Smokey Rover

[martin_t]

Hi

I have raised this topic before, but now I am days away from fitting my body (GD MK4) the issue of my smokey engine has come into my mind again. I guess I am looking for some reassurance that I won't have to take the engine out as soon as the car is finished!!!
Basically, when I fitted the engine to the chassis and fired it it for the first time after a complete rebuild, it smoked. I expected that with all the build oil etc. After running it for 20 mins aprox, the bulk of the smoke disappeared. What I was left with was a puff of white. smoke on the overrun. If I revved the engine up to 2000 and held it, it didn't smoke, but if I revved it and immediately backed off I get a puff of smoke.
This is concerning me for two reasons. Firstly does the IVA demand no visible smoke at all? And secondly I don't want to take the engine out again once the body is on. Some people have told me that these symptoms indicate possible valve guide issues? If that’s the case its not to bad as I can take the heads off with the engine in situ.
Maybe (he says hopefully) once the car is finished and I can put it under load on the road etc, the smoke will disappear as the engine beds in?

Any comments and advice would be gratefully appreciated.

Cheers

Martin

[martin_t]

No thoughts??

[craggle]

Hi Martin

You say the engine has been rebuilt? What was done, just new bits or a complete rebore Etc.

It sounds fine to be honest. I would get it together and run it again if you can but don't keep starting it and letting it tick over. It needs to be started then driven really to get the piston rings bedded in to the bore.
If the engine was only fitted with replacement rings without reboring then the bores may be slightly worn and the rings won't fit perfectly for a few miles.

Also you normally get a puff of smoke when revving an engine if the accelerator pump is putting a bit too much fuel in the carb. This can be set once you are up and running on the road.

Also moisture in the exhausts and headers can cause white smoke. This will disappear once you are up to temp and running on the road.

Don't worry and get the car finished!

Craig.

[martin_t]

Originally Posted by craggle

Hi Martin

You say the engine has been rebuilt? What was done, just new bits or a complete rebore Etc.

It sounds fine to be honest. I would get it together and run it again if you can but don't keep starting it and letting it tick over. It needs to be started then driven really to get the piston rings bedded in to the bore.
If the engine was only fitted with replacement rings without reboring then the bores may be slightly worn and the rings won't fit perfectly for a few miles.

Also you normally get a puff of smoke when revving an engine if the accelerator pump is putting a bit too much fuel in the carb. This can be set once you are up and running on the road.

Also moisture in the exhausts and headers can cause white smoke. This will disappear once you are up to temp and running on the road.

Don't worry and get the car finished!

Craig.

Hi Craig

Thanks for the response. I built the engine up from scratch. I had the bores checked and honed but not rebored. I put new bearings and rings in. I put a Viper Hurricane cam in with Rhodes lifters and have a Holley 390 carb sat on top of an edelbrock performer.
I guess the thing that concerns me is that I can't drive it and "bed it in" before the IVA. That being the case it may still be smoking for the test which I think is a fail.

Thank anyway

Martin

[cobraeddie]

Martin, possible valve stem seals hardened/going rotten from setting?
This would cause some smoke
Just a thought

Mark

[craggle]

Unless he's using the original SD1 heads that don't have valve stem seals.

These engines do leak down the valves but it usually only noticeable at startup.

Craig.

[martin_t]

Originally Posted by craggle

Unless he's using the original SD1 heads that don't have valve stem seals.

These engines do leak down the valves but it usually only noticeable at startup.

Craig.

Hi

They are the original heads but I had them skimmed 27 thou to accept composite gaskets. I kept the original valves but had them cleaned and new springs fitted. Got to be honest, I had this done at an engineering shop and as this was my first attempt at building an engine (let alone a car!!), I couldn't tell you if they put new seals on or not. I tended to trust them, but that was three years ago and I am a bit more sceptical now!!!

Cheers

Martin

[TonyD]

Martin,

I would suggest taking your car for a pre SVA MOT.

Book the car in and take it for a scenic drive to the MOT and give it a half decent spanking. Then ask the MOT's mans opinion. At that stage either its smoking like Dot Cotton and an emmisions failure, or you have burnt off residual oil and jobs a good un.

Bear in mind you can also drive to the IVA and the test is done after the car has also been idling for a good while and at the end of the day the testers are there to make sure you get a half decent crack at the whip, its highly likely what you deem to be smoke would be no more than "whispy vapour" to an IVA guy.

The MK Indy behind us at the last SVA was running an Emerald aftermarket ECU on Individual throttle bodies but had problems with the emissions and the SVA guy had the engine running at 4000rpm for 5 minutes in an attempt to get it to pass.......it didnt.

But I hadn't ever seen an exhaust manifold and downpipe on fire before either, so I'm sure a bit of smoke wont be a problem.

Do not panic, get a second knowledgable opinion and relax......

Cheers,

Tony