Converting a Zenith/Stromberg Head to a Twin 40 DCOE Head

[literarymadness]

  Back Atcha Turbo.  And BDA: Turbo used to live in Louisiana.

[BDA]

Another displaced cajun, eh? Who knew?

[TurboFource]

I am from all over as my Dad was in the Air Force and then I joined for two terms of enlistment as an aircraft machinist and welder (SR-71 was one of the planes at my base).

[4129R]

I have just had a conversation with Scholar Engines of Suffolk about converting the Zenith Stromberg head to a Weber 40DCOE head, and left 3 Twin Cam heads with them to determine feasibility and conversion cost, a Zenith head, a Weber head, and the head I cut up to see what was needed.

Alan who knows a lot about Twin Cams says there is a demand for the conversion so is trying to see exactly how this can be done on an economic basis.

I will let you know what transpires.

If this is economically viable, it may well be worth updating on the Elan Forum, as I am sure the demand there is greater than for Europas.

I sent him this link.

https://www.youtube.com/watch?v=PL0kcA2shRk&t=32s&ab_channel=JohnMcCoy
 

[BDA]

Does Omni-tech no longer convert stromberg heads?

[4129R]

This side of the pond would not know, and the logistics of shipping would not make that an option. 

[TCS4605R]

Many years ago I bought an Elan Weber head and had Dave Bean modify it to include the hole out the rear of the intake cam for the alternator drive.  I use 40 DCOE’s.  Worked out very well.

Tom
74 TCS - 4605 R

[4129R]

Good news for anyone with a Stromberg head who wants to convert it to a Weber head.

I have been working with Scholar Engines of Suffolk England, and they have found a simple way of converting a Stromberg head to a Weber head economically.

They are still working on the prototype for me, but when I saw their idea yesterday, and how they intend to finish it, it looks very good, and very simple.

They are doing it for twin 40 DCOEs but exactly the same method would be used for twin 45 DCOEs.

[4129R]

These people already have a casting.  It isn't cheap though.  https://www.ebay.com/itm/Lotus-Elan-Stromberg-Head-Conversion-for-Weber-Carburetor/401707452794?hash=item5d87a1497a:g:sywAAOSwcHRcZNpp

This is the route Scholar Engines are following. It seems to be economically viable.

[jbcollier]

Not experienced in this myself but I have heard that welding twink heads can be challenging.  Hope it works out though.

[4129R]

Not experienced in this myself but I have heard that welding twink heads can be challenging.  Hope it works out though.

Between the owner of Scholar (Greg I think), the previous owner who still works there, and the engineer who is actually doing the work, they seem to have heaps of experience, and confidence that they will turn out a strong good looking conversion, with the inlet ports all gas flowed properly, for a realistic price.

They had made a template to hold the cut manifold in situ to tack weld up in position. Next they will fill in all around the joint to make strong, then they gas flow, finally they finish the outside to make it look original.

I remember Scholar used to make Formula Ford engines in the 1970s.  They take pride in what they do, the current owner has an Emira on order, and he knows Lotus quite well.

He said that Lotus want to get production of the Emira up to 7,000 per annum (about 30 a day). He thinks the Emira will be the last Lotus made in the UK. He knows all the faults of the Merc 2 litre engine they will put in soon, apparently developing up to 350 bhp. It overheats, and the oil stops, causing everything to seize up.   

[BDA]

Sad if the Emira is the last Brit-built Lotus. Lotus was the last independent Brit car company. I heard that the Emira is going to be the last Lotus with a gasoline engine.

Then on the other hand, if they put motors that overheat and seize up in the Emira…

[EuropaTC]

I've no doubt that they can and will do a decent job, as you say they've been around for years and if they've retained the same core workforce, well, it's slam dunk.

I think they might struggle on price though if they're making a casting whereas a fabricated add-on should be quite possible. I'd hope they take it a bit better than that photo in the Ebay advert though, it looks like two cylinders have elbows in the inlet tract and that can't be as good as the OEM design.

Having said that, they have loads of race experience and I expect they'll bench flow to prove their conversion is as good as a standard head. I'd bet they make a straight inlet and weld them individually into place ? Can't see any obvious problems with that.

He said that Lotus want to get production of the Emira up to 7,000 per annum (about 30 a day). He thinks the Emira will be the last Lotus made in the UK. He knows all the faults of the Merc 2 litre engine they will put in soon, apparently developing up to 350 bhp. It overheats, and the oil stops, causing everything to seize up.   

30 a day ? 

good luck with that.......     have Lotus ever made anything at that rate ?  IIRC the Elise was the best thing they've had in recent years and it's a cheaper/simpler market but still nowhere near those numbers.

I love the shape of the car but I can't see those sorts of production numbers at a £75k price and even at £60k for the entry level it's a tough ask.  I wish them luck though and if they do get to those numbers, perhaps the Evoras will become "cheap as chips old bangers" and I can get one to play with !

Brian

[4129R]

At last I got my Stromberg head back from Scholar Engines.

They used a Weber manifold they had lying around, and did an excellent "cut and shut" job on the ally inlet manifold.

The R&D cost a few quid. They are working out a cost for me for converting the other Z/S heads I have lying around in my garage. They made up a steel template to hold the manifold exactly in place while they tacked it in place to the cut down head.

I think they did an excellent job.

[BDA]

I think they did a great job too! 

I suspect it was less expensive than what Omnitech would charge (I first heard about the conversion from Dave Bean but I suspect he was fronting for Omnitech but I could be wrong). Bean and Omnitech had bolt on rather than welded on solutions. Dave Bean claimed that it was better because it didn't interfere with the heat treatment. I'm sure Scholar took that into account. I never figured out why the intake manifolds were cast into the head in the first place!