Official Dual Carburetor How To Thread

[72alpinewhitebus]

I'm also noticing that the carbs are offset in the sense that the left is further back than the right by several inches. That means a different set of manifolds in order to make a bar type linkage work, right?

[67rustavenger]

The offset is normal. Other wise how can an apposed engine work?
No you don't need new manifolds. The HEX bar linkage should compensate for the offset.
Good Luck.
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[AlteWagen]

Not CSP linkage, looks more like BugPack copy of the old Deano setup.

Looks like there are only two CSP offerings for type 4, Porsche shroud IDF which would have the linkage arms towards the front

http://www.csp-shop.com/products/18235c.html

and hex bar IDF

http://www.csp-shop.com/products/23408b.html


Who ever set up your linkage up probably couldnt get it to work with the arms supplied and put the bends and flipped the linkage arms on the shafts to get it to fit. With the geometry on your setup I think it would be difficult to work properly.

CB and EMPI hex look easy to setup and geometry looks better.

EMPI

CB

Below pic added for reference

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Official Dual Carb Thread
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[george4888]

Seriously ----- what a messed up linkage system you have. Why did you not use the cross bar system ? What you have would be a nightmare to work and adjust with too many angles, too many turns on the linkage. I am surprised it works, at all.

With the cross bar system, you can at least get some clean 90 degree angles on the rods which drop down to attach to the carbs, giving you the same action on both of the dual carbs . The more angles you use, the more complex is your tuning of the carbs and to have the two open the same amount, when you press the gas pedal.

Try to buy the simple and straight linkage on any cross bar system and I think that will solve your problems. Also, you don't have to run the stock cable at some weird angle coming out of the rear sheet metal and can come up with a straight shot from the rear sheet metal hole to the drop down lever on the cross bar system.

----George K. ----
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[72alpinewhitebus]

Thanks so much for the honesty, I've never felt good about this setup but have always gotten it to work marginally. I just spent another hour in it today and at least got idle speed right and unisycnhed it fairly well. It's not responsive at the pedal and just feels sloppy. It snaps and pops but really doesn't backfire hard. I've got a couple camping trips this month and then I'm Gonna bite into it when I can garage it. The info earlier in this thread on setup was really helpful, so thanks for that!

Can I get a vote on which system? I have an old scat one in a box that is SO old it isn't even a hex bar it's a round bar. It may not look it from the engine bay but it's really a clean bus so I'm not really worried about going cheap.
Cheers and thanks, you've already saved me a ton of work stubbornly trying to make this function....

[AlteWagen]

The old round bar kits would always loose their sync as the clamp type arms would always work loose. Back in the day we would set the sync and weld them up then throw them away when they eventually wore out.

I have only worked with CB hex and the crappy empi kadron linkage on other peoples Type 4 stuff so cannot comment on the CSP hex or longevity of the other setups. I will say that on my upright engines Ive used the CB hex for over 25 years with success. Heims wear and the old aluminum hex also wore but I would usually get 8 or so years of daily driving use out of them before the slop would be too much for me to stand.

I would measure your throttle shaft linkage arms at half throttle to see if they are opening equally, with the popping you describe I think not. You might be synched at idle but you are not under load which makes one side of the engine have a lean condition which can lead to disaster. Type 4 bus heads have enough to deal with without lean conditions caused by poor linkage. I personally would fix it before any trips.
_________________
Grapes of Wrath $200 Engine Rebuild
Official Dual Carb Thread
Cylinder Head Quick Reference Sheet

[72alpinewhitebus]

I guess it is worth saying that I did not install this setup it came with the bus when I bought it in 99 for 200 bucks. At least I knew enough to know it had more than that value in the carbs alone.

If I go to a hex bar, how do I shift the throttle lever on the left carb to the front?

[AlteWagen]

[72alpinewhitebus]

Many thanks!

[72alpinewhitebus]

Ok so here's the linkage I already have. Can I make this work?
From what I can find its a bug pack. I'm not against going for a new hexbar type but if this can work I'd rather not waste it...

[AlteWagen]

Sell it and go hex. The pinch bolts for the arms WILL loosen and you will loose sync at the worst time. The chrome makes it worse.

Back in the day we would grind down the chrome and add spot welds to hold the arms in place when there were no other options.
_________________
Grapes of Wrath $200 Engine Rebuild
Official Dual Carb Thread
Cylinder Head Quick Reference Sheet

[72alpinewhitebus]

Done! That's all the reassurance I needed. I found an empi hex bar on cip1 I'm gonna go with. Thanks.

[AlteWagen]

If you go empi hex make sure to buy extra plastic bushings as they do wear quick. Better yet machine the end balls to a cylinder shape and get bronze bushings from McMaster. I do the same for CB hex and they last a LONG time
_________________
Grapes of Wrath $200 Engine Rebuild
Official Dual Carb Thread
Cylinder Head Quick Reference Sheet

[Albertoprop17]

Hi, I've got a '54 oval with a 1600 engine without heating. I want to mount dusl 36 idf but I don't know what manifols should I use. Straight or offset?

Greetings from Spain

[AlteWagen]

You can use either type of manifold just be sure to get the matching linkage base plates if using hex bar type.
_________________
Grapes of Wrath $200 Engine Rebuild
Official Dual Carb Thread
Cylinder Head Quick Reference Sheet

[oprn]

Hi I have been going through this thread, very helpful I must say! I have been away from air cooled VWs for a number of years and even back then most of our stuff was box stock.
I recently picked up a Manx copy street buggy with a dual port 1600 in it, a 009 distributor and Kadrons. Ran ok on acceleration but popped and farted at steady speeds. fuel mileage was horrible and any where below 1200 rpm the front two cylinders cut out. No chokes on these carbs either or thermostat on the engine so cold starts were not fun and warm ups long and arduous. I could set idle speeds and idle mixtures to a reasonable idle cold or hot but never both.
to make a long story shorter I pulled the engine out to find that because these carbs are so tall the air cleaners were not serviced properly and did not have proper gaskets so the engine has been dusted and needs an overhaul. Oh and the distributor is warn out too.
Plan #2, I have a bus engine sitting around so decided to use it. It already has 96mm jugs in good shape, 66mm stroke with bottom end fair except the cam. It shows signs of severe heat as one head is cracked and the oil is burnt on black everywhere in the engine. The original twin carbs are so badly plugged up with dried on varnish from the old gas as to be pretty hopeless.
So a fresh set of rings, bearings and heads are the way to go. No problem, but... what to do for carbs? Basically a stock 1911cc engine with a mild street cam.
Here is my goals:
Budget project so don't want to buy carbs twice.
Need better clearance to be able to service the whole fuel system in place.
Drivability and fuel economy over all out power.
Don't want to have to tinker and tune every time we run this thing!
Want to retain vacuum distributor for the boost in part throttle mileage.
Need Chokes for starting - cold climate here.

Suggestions?

Thanks in advance. Merv

[oprn]

Can't sleep... try to cough up a lung every time I lay down... stupid cold!!

So - more questions to plague you guys with.

Ballancing the carbs. Ya, ya I know buy a snail or two and have at it. But - all you are doing with a snail is checking that all the cylinders are pulling the same vacuum - correct? Why not just attach a sensitive vacuum gauge to a port under the throttle plate? Or do we read it above the throttle plate? I have access to electronic vacuum gauges at work that read out in hundredths of an inch water column.

Now for setting up mixtures. Take it to a shop that does emissions testing for the government they say. Well, not aware of any such place in our part of the country. Emissions laws are not enforced here so even if by chance I found a machine in the city(minimum 3.5 hour drive)would they be competent on an air cooled engine? Or would I be driving away with carbs set up lean for a water pumper and burn up a new engine on the trip home?

Ok I can read the plugs. Sure. Somewhat time consuming no doubt as the engine needs to run on each circuit to be tested long enough to get deposits to read.

Many years ago when I was just a lad(0h Lord here he goes again the old fart!), Popular Mechanics ran an article on a product from England call Color Tune. Remember that? Basically it was a sparkplug with a glass insulator that you screwed into the engine and you could see the color of the flame as the engine ran. They even supplied a chart to tell you when the color was right. Made sense to me! Anyone have real life experience with those?

Thanks again, Merv.

[AlteWagen]

[oprn]

[AlteWagen]