M62, 4.4 2002 cylinder compressions

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bob.lydon

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Hi All,

I have looked all over the internet to try and find what the cylinder compressions should be for my engine, before i decide if i need to pull the heads off and have them refurbished.

Cylinders 1, 3, 5, 7, allread between 85-100 PSI, where as Cylinders 2, 4, 6, 8 all read 145-150, clearly something is not right on the first 4 i tested, what should i be looking for, engine has done 96,000 miles.

Thanks in advance for any help.

Bob
 
I'n no expert on the 4.4 but I'd say you have a problem on that bank of 1/3/5/7. 85-100PSI is far too low. 145-150 is marginal for a newish engine I would have thought. (I get 160-170 out of my 20 year old 3.9). It's odd though just to have a whole bank go down. Did you test them all identically i.e. all with the throttle open etc? Are there any signs of anything amiss? Smoke etc? What caused you to check them in the first place?
 
bob.lydon said:
Hi All,

I have looked all over the internet to try and find what the cylinder compressions should be for my engine, before i decide if i need to pull the heads off and have them refurbished.

Cylinders 1, 3, 5, 7, allread between 85-100 PSI, where as Cylinders 2, 4, 6, 8 all read 145-150, clearly something is not right on the first 4 i tested, what should i be looking for, engine has done 96,000 miles.

Thanks in advance for any help.

Bob
Click to expand...

Take the heads off mate you have a problem.
 
Thanks lads for the replies lads, thats what i thought, just wanted it confirming.

Since the original post i put a bit of oil through the spark plug holes and retested cylinders 1, 3, 5, 7, and they went up to around 135 PSI each, what PSI should i be looking for as i did'nt think bank 2 was to bad.

Bob
 
bob.lydon said:
Thanks lads for the replies lads, thats what i thought, just wanted it confirming.

Since the original post i put a bit of oil through the spark plug holes and retested cylinders 1, 3, 5, 7, and they went up to around 135 PSI each, what PSI should i be looking for as i did'nt think bank 2 was to bad.

Bob
Click to expand...

Your piston rings are knackered. Depends on compression ratio on a good HC engine 160+.
 
Thanks Wammers for the quick reply, it seems strange why one complete bank would be low and the other one fine, especially when all 8 cylinders where tested exactly the same, there is no signs of smoking Dereck, the engine is a bit lumpy, the only fault the launch x431 gives is vanos timing fault bank2....this does not even put on the engine light.

Do you think theres a chance that bank 1 cylinder head is knackered, hence causing the low readings??, or is that not possible on all 4 cylinders.

Going to start stripping it in the next few day's and keep me fingers crossed that it's not to bad.......however as it's a range rover i will expect the worsed and the most expensive option.

Keep your fingers crossed for me!!!!
 
bob.lydon said:
Thanks Wammers for the quick reply, it seems strange why one complete bank would be low and the other one fine, especially when all 8 cylinders where tested exactly the same, there is no signs of smoking Dereck, the engine is a bit lumpy, the only fault the launch x431 gives is vanos timing fault bank2....this does not even put on the engine light.

Do you think theres a chance that bank 1 cylinder head is knackered, hence causing the low readings??, or is that not possible on all 4 cylinders.

Going to start stripping it in the next few day's and keep me fingers crossed that it's not to bad.......however as it's a range rover i will expect the worsed and the most expensive option.

Keep your fingers crossed for me!!!!
Click to expand...

If you put oil in and it goes up that means the rings are suspect. If you put oil in and it does not move valves. It is hardly likely that ALL the cylinders are blowing into each other by way of the head gasket. The fact that the compression was raised on all cylinders to 135ish on the addition of oil seems to point to rings.
 
160 ish sounds about right. More importantly is the discrepancy between highest and lowest, which, as posted should be around 10% variation.
Unlikely that all the rings have died on the one bank alone. Wammers is right in saying that the oil test discriminates between the valves and rings but I think there is more to this than appears. The head needs to come off and further checks made.




juiceyv8 said:
Way to low. should all be within 10% of each other.
Click to expand...
 
Cheers Wammers and Irish, have started stripping the engine, hopefully will have a better idea over the next few days whats went wrong.

I have two cylinder heads from a previous 4.4 M62, which were fine when i removed them ( piston and cylinder wall had holes in them ), so since my earlier post i have dropped them into my local machine shop to be pressure tested, have the heads skimmed and valves reseated, will get them back in a few days if all is well.....

Also hoping that the vanos timing kit etc arrives from the states in the next few days, am also checking the cost of the gasket kit to see if it's cheaper through land rover or bmw, will post the prices.

bob
 
Wammers is right in saying that the oil test discriminates between the valves and rings but I think there is more to this than appears.
Click to expand...
I'm inclined to agree with Irish here. For a whole bank to go down like that is rather strange. Maybe the word 'Vanos' is a clue. If the valve timing has got totally messed up on that bank, you'd get a similar effect. Maybe the rings are a bit tired as well as Wammers says but the compression only went up to 135psi so I think we're missing something else here. It'll be interesting to see what Bob finds.
 
bob.lydon said:
Cheers Wammers and Irish, have started stripping the engine, hopefully will have a better idea over the next few days whats went wrong.

I have two cylinder heads from a previous 4.4 M62, which were fine when i removed them ( piston and cylinder wall had holes in them ), so since my earlier post i have dropped them into my local machine shop to be pressure tested, have the heads skimmed and valves reseated, will get them back in a few days if all is well.....

Also hoping that the vanos timing kit etc arrives from the states in the next few days, am also checking the cost of the gasket kit to see if it's cheaper through land rover or bmw, will post the prices.

bob
Click to expand...

Be sure to get back and tell us what the problem was, it is as others say very strange that all cylinders on one side dip at the same time.
 
Not really much else to tell at the moment, except the spare cylinder heads have just been skimmed, pressure tested, valves reseated and new seals fitted, so they are now as new and ready to fit.

Got a price for new head gasket kit from both bmw and land rover.......strange thing there though, have you ever heard of a head gasket kit that does not include the head gasket's.......robbing barstwerds!!. Am not quite finished making the waterpump locking tool ( busy at work ), but hopefully will it finished and ready to start the strip down at the weekend......new waterpump and the Vanos setup/timing tools still not arrived as yet.

Will keep you all informed as i get stuck in, it's not to hard of a job, just time consuming and bloody back breaking reaching over the front of the car.
 
Just a quick update, engine is now stripped and the heads are off ( arms are bloody knackered with reaching over the front of the car ).

Cant see nothing to bad, the cylinder bores are all nice, smooth and clean, however on the removed heads, the one with low compressions seems to show slight wear between the cylinders compared to the good compression side.

The newly refurbished spare cylinder heads are now back from the machine shop having been pressure tested, skimmed, valves cleaned, reseated and new stem seals..including the head gasket kit it's set me back over a grand.....ouch!!!!!!!!

Will be starting the reassembly over the next few, will keep you informed.

bob
 
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