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Smokey from one exhaust pipe.

Posted: Tue Apr 16, 2019 1:16 am
by brebner89
Unfortunately my car has smoke from only one exhaust. (Passenger side)
Smokes when it gets up to running temperate.
The possible symptoms are i guess:
Valve stem seals?
Piston rings?
Anyone had this issue or similar?
Anything else i can check.
If its rings i now wont be a cheap fix but could be worth the expense without breaking the car.
Any help would be much appreciated.

Re: Smokey from one exhaust pipe.

Posted: Tue Apr 16, 2019 7:48 am
by pimgmx
Worn valve stem seals usually show at startup, rather than when warm?

Are you sure it is oil smoke, i.e. blueish in colour?
Have you noticed above-average oil consumption?

Re: Smokey from one exhaust pipe.

Posted: Tue Apr 16, 2019 8:39 am
by Brake buster
i would start with a general check of all fluids , and make sure they are correct level and not cross contaminated

next would be to do a compression check on all cylinders

this will give you a base line

the V12 valves have been known to stick ,

just for elimination , the vacuum modulator on the auto gearbox has a seal, if this fails ATF can be drawn up the vac line to the engine causing white smoke , this can be intermittent to start with then full on white smoke as the seal gives way completely ,

hope its a simple issue , as v12 head removal or piston ring replacement is a big job

BB

Re: Smokey from one exhaust pipe.

Posted: Thu Apr 18, 2019 10:56 am
by NMV 1E
I'd also check the vague possibility that the brake servo (booster) isn't letting brake fluid into the inlet system :?: Though on second thoughts very unlikely with the "Tives" system used on the 40 / 81 :?:

Re: Smokey from one exhaust pipe.

Posted: Tue Apr 23, 2019 4:58 am
by brebner89
Yes blueish in colour. Havent noticed the consumption as it has been like this since i bought it.
Have not done a lot of miles with it yet to find out.

pimgmx wrote:Worn valve stem seals usually show at startup, rather than when warm?

Are you sure it is oil smoke, i.e. blueish in colour?
Have you noticed above-average oil consumption?

Re: Smokey from one exhaust pipe.

Posted: Tue Apr 23, 2019 5:02 am
by brebner89
As its only one exhaust it means its only one bank of cylinders?
the car had been sitting about 4 years prior to my purchasing it so could be sticky valve.
The gearbox oil connected to exhaust?
I understand any work on the bowls of the engine will be a big job. Will need to be 100% sure on the fault.

Brake buster wrote:i would start with a general check of all fluids , and make sure they are correct level and not cross contaminated

next would be to do a compression check on all cylinders

this will give you a base line

the V12 valves have been known to stick ,

just for elimination , the vacuum modulator on the auto gearbox has a seal, if this fails ATF can be drawn up the vac line to the engine causing white smoke , this can be intermittent to start with then full on white smoke as the seal gives way completely ,

hope its a simple issue , as v12 head removal or piston ring replacement is a big job

BB

Re: Smokey from one exhaust pipe.

Posted: Tue Apr 23, 2019 5:04 am
by brebner89
Whats the TIVES system??
NMV 1E wrote:I'd also check the vague possibility that the brake servo (booster) isn't letting brake fluid into the inlet system :?: Though on second thoughts very unlikely with the "Tives" system used on the 40 / 81 :?:

Re: Smokey from one exhaust pipe.

Posted: Tue Apr 23, 2019 8:06 am
by pimgmx
Teves was the manufacturer of the XJ40/81 brakes.

Theirs used an external pump and pressure sphere for a brake booster instead of the more common engine vacuum-driven systems.

This setup suggests you can rule out brake fluid leak/contamination as a potential cause for your smoke issues.

Per BB’s suggestion: a fluid and filter change (and perhaps an engine oil flush) is a good starting point before digging any deeper.

And yes: smoke on one side only suggests that a single cylinder bank is affected.

Re: Smokey from one exhaust pipe.

Posted: Tue Apr 23, 2019 8:40 am
by leo_denmark
brebner89 wrote:As its only one exhaust it means its only one bank of cylinders?
the car had been sitting about 4 years prior to my purchasing it so could be sticky valve.
The gearbox oil connected to exhaust?
I understand any work on the bowls of the engine will be a big job. Will need to be 100% sure on the fault.



The gearbox is connected via a vacuum line. If the diaphragm at the gearbox end cracks, the inlet manifold will suck in gearbox oil through this line. If it's anything like an XJ-S V12, it's on the A-bank, RH side.

BR Leo

Re: Smokey from one exhaust pipe.

Posted: Tue Apr 23, 2019 2:31 pm
by Brake buster
this is the issue with remote diagnosis ,

as i said, do the basics , work from there,

as its sat for four years, a good run of the engine a few times to allow a full heat cycle will do it some good , if you can live with the smoke while doing it

ALL V12 engine will produce white ' steam' during the ' choke ' warmup stage , this is not right from the starting of the engine, mine does it a few minutes into being started up from stone cold and then this ' steam ' stops , its like the exhaust is clearing its throat.........ahem

BB