Rolls-Royce and Bentley Forums banner
1 - 16 of 16 Posts

·
Registered
Joined
·
63 Posts
Discussion Starter · #1 ·
SRX2576
Hello all,
On cold startup I notice a good amount of smoke from exhaust. It looks like a typical White condensation smoke but lasts until the car warms up - a good 5-7 minutes, at which point it diminishes then disappears. I expect some smoke on a 40 degree morning but this seems excessive. I’ve pulled the plugs to inspect ( picture of a couple attached) and replaced all. The flame trap and fuel mixture are on my things to do list. The car has no oil leaks but it does suffer from lack of use with only 15k on it. Are there any other usual suspects or is this something that happens when these cars aren’t regularly driven?
 

Attachments

·
Registered
Joined
·
585 Posts
Any car sitting their and allowed to run for only 5 to 7 minutes from start up isn't warmed up.
Pulling the plugs afterwards and using what you see on them is not a good indication of how the engine is doing.

Start the car and let it run for about 5 seconds and drive it right away.
Drive it gently until you feel good heat is coming from the heater and the temp gauge has gone into the normal range, or at least where your normal is.

You want the vehicle to warm up as soon as possible and this done by driving, not sitting there idling from cold.
Your engine will be happier if you change to full synthetic and the filter as well, synthetic oil will be the correct viscosity from cold start up, it doesn't have to be warmed up to become its correct viscosity on cold start up.

Given that, the plugs do look like the engine is running rich over-all, but one can't be sure until you put some cleaner plugs in and drive it for at least 1/2 hour (20 miles) at highway speed, fully warmed up as described above.

Allowing the car to idle from cold for 5 to 7 minutes is hard on your engine, it takes longer for the choke to shut off when you do this.
More fuel is being dumped into the engine when the choke is on, this causes excessive soot built up, more moisture enters the combustion chamber and into the oil.
This in turn builds up as condensation and turns into sludge in the engine.
Piddling around town in an attempt to warm the vehicle doesn't work well either.

If the choke is healthy and set up correctly, you will be able to drive the car right away from cold.
I have no idea where this myth came from that any vehicle with a choke, carbureted or other wise has to sit there in the drive way and warm up.
I think people do it because it's uncomfortable driving around in a cold car in the winter time.
If the car is parked outside, it's time to put the poor thing in a heated garage or put a block heater on it, especially a Rolls Royce Silver Shadow.
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #3 ·
Thanks for the response. I kicked down the fast idle after a minute or so and let it continue to idle to see if it would stop. Afterwards, I drove it for a few miles and it did reach operating temperature, again with no smoke. I’ll recheck plugs to see how they’re doing after some more driving. I agree that the plugs seem to indicate it’s a running a little rich. The amount of smoke just seemed a lot, even for a cold engine.
 

·
Registered
Joined
·
585 Posts
You also have to remember that if you're not fully driving it, there may will still be some moisture in the exhaust adding to your smoke problem.
From what you told me, I think it's just cold, monitor your coolant and oil level.
And as I said, check new plugs after a good drive, then again in a week.

What you're looking for is a consistent colour on the plugs, sooty or not, then you can start trouble shooting if need be.
Even driving a few miles will not be enough so you can read the plugs properly.
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #5 ·
I agree and thx for the input. The car had 11,000 miles on it in 1986 according to service records. It’s only gone 4,000 miles since then. It’s long overdue for a road trip!
 

·
Registered
Joined
·
3,353 Posts
Clean the flame trap. It acts as a PCV, if not cleaned and allowed to breathe, there is a good possibility the motor is sucking oil past the valve stem seals and guides.
Most of the time it is water vapor, which you know is a by-product of combustion.
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #7 ·
Yes, I saw some previous posts concerning the flame trap which is something I was unaware of. I’ll definitely check that out as I doubt it’s ever been looked at.
 

·
Registered
Joined
·
3,353 Posts
After a run, I pop the bonnet, and snap open the oil fill cap to let the motor exhale. Never had and tan muck that is often found and the cork seal remains rather clean. Just make sure you close it before the next trip!
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #9 ·
Hello Wraithman,
On the flame trap, are there any gaskets, seals, etc that will need to be replaced after I take it apart? Just want to be prepared.
Thx again
 

·
Registered
Joined
·
585 Posts
To the OP, go to page E41 on Wraithman's link.
The breather tube may be hard as a rock and may need replacing, also, take the system apart and check that it's free of carbon build up.
 

·
Registered
Joined
·
63 Posts
Discussion Starter · #12 ·
Thanks, I see the whole setup now. Looks pretty straightforward. Are the o rings unique in any way or are they readily available? I anticipate they may deteriorate over time.
 

·
Registered
Joined
·
816 Posts
I've just cleaned my breather tube so thought I'd put up some pics.

As Jeff R mentioned the breather tube on my car is rock solid, so it can't be pulled off. I needed to remove the carb intake duct, unscrew the single bolt at each end of the breather tube and maneuver it off.

I replaced the 4 o-rings with standard nitrile(buna-n) type, available at hardware stores. These are resistant to gasoline/oil. Note - never use these on hydraulic/brake components - always use EPDM o-rings.

The gauze filter just tapped out of it's housing. After removing the excess crud I used a propane torch to burn off the residues on the gauze filter. Just a few seconds of heat until the gauze glowed with low red heat. Job done.
 

Attachments

·
Registered
Joined
·
585 Posts
One has to show respect with older cars, no cheap plastic parts, everything is cast and machined, even for the simplest of systems.
 

·
Registered
Joined
·
43 Posts
One has to show respect with older cars, no cheap plastic parts, everything is cast and machined, even for the simplest of systems.
Thanks for the tips and the pics everyone. I have a similar issue which I posted recently and is discussed in a recent group of posts. I hope I can come back and ask for photos of some of these locations not already shown
Cheers
GAM
 
1 - 16 of 16 Posts
Top