Smoke at start up

[olmate]

The engine in my 2A was rebuilt just over 18 months ago and now runs on unleaded. Runs very well, smooth, quiet and clean out the back. However, regardless of starting clean in the morning, she will start with a puff of smoke in the afternoon. This is only a very quick puff of smoke that seems to occur as she initially cranks and comes to life. She starts very well so it is not much at all, but it is annoying.

I have been told a few things:

1. I need to wait for her to run-in.
2. The rubber seals on the valve ends may be buggered.
3. The oil drainpipe at the rear of the head may be blocked.

Considering that she is over 18 months old and runs well I would have though that she would be over any running-in period. But saying that, I am open to any suggestions or advice as this situation is annoying to say the least.

[vnx205]

On my Series III, it was always the valve stem seals that gave me exactly the symptoms you describe- a puff of smoke at startup but low oil consumption.

The seals seemed to harden and need replacing every couple of years.

[olmate]

That is what I have tended to think the problem is. But as they were not that old I thought it couldn't be and must be something else.
Could it possibly be that the seals are not of good quality and I should look elsewhere for a set? or is this that common that I should just live with it ?

[Rangier Rover]

The engine in my 2A was rebuilt just over 18 months ago and now runs on unleaded. Runs very well, smooth, quiet and clean out the back. However, regardless of starting clean in the morning, she will start with a puff of smoke in the afternoon. This is only a very quick puff of smoke that seems to occur as she initially cranks and comes to life. She starts very well so it is not much at all, but it is annoying.

I have been told a few things:

1. I need to wait for her to run-in.
2. The rubber seals on the valve ends may be buggered.
3. The oil drainpipe at the rear of the head may be blocked.

Considering that she is over 18 months old and runs well I would have though that she would be over any running-in period. But saying that, I am open to any suggestions or advice as this situation is annoying to say the least.

I have a few series still going here and all have done the same. Some times I've found the valve seal part way up the valve They do go hard quick. I don't worry about mine doing it here anymore as they don't seem to consume much oil.
If your head hasn't got hardend guides they may not be as durable on ulp with no flash lube.
Tony

[JDNSW]

If it is blue smoke it is almost certainly valve stem seals.

John

[olmate]

Thanks Tony / John,
I think that I shall have to learn to live with it also. The head has been done up properly for the ulp conversion so I suspect that the seals have done as you suggest.

[Rangier Rover]

[QUOTE=olmate;847041]Thanks Tony, I think that I shall have to learn to live with it also. The head has been done up properly for the ulp conversion so I suspect that the seals have done as you suggest.

Warning.... Can be a bit embarasing in a car park of near a pub
Tony

[olmate]

Warning.... Can be a bit embarasing in a car park of near a pub
Tony

I know Exactly what you mean

[Aaron IIA]

I will address each numbered point.

1. How many miles has the engine done since the rebuild? Were the valve stem seals replaced? Were the valves replaced? Were the valve guides replaced?

2. When I rebuilt my 2.25L, I could see daylight between the valve stem seals and the valve stems. The engine was not consuming more oil than normal. The valves were a good fit in the valve guides.

3. The oil pipe at the back of the head is actually the pressurised oil feed to the head. The oil drains from the head throught the channels for the pushrods.

I would not be worried about a puff of smoke at start up. If it puffs every time after idling for a while, such as when taking off from the traffic lights, it may get a bit annoying and warrant investigation. If your engine has the later style valve stem seals, the version that are like little cups that slip over the valve guides, they can be changed without removing the head. If your engine has the early style valve stem seals, the O-ring version that sits inside the valve guides, you need to remove the valve, and hence the head to change the seals.

Aaron.

[Rangier Rover]

I will address each numbered point.

1. How many miles has the engine done since the rebuild? Were the valve stem seals replaced? Were the valves replaced? Were the valve guides replaced?

2. When I rebuilt my 2.25L, I could see daylight between the valve stem seals and the valve stems. The engine was not consuming more oil than normal. The valves were a good fit in the valve guides.

3. The oil pipe at the back of the head is actually the pressurised oil feed to the head. The oil drains from the head throught the channels for the pushrods.

I would not be worried about a puff of smoke at start up. If it puffs every time after idling for a while, such as when taking off from the traffic lights, it may get a bit annoying and warrant investigation. If your engine has the later style valve stem seals, the version that are like little cups that slip over the valve guides, they can be changed without removing the head. If your engine has the early style valve stem seals, the O-ring version that sits inside the valve guides, you need to remove the valve, and hence the head to change the seals.

Aaron.

Just thinking my 69 11A had the feed line block and stuffed all the rocker gear completely. Had a bit of a rattle at 1st. It gave a heap of warning. But well I kept driving it We sometimes learn the hard way
Tony