New built engine blue smoke for second time
Turbo Mini Forums

Hi All,

On Friday I started my car and a guff of smoke came from the exhaust, I left it ticking over and every time I revved the engine it guffed smoke. I drove it home ( about 8 miles) each time I set off it guffed.

I have looked at it today and tested the compression 123 cylinders for the fan side was 170psi and number 4 was 165psi. I checked the valve seals number 1 & 4 valve guide seals where off so I refitted them. When I fire it up from cold it starts first time with no smoke..... When it warms up it guffs again when I dab the throttle, I turned it off and restarted it again and it kicks back (borking) a few times before it starts and a puff of smoke comes out.

I have just had the engine rebuilt for the second time and set up on a rolling road. The same thing has happened again after less then 200 miles...... Any ideas what could be happening?

Pete

Leak down test? To check the rings.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Been thinking.....could it have a slightly bent conrod? Number 4's cylinder has a compression of 165 psi where the others are 170. It was fully rebuilt last year with omega pistons and after 200miles it was smoking..... The engine builder took responsibility and rebuilt it with new omega pistons and AP head bolts and AP bottom end. I wonder if it has a slightly bent conrod??? These have not been replaced... It may explain the low compression and kickback??? Possibly

Has the engine been properly run in?
What method?
Sound to me like you took it steady for 200 miles

Also is it turbo? If so whats oil grade and pressure?

Yes i moved to the darkside

Instagram @jdm_brett

The engine was run in on the rolling road, but I had driven it normally, not revving it more than 3-3.5k. oil is 10w/50 and it is showing 100 when cold and drops to around 40-50 warm (at tick over) it has only done 120 miles this time last time 280. the last time the oil rings had worn, but a component in the gear box has failed and there was metal in the oil, Guessworks have rebuilt it this time. the symptoms are exactly the same, starts and runs fine.... then one day smoke and kickback on starting. when it fires it runs fine, pulls fine but guffs smoke. ?????
plug four (clutch end) is darker than the rest with compression is 165 5psi less than the others.....new turbo fitted at the first build.....this time new pistons, new big end and small end bearings, AP head kit, AP bottom end Kit, New turbo oil pump, stripped cleaned and rebuilt. has been ran for 40hour on the rollers by the engine builders and set up.

as above is this a turbo lump

if so 100 psi is waaaay to much for a turbo and will push past the seals. sounds like you stick a standard oil presure relief valve/ sring in for a start.

also 10w 40 is maybe a bit thin, 20w 50 gets my vote.

and next to no chance of a bent con rod, 5 psi difference is not a lot really

Yes Metro Turbo, o.6 bar boost, would 100psi of oil pressure that cause the problems i am having????

I bought the engine second hand 18month ago, the engine was dropped of straight to the engine builders august 2015 and I got it back October 2015 after a full rebuild. it was set up on the rolling road it lasted 280miles and started to guff blue smoke when starting and setting off. it went back under warranty, we found a bearing in the gearbox had failed and aluminium and bearing was floating around in the oil, the oil rings had worn out and the piston skirts scored. the engine was also kicking back when we tried to start it. I sent the gearbox to Guessworks for a full rebuild and crosspin diff while the engine was rebuilt again. The engine builder has ran the engine in and set it the boost, fuel pressure and timing. it has been on the rollers for nearly 40Hours..... I have driven it on the road at normal road speeds for a further 120miles, then the exact same problem as last time. so I am looking for things they might of over looked..... Pete

What is the ignition system, it should not be kicking back or running on.

New Metro Turbo Electronic distributor and coil.....

If it was rings you'd likely get constant smoke and high crankcase compression. 5psi difference on one cylinder is nowt to worry about.

Do the plugs look oily? Is there oil in the intake hoses from turbo to carb?

If neither of the above, likely to be oil in the turbine only.

As above, try 20w50 and lower the oil prressure (minispares sell an adjuster thing).

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Going for a leak down test tomorrow......will let you know....

thinking out loud and listing stuff to check/try....

oil/pressure (as above)

crank case vents (as above)

goosed turbo ( check for oil in the pipes/ play

bad setup so the engine has detted its ars of and destroyed the ring lands, this should show up as low compression though.

troublsome valve seals, although this soesent sound symtomatic of them, usually smoke at startup which goes off

When I first start it the engine kicks back for a couple of rotations then starts.... No smoke...leave it ticking over for a few minuets and blip the throttle puffs of smoke from the exhaust....I have asked about the oil pressure and was told 100psi is fine when cold and when it is warm it drops to 40-50 on tick over and 80ish driving. .??

still not mentioned if this is turbo'd or not,

if it is then the oil pressure is way too much. if it isnt then its still a bit much.

one more thing to check, if the end cam bearing is in wrong the rockerbox can fill with oil if its not being regulated by the cam bearing and groove in the cam jounel( its meant to pulse feed the opil to the head not feed continous) if the rocker box fills up the olil will piss down the guides and cause smoke.

as a rule with turbo's you want 50 PSI max, normaly you'll see about 20 at idle. ok you might see 60-70 cold but much more than that wants looking into.

with the kick back at idle it sounds like the advance curve isnt suited, basically theres too much advance at cranking. tbh thats a sepperate issue.

I concur with Joe.

70 when cold, 40 to 50 max when running and 20 when idling.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Yes Sorry, Metro Turbo...... The engine builder said that he thought the weights in the dizzy were a bit light???? I have checked with the supplier and they tell me it is the right application? I ran it at the weekend with the rocker box off and there was no heavy flow of oil. What is the effect of high oil pressure when cold? the engine guy did not seem concerned when I pointed it out he said as the valve opens when it warms up it will go to normal?
I should find out tomorrow the result of the Leak down test.

hmmmmm,

your engine builder dosent fill me with confidence with the pil pressure comment.

essentially high pressure when cold is not a big problem, but normaly high pressure when cold and high when hot go hand in hand, basically you do want to set it to 45-50 when hot at speed, as said more than that and it will push past the turbo seals.

regarding the timing, thats not so much of an issue, weights and springs are not a fantastic way of creating an advance curve, but they do work, personally I would just oput up with the dizzy as it is and then convert to mapped ignition later. you muight find a foot full of throttle while cranking stops it kicking back, as IIRC the wac advance is taken from the manifold so at cranking could advance a bit. opening the throttle will stop that if thats the case.

That's interesting. ...it is 100 at first. ..then about 5 minutes or so it starts to drop. It tick over its 40-45 and rises to 70-80 at speed when warm. I wonder if it pushing oil past the Turbo seals when warm? Which would explain the blue smoke. It only smokes when it warms up. Nothing for the first 10 minutes or so. ?

FFS,

I've said exactly that about four times, cut the relief spring down already...

45-50 psi hot at speed...

The car is with the engine shop, I will call in tomorrow and have a word and give you an update......still does not explain the sudden coincidental kickback???
They are going to check the timing too!

Keep you posted

Edited by Brett on 5th Oct, 2016.

Yes i moved to the darkside

Instagram @jdm_brett

you want oil flow not oil pressure

like has been said already 20 psi idle and 45psi at speed any more is just wasting hp and adding heat to the oil

not to mention potentially pushing it past the valve guides and turbo seals

myself ive had as low as 10-15 psi idle hot and 25psi max when up in the rpms everything looks fine its the actual volume of oil that takes heat from the bearings and anyway the crank and rods ride on a dynamic oil wedge so as long as your have some kind of oil flow you will have an oil buffer lifting the parts

forget about the tank about high oil pressures and think more about your bearing clearances and the fact that as the crank rotates its pulling oil in under the leading edge forming an oil wedge that lifts it off the bearing this hapends no matter what pressure you have as long as you have enugh flow to replace the oil that gets pushed out and flung out by the rpm

an oil pump moves fluid per rpm no matter what if its 10 psi or 100psi it will move its displacement for its rpm

just my opinion and short experiences