1937 Ruby spark plug colour ?

[Joe eck]

After fitting hotter NGK Bp5 plugs and taking my Ruby out for a 50 mile run without a hint of its normal sooting up, I removed the plugs and found them to be a very light grey in colour.
The car ran very well and pulled cleanly up the many hills round here in West Yorkshire.

I am a little concerned that the light grey may indicate too weak a mixture and wanted to make sure that I am not going to cause engine damage . If I remember correctly the ideal plug colour should be more of a beige colour ?
Can anybody please advise.

Regards
Joe.

[David Stepney]

If the car is running well and ticks over evenly when hot, It appears that all is well. Modern fuel mixtures tend to burn cleaner than the 'old' petrol. hence the greyer colour.

If you are running on a Zenith 26VA carb, if the car is ticking over hot, snap the throttle open and let it fall back to its stop as the engine picks up. It should pick up cleanly. If, when the throttle is released, the engine slows, dips and then picks up back to idling speed, the mixture is too weak.

Hope this helps.

[Joe eck]

Thanks David.
The engine picks up fine on snapping open the throttle but does dip slightly on release before returning to a nice steady tick over.
I have recently fitted a new needle valve to the 26va complete with all the washers supplied.
Am I correct in thinking that a richer mixture may be achieved by removing some of these washers to raise the fuel level or is it a jet change ?
Thanks again
Kind regards
Joe.

[David Stepney]

If you got your needle valve kit from Burlen, then the three washers included are all alternatives. Fitting then all will reduce the float level quite considerably.. When i overhauled my carb, I chose the washer that was closest to the one that I had removed. Not had any problems since.

To richen the tickover mixture, the little brass screw on top of the carb is screwed in - to weaken, screw it out. Don't go mad with it, it is very sensitive and the slightest turn will make a difference. try screwing yours in about 1/8th of a turn and see if the slight dip goes away. Then fiddle slightly one way or the other to get the most even tickover.

I have checked my plugs recently (nearly new D16's) and they are burning a sort of ash grey too.

[Joe eck]

Thanks David.
I did fit a burlen kit in order to stop a carburettor dribble when the car was switched off.
Unfortunately the previous needle valve had been fitted with a rubber o ring !! , so I was unable to say for definite the previous thickness.
I will experiment and try each washer to see which gives best results as well as tweaking the idle mixture to get rid of the dip.
Thanks again.
Kind regards
Joe.
 Ps. We enjoy your regular updates on " what have you done today" in and around the Bala area.
Having had a caravan in Glan Yr Afon for many years, it's nice to reminisce about the good times we had in and around the area .

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[Reckless Rat]

I heard you the first time!
Pardon?

[Joe eck]

I sometimes hate this flaming computer !!!

[Reckless Rat]

Just click on the "delete" button in each unwanted post to remove it.

[David Stepney]

Joe,

If you have a carb dribble, it could be the fuel pump. What pump are you using? If it's as original 'T' type, then there shouldn't be a problem from it. If it is a replacement 'U' type, though the return spring (the one that sends fuel to the carb) tends to be too strong and will overfuel the carb.

There is a thread on this problem on the forum somewhere too.

PS Thank you for your kind comments.

[Joe eck]

Thanks David
I have a low pressure SU electric pump fitted so will remove washers and see how I get on.

I have, however just found that, from a previous post about " carburettor problems " that I have a type 2 carb body fitted with a type 1 float chamber which won't be helping matters.

If anybody has a good " flat bottomed " float chamber that they may sell me I would be grateful.

Thanks
Kind regards
Joe.