Help understanding compression test results

[stocious]

My 3B is smoking constantly, a white-ish grey coloured smoke, with puffs of after a hard rev and also under boost, fumes from exhaust is suffocating when started indoors, engine has used so much oil when dipped it was barely showing on the dipstick, car has a drip from the rear main seal but nothing to the extent that it would near empty engine.

So the plugs came out for a look, some lightly fould some not, cant remember which ones of the top of my head.

Then compression tester came out,

All tests done with all plugs out and throttle wide open.

COLD DRY COLD WET
1. 10.9 BAR 1. 12.6
2. 10.3 2. 12.4
3. 10.1 3. 12.4
4. 9.9 4. 12.4
5. 10.3 5. 13.1


HOT DRY HOT WET
1. 10.9 1. 12.5
2. 10.9 2. 13.4
3. 11.3 3. 13.1
4. 11.2 4. 13.5
5. 11.1 5. 13.6

Any help/advice is welcome.

steve

[UrS4boy]

20VT Compression Testing Procedures and Results

Rings. Compression goes up under the wet test = rings. Compression doesn't go up (much) under the wet test = valves. (You might still have some valve stem seal issues too based on what you said)

***********************
20VT Compression Testing Procedures and Results

To start, remove the spark plugs, as detailed in the Spark Plug Replacement post.

To disable fuel going into the cylinders during this exercise, pull the fuel pump fuse *AND* pull the injector connectors off OR remove the injector fuse.

From a previous kinderutz post:

Compression pressures
New: 9-14 bar (131-203 psi)
Wear limit: 7.5 bar (109 psi)
Max. permissible pressure difference between all cylinders: 3 bar (44 psi)

Check page 42 of 93 in this pdf: http://s2-audi.co.uk/workshop/aan/aan.pdf

[AndyP]

I would say there's nothing wrong with your compression results. How many miles has the car done? I'd go with turbo needing an overhaul if you've been running it at 280bhp for a while

[stocious]

4. things to add, i must change the bhp figure in my signature, car has 2.5 bar map so i think the software is 260 ish, correct me on that if wrong, the car had an indicated 150 tho miles when i got it but have changed clocks since then, car cant have drove no more than 100 miles, mixed driving , turbo was replaced with a very minimal play unit which did have a slight mark on compressor blade.

between the car being started every so often and the 100 miles driven its almost ran dry.

[stocious]

car also smoked with old turbo, its almost shocking how fast it went through the oil

[stocious]

car pulls strong and drives well, slightly rough idle tho

[popdemonic]

Nothing's wrong on your compression readings.
I'd check the pcv first thing first.if they're all good.
I would remove the wastegate and checking there's
Oil collected in the exhaust manifold.i have seen
A couple I5 heads on these days has worn valve guides,
And stem seals.yes, both of that failures could case excessive
Using oil and puff of smoke out.

[stocious]

when i first got the car i replaced all hoses and the pcv valve itself, the only thing is that the flame arrestor is missing,
as for the stem seals, the car does not smoke from startup, it has to get a bit of heat into itself before the smoking starts.
im confused to be honest

[stocious]

Is it possible to have bad oil control rings and good compression rings ?

[JP]

yes

[pasbogdan]

Compression pressures
New: 9-14 bar (131-203 psi)
Wear limit: 7.5 bar (109 psi)
Max. permissible pressure difference between all cylinders: 3 bar (44 psi)

That 7.5 bar i do not know what manufacturer wanted to say.
Have seen +0.35mm at bores and 1.75mm ring gap(long gone wear limit) with dry compression test 9.5 bar.
Also seen 0.8 mm ring gap and +0.03mm bores with 10 bar dry compression test.Difference?Second one did 7 bar at first crank rotation,then at next compression cycle 10 bar.
Check pcv as other member advised and turbo.If valve guides and or valve seals are gone car should smoke on deceleration,or in boost after a some time at idle or part throttle driving.Check if it smokes when you boost it some good minutes.If it does not means valve guides/seals are bad.If it still does check pcv,turbo,air filter,rings,bores,pistons.

Regards,

[JP]

For the amount of oil the engine is consuming it can only be through rings,
Ķk

[pasbogdan]

Might be,but not 100%.
Plastic hard valve seals can leak tons of hot/thin oil.Also worn valve guides combined with old seals can get exhaust back pressure and/or boost to create pressure in pcv system.
That combined with a bad pcv system and clogged air filter element can cause oil or oil fumes to be aspirated into turbine and combustion chamber.
If pcv is ok,air filter ok,turbine ok,engine must be opened.

[Bowie69]

White-ish grey smoke could be a stuck open fuel injector, especially if it burns the eyes really badly.

[Rusty]

Could also be a leak from somewhere - look for fresh oil at joints, gaskets etc.