Lotus Elan

Converting to Strombergs.

PostPost by: billwill » Tue Oct 05, 2010 10:15 pm

If I buy Mark's engine I will be converting my Elan from Weber/Dellorto to Strombergs.

Has anyone else done this?

What else other than a bulge in the bonnet would I have to change ? Throttle linkages ? Anything else.

Anyone know where I can get a bonnet with a bulge or who would be best to fit one into mine?

I'm in the UK, North London.

I wish I knew who Vegantune (Finchley) used to paint my car last time (c 2001) as the bonnet would obviously need a new paint job and it would be best if it exactly matched the existing yellow paint & hence the rest of the body.


Hmm, it might be interesting to paint the bonnet black with gold edging to match the lower half of the car making it an even-more unique colour scheme, but I suspect that might look horrible.
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PostPost by: Frank Howard » Wed Oct 06, 2010 1:11 am

Bill,

As the bottoms of the Webers are slightly lower than the bottoms of the Strombergs, the Strombergs will contact the bulge in the bonnet unless one of the motor mounts is replaced with a mount specifically designed for Stromberg engines. Can't remember if the Stromberg mount on the carb side lowers that side or if the mount on the exhaust side raises that side (which lowers the carb side). Maybe somebody else can.
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PostPost by: 69S4 » Wed Oct 06, 2010 6:22 am

Even with the correct mounts it's a tight fit. I had to slot the bolt holes in the carb side mount so I could fine adjust the engine height to get the best balance between the float chambers hitting the footwell and the top of the damper rods hitting the bonnet. Get the carbs badly out of balance and it's tap, tap, tap at tickover.

When I bought the car I found that the p.o. had put a sheet of aluminium under the carbs, presumably to stop the bottom punching a hole through the glass fibre.

You'll also need a new airbox and check that the cam cover has the cable mount bit cast into it.
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PostPost by: Frank Howard » Wed Oct 06, 2010 2:18 pm

69S4 wrote:Even with the correct mounts it's a tight fit. I had to slot the bolt holes in the carb side mount so I could fine adjust the engine height to get the best balance between the float chambers hitting the footwell and the top of the damper rods hitting the bonnet. Get the carbs badly out of balance and it's tap, tap, tap at tickover.
Stuart,

Years ago, Christopher Neil sent me the Weber mount or mounts. The result was that my Strombergs were contacting the bonnet. Once they sent me the Stromberg mount (or mounts), the noise went away and the carbs never touched the footwell.
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PostPost by: elan_fan » Wed Oct 06, 2010 5:46 pm

You will also need a 40953 distributor.
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PostPost by: billwill » Wed Oct 06, 2010 5:49 pm

elan_fan wrote:You will also need a 40953 distributor.



? I'm puzzled, why?

Is that different from a Weber distributor? Different Advance cams or some such?
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PostPost by: summerinmaine » Wed Oct 06, 2010 6:51 pm

billwill wrote:
elan_fan wrote:You will also need a 40953 distributor.



? I'm puzzled, why?

Is that different from a Weber distributor? Different Advance cams or some such?



Advance curves from Miles Wilkins' book.


Advance Curves.jpg and



Looks to me like the Weber and Stromberg curves for the two 40953s are the same, just different static advance settings. But the 40953 is certainly different from the 41189.
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PostPost by: billwill » Thu Oct 07, 2010 12:52 am

Hmm, interesting.. I never knew that.

Fortunately Mark's engine already has a distie, so I hope its the right one.

Since my own engine was converted long ago to Big Valve and its distie was changed long ago (possibly to match the big valve one shown in that diagram), my existing one is probably 41189.

How does one find out which version one has ?
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PostPost by: summerinmaine » Thu Oct 07, 2010 3:22 am

billwill wrote:Hmm, interesting.. I never knew that.

Fortunately Mark's engine already has a distie, so I hope its the right one.

Since my own engine was converted long ago to Big Valve and its distie was changed long ago (possibly to match the big valve one shown in that diagram), my existing one is probably 41189.

How does one find out which version one has ?



IIRC the number is on the casing, but I can't go look at mine right now. Of course, with any unit, the springs and weights could have been changed. You should be able to have the advance curve checked and plotted by any garage with the proper tester. I haven't used one since auto shop in high school, but it was easy to do and took less than five minutes.

BTW there is a pretty good write-up on checking the advance curve without the fancy tester on this site: http://www.gofastforless.com/ignition/advance.htm
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PostPost by: 69S4 » Thu Oct 07, 2010 6:51 am

billwill wrote:
elan_fan wrote:You will also need a 40953 distributor.



? I'm puzzled, why?

Is that different from a Weber distributor? Different Advance cams or some such?



I'm trying to sort that side of things out at the moment. Some years ago I had to replace the original distributor when the casing developed a crack around the mounting clamp (prob overtightened) and I took whatever CN had in stock at the time (a 43D4) The car started and ran much as before but just wasn't as crisp at the top end.

The bob weights have a "7" stamped on them and a quick measurement with a protractor confirmed that as 14 degrees of engine advance. Add in the 9 degree static and it's 23 degrees total - well below the Stromberg 40953's 30 odd requirement. Until recently I've just lived with it but weights and springs are available now so it'll get sorted shortly. Just got to work out whether with skimmed head and modern fuels the original curve is still the one to go for.
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PostPost by: billwill » Thu Oct 07, 2010 6:03 pm

If it starts getting expensive in time/effort I suppose one could go for one of those electronic disties that have 16 curves selectable by twiddling the built-in switch.
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PostPost by: Mark B » Tue Oct 12, 2010 3:54 pm

Bill, all,

I've had a look at the distributor fitted, it's a Lucas dissy but can't find any numbers stamped on it. If it helps I'll take a piccy of it unless there's any other distinguishing features?

There is an airbox with it aswell btw, I do have an s4 bulged bonnet for my zetec car, I don't think I need the bulge so would be willing to swap for your standard bonnet as long as it's as good a fit.

Cheers,
Mark.
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PostPost by: oldelanman » Tue Oct 12, 2010 6:53 pm

Mark B wrote:I've had a look at the distributor fitted, it's a Lucas dissy but can't find any numbers stamped on it.


If it is marked it will be on the raised portion on the opposite side to the LT spade connector.

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Attachments
Distributor OE (spare) 001.jpg and
Distributors (spare) 001.jpg and
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PostPost by: oldelanman » Tue Oct 12, 2010 7:09 pm

69S4 wrote:I'm trying to sort that side of things out at the moment. Some years ago I had to replace the original distributor when the casing developed a crack around the mounting clamp (prob overtightened) and I took whatever CN had in stock at the time (a 43D4) The car started and ran much as before but just wasn't as crisp at the top end.

The bob weights have a "7" stamped on them and a quick measurement with a protractor confirmed that as 14 degrees of engine advance. Add in the 9 degree static and it's 23 degrees total - well below the Stromberg 40953's 30 odd requirement. Until recently I've just lived with it but weights and springs are available now so it'll get sorted shortly. Just got to work out whether with skimmed head and modern fuels the original curve is still the one to go for.


Hi Stuart,
You might find this info useful - if you haven't found it already !........

http://simonlacey.com/pages_new/content/documents/lucastuning.pdf

http://www.mgaroadster.co.uk/Technical_Information/lucas.pdf

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PostPost by: summerinmaine » Tue Oct 12, 2010 7:47 pm

Mark B wrote:Bill, all,

I've had a look at the distributor fitted, it's a Lucas dissy but can't find any numbers stamped on it. If it helps I'll take a piccy of it unless there's any other distinguishing features?

There is an airbox with it aswell btw, I do have an s4 bulged bonnet for my zetec car, I don't think I need the bulge so would be willing to swap for your standard bonnet as long as it's as good a fit.

Cheers,
Mark.



Here's mine:

Lucas 23D4.jpg and


Edit: Looks like I've been scooped. :D

Not sure when Lucas quit marking the casings.
Last edited by summerinmaine on Wed Oct 13, 2010 12:33 am, edited 1 time in total.
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