Hubs and DCOE's

[Reddragon]

My questions are to our brothers in the mother land. Since it seems that you have the people that do things or have the people with the skills.

Has any one just taken the hub from a SD-1, with out using the whole strut assembly, and mated it to the TR-7 strut? How much difference, demension wise, is there between the two hubs? Or is it a matter of the splinde on the strut that the hub will not fit?

This next question, I have been reading the post on adjusting DCOE's with interest, is to the ones that may have or know of some one that is running DCOE's on a Ford Zetec, Lotus 7. I have read that there is a special DCOE with a 5 hole progresssion setup. Are these holes in the carb body or are they in the emulsion tubes? Can the DCOE's on a Zetec be tuned to run with out these extra holes?

Any information that this group can give me on these subjects will be appreciated. Thank you.

Dale
1974 TR6
1977 TR7 FHC

[Craig C]

I can chip in on the hub question: The hub bearings are different and there is no bearing which has the same ID as the TR7/8 spindle and OD as the SD1 hub. Hence why I bought two NOS SD1 struts off Rimmers when they had a sale..

Craig
Tr7V8

[Troy ODoherty]

Hi Dale

To help with your question on the DCOEs. The progression holes are under the brass plug near the mixture screws. The number and location of these is critical. When we were tuning rotaries with 48 IDAs on them some people insisted that it was wise to drill extra progression holes. To my mind this was a lot like do it yourself brain surgury, only for the brave. The number of these holes can at times have an effect on some engines that is poistive. HOWEVER Weber spent a lot of time and money deciding were they should be and then built a huge amount of adjustability into the DCOE. The number after the DCOE ie 13 or 17 or what ever will tell you things like progression hole location and the set up of the carby as it left the factory.

It is in very rare cases that you cant tune very small problems out of these carbys. This is when the true masters of them may suggest a change from one model to another.

The DCOE is the road version of the Weber side draught for race use we run DCO, the main difference is the lack of choke ( cold running ) system.

There is a large range of emolsion tubes available for these carbies, but only 5 or 6 that are commonly used today. Beans mentioned that his tuner drilled extra holes in his tubes.THis suggest that his guy is very experienced and has at some stage had access to an engine dyno and lots of spare time. And the ability to drill these holse very accuratley. Or he is very brave and got lucky. I tend to think it is probably the first.

Without personal experience of these engines it is hard to say if the 5 hole carby is necessary or not , but remember that these holes only affect the performance when the engine is moving from idle onto the accelaration phase.

I hope this helps[:)]

Cheers Troy

[Reddragon]

Craig - Troy

Thank you both for the replies.

I thought it would be to easy to use the SD-1 hubs on the Tr-7 spindles. But it was worth a shot as if not asking one does not learn.

Some where down the road when I get this engine running I will let you know if I can tune around not having the extra holes. Troy the number after on mine is 51. What does that tell you about the Carbs progression?

Thanks

Dale
1974 TR6
1977 TR7 FHC