Low compression in all cylinders

[LavisLane]

It's the news I knew was coming. Low power and a bit of smoke out the back under revs were a sign that things were on the down hill.

Compression test today has shown that all cylinders are around 110 when they should be closer to 150. See attached...

It's not the end of the world of course, she still runs fine and I don't see a problem with continuing on as is. Unless i'm planning a trip with a large caravan on the back, I should be fine. Just something to wear with any car over 10 years I guess.

However, it's going to be in the back of my mind every time I put my foot down with the little voice on my shoulder telling me to find the $8k to get it fixed.

Anyone else gone through this? Importantly, any suggestions on a fix? Is it something anyone with minor engine experience and too much motivation should attempt?!

Dave

PS - not sure if i should recommend that anyone else get this done. It was nicer living in ignorance... ;)

[VladTepes]

$8K for what ?

[wayneg]

Now if you are going to live with it for a while and you are a gambling man have you seen this ( SNAKE OIL?) product?
http://http://cgi.ebay.com.au/Noisy-tappets-Cured-Try-AMETECH-ENGINE-RESTORE-OIL-/390268164033?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5addcb97c1 (http://cgi.ebay.com.au/Noisy-tappets-Cured-Try-AMETECH-ENGINE-RESTORE-OIL-/390268164033?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5addcb97c1)
I know, I know what these type of products promise, but I think I would take a punt just to convince myself I was making an effort
Anyone actually tried this?
For those who dont know of Quentin Wilson he is a well regarded down to earth motor journalist

If you do try it please give us an after compression test result.

[LavisLane]

$8K for what ?

To get the compression up to a normal level i'm told i'll need to;


New liners
Clean and machine pistons to suit new liners
Clean and grind crank
Timing chain
Have my wallet surgically extracted from my a$$ :eek:


does this look about right to anyone that's gone through this?

[Keithy P38]

A full rebuild shouldn't cost anymore than $5k... I built a performance motor for a friend at $5.5k and that was cost price (no trade discount). If you shop around I rekon you'd find a N.O.S 4.6 from overseas and have it on your door for cheaper than that!

Cheers
Keithy

[justinc]

A full rebuild shouldn't cost anymore than $5k... I built a performance motor for a friend at $5.5k and that was cost price (no trade discount). If you shop around I rekon you'd find a N.O.S 4.6 from overseas and have it on your door for cheaper than that!

Cheers
Keithy

Not with Liners, Pistons, machining, gaskets, bearings, rings etc, and labour to fit it all together and IN the vehicle, filled with all fluids, radiator tested/ cleaned, tested and delivered. 8K is cheap.

JC

[davo52]

I had mine and my wife's HSE's both give up the ghost last easter. Rebuilt one with a tophatted short motor with new cam and followers and the other with a tophatted block for about that amount. Labour was my own though.

[Pedro_The_Swift]

and no sane reason for spending that amount and NOT getting top hats,,,

[Pedro_The_Swift]

I had mine and my wife's HSE's both give up the ghost last easter. Rebuilt one with a tophatted short motor with new cam and followers and the other with a tophatted block for about that amount. Labour was my own though.

His and Hers HSE's,,
ya gotta love that!:cool:

Pics?:angel:

[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?

[BusinessConnected]

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 :)

[DT-P38]

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

[LavisLane]

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?!

[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.

[LavisLane]

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?

[jsp]

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.

[p38arover]

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).

[Blknight.aus]

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.

[PaulP38a]

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

[Blknight.aus]

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.

[LavisLane]

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.



Sounds like a plan. A few things i'll need to sort first though;

- How can I see TDC - looking through the empty spark plug hole?
- What if i'm getting leakage from the exhaust - is it rings?
- Should I just find someone professional to run these test for me (Graeme Cooper advised after the compression test that there were no more tests they could do!?)

She's definitely using oil but no leaks, so i'm guessing rings. It's running ok, maybe a slight miss but can't see an issue continuing as is aside from the oil consumption. So, I should really sort this out one way or another.

Dave

[PLR]

Sounds like a plan. A few things i'll need to sort first though;

- How can I see TDC - looking through the empty spark plug hole?
- What if i'm getting leakage from the exhaust - is it rings?
- Should I just find someone professional to run these test for me (Graeme Cooper advised after the compression test that there were no more tests they could do!?)

She's definitely using oil but no leaks, so i'm guessing rings. It's running ok, maybe a slight miss but can't see an issue continuing as is aside from the oil consumption. So, I should really sort this out one way or another.

Dave

G`day Dave ,

it`s disapointing to read a story like yours , i don`t mean how your car is behaving but what you`ve been told .

A basic compression test that doesn`t follow all the rules will only be any good to find a major fault in a cylinder or cylinders and only 1 set of figures suggests this .

The fact you`ve been told there are no more tests , for mine in this instance would indicate i found another business to spend my money at and the reputation i`ve read of for Coopers would be of no influence after what you`ve been told , they may have had an off day but it`s your money .

I`d suggest you Google " compression test " , " leak down test " , " vacuum test " and how they are used , the procedures that need to be followed and their relation to diagnosis of an engine .

Peter .

[Blknight.aus]

no more tests......?

how long a list of diagnostics tests would you like and would you like that list limited to my field type tests or the ones where I go and get all scientificy and bring out/borrow some serious techology?

theres a few ways of assessing TDC...

the easiest is with a long shank screwdriver that fits in the spark plug hole, wind the engine over a bit and poke the screwdriver in slowly turn the engine over and it will rise, once its stopped rising bingo TDC.

wind in the spark plug with the air fitting (do it right and you can get a piece of fencing wire down through that so you dont have to take it out every time to check TDC.

put the air on if you get a massive loss of air you're out 180 on the cam and the valves are open (your transitioning from exhaust stroke to inlet) spin the crank one full turn and your on compression.

in a perfect world there should be no leakage out the inlet manifold
none out the exhaust either
and a small percentage down past the rings (they dont seal perfectly while static)

[PLR]

no more tests......?

how long a list of diagnostics tests would you like and would you like that list limited to my field type tests or the ones where I go and get all scientificy and bring out/borrow some serious techology?

theres a few ways of assessing TDC...

)

If your directing this my way .

What is the problem ?

Do you have something to do with Coopers or are you the one that told him there is only 1 test and it`s been done ?

I`d like to see a long and detailed list of diagnostic tests of any kind from anywhere , thanks .

[Rupert Prior]

if this is the car i just spoke to Peter Davis about, i think the guys that did the original testing should double check their equipment and their ideas.

[LavisLane]

Thanks to all for your input. Rupert, correct. Thanks for taking a look at this one.

Turns out that the only low compression is in cylinder 2 at around 105. All other cylinders relatively normal.