000mls. Engine warm, WOT. Landrover manual states 170psi minimum for 3.9 engine/9.35:1 compression ratio so this figure will, I imagine, be higher for a 10:1 ratio. The engine performs well and there is no sign of burning oil, although oil consumption is quite high, around 1ltr per 1000 mls.
Results in psi, dry:
Cyl 1, 170
Cyl 2, 140
Cyl 3, 160
Cyl 4, 155
Cyl 5, 160
Cyl 6, 160
Cyl 7, 155
Cyl 8, 160
So cylinder 2 is a bit low in comparison to the rest and all a bit on the low side. With a couple of squirts of engine oil in cyl 2 the pressure rose to 145, not a big difference? There was a similar rise with some oil in a more average cylinder. Worth a leak down test? Opinions on these results? The Landrover manual also states that if there is a 20% difference on any one cylinder and a slightly rough idle, it could indicate a worn camshaft lobe. I'm not sure if the idle is slightly rough or not, it seems fine to me.
Regards the oil consumption, are the valve stem seals known for wear? If so, I'm thinking it may be worthwhile removing the heads to replace the seals, inspect the stems, and if OK, lap in the valves. Good time to have a look at the cam also.
Thanks, Dougal.

Edited by Dougal9887 on Sunday 16th September 14:45

Edited by Dougal9887 on Sunday 16th September 17:18

[Chimp871]

You can check the cam lobe lift without having to remove the heads. You can either measure cam lift from the rocker or remove the rocker shaft and you'll have direct access to the pushrods to measure lift.

The oil seals can be changed in situ, remove rocker shaft, pushrods and then use a special(ish) tool with magnets to hit the spring and remove the collets. There is an element of risk as you do not want the collets to fall into crank area.

However, the next step which is less invasive is to do a leakdown test this'll tell you if air is leaking past inlet valve (listen to air intake), outlet valve (listen to exhaust pipe) or piston rings (listen through oil dipstick). It's a better test TBH.

But in all honesty I wouldn't worry too much about the results they're close enough and if you don't have idle/power issues just enjoy.

Fyi - I don't have perfect compression/leakdown test results, in fact something similar to yours, but my 450 kicks out ~280 bhp which is as it left the factory.

Edited by Chimp871 on Sunday 16th September 18:06

[Classic Chim]

^^^^^^. This
All it takes as some carbon build up or a poor valve seating to show lower compression.
The oil usage is in line with old style engines so nothing much to worry about.
There’s bound to be some wear inline with engine mileage

[Dougal9887]

Thanks for the re-assurances! Whilst the engine's running well there's not much sense looking for trouble.
I've read about those collet removing tools and the various ways of holding the valve shut from rope down the spark plug hole to compressed air - all sounds a bit dodgy, especially when your luck has to hold out 8 times! And if I removed the heads to do the job, I'd most likely find some wear on the stems and so it would go on.......

[Boosted LS1]

I wouldn't worry about those readings. Just drive it ;-)