Lotus Elan

stromberg distributor ?

PostPost by: brettfcars » Sat Nov 26, 2011 4:47 pm

Hi,
I have a uk, lotus twin cam fitted with stromberg's, has anyone information on the distributors fitted to these engines ?
i am asking as i appear to have the correct distributor stamped with the following 234d 40953. My understanding is the advance curves were different and these are hard to find ?
However this has been damaged and the body has been alloy welded, tightening on to the shaft :cry: although the shaft is ok and checks out as not being bent.
As can be seen i have dismantled the distributor, aiming to throw the body away. The only other damage being a melted internal seal.
The advance part seams to have 10deg stamped on it ? and i have the weights and springs !

Now a couple of question to those in the know ?
1. was this the correct distributor for my type of engine ?
2. can the weights, springs and 10 deg stamped part be swapped in to a more common distributor ? or is the shaft different as well ? ( i happen to have a 41189a fitted but not yet run ).

Brett
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PostPost by: redskatejbf » Sat Nov 26, 2011 10:09 pm

Hi Brett, I have a Jan. 1970 Stromberg S4 Twincam it has the 23D4 40953A distributor, but it has a 12deg. advance bob weights (not 10deg.) I have had this car from new so I know that is what was supplied. I do not believe the 41189A was ever fitted to the Stromberg carb. engine but I do not see why the `guts` cannot be fitted to it from your 41189A although I could be totaly wrong on that. Fitting the 10deg. weights would not give you the full advance the engine needs about 33deg. I think, so you would be about 4deg. short.
Someone will be able to suggest a company that rebuilds distributor in the U.K. to your spec. I can`t think of the name at this time, I am sure someone will come up with it .

Good luck John.
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PostPost by: brettfcars » Sat Nov 26, 2011 11:03 pm

Thanks John.
As you can just see in the previous photo the variable top part of the distributor shaft has 10deg stamped on it, i am also guessing weights and springs could be changed to change the advance curve but the max advance is set by the 10deg part. (which cold be ground back to allow 12deg. Which if its an angular measurement, could easily be calculated).

I have got the Miles Wilkins, "Lotus twin-cam Engine" book and i was trying to make sense of it all, as it also says a max advance of 33deg.
So i presume when the advance weights say 10 or 12deg this has to be doubled due to the distributor running at 1/2 the engine speed ? and then you add the static timing which is mentioned at being 9deg. O
Hence the 33deg advance of yours, or the 29deg of mine ????
I wonder what or where my 10deg part has come from ?

I haven't opened up the other distributor yet as its still on the engine, so i wonder what i will find in that ?

Brett
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PostPost by: bcmc33 » Sat Nov 26, 2011 11:04 pm

Brett,

Talk with H&H. http://www.h-h-ignitionsolutions.co.uk/index.htm

They know all there is to know about distributors. They do rebuilds as well as new distributors.


No connection.
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PostPost by: prloz » Sun Nov 27, 2011 1:21 am

Brett,
40953A distributor should have 12deg. cam
40953A and 41189A distributors share the same shaft, but have different weights, springs, and cam. (7deg. cam for the 41189A)
10deg. cam is probably from 40845, 40903 or 41202.
Regards,
Peter.
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PostPost by: reb53 » Sun Nov 27, 2011 5:11 am

As stated by Peter, my recently dis-assembled 40953A has a 12 degree cam in it.

Why it is fitted to my 71 Sprint, and what the hell the static advance should be, is a question for another time, and another thread, so as not to hijack yours.

Cheers
Ralph.
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PostPost by: brettfcars » Wed Nov 30, 2011 7:24 pm

Thanks for info received,
It got me trawling the inter-web and I found the following and thought i would share. (see attached pdf )
it imply's my thoughts on grinding 2deg off the 10deg part would work thus turning it to a 12deg, its even mentioned as having been done. ( so that parts easy).
Also all weights are the same but its just the springs which govern the curve :!:

As you may recall from the first post the plan was to swap over all the correct bits into the 23D4 distributor currently on the car, as the stripped distributor's body is damaged.
However i now find the as yet untouched distributor on the car, is a 43D4 distributor :o so no parts can be interchanged :? ( this did not originate on this engine, not sure where it come from !)
Not only that but it has a Aldon logo on and marked up as 103FXYS.
Their web site says the following.
103FXYS IS a non-vacuum distributor, which suits most tuned X/Flow engines using
camshafts such as A2, BCF1, Piper 270,285, Kent 234,244 in conjunction with side draught carburettors and has a 90deg cap.
I am guessing this would be a 7 deg Webber engined unit, and so no use to me (ebay ?).

A quick trip to my local breakers today found a very good condition 23D4 distributor. The label said it had come off a marina ! and since it had been on the shelf for years it cost me ?5 :P
Once apart and checked all casting sizes and bush diameters are the same. :D

Now whether to rebuild myself or entrust to a specialist ? as the only questionable part would be the spring rate's ( advance curve ) and these could be tested and the advance curve measured once the engine is running ?

Brett
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PostPost by: prloz » Thu Dec 01, 2011 12:21 am

Brett,
Don't assume all weights are the same. For example, 40953A and 41189A distributor weights have different part numbers.
Regards,
Peter.
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PostPost by: Jason1 » Thu Dec 01, 2011 1:02 pm

http://www.distributordoctor.com/?PHPSE ... 5f732ef3c8

This guy has an email and is in the UK.
It may be worth dropping him an email?

Jason
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PostPost by: brettfcars » Thu Dec 01, 2011 5:13 pm

Thanks for that link Jason !
I talked to them and have parts on the way to me in the post !
They can supply the original fit springs for under ?13.00
Worth doing for that price, as after ??? Years they can't be at original strength !
They can of course rebuild and test your own distributor for compleat peace of mind !
Brett
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PostPost by: Jason1 » Thu Dec 01, 2011 6:28 pm

Glad you found it useful. I was thinking of renewing my springs when I get it back on the road.

They have a good website; have you seen the page with the guy standing amongst the boxes of old dizzies? They have plenty of spares?

http://www.distributordoctor.com/used-l ... utors.html


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