Compression test data on 300 tdi..

I have half compleated a compression test on my 300tdi D1 to see where blue smoke is coming from, but cannot find what the standard pressures should be. Only info i could find was in the haynes manual that said there should not be a difference greater than 70 psi. Could not find the info on my rave cd. Here is the results i got before coming in for tea. All pressures were taken from the glow plug hole and let the engine turn over 10 or so times to read the pressure. C1 - 450 psi c2 - 460 psi c3 - 460 psi and c4 - 430 psi. These are all dry figures, had to come in for tea before i could do the wet ones but these seem ok dont they??

Simon

yes a difference of more than 10% is getting poor ,but yours would seem okay

Thanks for that, will do the wet test after. Im hoping that they will be ok, which leaves the valve and guides or the breather pipe is blocked which is causing the crankcase pressure im getting and blue smoke (which is a bit more noticable now that the pump is adjusted correctly). Turbo seems ok and there does not seem to be any oil in the intercooler pipes now that i have disconnected the bypass hose.

Simon

turbo will allways pass some oil even a new one will ,you can have good pressure but poor cross hatch and oil burned, poor injector etc

well got the wet results, all these results started low about 150 or so and build up over 10-11 cycles..

cylinder dry wet
1 450 480
2 460 530
3 460 530
4 430 460

What the verdict? Rings? Mate suggested that i put some redex down the bores??

Simon

did you use the same amount of oil

Yes. It was the same amount of oil in each bore. However as it was down the glowplug hole, i could not be sure that the oil got to the bores and not just filled the piston depression up. I have a pretty good service history with the disco and cannot see anywhere where the engine has been out or even had the head off and its done 176K so guessing it could do with some TLC. I guess its worth pulling the head off and having a look as i dont have a leak down tester. Because of the PO messing with the pump and badly overfuelling it, i just have it in my head that the bores are now glazed, but from the results of the test i have done not too badly worn so hoping that a hone and re-ring will sort it. I dont really want to put a full engine rebuild onto the list of jobs i have to do!!!

i might be temted to remove head and also check crank bearings

Thanks, that was i was thinking. Will post the outcome next week when i do it as i need it this weekend to pickup a transfer box i won off ebay.

Just a thought, Can the main bearings be changed without taking the engine out??

Well got the head off. Full of carbon and the bores were as shiny as a shiny thing. Good mate borught round his bore comparitor, what a bit of kit. I carefully cleaned off the carbon round the top of the bore and compared the top of the bore with that about 20mm or so further down and only seemed to be about 2 thou max difference so hopefully a good glaze bust and they should be ok. Got too wet even with with CAR TENT(TM), (gazebo) over the front of the car to drop the sump and remove the pistons and check them. Will do that tomorrow along with checking the head over.

So, so far been a better day than i was expecting..



Number 4 bore before i started decoking.



CAR TENT(tm). Picked this up from b&q for 17 quid. Well worth it.


Simon.