Thread: Low compression in all cylinders

that Xado works well apparently... recently saw in an old Overlander editorial that independent industry testing supports its stated benefits

Originally Posted by Rupert Prior

if it has blue smoke out the back it is probably past help but, how many K's on your motor and what service history? have you tried a wet test? does the the cam have any lobes left?

It's on 177k, smoke out the back isn't too bad. No idea on the lobes. What's a wet test?!

Worn cam lobes is not uncommon on old Rover V8s.

I'm no mechanic but I imagine if the valves don't open fully, the compression will be affected (the reason compression tests are done with a wide open throttle).

I assume the wet test referred to by Rupert is done by pouring a small amount of oil down the cylinder to seal the rings. I usually do that after the initial compression check. If the pressures rise, it indicates the rings may be worn. If thy don't the problem could be valves.

Originally Posted by p38arover

Worn cam lobes is not uncommon on old Rover V8s.

I'm no mechanic but I imagine if the valves don't open fully, the compression will be affected (the reason compression tests are done with a wide open throttle).

I assume the wet test referred to by Rupert is done by pouring a small amount of oil down the cylinder to seal the rings. I usually do that after the initial compression check. If the pressures rise, it indicates the rings may be worn. If thy don't the problem could be valves.

Thanks Ron, does this mean i may have options? Maybe I can ask to have the additional tests to confirm valves vs rings?

have you had it vacuum tested? Mine was showing a range of compression readings from 120-130, and all were constant when done wet, but the compression was quite low, and almost non existent under load.

My car seems to be smooth and happy, just sluggish at certain temp levels/rev ranges. I would bet mines rings and cam going.

Originally Posted by LavisLane

Thanks Ron, does this mean i may have options? Maybe I can ask to have the additional tests to confirm valves vs rings?

Yes, you may have options.

Worn bores is not normally a problem with Rover V8s so I doubt they are worn enough to require replacement liners - unless you want to have them done and top hat liners fitted instead.

I've seen high mileage Rovers with still visible crosshatching on the bores (that's good).

a progressive leak down test, you can do it yourself if youve got a semi decent compressor (a $90 240v job from aldi is workable) some knowledge (which you can get here) and someone who can help you fabricate a couple of simple tools then assist with the testing.

it would be really cool if one of our talented members did a tutorial with pics on how to do this.... <hint>