Smelly fumes inside car

[Tattybogle]

I have recently started to experience fumes inside my RN box saloon for the first time since I purchased it ten years ago. They cause the eyes to sting and catch in the throat.

The fumes become apparent when the engine is hot and the driver is pressing on - ie, a steady 40 mph for half an hour or more.

I have checked the exhaust, and modified the valve cover plate by blocking off the 3 holes and fitting an extension pipe which extends below the chassis to carry away any by-pass fumes.

The fumes are still present, but seem less than before.

One thing that occurs to me is that they seemed to start becoming apparent when I fitted a 4-blade fan to try to overcome the effects of modern fuel vaporisation, causing the engine to splutter in hot weather when driving slowly or pausing at a junction etc.  I wondered if the greatly increased air being forced over the engine by the new fan could be pushing fumes into the car via the various bulkhead orifices, many of which cannot be completely blocked up. 

Has anyone else experienced this problem?

Thank you.

[Jack in the Box]

When we were new to A7's, we had an RN with a tired battery and tended to run in "Winter Charge" mode as we only undertook short runs. When we did the 2015 London to Brighton run, we drove up in the dark on Winter Charge and for some reason kept it their on the way to Brighton in the daylight. Coming through the Ashdown Forest, both my wife and I experienced stinging eyes and irritation in our throats. Turns out we were over charging the battery. I think you ony do this once ......

Just a thought.
Alan

[Bob Culver]

Fumes generally originate from exh leaks, oil on the exh, or blow by. Oil on exh leaves black marks. Blow by evident as fumes from filler tube and possibly puffs when idling, and may be obvious from crank handle compression. From the distant days when very worn bores were common with most makes, severe blow by often seemed to cut in at some reasonably high revs.

[Andy Bennett]

I had the same problem with my RP and it was fumes from the valve chest cover.
Like you I made a bypass tube from some copper plumbing pipe. I did find that I needed to make the pipe quite long so that it came out right under the car, effectively under the passenger seat.
Could it be that your bypass pipe is not long enough and an eddy current under the car is sucking the fumes back up into the engine bay and so into the interior?
Andy B

[Tattybogle]

When we were new to A7's, we had an RN with a tired battery and tended to run in "Winter Charge" mode as we only undertook short runs. When we did the 2015 London to Brighton run, we drove up in the dark on Winter Charge and for some reason kept it their on the way to Brighton in the daylight. Coming through the Ashdown Forest, both my wife and I experienced stinging eyes and irritation in our throats. Turns out we were over charging the battery. I think you ony do this once ......

Just a thought.
Alan

Gosh Alan, I think you may have put your finger on it!

During the past year or so I have changed all lights to LEDs and keep the battery connected to an Accumate conditioner when in the garage.  I always start the car on the handle from cold. Therefore not only are my current demands low but the battery is always fully charged when I leave home.

But, of course, I haven't adjusted the dynamo output with the 3rd brush so even on the summer setting it pumps out about 3 to 4 amps.

I shall adjust the dynamo to give minimal output on summer setting and report back.

And thanks to the others who replied with helpful suggestions.  I shall double check those too.

[Bob Culver]

Precise management of the battery can be a challenge. Yet Ford 8s did not even have the Summer option. I know for decades the battery life on my RP was about 2 years.....
Later on long trips I used to remove the dynamo fuse and switch to Summer, so no charge. (Will not work if car has acquired a complete 4 pole DEL dynamo).  I  fitted a voltmeter but found I could not take eyes off the road long enough to read! 
A digital meter even inside the cabin may not cope with the unsuppressed spark and other noise. An analogue meter fitted with a zener to expand the scale, calibrated from a digital,  can be useful. If a dynamo off switch is fitted it should be wired to switch the fileld wire not the output.

[Tattybogle]

Precise management of the battery can be a challenge. Yet Ford 8s did not even have the Summer option. I know for decades the battery life on my RP was about 2 years.....
Later on long trips I used to remove the dynamo fuse and switch to Summer, so no charge. (Will not work if car has acquired a complete 4 pole DEL dynamo).  I  fitted a voltmeter but found I could not take eyes off the road long enough to read! 
A digital meter even inside the cabin may not cope with the unsuppressed spark and other noise. An analogue meter fitted with a zener to expand the scale, calibrated from a digital,  can be useful. If a dynamo off switch is fitted it should be wired to switch the fileld wire not the output.

Thanks Bob, but I don't understand. Do I understand you to say that if the field fuse is removed, the dynamo will charge in the Winter setting but not in the Summer one? When I remove my field fuse, the dynamo doesn't charge at all, as I would expect.
I have a standard 1932 Lucas CF 35 set up. I have moved the 3rd brush back as far as I can and it charges at about 2A in Summer setting. If I move it any further, it doesn't charge at all in either setting.
Tomorrow I shall take the car for a 50 mile run and hope my troubles have gone away.
Interestingly, some other cars with 3rd brush dynamos have a 'dynamo off' setting ( e.g. Riley 9) for just this reason, but relied on the driver to understand when to use it - or not.
As an aside, it must be a wee bit irritating to be called a Junior Member on the new forum when you have been posting on the old one for as long as I can remember!

[Bob Culver]

Sorry, the intention was to indicate to all that measures to reduce charging may be applicable. As per the diags in article A Charging Refresher, only applies to late RP and following cars or cars wired as these.

On RN with C35A dynamo I dunno how practicable it is to extend wires and switch the fuse leads remotely and directly before the fuse. Any switch preferably not too obscure or someone may end up wasting money on an auto electrician! (The main dynamo output lead must not be switched.)

If car has a 4 pole DEL dynamo or the 1928 to 1931 wiring, any fuse must not be removed or switched.

[Tony Press]

Tomorrow I shall take the car for a 50 mile run and hope my troubles have gone away.
Interestingly, some other cars with 3rd brush dynamos have a 'dynamo off' setting ( e.g. Riley 9) for just this reason, but relied on the driver to understand when to use it - or not.
As an aside, it must be a wee bit irritating to be called a Junior Member on the new forum when you have been posting on the old one for as long as I can remember!

The Lucas  SM3 switchboard only has a simple on  off switch for the dynamo, relying on the driver to control the battery charge.
The later Lucas  SM 5 has a summer and winter charge position, still requiring driver selection but a little more control.

Re the annoying Junior Member -  this can be changed - but I have forgotten how :-(

Cheers, Tony.

[Tattybogle]

When we were new to A7's, we had an RN with a tired battery and tended to run in "Winter Charge" mode as we only undertook short runs. When we did the 2015 London to Brighton run, we drove up in the dark on Winter Charge and for some reason kept it their on the way to Brighton in the daylight. Coming through the Ashdown Forest, both my wife and I experienced stinging eyes and irritation in our throats. Turns out we were over charging the battery. I think you ony do this once ......

Just a thought.
Alan

Gosh Alan, I think you may have put your finger on it!

During the past year or so I have changed all lights to LEDs and keep the battery connected to an Accumate conditioner when in the garage.  I always start the car on the handle from cold. Therefore not only are my current demands low but the battery is always fully charged when I leave home.

But, of course, I haven't adjusted the dynamo output with the 3rd brush so even on the summer setting it pumps out about 3 to 4 amps.

I shall adjust the dynamo to give minimal output on summer setting and report back.

And thanks to the others who replied with helpful suggestions.  I shall double check those too.

Well, I went for a 50 mile round trip yesterday with the dynamo giving the lowest output possible and the fumes seemed to be negligible now.  Although at the end of it the battery cells were gassing, indicating that they had been taking a significant charge.

Next time I shall check the battery voltage before, during and after the trip to see what is happening there.
I think it would be preferable for the battery not to receive a charge from the dynamo when it is fully charged.  Now that I have LED lights the current requirements are virtually nothing when the engine is running.  So I am pondering what the best solution would be.

I wonder how easy it would be to make the charging switch  turn the dynamo 'off' in the summer setting and only charge the battery in the winter setting.  This would give me manual control over things. Any suggestions???

Alternatively I could convert to a later Seven set up with a regulator, or even go over to one of the new Accuspark Stealth alternators which are a direct replacement for the dynamo but has built-in regulation.