fbekholden.com

Hi everyone,

I'm currently doing up a twin carb setup for the wagon, and am wondering about a couple of things....

1. Vacuum line to the distributor; is it better to be run out of one of the carbs or out of the manifold? presumably the vacuum would be halved at each carb - is it enough for normal distributor advance operation.

2. Jet sizes; I plan to drive the car fairly regularly, so would like to look more for economy than outright power.

3. Choke; does it need to be activated on both carbs?

Any input would be great

Cheers,

Matt

Someone out there into HD/HR models may be able to help. ie X2 setup.

mate i takled this problem no more than a year ago, the vaccum pipe was fitted into the first carby, and being an fb, the second vacuum outlet in the second carby would of been good for the wiper motor needs.

As for the jet sizes, well mine are stock jets off two fj carbies, not sure internal diameters, as they were rebuilt and matched for someone elses ex project.

If you are doing an ek, well block the second vaccum out off carbie 2. I have recently done this as im now running a electric wiper motor (much regret as it let go in heavy rain the other day).

For fuel economy, im not sure whats best, maybe talk to an old mechanic, or someone else here might have ideas, i did not think of that as mines more of a once a month ride, if that.

Good luck, trust me the two carbs on the right set up, is absolute gold, but it will need a good ear to tune it right.

You know what, try alex (roknrol) on the fe fc fourm... part owner of misbehavin a period style grey motor drag car, last i saw it it was running twin strommies. also that listing on the fe fc fourm had a link to a carbie mob webpage, if that helps.

Good luck

oh and the choke, i was told to link it to the rear carbie, but mine is still floating around as i find the twins throw in enough petrol to keep her going during warm up.

Thats my two cents worth. any how good luck.

Matt,

I threw a similar question up on either here or FE/FC forum a while back but can't find the answers at the moment.Some blokes with experience in running twin carb setups told me this.

That to get the twin carb setup running to a point that it would increase performance but also give a reasonable economy payback, the carb jets would have to be around a size 46 to 50 or so ( that was for a mildly modded engine, standard engine might need smaller again ).

Problem I've found is that I can't seem to find anyone who still sells different size replacement jets ( anyone here know a supply source ???) and the ones I've rang have really no idea at all.

It was also suggested buying blank jets and redrilling with a number drill to the size required ( again, where to find a supplier of blank jets ?? )
or alternatively, soldering up the jet hole and redrilling a smaller hole with a number drill to achieve the jet size you need.

If you have a stock motor I'd try a pair of 46 or smaller jets especially if economy is what you are after.

I'll give you the specs for X2 carb jets from my book when I get home from work tonight if that helps but I'd say they'd be too big for a standard grey.

Do what sunnytim has said, that is, hook your chokes up in tandem and get them working via the cable.Don't leave them floating.

Hope this helps,

Terry.

X2 engines used size 55 main metering jets.

From the X2 specs I have they were near identical to standard 149 and 161 carbs with some slight differences from what I can see.

FX engines used a size 50 main metering jet and all other greys used a size 51 jet on standard engines.

So to help bring down the excessive fuel usage problem I guess that anything under a size 50 main metering jet would probably help.

Terry.

Good stuff guys!

The FB runs EK wipers, so blanking off the vacuum to one carb isn't a problem, nor is tandeming the choke. Currently there are .051 jets sitting in the carbs, though I'm sure some smaller ones can be located within the grand spare parts bin.

Has anyone had any experience using a variable main jet? would 2 of these help or just complicate things...

Hi Fella's

I'm no expert when it comes to techno-crat stuff, but I am of the opinion that the size of jets are marked in two ways.

These are by drill size and imperial size.

The drill size actually gets smaller as the number increases eg. a 50 drill jet is larger than a 55 drill jet etc.

I think the imperial size is marked in thou's of an inch eg. a .050" jet is smaller than a .055" jet.

I may be wrong but I am yet to be advised otherwise...........

frats,
Rosco

Yeah, could be right there Rosco.I haven't got any number drills and haven't had the need to use any for well over 20 years so maybe they do go the way in size that you mentioned.

I can't remember now.

Terry.