Heavy smoke on lift off.

[Stella Artois]

Just got the car back from having the exhaust replaced and the drivers side rear hub replaced after the lock nut failed, driving back I noticed smoke from the rear left exhaust on engine braking. I initially put this down to the new system but as I had to travel 120 miles back it gradually got worse. On normal acceleration there is no smoke from either bank, on heavy acceleration, on boost a small puff of bluish smoke from the front bank (left hand exhaust) when changing gear, but when you throttle off and allow the engine to brake there is a massive amount of blue smoke from the left hand - quite embarrassing!

I do get 2 pop surges on full boost at 4500 and 6000 rpm, but this I believe is down to the mapping that needs to be sorted since the new exhaust went on. Its only noticeable on full throttle, and the turbos just pop and it misfires for a fraction of a second. The turbo hoses have been off and there does not appear to be any signs of oil from the turbos.(They were serviced last year). So its leading me to think valve stem oil seals.

I know that these can be done in situ, but I'm not sure that there is accessibility with the position of the engine to do them without the heads coming off. Pisser, really as the heads were off last month for the head gasket failure. Is there any way do confirm this? A compression test?

Any help would be appreciated thanks.

BTW, I'm quickly going off the Noble, as its just one thing after another

[Rollcage]

Piston rings. (Or recurring HGF)

If it was valve stem oil seals, you would get smoke pulling away after idling and on start up.

Edited by Rollcage on Sunday 29th November 10:04

[Stella Artois]

Rollcage said:

Piston rings. (Or recurring HGF)

If it was valve stem oil seals, you would get smoke pulling away after idling and on start up.

Edited by Rollcage on Sunday 29th November 10:04

I do get a small amount of smoke from start up, but I get enough to engulf the car on overrun. I actually had to stop on the M11 as I thought the back end was on fire....... again!

[Rollcage]

Stella Artois said:

Rollcage said:

Piston rings. (Or recurring HGF)

If it was valve stem oil seals, you would get smoke pulling away after idling and on start up.

Edited by Rollcage on Sunday 29th November 10:04

I do get a small amount of smoke from start up, but I get enough to engulf the car on overrun. I actually had to stop on the M11 as I thought the back end was on fire....... again!

AS you were - misread your OP as heavy smoke when accelerating.

New brain needed!

[Boosted LS1]

If this has happened since the exhaust was replaced then I'd look for a leak or problem in there first. Valve guides wear slowly and I doubt you broke any piston rings on the way home unless you really caned under detonation it or did something silly.

ETA, I'd also check turbo oil supply pipes, drains and any fuel vacuum/pressure lines in that vicinity.

Edited by Boosted LS1 on Sunday 29th November 10:41

[TuxMan]

when Mark popped round yesterday ,we took off the main throttle body pipe from the intercooler and while ticking over it does smoke but if you take the pipe off it stops smoking ?? although there are no signs of oil in the boost pipes ...bit odd . guess you could take the plugs out and compare the colours ,see if any are oily ?

Edited by TuxMan on Sunday 29th November 11:39

[andygtt]

I seem to remember my cossie smoking on overun but was fine under load... it was the oil seals on the turbo...
Not 100% sure these were the only symptoms as it was over 10years ago and I was running much higher boost.

[Gadgeroonie]

i suspect your turbo has failed

what exhaust did you get fitted ? a reduction in backpressure may have highlighted the problem, did they replace the exhaust system from the downpipe back

you said the car pops on full boost - how much boost does it run ? you may be tripping the boost limit
(a set of new plugs may sort the problem)

is the car a 2.5 or 3.0 ?

[Stella Artois]

Gadgeroonie said:

what exhaust did you get fitted ?

Hayward and Scott - Full system from headers back.

Gadgeroonie said:

You said the car pops on full boost - how much boost does it run ?

On full boost, 1.2bar - I know thats in excess of the standard 0.7bar, I believe (90% sure) that this was mapped by Yellowshed maybe 18 months ago, if I remember the date of the receipt, and to all intents and purposes until the head gasket failure it always went like stink and ran perfectly circa 7000 miles.

Gadgeroonie said:

is the car a 2.5 or 3.0 ?

Oh, its a 2.5.

[lotus160sport]

Could it be that one of the cats is on it's way out I got heavy smoke from mine when one went.

[AC Motors]

Have you checked the brake fluid? do you have to top up regularly, could be the servo letting brake fluid into the inlet manifold. Unlikely but worth checking.

[Stella Artois]

lotus160sport said:

Could it be that one of the cats is on it's way out I got heavy smoke from mine when one went.

Doubt its the Cat, as they are behind the drivers seat at present, rattling around.

[Stella Artois]

AC Motors said:

Have you checked the brake fluid? do you have to top up regularly, could be the servo letting brake fluid into the inlet manifold. Unlikely but worth checking.

Brake fluid? - Are the two systems even connected together in some way?

[Gadgeroonie]

1.2 bar ! thats probably why the turbo failed

[Stella Artois]

Gadgeroonie said:

1.2 bar ! thats probably why the turbo failed

Assuming it has. Its been running 1.2 for 6 months quite happily to date.

[Boosted LS1]

Stella Artois said:

AC Motors said:

Have you checked the brake fluid? do you have to top up regularly, could be the servo letting brake fluid into the inlet manifold. Unlikely but worth checking.

Brake fluid? - Are the two systems even connected together in some way?

Manifold vacuum will suck on the servo when you lift off the throttle. If there are any weeping seals in the master cylinder the fluid can leak into the servo cannister.

[mgbond]

Stella Artois said:

Gadgeroonie said:

1.2 bar ! thats probably why the turbo failed

Assuming it has. Its been running 1.2 for 6 months quite happily to date.

Just to confirm for everyone, your running 28s right.

Bondy

[Gadgeroonie]

i would get yourself a compression and leakdown test done at the same time as you check the turbo

[Stella Artois]

mgbond said:

Stella Artois said:

Gadgeroonie said:

1.2 bar ! thats probably why the turbo failed

Assuming it has. Its been running 1.2 for 6 months quite happily to date.

Just to confirm for everyone, your running 28s right.

Bondy

The receipts I have for the new turbos are for T28s. They were done approx 14 months ago. Its been mapped for T28s. However, I have not done a physical confirmation of them. When discussing with Tuxman on Saturday he offered me his T25's, but as its looking as the front bank is at fault, I do not have the facilities on my drive to carry out the work. Catch 22 also, Its my daily usage, so I have to maintain the downtime to a minimum.

I know that the T28s can run higher boost and that would tie in with the remap to 1.2bar and the dyno of 350bhp. I have learned not to take anything for granted with the Noble, but as far as I am aware they are T28s, yet I will find out for definate as I'm starting to doubt it. The performance of the car also leans to being T28, as you commented on its pick up compared with yours martin, but that could just be running too much boost.

[Stella Artois]

Boosted LS1 said:

Stella Artois said:

AC Motors said:

Have you checked the brake fluid? do you have to top up regularly, could be the servo letting brake fluid into the inlet manifold. Unlikely but worth checking.

Brake fluid? - Are the two systems even connected together in some way?

Manifold vacuum will suck on the servo when you lift off the throttle. If there are any weeping seals in the master cylinder the fluid can leak into the servo cannister.

Ta, was wondering how they could be related.