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Sammas09

Vacuum advance

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Hello everyone. 

Ok so here's my query, 

 The previous owner of my robinhood swapped the carbs from the 2l pinto engine from weber twin dcoe 40s to weber 32/36 dgev. After the swap the vacuum advance was never connected up due to it being broken on the distributor. The engine has never run perfectly since I've owned it, which I believe is down to it not having the vacuum connected. The car does drive and is useable but I'd like to improve engine power, as it gets up to 60-65mph it runs out of pull.

Now it's off the road for the winter, I've been wondering about the vacuum port on the carb, will it have been blocked or is it a simple case of fitting a new distributor and connecting the pipe up?

Thanks everyone

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Vacuum advance is mainly an improvement in MPG and not essential for running.. At large throttle openings there is little vacuum so the slight leak from the small take off point on the carb will have little effect.

Reading your post I understand that you now have a 32/36 DGEV twin choke carb fitted.

The first question to ask is what cam is fitted as DCOE40s on thier own will not do much so the cam is probably an upgraded one, is it timed right?

Then the jets on the carb will need changeing to suit the cam and any changes to the porting work in the head.

Also the advance curve of the distributor will need checking, does the ignition advance when the revs build up?

More information is needed to say what is wrong.

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As this has an electric choke, has it been wired in correctly and does it work?  I also agree about the cam, when I bought my engine it wouldn't run properly.  I found that it had been fitted with a competition Rally cam which was never designed for road use.  I changed it and the engine runs great.

Edited by cb750

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Hi, thanks for replies. 

Yes it does have a non standard cam in. I believe it to be a fr32 Kent cam.

Yes it has electric choke. I assume it to be working, how would it be tested? 

 

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to check the choke is working remove the air filter and you should see the choke butterfly closed when cold. Turn the engine on and as it warms up you should see the choke butterfly open. If it doesn't it ain't working.

as above though if you have a strobe light connect it up and raise the revs and you should see an increase in advance. A tipex pen is useful for marking the timing mark so its easier to see.

Edited by agent_zed

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If you were running twin 40’s and FR32 you would be very near the max airflow the engine required.

40’s can only accommodate a 33mm venturie and are only used on a relatively standard engine.

twin 45,s allow venturie up to 38mm, you probably need 35 to 36mm venturies for an FR32 cam.

you will need to get whatever carbs you put on the car rolling road tuned to make it work

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According to Dave Andrews, Weber 40s can take a 36mm choke, 45s can take up to 40mm.

http://www.s262612653.websitehome.co.uk/DVAndrews/webers.htm

I changed the cam on my pinto first, to an fr32. I then changed from a 32/36 to 38DGAS which was a big improvement,

but when I fitted twin 40s with 36mm chokes the engine really came alive.

Even with a 32/36 it should pull to well over 100 (only on a track). Make sure that the vacuum into the engine/carb is blocked off it its not connecte to the dizzy

Make sure that the second choke is actually opening, if it is I'd recommend a RR session to get the ignition and jetting right.

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Vizard says 7mm less venturie than carb number.

yes the 40’s can take a wider venturi but you get less of the venturi effect

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