2E oil loss - low oil pressure & knocking (video)

I've recently finished my 2E 2.0 conversion on my mk2 digi 8v (2E block with a PB head). Everything was great...for a couple of days...

Engine pulls and drives very well however I'm burning a fair amount of oil in not a great deal of miles - most noticeable symptom is a plume of blue/grey smoke on gear change at high revs. I ran a compression test today to see what was going on and these are the figures (seem ok to me?):

Engine cold:

Cylinder 1: 190 psi / 13.1 bar
Cylinder 2: 190 psi / 13.1 bar
Cylinder 3: 200 psi / 14 bar
Cylinder 4: 200 psi / 14 bar

Engine up to temp:

Cylinder 1: 190 psi / 13.1 bar
Cylinder 2: 190 psi / 13.1 bar
Cylinder 3: 195 psi / 13.5 bar
Cylinder 4: 200 psi / 14 bar

Spark plugs look in reasonable health after 800-1000 miles. Plugs were bone dry and not oily, just a little black where it was running a little rich for a few miles:

Cylinder 1:



Cylinder 2:



Cylinder 3:



Cylinder 4:



Really not having much luck with this car and if anyone could possibly shed some light as to what's going on it would be appreciated. I'm really really hoping the rings aren't on their way out . Am I right in thinking it would smoke constantly if they were?

Thanks

 

Those compression figures are fine.
Was this a replacement head you got after the last one burnt the valve? If so, was it checked over, especially for valve rock which is a sign of guide wear?
It could be the guides are worn and the valve stem seals are tired causing the oil use.
If rings were on the way out then the engine tends to breathe heavily and leak oil due to the increased crankcase pressure.

 

Cheers for the reply Danster.

Yes this was a replacement head, although it is the original from the car refurbished (previously removed to fit the one that burnt a valve). It was sent away to a reputable builder and was fully checked over with new stem seals, guides and a slight skim. The seals used were not genuine though and as it was sent away this is one part of the process I did not oversee.

Haven't noticed any major oil leaks, it's definitely being burnt however are there any areas I should be checking to see if it is indeed breathing heavily? I ran some engine flush through to clear the bottom end if that adds to the picture at all.

I really hope it does point to the head as I do not want to take the bottom end out again . The bores looked very good and it's supposedly from a 100k car (although I do not have proof of this).

 

blue plume on over-run/ gearchange usually points to valve stem seals, no?

as blue plume on power tends to be rings??

I fitted a stem seal poorly once (easy to do tbh) and this led to plug fouling on that cylinder if the car was doing city miles (ie lots of idling at high vacuum, so sucking oil down the valve guide), but clean on motorway miles. Your plugs are clean.... your compression looks good

do you have any misfire at idle? (with my dodgy stem seal, if left idling for a while the car developed a miss, which I assume was the plug getting mucky)

 

Thanks for the reply.

Slight misfire at idle perhaps but nothing really worth mentioning.

Excuse my ignorance with diagnosis but if the rings were letting oil through would I be seeing much more of a considerable difference in the compression test results? Short of actually replacing the stem seals again are there any other diagnostics I can try to build a better picture?

I can only see the plume at high revs - I don't think it's smoking all of the time (if it is it's considerably less i.e not noticeably when driving anyway). Seems clean at idle.

One other thing I did think of - I'm running a home brewed breather setup using a mix of mk2 and mk3 parts - that wouldn't be affecting anything would it?

Chuffing car

 

plus one with dan the man

 

Cheers, would just like to try narrow it down a tad more before I go back to the head builder.

One thing that did cross my mind - I'm using the 1.8 dipstick in the 2.0 - same length as the 2E one as I checked but didn't think to check the marks (assumption may be a fall down point here). Perhaps it's overfilled slightly?

 

Have you cleaned the breather out? Could be old oil residue.

Did you remember to put the oil scraper back over the top of the cam? If not, it'll be chucking oil down the breather in the rocker cover - is the inlet manifold full of oil

 

As Danster says, compression test results look fine. I'm assuming it only took 3-4 compression strokes on each cylinder to reach those figures?

As a rule blue smoke at high revs points to rings, blue smoke at idle points to valve stem seals. Look for a puff from the exhaust when starting from cold too, since oil can leak past the seals into the cylinders while the car is stood.

Overfilling could be a possibilty; I've done it and had an oily exhaust as a result. Shat myself too as I thought I'd melted a piston

According to a quick look over ETKA the PB and 2E dipsticks are the same; not sure about their respective tubes though..

 

Yup oil scraper is back over the cam. Breathers were cleaned although I guess there may be a little residue in there still from the flush.

Thanks for checking the dipsticks Mike. Yeah those results are from about 3 strokes. The smoke is at high revs but literally on over run or sudden deceleration i.e changing gear. It doesn't smoke when idling or starting up (but does whiff a bit) or any another time during enthusiastic driving, it's literally only on gear change when up in the higher rev ranges (5k +).

I might try draining a little oil out and seeing if that makes any difference at all.

 

Ok this problem has got worse

The car is using quite a bit of oil now. Exhaust smells quite fumey on idle but the smoke still only happens at high revs on gear change. No puff on start up and no sign of smoke any other time (i.e idle, any other time driving etc). Compression tested the car again yesterday and it all seems good with similar readings to those originally posted (engine warm, fuel pump relay removed, coil disconnected, throttle fully open). As does the oil pressure on the VDO gauges.

I'm debating about ringing the guy who refurbed the head and seeing what he says. Only thing is, I'm not really sure what to say and I don't want to go making accusations I don't really know much about. Me and mate fitted the head however the actual head work done was nothing to do with us.

I could get the stem seals replaced again although this is likely to cost around 200 as I can't do them myself without removing the head - something I want to highly avoid. There's no guarantee it is this though.

If the rings were gone would I get a constant plume of smoke from the exhaust on acceleration?

Any advice appreciated as I'm at a bit of a loss. I'm starting to loose the love for this car. One day I may actually get a working engine

 

oil

broken,damaged or worn valve guides?

 

Possibility of damage but all the guides were replaced and the valve seats recut during the refurb.

 

I spoke to the head rebuilder today and he's happy to have a quick look at it. Unfortunately he seems to think it's a piston ring issue

Would it be worth getting a garage to do a leak down test to try and pinpoint the problem? Also if I were to wet compression test it do I literally just put a few drops of oil down the spark plug hole? I've read in another thread that the wet test is virtually no use on an 8v, due to dished pistons. Is this true?

Cheers

 

Wouldn't piston ring problem(s) show up as poor compression figures though?

Here's a plan for you...


...if it is stem seal(s) you might be able to see the results of leakage on the backs and stems of the valves, with inlet mani removed looking through the ports?? I'd've thought with a freshly rebuilt head, there should be absolutely no black sludge to be seen anywhere. If one or more stem seals is leaking, you might see some residue?

Worth a look?

Edit: Course, this would be a waste of time if (an) exhaust valve stem seal(s) alone was the problem...

 

I haven't got a replacement gasket currently but I'll try find time to whip the inlet off over the weekend and have a look.

I'm really hoping it is just the one stem seal to be honest or something along those lines - I find it hard to believe all of them would have been incorrectly fitted. I just hope to god it's not a piston ring letting go. I bought the block in good faith and really don't have the time nor money to strip the car down again.

Can anyone confirm about the 8v wet test or indeed whether a leak down test is worth doing?

Thanks for the advice btw, appreciated

 

I tend to agree with you on the wet comp test being a bit of a joke on an 8v due to the dished pistons. You are effectively going to have to fill the piston bowl with oil to get it to the ring land, yeah some might get there quicker, but the volume of oil in each cylinder will vary and alter comp readings anyway.
I just check them all dry, and iirc yours were all good last time you did this.

 

Cheers for the input chaps.

Yes the compression tests were done cold. I've tried it with a cold engine (to try and show up any worn rings) and carried out the test twice when it's upto temp. Pretty much same readings on all occasions.

The head builder is a reputable chap however I have a feeling he's going to just say 'it's the rings' when he takes a look next week. It's just a guessing a game, an expensive one at that, so before I strip anything down I wish I could get a more definitive direction. To be honest, I'm debating chucking the towel in if the bottom end is fubbard.

Points to seals - smells on idle, compression is good, smokes between changes gears for a few seconds, doesn't smoke any other time.

Points to rings - using a considerable amount of oil, doesn't smoke on startup.

I have an oil pressure VDO gauge I can get some readings from - would that give any more of an indication?

Again, thanks for the help - CGTI really is a fountain of knowledge.