20XE burning oil

My "1000 miles of trouble free motoring" celebration is a little premature I think.

Went out for a blast yesterday and did probably 150 miles, and it looks like in this time it used just under 0.5L of oil. Can't see any leaks so initial assumption is it's burning it.

Engine was rebuilt by me 1000 miles ago with new pistons, rings, Cometic headgasket, new stem seals etc.

A few mates followed me out the weekend before last and said it smoked a bit on overrun but not under acceleration so assume this is when it's burning it.

Suggestions? Planning on doing a compression test and checking the plugs while they're out...

When its left overnight and you first start it up do you get a bit of blue smoke at first start up?

Sounds like the stem seals.
Which is a head off job :(

I tried starting it/revving it from cold today and there was no blue smoke, nothing noticeable anyway

A newly built engine will use a bit of oil and if you are driving it hard it will use a bit of oil too, I would monitor the issue and see if the consumption gets worse. What oil are you running it on?

10/40 mineral oil. Expected some oil loss up to 500 odd miles but had expected it to stop using as much by now?

Oh forgot to say, removed the plugs and #3 looked a bit black and shiny on the threads, but the tips overall looked okay.

If its used .5 litres that quickly you should notice if its burning it (smoke etc)

But as said - it will burn a bit more than normal as its a fresh lump, so I wouldnt worry.

I'll get it up in the air and double check for leaks then, I don't see plumes of blue smoke in the rear view mirror! I'll give it another 1000 miles before worrying then :)

I take it you've run it in correctly ?

Had it under load and engine braking almost constantly without going over 4000rpm for the first 500 miles, oil changes at 100 and 500 miles with mineral oil.

Had someone follow me today down the lanes, it produces a little bit of blue smoke on powering on and a bit more when letting off. Not producing enough for me to see in the rear view though.

It also smells really bad if you're behind it.

Got through another 0.5L or so in the past few days again...

Suggestions?

Edit: its now done 1500 miles btw

i had a car a while ago (non vaux) and as soon as you lifted off the throttle on the over run its smoked like feck

did you change the valve stem seals?

Fitted new ones when I built the engine.

I've just had it ticking over on the driveway, put my hand over the exhaust and it spat black specs out. Could this be unburnt oil?

This is what the driveway looks like after revving it 3-4 times

http://iainel.co.uk/images/forums/Black1.JPG

And a piece of paper held over the tailpipe for 15 seconds on idle:

http://iainel.co.uk/images/forums/Black2.JPG

It's quite moist on the paper. Is this concerning or just normal?

have you done a compression test, also did you get the rings checked to see you fitted them correctly prior to building?

Not managed to do a compression test yet as my compression tester broke. I did not get the rings checked.

well its only a wild guess at this stage, with the amount of unburnt oil on the paper and it being newly built i'd be looking at the rings as suspect, far to much there for it to be a stem seal but you never know it might just be weeping and oils sitting in the exhaust,its a nice car shame if you need to strip engine already but just one of them things as they say, you should ask lee303 on here or mig seems to know his stuff with engines/rebuilds:thumb:

Sure you didn't fit a diesel engine? :p

If it were the rings would it not be burning a lot more rather than spitting it out unburnt?

I've posted on MIG mrT in the hope Lee sees it :) Thanks for your help

Hand over the exhaust today and it wasn't spitting black out, and won't leave any marks on the floor, so it's quite intermittent. Results from compression test:

Hot + dry, average:
1 = 230
2 = 232
3 = 248
4 = 248

Hot + with a dribble of oil down the bores (first go then second go):
1 = 290, 280
2 = 300, 295
3 = 290, 280
4 = 298, 277

Id say you have a problem with #1 and or #2

You have done the test with WOT?

Yes sir

Weirdly the two plugs that have looked slightly oil upon removal are 3 and 4...

Quote:

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Originally Posted by Iain

Yes sir

Weirdly the two plugs that have looked slightly oil upon removal are 3 and 4...

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Not really, the oil leaking into them would give you the higher compression (would be a 'damp' test lol) and suggest you have a problem besides rings.

Looks like the heads going to have to come off?

Yeah maybe Paul, just trying to get all the info I can now and work out a plan of action... Like if I take the head off how can I test if the rings are bad/haven't sealed?

I might buy and recon a new head ready for whatever I do lol

I'm gonna put £10 on head gasket. 2 cylinders next to each other suggests it may not have sealed properly, stem seals being put in wrong or early failure etc on 2 cylinders side by side would be less likely I reckon, and no other routes for oil into the engine besides a cracked head or block.

Compression is your test for rings really, if one was bad then it would show up, unless the oil scrapers aren't functioning, but tbh they're more to apply oil to the walls than get rid of it, the compression rings would still scrape the walls clean under pressure.