twink inlet manifold dimensions

[bob_rich]

Hi Folks

Has any one got the exact dimensions of the inlet manifold and the pattern of the 8 studs that hold the two webers (or dellortos) on the twink head. I have got the relative dimensions of the 3/4 and 1/2 inlet port from carburetor drawings but need to know exact info for the relative positions of the 2/3 inlet studs.

I have measured them but would like to know what the officlal figure should be with tolerance if possible.

cheers

Bob

[rgh0]

Hi Bob

I have never seen any dimensioned and toleranced twin cam head drawings. Lotus must have had them and the people making the reproduction heads now must have produced them new by measuring heads or got the Lotus ones.

I dont think anyone will publish them as they would all consider the drawings their intellectual property.

I think you will have to make do with you own measurments and then reverse engineer the dimensions and tolerances you want. If you want I can measure a few of my spare heads to give you some more data to help do that.

cheers
Rohan

[robertverhey]

If you can get all the studs out you could probably get a pretty accurate stencil by holding a piece of A3 paper against the inlet tract faces and rubbing around the various bolt/tract holes. But you'll need to find a way to keep it steady.

Robert

[paddy]

From a gasket?

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... _792wt_883

Paddy

[bcmc33]

From my records the distance between 2-3 inlet ports is 101.75mm.

[types26/36]

Has any one got the exact dimensions of the inlet manifold and the pattern of the 8 studs that hold the two webers (or dellortos) on the twink head.
Bob

This pic may help you although it is for Dellotos, I had to reduce it so if you cannot read the diamensions send me your email and I will try to send you a larger version.

[bcmc33]

From my records the distance between 2-3 inlet ports is 101.75mm.

As a matter of accuracy I've just checked the dimension on the fuel rail made by Jenvey and it is 101.6mm - exactly 4". This seems to make more sense as the head would have been designed in imperial measurements.
It's my best guess that the tolerance would have been ? 1/16" for an unmachined cored casting finish.
It will be simple to work-out the stud dimensions from this information. The tolerances of which would have been ? 5 thou.

The 1-2 & 3-4 ports would have been metric at 100mm.

[bob_rich]

Hi Folks thanks for all the replies

I have got the weber and now the Dellorto ( thanks Brian would like that drawing full size will PM you With my e-mail). The key dimension I needed was the spacing between the manifold stud fixings of the the 3 and 2 ports. but as pointed out ( by other Brian) and confirmed ) the centres between 2 and 3 ports at around 101.75mm ( 101.6mm) should allow me to work out the fixing stud dimensions.

want the info to design and build up my own air box as one I have is shot

thanks for all the help

cheers

Bob

[bcmc33]

The 1-2 & 3-4 ports would have been metric at 100mm.

Spot the delibrate error - of course this should read 90mm

[john.p.clegg]

Bob

Stainless or Aluminium?

John

[bob_rich]

Hi John

thinking of stainless for the back plate as can be thinner 0.7mm or 1mm for same strength.

Bob