[DG330]

Hi,

I ran a compression test and had good results on5/6 cylinders of 380/390. One on the first two attempts were 250/260.

My dad put the adaptors in so once that result came in we switched back to cylinder one to check the equipment and was all fine. I then put it back in 3 and the results after 8-10 cranks was up at 380.

We carried out another 5 tests and they all came in on 380 and left it an hour before trying again. Was still 380.

My question is - this was a dry test on all cylinders and a cold engine. Could the first two rounds have leaked oil into the cylinder to bump the pressure up by 120psi?

As the oil wouldn’t be burnt off it would just sit there sealing any gaps? Or am I just being silly? I recorded two videos of of cylinder 1 and 3 and both make the same jumps per crank.

My only issue with my car is blue smoke and some black on boost WOT/revved. No power issues to report.

Video one is cylinder 3 and the close up video is 1

Will have to upload to YouTube as too big for here

[DG330]

Cylinder 3

[DG330]

Cylinder 1

[DG330]

To add to this.

All plugs were out at the time of testing. So should oil have seeped it way into cylinder 3 surely it would have been atomised and pushed out the glow plug hole when cranking on the on the cylinder.

Will run a second test on it tomorrow for piece of mind, but a view point from anyone who knows compression test better than me would be appreciated

[DG330]

To update -

Ran the tests this morning after the car has rested over night. All fine.

Condition of the test - all glow plugs removed, intake removed, injectors unplugged and cold engine. This will provide higher PSI results due to no compression in the cylinders not being tested.

Results are on eight cranks and 1st crank pressure.

[Nadir Point]

That engine is definitely getting long in the tooth. Whether or not that is your problem is still anybody's guess, but looking more like it all the time.

How many miles on it?

[MrSweet1991]

Intake and Exhaust valves that aren't seated correctly would cause a loss of compression as well wouldn't it?

Also, where did you get the compression tester from? Might get one myself

[DG330]

Originally Posted by Nadir Point

That engine is definitely getting long in the tooth. Whether or not that is your problem is still anybody's guess, but looking more like it all the time.

How many miles on it?

haha what do you mean?

155k miles now. Compression test results on the final test after a good day of rest with no cranking showed more level results. lowest total was 370 and high 390 on eight cranks

strongly recommend using high temp grease on the threads of the glow plugs when refitting. Did this on mine and they're so easy to come in and out. Also put this on my injectors.

[DG330]

Originally Posted by MrSweet1991

Intake and Exhaust valves that aren't seated correctly would cause a loss of compression as well wouldn't it?

Also, where did you get the compression tester from? Might get one myself

hi mate, yeah it could do. I had two dodgy readings (where my dad fitted the plug and adaptor) then I did it myself a further 5\6 times on day 1 and all fine. Then re-did the test a good day later and all was fine. To make sure I didn't pull anything into cylinder 3 while testing the other I did that first, so essentially a completely dry test.

you will get lower results with the glow plugs as it will reach full compression on 5/6 cylinders. So, either 1 at a time with plugs in, or all out with a higher reader.

The kit was from ebay mate, about £22.

Let me know what results you get if you do

[Nadir Point]

I wouldn't expect that much variance on a healthy engine.

[DG330]

Originally Posted by Nadir Point

I wouldn't expect that much variance on a healthy engine.

The car has done 155k. Compression results are solid and variance on low to highest is 5.4% on eight cranks.

https://www.waybuilder.net/sweethave...Num=7&modNum=6