swapping the cylinder head from Strom to weber

[Europa73]

Hi all,

Not sure if this is a simple question with a complicated answer.

I currently have the Stromberg head and might have access to a weber head with Webers fitted from an Elan

The question I have is - is this a simple swap with the Elan head?


thanks,

[4129R]

No.

The inlet cam is different, because of the alternator pulley.

You have to use the Federal spec cam which reduced the power output from the UK spec cam, or buy a new set of UK cams.

Also, you need to get a groove cut at the back of the head for a ring to seat on the Europa cam and very few machine shops have the equipment to cut the groove.

I got QED in Loughborough to do mine. I had to warn them in advance so they could set the machine up, and leave he head there for the day.

Next question.

Alex in Norfolk.
 

[Europa73]

Thanks for the note.

Things are never as easy as one hopes :-(

One question for you - was the conversion worth the effort?

[jbcollier]

Aesthetically nothing beats a set of Webers or Dellortos.  If it was mine, I would remove the Strombergs and fit flat slide motorcycle carbs.  They flow way more than any Italian side draft.

[Rosco5000]

Plus 1 on John's comment.  Some of the new motor bike carbs are light years ahead in the way of performance over those old carbs and it might not be worth the time or money for the full on head swap to just upgrade to those bike carbs.  I think there are kits that allow you to use the Mikuni Harley Carbs that are supposed to be good for the under 2L displacement engines.

[4129R]

Thanks for the note.

Things are never as easy as one hopes :-(

One question for you - was the conversion worth the effort?

I went for the full Monty with a head pushing out 145 bhp, so yes, but it was very expensive.

[Roger]

Presumably the Stromberg head already has camshafts, so you could reuse them. You'd also use your cam cover, leaving the groove to be cut.
The "Federal" cam is the older SE cam, so you won't get quite the same HP as you might from D-type cams. What Elan is the head from?

Even with modern bike carbs, a Stromberg head still has the siamesed ports etc., and has less potential than a Weber head.

[TCS4605R]

Many years ago, I bought an Elan Weber head and sent it to Dave Bean in California.  Dave machined the cutout for the intake cam and mounted a set of Weber 40DCOE carbs.  Best thing I ever did.  I also installed a set of Cosworth forged pistons (10.5/1 CR) and Dave included what I think are called 'L' cams.  Dave also did some machine worth to the valve pockets to allow for the higher lift of the 'L' cams.  Dave says the engine should develop 150 HP.

Tom
74 TCS - 4605R

[Certified Lotus]

I'm in the midst of having Quicksilver Race Engines build a Weber head TC engine for my Europa that will have about 150HP. Why? I like Weber head twin Cam's. Nothing sounds like them when the throttle bodies are wide open ;-)

[jbcollier]

I believe it was Richard Banks who said that Stromberg heads are limited to about 180 hp.  Considering that all sorts of other issues arise at those dizzy heights -- longevity being but one -- it's down to mostly aesthetics and available cash.  Not invalid concerns, I hasten to add.

[RoddyMac]

There's always the option of sending the head to Omnitech and having the Stromberg manifold carved off and bolting on a Weber manifold avec carbs.  John McCoy recons he can port a converted head better than a Weber head.   Which brings up the question, was it Alex (or someone else) who was trying his hand at doing the same manifold carving?  Any updates on that?

[4129R]

Unless I learn how to weld aluminium, welding the flanges on the cut back head would be expensive.

First you cut back the head, not for the faint-hearted.

Then you make 4 flanges to weld to the cut back head to mount the trumpets to.

Then you make a jig so the trumpets and Weber flanges can be welded accurately.

Then you make 4 tapered trumpets for the inlet tubes on a lathe, quite good fun actually.

Then you make 4 Weber flanges. stick the trumpets and the Weber flanges in the jig, and weld the whole lot together.

Then you carefully polish the welds and do the porting.

Very do-able if you can weld ally carefully. My shell for 4688R came back from repair, so I have spent the last 5 months rebuilding that car from bare shell upwards. The fluids went in last week. The electrics continue to be tested this weekend for fire up not too far away.

Alex in Norfolk.