Low compression in all cylinders

I've used the Ebay Snake Oil Stuff listed in that link on the Following Cars
- Jaguar XJ40 with LPG Engine 450,000km (Stuffed)
- Range Rover P38 HSE 4.6L (Good Comps but Noisy Tappet)
- Ssangyong Musso 3.2L (Stuffed & Noisy Tappets)
- Volvo 240 with No Oil & No Coolant Mixed with Xado Engine Revitalisant

The Jag, Range Rover and Musso all benefited.. Jaguar was most dramatic... Range Rover Tappets have been quiet since (and I tried some other Supercheap of the Shelf jobbies ete... to no avail)

The Volvo 240 was part of a "Competition" for Christmas Party at my Mechanics... No Fluids it revved to 5000rpm and sat there for 4 Minutes... it would not bloody blow up....

The Ford Cortina without Xado blew up after a minute :)

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

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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?

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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.

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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.

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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.

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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?

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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> ;)

no pics required.

get an old spark plug, gut it and weld a air line fitting to it.

remove all your spark plugs and wind that one into the pot you want to test.

turn the engine over by hand (use a ratchet on the nut on the alternator pully) untill the engine is a TDC compression stroke on the cylinder you want to test

apply compressed air to the spark plug/airline adapter

listen for air leaks at the exhaust pipe, air inlet, oil filler and other plug holes.

if you get "some" leakage out the oil filler, put 15-20ml of thin engine oill down the cylinder wind the engine slowly for 4 full turns of the crank then repeat the test at TDC compression. if the leak is stopped then its not likely to be your rings

Allow the engine to slowly turn over to test the integrity of the ring seal at various positions of the stroke.

done.