Exhaust smoke

gsi2000

Hi all, having a problem with the veccy c
On start up it smells sweet from exhaust, sometimes theres white smoke/vapour altho sometimes not until it warms up. generally its when idling and disappears when driving.
over 3k rpm blue smoke appears, i have been using alot of oil, but varies could use 1l every 100 miles or every 200 miles. i know its gonna be a piston job but my concern is the white smoke. oil colour looks fine, no loss of coolant, no overheating. drives fine although a bit sluggish sometimes underload at low revs.
Any ideas?

Cheers

KevinH

The blue smoke at high revs is likely to be the valve stem seals and the white smoke could possibly be a burnt out valve.
A compression test, both dry and wet, would tell you if the rings are damaged - if the readings are significantly higher on a wet test then the rings are suspect..
The oil control rings could also be gunged up in which case it's worth doing an oil change together with an oil flush - recommend Forté Advanced Formula Motor Flush (http://www.forteuk.co.uk/products)

If it is a white vapour (rather than smoke) then that usually indicates that water/coolant is entering the cylinders. Maybe remove the ignition module and check that none of the spark plugs have water ingress which could indicate a crack in the cylinder head due to plugs being over tightened.

Hope that may help. 🙂

gsi2000

Cheers for reply kevin, gonna try and get round to doing compression test amongst other things this weekend see what it throws up.
is it possible the catch tank could cause the white vapour/smoke? how ive fitted it is pipe from rocker cover to tank then another pipe from tank to induction pipe.
Had ignition coil off a few days ago but didnt notice anything of concern in the plug holes, bone dry.

KevinH

Just to add to your list of jobs, you could also remove the throttle body to check if there is a build up of oily gunk beneath it in the induction manifold intake chamber (if you haven't done so already) - can use carb cleaner to remove. 🙂

gsi2000

Ive done that last week, id cleaned it out a few months ago but thought id do it again, wasnt as gunked up as previously but still a bit of oil collected in bottom of inlet manifold. used carb cleaner on throttle body. EGR is blanked off too 🙂

KevinH

OK, I was just thinking of any others reasons for the smoke but I guess it may be a slightly more serious problem as mentioned above. :banghead:

gsi2000

any idea why the oil collects in inlet manifold or is that normal? just seems to form a puddle lol

KevinH

You could try Forté Seal Conditioner, if it doesn't work you won't have lost anything:
More information here http://www.forteuk.co.uk/product-detail/24/Seal-Conditioner

available here
http://www.ebay.co.uk/itm/FORTE-SEAL-CONDITIONER-HARDENING-AND-LEAKAGE-125ML-/222205365727

🙂

KevinH

gsi2000 said:
any idea why the oil collects in inlet manifold or is that normal? just seems to form a puddle lol

I would guess if the engine is burning oil then part of the residue works it's way back into the induction manifold via the EGR pipe and gradually builds up.

gsi2000

KevinH said:
I would guess if the engine is burning oil then part of the residue works it's way back into the induction manifold via the EGR pipe and gradually builds up.

Would that be the case even with the egr blanked off and the pipe from egr to inlet blanked off too?

KevinH

gsi2000 said:
Would that be the case even with the egr blanked off and the pipe from egr to inlet blanked off too?

I assume if you blanked the EGR pipe off as well this would eliminate the oily residue accumulating in the induction manifold.

gsi2000

KevinH said:
I assume if you blanked the EGR pipe off as well this would eliminate the oily residue accumulating in the induction manifold.

will do compression test on weekend and report back with both wet and dry test. i cant think of anything else it could be either lol

KevinH

Yes, a compression test would be a good start to deducing why the oil is burning.

For info
Z22SE compression pressures should be between 12 to 15 bar (174 to 218 psi) as long as the following are observed:
Maximum difference between any two cylinders: 1 bar (14.5 psi)
Pressure loss: Not more than 25% max per cylinder

For the 'wet' test add about 5ml of oil to the cylinder. If the readings temporarily improves the compression reading, this indicates bore or piston ring wear is responsible for the pressure loss. If there is no improvement in the reading, this suggests there may be leaking or burnt valves, or a blown head gasket.

Post the results back here and I'm sure someone will be available to help/advise you.

As mentioned above the valve stem seals could also be the culprit for oil burn.

🙂

gsi2000

KevinH said:
Yes, a compression test would be a good start to deducing why the oil is burning.

For info
Z22SE compression pressures should be between 12 to 15 bar (174 to 218 psi) as long as the following are observed:
Maximum difference between any two cylinders: 1 bar (14.5 psi)
Pressure loss: Not more than 25% max per cylinder

For the 'wet' test add about 5ml of oil to the cylinder. If the readings temporarily improves the compression reading, this indicates bore or piston ring wear is responsible for the pressure loss. If there is no improvement in the reading, this suggests there may be leaking or burnt valves, or a blown head gasket.

Post the results back here and I'm sure someone will be available to help/advise you.

As mentioned above the valve stem seals could also be the culprit for oil burn.

🙂

Cheers thats a great help.

gsi2000

KevinH said:
Yes, a compression test would be a good start to deducing why the oil is burning.

For info
Z22SE compression pressures should be between 12 to 15 bar (174 to 218 psi) as long as the following are observed:
Maximum difference between any two cylinders: 1 bar (14.5 psi)
Pressure loss: Not more than 25% max per cylinder

For the 'wet' test add about 5ml of oil to the cylinder. If the readings temporarily improves the compression reading, this indicates bore or piston ring wear is responsible for the pressure loss. If there is no improvement in the reading, this suggests there may be leaking or burnt valves, or a blown head gasket.

Post the results back here and I'm sure someone will be available to help/advise you.

As mentioned above the valve stem seals could also be the culprit for oil burn.

🙂

UPDATE:
cranked engine over for 4 seconds per cylinder when doing each test
Compression results are as follows

cyl 1 - 145 (dry) 160 (wet)
cyl 2 - 140 (dry) 160 (wet)
cyl 3 - 140 (dry) 160 (wet)
cyl 4 - 145 (dry) 160 (wet)

KevinH

Well that test obviously shows that compression is low on all cylinders by 14 psi to the lowest acceptable reading, and they are all down by 27% to a good/new engine.

Unfortunately it's looking like new piston rings required. I'm assuming no valves were changed when you did the chain work, which may be worth considering along with stem seals and you would then have a sound engine. 🙂

Did you fit genuine GM chain kits ?

gsi2000

KevinH said:
Well that test obviously shows that compression is low on all cylinders by 14 psi to the lowest acceptable reading, and they are all down by 27% to a good/new engine.

Unfortunately it's looking like new piston rings required. I'm assuming no valves were changed when you did the chain work, which may be worth considering along with stem seals and you would then have a sound engine. 🙂

when i did chain i didnt take head off so nothing has been done regarding valves etc. if as you say it needs new piston rings then doing other things at same time is gonna be the best option while its stripped down.

Ive taken my catch can off so hope over next few days i see a reduction in the white smoke on idle, catch can contents were mainly water with a hint of oil.
I was let down at last minute regarding delivery of genuine chains so ended up having to go with FAI