DG 32/36 Settings For A2 Cam?

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02.08.23, 3:42 PM
Iamscotticus

DG 32/36 Settings For A2 Cam?

I have a Caterham built Samcor 1600 AX block with A2 cam but standard valves and ports, I believe.
It is set up to run 2x DCOE40s on 37mm chokes.
I am wanting to convert to downdraught DG 32/36.
Can anyone suggest a tube and jet combination for street and highway?
I currently run on 13" wheels that are 23" circumference.
Final diff is 3.6:1.
Four speed from a English Ford Escort Sport, not sure of the 4th gear but 65MPH sees rpms in the mid 5k. I hope to change that with a T9 5 speed soon.

I'll answer the obvious question, shy do I want to go DG from DCOEs? Im wanting to replicate the '68 Lotus S3. Most of my driving will be street so the progressive my have better manners than the progression.
02.09.23, 1:09 AM
DanW

The 32/36 DGV is a good road carb for a stock engine with a Cortina GT cam. Once the revs climb above about 5500 rpm, the carb goes lean unless it has been fitted with "dump tubes" that add raw fuel from the float bowls, completely bypassing the main jets. This is what we have to do to make power and keep from going too lean on our 32/36DGV fed FF Kent engines. A properly timed A2 cam will run to 7K

There is a web presence for some creative DCOE tuning run by a friend of mine. The site dates back a long time so there is a lot to digest, but Keith has developed idle jets, main jet emulsion tubes and jetting to get rid of the dreaded lean stumble at low RPM and provide either decent fuel economy or impressive performance(choice of emulsion tubes). I believe your chokes are a bit large for the cam and carbs which further hurts drive-ability. He also developed a very slick way to determine running float level and a straightforward means to adjust it.

https://vintagetechnologygarage.groups.io/g/sidedraft
02.09.23, 10:50 AM
Iamscotticus

Thanks

Good stuff there.
So, a non-dump tube DG is good to 7k on an A2?
Im not racing and crank is stock limit to 7k.

Yes, I can go smaller on my DCOE chokes.
02.09.23, 12:43 PM
DanW

Quote:

Originally Posted by Iamscotticus

Good stuff there.
So, a non-dump tube DG is good to 7k on an A2?
Im not racing and crank is stock limit to 7k.

Yes, I can go smaller on my DCOE chokes.

I'm not sure a DGV will rev to 7K without dump tubes. It might. The only way to confirm would be with a tight exhaust system and use a wide band O2 sensor or thermocouples in each exhaust primary. I recall some older Caterhams used a DGV. Have you checked the Seven forums? https://usa7s.net/ips/