PDSIT Project

[Pruneman99]

Wow great pictures. IDK how I couldn't find them. My wife complains that I can never find anything, she might be right.

If I could find some throttle arms like that, I could undershoot the alternator. As they are now, the angle wouldn't be correct. They need to be pulled up and down, not left/right. If could find or make a center section like Puma posted, I could basically flip it over and overshoot the alternator and utilize the pivoting arms on the carbs. I'll be using a 36hp shroud so airhorns won't be an issue. I'll post a picture shortly.

That makes sense that the vacuum signal would drop with the bigger vents.. maybe one of the 40 horse cast iron distributors might work, I think they use a weaker signal. If I can't get a vacuum distributor to work, I do have a German Bosch 009 that should work good enough.

[Pruneman99]

Throttle closed:

WOT

Nevermind the dirty choke element. Haven't cleaned that up yet. I just installed it to see how much clearance I had to work with.

The pictures really helped, I think I have an idea. Kinda like the linkage Puma posted that bolts to the fan, but upside-down. That way I can set up a center pull-pull.

[PumaVW79]

If you do not want to make permanent mods in those carbs, my suggestion is first to remove and store the links marked in 2nd the pic.

Then cut (from a donor) or make from scratch (only requires ordinary tools) right and left throttle links as shown in the 1st and 2nd pics. The bottom links can be used to hold the springs

Ball joints or studs like the ones in the last pictures are also easy to find.

As long as the ball studs on the center section won't be positioned upside down, I think it is a good idea to attach it to the shroud/alternator tin because it works just fine.

Patina is the new name for dirt

[esde]

[Alstrup]

Larger venturies does not alter the vacum, apart from that brief moment where the butterfly is opening. And that´s where you want it to change anyway.

If the carbs are the old version with only 23 mm venturies there is a good chance they are from a 1500S. Then you need to be very carefull, because one year they used a mechanical and vacum assisted ignition, (08/64 to 08/65 I think, but I am not sure on the dates) These engines have a ½" balance tube and a WOT enrichment system. These can be a little tricky to get to run right with a 26 mm venturi.
If it is the newer version from 08/69 -on there is no problem apart from a rejet. A set of type 3 carbs with 26 mm venturies can support approx 83 hp. If the engine is very efficient a little more.

T

[Pruneman99]

I could Fab up some new arms pretty easy. They would have to orientate downward probably because the piston housing for the choke doesn't leave much room over the top. No big deal, I would just need a push-push system that would undershoot the alternator.

Like this one:
https://www.thesamba.com/vw/classifieds/detail.php?id=684045

Think this one would work?

Thanks for the Pictures Rome, it helps to visualize how the parts need to fit together.

I only saw one br8 distributor at the last swap meet, and the guy wanted like 200 bucks for it. A bit rich for me on a gamble. I'll definitely keep an eye out for one next time though.

The carbs are from a '66 so not sure if that means I can run the 26mm vents without too much issue. If they could handle 80ish HP, that would be great. I guess it would give me an excuse to build a mini-stroker crusier engine. Once I get these all sorted, they will go on a new 1600 for proof of concept. If I like them, mini-stroker it is.

[Frank Bassman]

The Vintagespeed linkage works GREAT.

I run it in my daily and in fact I bought it because it is a real quality product. Ball bearings, all stainless steel, nice NICE hardware and rods.

BUT. I had to open up two holes on the bell crank center closer to the central shaft in order for it to clear the alternator stand.

I am running it with dual PDSIT carbs from CB Performance. You may have to bite the bullet and change or add a tab to orient the carb linkage as was posted below. What I did was modify the system from a push push to a pull pull by reversing the attachment of the rods... a mess I got to work very well in the end. You could save yourself quite a bit of my trouble by using these in conjunction with the Vintagespeed linkage...

http://www.cbperformance.com/product-p/3410.htm


-Frank

[PumaVW79]

Volkswagen had used a pair of those carbs (H34 pdsit 2/3) in the 1678cc SP2 engine gaining 10 hp compared to the 1584cc of the era (75 vs 65 hp).
They had 26mm vents, 152,5 mains 115 air and 47.5 idle. They also had the WOT enrichment circuit, I don't know if they had balance tubes.

Surprisingly, VW used a vacuum only distributor in this engine. Even though the idea was a sports car, the performance was disappointing even for the standards of that time - mainly because VW was very conservative on cam, heads... and probably distributor choices in a somewhat heavy car.

But some guys claim close to 100 hp (+-) in modified 1600 engines also modifying carbs of that family, especially the internal "flutes" (emulsion tubes).

Pic from the website linked above

[Pruneman99]

That's exactly what I wanted to know Frank. Got any pictures of your setup? The link arms look like they would work too.

I'll probably go ahead and order the vintage speed linkage. It will give me the best starting platform I think. I'll have to wait until tomorrow because I need a new bank card. Someone stole my card number again.

I believe I robbed the 26mm vents out of a set of 34 PDSITs like you're talking about Puma. I went with the earlier carbs from the type 3 because they seemed more simple in design. If I'm successful with these, maybe I'll take a crack at the 34s.

[PumaVW79]

Why to spend $125 $145 when you have virtually everything to make it work properly spending only a little time on it?

[vwfreek61]

I just installed a set of PDSIT carbs with Type 3 manifolds on my Trike. I ended up using this chinese linkage: https://www.ebay.com/itm/New-Crank-Linkage-for-VW-...04?vxp=mtr

There was enough thread on the throttle shaft to put the new throttle arms over the top of the originals with some grinding for clearance.
_________________
Kenneth
1964 Bug with Saxomat
1976 VW/Harley Trike Autostick
1987 Vanagon Westy w/Subaru EJ25 and reversed 4EAT

[Pruneman99]

Well I would need ends, rods, ball joints, left hand thread tap, left hand thread rod. I've got the center section from a type 3 that would have to be cut and welded. The linkage VWfeek linked to looks to have the parts I would need for 50 bucks to my door, although it's definitely not as nice as the vintage speed linkage, it looks like it would work.

[Rome]

prune, a few other details to consider. It seems as though you don't have a center linkage at all. VWfreek's chinese linkage for his trike could work for your engine also.

Will you really need working chokes? The factory had to, for ensuring a smoothly running engine during warm-up. Most dual carb kits don't use a choke. If you would disconnect the lower choke rod for the choke "piston" and just tighten the choke element so it's always fully open, then you could simplify your throttle arm and the type of linkage. You could disable the upper stock ball end and the L swivel bracket.

For the throttle arms to work well and smoothly through the entire throttle range, you need to orient them so that the ball stud is the same angle relative to the throttle valve when closed, as the same angle when fully open. You can see that in Puma's photos. It appears as though the ball would be 45 degrees to the left of vertical when throttle valve is closed, would be at "0" (highest position in arc) when at half throttle, and at 45 degrees to the right of vertical at full throttle (throttle arm against carb body stop).

If you use the PDSIT throttle arm, know that it is hardened steel. If you want to drill out the factory ball end, and/or drill a new hole for a new ball end, you must heat up the back side of the ball end with a torch so that it gets very hot. That will enable the drill to penetrate the back side of the ball end/throttle arm surface. I learned this 30 yrs ago on some of my first attempts to modify a Solex carb throttle arm. If your center swivel linkage kit comes with the throttle arms, try them out on the throttle shaft (flip them upside-down) so that your crossbars clears the underside of the generator.

In the past 2 years I took a spare set of swap meet 32PDSIT (checked first that the throttle shafts were not worn), CUT OFF the entire choke assembly (chunk of choke carb body was already broken off) with a fine-blade hacksaw, and made my own crossbars using aluminum tubing; 3/16" dia. I think. I still utilized the top "L" swivel bracket and made another short rod down to the throttle arm. Bought the ball socket ends from McMAster, and cut threads on the ends of the tubing to match the threads of the ball sockets (heim joints aka spherical ball ends). This was for my '70 Fastback so I was able to use the stock Type 3 PDSIT center swivel linkage. I also replaced the 24mm venturies with 26mm (maybe even 27's) from aircooled.net and installed a 135 main jet. I did not have a larger one at the time. Distributor was an older 009. Due to alot of rust on the car and a rusted-through main brake line, I was only able to run the engine with the car in the driveway. But once warm, it ran smoothly and did not have a flat spot. That engine is a 1679cc with home-ported stock valve heads and Engle 100 cam.

I have another swap meet set of PDSITs which I want to prep for a Type 1 single-port use, per my sawed-off chokes. That makes the carbs very compact. I'll use a set of Weber 34ICT manifolds which orient the carbs the same way as the PDSITs. Carb mounting stud spacing on the manifold's top flange is different though. Center swivel linkage will be a modified Type 3 per my comments in my first response. Or spare the expense of the ICT manifolds and take two single-port stock Beetle intake manifolds to cut apart and fabricate my own manifolds. DONGKG did that with some PICT-1 carbs and manifolds for a vintage speed look.

[PumaVW79]

[Pruneman99]

I don't think I want to go as far as cutting off the chokes although that would allow the use of hex bar or the like.

You guys gave me some great ideas here. I'll be ordering linkages/parts tomorrow.

[Pruneman99]

Ok I ordered linkage. Should be here in a few weeks. I'll finish rebuilding the carbs (they just need a kit thrown at them, they are cleaned and ready to go) and fluff the intakes to get rid of a bit of rust inside and to take down the casting lines. Not sure if I should run a balance tube or not. What do you guys think?

I decided to get the Chinese linkage to keep the sprit of the swap meet build. I can sell one cleaned up distributor I got in the lot to cover the whole 50 bucks. I'll let you guys know what I think of the linkage when it gets here. If it's total garbage and the carbs work, I'll upgrade to the vintage speed.

Again, thanks for the pictures, help, and suggestions. I've been looking at these things on my mock up engine for awhile not sure where to go with it. I think I'm moving forward again.

Oh, and does anyone know where I can get replacement filter elements for the puma/brazilla type filters I've got?

[FreeBug]

[Pruneman99]

These have the metal pistons. They cleaned up well with little discernable wear. If the chokes give me a problem, I'll just disable them. No big deal to feather the gas for a few seconds. Not too cold here in SoCal.

[PumaVW79]

[Pruneman99]

I have the pre 78 ones. Now I just need to find some here in the US. The ones I have are a bit past their use by date.