I suddenly find myself owning 1970 4-cylinder 2.4 with Web hot street Cam idles nicely and pulls hard at WOT. Part throttle response is not great, often with carbs coughing and even backfiring on trailing throttle. My use is mostly street, so I'd like to get this part throttle stuff sorted.

Here's pictures of the stuff that's in there now. I guess that's the infamous Bosch 009 with no vacuum advance and a PerTronix 1847A. The carbs are Dellorto DRLA 45s with short velocity stacks and these tall foam things that don't seal against the air cleaner housings. I'm willing to learn about the carbs but I don't have much confidence in the 009 for running nicely on the street. Please correct me if I'm wrong about any of this stuff.

Also from other threads I gather that switching to EFI such as MicroSquirt would cost $5K or so ... though I'm not ruling this out completely. Correct me if I'm wrong about that.

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Is this kind of linkage OK?
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Here's the idle you may have seen in another post:

https://www.youtube.com/watch?v=-AC53RRrXOU


Any help you can provide is appreciated!

--Michael in Seattle

I don’t think a micro squirt conversion runs that much, but I’d look for ignition control if you were switching over. The Bosch 009 doesn’t work that well from what I’ve heard, but perhaps others can chime in what has worked for them.

Cheapest would be to ditch the hex bar and get a CSP linkage, then find a redtop Mallory dizzy. You could ditch the points and add a pertronix, plus get grey/grey springs from aircooled.net

Buy the CBPerformance Dellorto book and your carb problems will go away as to spitting and coughing or other carb issues

Once upon a time long, long ago in a galaxy far, far away (pre-internet) I was researching recommendations for a jetting for Weber 40 IDF's on a 2056 with a hot cam. I called several Weber suppliers, and they all recommended major upgrades to the ignition system as a starting point. This included a multi-spark box, upgraded coil and a point replacement system. I went with the Crane Hi-6 and PS-91 coil and a Pertronix and it made a major improvement in driveability.

As time went by, the internet came along and I found out the 009 distributor the Previous Owner installed was nor really suitable for Ty4 engine. The Mallory was recommended, but the original equipment Bosch would be vastly superior to the 009. Since the PO had included the original distributor with the car, I reinstalled that and again found a significant improvement in driveability.

Harvey

Invest in the CB dell manual and a synchronizing tool. Pelican (among others) has them, #PEL-TOL-STESK. Or be prepared spend $100+an hour to have someone sort the carbs out. You could buy a 123 dist for a carbed engine and have money leftover just to discover what might be amiss if subbing out the work. While the 009 will fuction, your ingnition will not be optimized.

Do those tall air filters interfere with the rain tray?

PS replace the fuel line clamps with the shouldered variety as opposed to the slotted type.

I found what might be the linkage Mark's recommending?
http://www.mamotorworks.com/VW/product/car...engine-325064-4
It says for IDFs... also suitable for DRLAs?

But I'm guessing that there's not much point in tinkering with the carbs until a more appropriate distributor is installed -- is that correct?

Sorry for a possibly dumb question: I'm actually not 100.0% sure that's a Bosch 009. I assumed that it was because I googled the number on the rotor "1234332215 .08" and it was associated with the 009. Do I definitely have a 009 now?
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Another view showing the PerTronix 1847A position sensor. I guess I'd need to move that oil pressure sender if I installed a Mallory?
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I'm reading about the Mallory distributor now. I found some old posts where Jake Raby is recommending the non-vacuum advance models because those mechanisms are hard to tune and unreliable. So that's interesting.

A previous owner installed the PerTronix Flame Thrower coil in 2010 along with the breakerless ignition.

The previous owner provided Bob Tomlinson's 1995 "The Dellorto Superformance" book.

The foam things don't look like they're sealing well. I haven't found air filters that would fit online yet. I'm curious why the current air cleaners are so much taller than the velocity stacks... maybe someone was thinking about top end only?

In progress -- thank you!


I wasn't aware of this option. Thank you.

John Walker said he *might* look at my car if he's available mid-December. My theory now is that the 009 (and the hex linkage?) by themselves may be sufficient to explain the poor street behavior.


Yes, they would interfere with a rain tray. The car came from San Jose with boxes of parts I haven't even opened yet. I'm guessing a rain tray is not amongst them. I drove it in the rain once to get it the rest of the way home from Auburn. It wasn't an experience I'd like to have again.


Thank you! I will do that, or have it done so I don't screw it up. Any other changes you'd make, especially safety related?

The Mallory distributor body is rather large. Dimpling of the pass side engine tin is required. As I understand the situation, sourcing new modules for the mallorys is difficult.

In your carb pic the vacuum advance port isn't capped off ??
If you are infact running a 09 it will need to capped off,check the other side carb also ,you may or may not have the same there.
Do you know the spec's of the carbs ?? ,been said many times but they are still large carbs for even a 2.4 if not setup right...that will leave a very soggy mid range if not right.
If your carbs are close to being dialed in you could try a vacuum advance dizzy such as the SVDA or 034 (?) Bosch type if you have vacuum ports on both carbs ,larger carbs and a hot street cam will most like see the 09 being even less desirable.
Are you running the right fuel pressure ?,is your fuel from a regulated source or direct from a LP pump ?.
Someone like John Walker will most likely need to see the engine fully tuned (plugs ,leads,timing and valve clearances ) before he will attempt tuning the carbs ,that's the order its done in.

I have a 2056 with Dellorto 40's. My car came with a 050 distributor which is supposed to be better suited to a 914 that the 009. I played around with the 050 trying to get is set up to work right in my car.... installed a Pertronix and a different coil. Tried running a CDI box. Had a flat spot just off of idle that I couldn't ever get rid of. Bought a $75 used dual point Mallory and converted it to a Pertronix II. The Mallory is way superior to the Bosch 050. The bushing/bearings are larger, the distance between the plug wires is further apart and work better and aren't as prone to spark scatter. The advance mechanism is easily user adjustable. I did not have to modify the tin or the oil sender in any way. The Mallory is the way to go if you ask me it made a huge drive-ability difference.

From my perspective you can't really pay some one to set up Dellortos for you because of the trial and error involved. You have to learn how they work and how to adjust them. I rebuilt mine and change the vents size & jet size and got them working really well. Once they are set up they don't require much in the way of adjustment. Make sure the cross-bar linkage is set up properly and the carbs are both opening at the same rate.

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I assumed when you test drove the car it was running strong

But you have to remember a big 4 is not going to run like a
Toyota camry

Its a carbed , 91 octane , with headers brute . Abrasive and snorting burbbling monster


So minor adjustments aside it should run more like a race /track car then a street or cruiser

My 2.3 has webbers it runs smooth at all
Rpm but everything was dialed in at a shop
Its close to perfect

I read the whole thread about the 123 Distributor Group Buy at http://www.914world.com/bbs2/index.php?showtopic=318153. I enjoyed reading how everyone was super excited at first, then ran into some problems, and then mostly worked them out. Well, except the guy who seized his engine.

Anyway, the 123 sounds like the most fun to me at the moment, and still way more affordable than aftermarket EFI. The Bluetooth version with the 12V switch between two modes is especially interesting. I could see having a conservative “try not to cough” mode while the car is warming up, and an aggressive mode.

I could not tell from the thread whether the 123 would require relocating the oil pressure sensor or bending any tin. It sounded like no.

It’s the backfires that bother me the most, thinking that too many of them might cause damage. But yeah, I’m not expecting it to be as inoffensive as my Miata.

Do you remember which model Mallory it was? I’m guessing the dual point feature doesn’t matter for the PerTronix II, but my guesses seem to be wrong half the time.

Mark, where do you get your jets and air filters for your Dells? Someone can tell me if I’m wrong, but I can’t see how the foam wraps my car’s previous owner was using would stop much of anything.

Whoa, in the photo it sure looks like it’s not sealed! I’ll check both of those. Now I’m confused how it could idle so smoothly. I guess I should check for vacuum leaks in general.

Thank you (and everyone else) for this help. With my first two 914s in the 1980s I was pretty much alone with these problems, unless you count the Haynes manual. Now the cars are much older but there’s so much more advice online. Also I don’t have to live in fear of getting it back together by morning since I don’t depend on it to get to work. And spending money on stuff is way less of a problem now.

OTOH, wife does not understand why I’d spend time on this at all! She was especially annoyed when I told her I’d keep my Miata as a rain car. Why would this annoy her any more than me upgrading the SSD in my computer?

Anyway, thanks all. You’ve given me a lot of homework and I’ll do my best.

Any red cap VW Mallory will do the job, you can convert it to a pertronix, but if you run single point with a MSD or Crane CDI box the point wear issue becomes minimal.

Some of the older Mallory's have manual oiling, not a huge issue but you must oil with a pin oiler say once a year.

There are always a few Mallory VW Distributors for sale on Ebay. I don't think it matters whether you get the dual point or the single point model.... the entire point plate gets replaced as part of the Pertronix. Mine is part # 2554101. Here is one for sale now:

https://www.ebay.com/itm/VW-AirCooled-Beetl...2wAAOSwo4pYG2km

The filters came from CB Performance. They are the 3 1/4" and clear the rain tray.

All of the carb parts came from a guy that has a web store on Ebay. I think its called ALPHA1750S ....he is in Italy and sells most every DRLA part you could need.

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It's quite possible - likely - that your idle circuits are plugged or dirty. "Ask me how I know".

+1 on the CB Performance bible, snail-style airflow gauge, and learning about them yourself. The book can be a bit disjointed at times - for example, some pages are out of order...he really should have had someone edit it for him - but it's fantastic information.

While you're placing that order, go ahead and order a couple gasket/rebuild kits. You'll potentially arrive at what I did, and that's spend an afternoon rebuilding/cleaning carbs.

<---- 40s on the race car now a big Del fan...though I really like the stock fuel injection on the stock 2L street car...

Mine has a black cap... I bought a second one as a spare and it also has a black cap. I think the black and red caps are interchangeable and the red came on the newer models.

I don't believe those ports are active on Dellortos. Mine were not.... I put rubber plugs on them but when I put a vacuum gauge on them I never got a reading.... I think the carbs have to be drilled for those to work.

My carb experience has been with Webers but your symptoms to me indicate what in my case were clogged idle jets. Also possibly an intake leak. I use the Petronix Flamethrower distributor and have had good service from it for 5 years now. The body of this Petronix is also very wide and took some tweeking of the cooling tin to install.

No, they're not interchangeable.

Some carb sets come with only 1 port in the pair,can't remember if its the left or right one ,the 2 ex- Alfa sets I have are that way,if they ports are there they are drilled and will have vacuum....least mine are.
However I read on a UK forum some sets had vacuum ports on left and right ones as supplied new.
There are 2 hex screws on each carb below the height of the throttle shaft these for balancing maximum vacuum when tuning,I believe this is because the carbs never came with velocity stacks so couldn't be balanced with a conventional synchrometer.

Not sure this engine would idle as per the supplied video with blocked idle jets....seemed to run to smooth for that.

OP needs to pull a carb and see what he has...I think that's also a good starting point also.

I think you are correct. The red has a different rotor that may only work with a red cap. The black cap rotor is round at the back and the red rotor is triangular at the back. The red cap looks like it could be taller so maybe that the difference..... the distributors all look identical. one of my distributors has a different part number ... YL-570 A2.

Well ...I know I'm correct.

Black the can (body) is taller, cap is shorter and clips sit lower on the cap. The caps centers on a notch on the can.
I believe all the black tops must be oiled with a pin oiler.

Most red tops have an oil hole machined (auto oiling) near the drive gear, the lip of the cap fits over the can like a stock bosch dizzy cap and centers on a pin on the outside lip of the can. The notch is on the cap.
Both styles have different rotors, in fact IIRC there's about 5-6 different rotor styles.

I've had many of each style in my hands over the years.

I don't have a vacuum gauge (actually there's one in the dash but I don't know whether it's hooked up to anything or if it even works) but I tried covering it with my finger and couldn't detect any suction. Then I tried squirting a little water into it and didn't hear any change in how the engine was running. If I had any rubber plugs I guess I'd put those over them.

In case anyone missed it, three things the engine seems to do well: start, idle, pull like a clydesdale at wide-open throttle. Poor running seems to happen at certain combinations of part throttle and engine load. The backfires might be most common after a hard run. Temperature is in the 40s (Fahrenheit) here, and the oil temp takes a long time to reach 170ºF.


Thanks -- I'm reading the Dellorto Tech Book now about how to do that so I don't screw something up. I'm not clear whether I can easily check the main venturi size without removal.

The book suggested I should not trust the numbers on the jets, if they are even legible, as they may have been reamed. It suggested using jet gauges. I don't have those yet. Is this taking it too far?

I ordered the carburetor synchrometer from Pelican, part # PEL-TOL-STESK.

I ordered what I think are the same 3 1/4 inch air filters MarkV is using from CB Performance, their part #3301. A lady at CB Performance named Marieanne was knowledgeable and kept me from ordering the wrong filter.

Regarding the CSP linkage, she said CB Performance doesn't carry it. It looked like MarkV had no complaints about the same hex linkage I've got, so I may hold off on changing that.

No one suggested keeping the Bosch 009, or any reason not to get the 123 distributor I'm so intrigued with. I ordered the Bluetooth 123 distributor using the group buy code. I don't think I've changed a distributor before, so thinking I might seek help with this.

The roughness at part throttle and sensitivity to engine load make me want to experiment with vacuum advance, hence the interest in the configurable distributor.

Vacuum advance doesn't play well with dual carbs, as they have poor vacuum. If you add a hotter cam Vac becomes even worse.

I didn't realize that dual carbs don't produce a good vacuum signal but it makes sense. I didn't find a port on the DRLA's with a vacuum signal and I didn't want to drill them.

I have a cross bar linkage because it came with the car and it was at one time all that was available. It's probably harder to set up but once it's set it works fine. Just make sure that both sides open at the same rate.

The jets are marked ..... easy to enough to read. You can pull a venturi with out having to remove the carb by just pulling the top off the carb. They have a cone shaped set screw on the end of the barrel. The venturi are marked. I am running 34's you made need something bigger. If you take the top off a carb be careful not to damage the gasket or inadvertently bend the float tangs and change the fuel level.

Do a search here I am sure there are a bunch of threads concerning dialing in carbs. This one is pretty useful: http://www.aircooled.net/synchronize-dual-...arburetors-103/

Sorry but just want to make sure all the facts are there

You are running premium gasoline ? Correct

I think so. Previous owner said he was. I finally saw the low fuel light yesterday and filled it with 92.

I didn't ever hear anything resembling pinging. In Arizona both my 914s pinged a lot unless I retarded the timing so far the cars were slow.

Sounds like you have a lot more experience with these cars then i do

But ive always heard dellorto s are supposed to be the
Technicallly superior carb because of their
Behavior when not at wot
Like a partial circuit or something.

So they are smoother , more street oriented then
Webbers

Thats not necessarily the story here but then again
Did the guy who built it use dellorto for a reason
Or thats just what was available

As y'all advised, I bought an air-flow meter. I was able to measure what was happening at idle. At the time the engine was warm and idling fast, around 1200 RPM. It often idles lower than that.

With only one meter, I didn't see a way to compare the behavior at speeds other than idle. Is there some trick to this that I don't know? If not I guess I'll buy another meter(s) to watch more than one throat at a time while revving the engine. Sometimes when I'm driving, I'm wondering whether it's running right at slight throttle, just off of idle.

At idle I noticed slightly less flow from cylinder #3. It reads 5 while the others read almost 6. Is this a significant difference?

Cylinder #4 below:
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Cylinder #3 below:
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Idling fast at the moment:
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Cylinder #2 below:
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Cylinder #1 below:
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I also got more legitimate looking air filters from CB Performance to replace the foam things the previous owner had for some reason. But I still have the long studs, so removing the air filters is more of a hassle than it should be. I don't know if it's easy to find shorter studs. I'm tempted to buy taller filters just to reduce the hassle.

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I always disconnect at least on carb from the linkage. You don't need 2 meters just move it from throat to throat. I set my idle at like 900....1200 is too fast. You adjust the idle screws on each carb to get the flow to match. Slow the idle on the carb that is flowing the most air. When you first start playing with them it can be frustrating but one you get the hang of it it's really pretty easy. Then set the mixture screws.

Get the timing set up where you want it before you set the carbs. If you change the timing after you adjust the carbs it will change your idle speed.

No reason to by new studs just measure them and then cut them with a hack saw. The studs are an american thread size I believe. I was able to buy a set at the local ace hardware.

If you cut them with a hack saw remove them first.

The studs are #10 X 32 thread size.

Cool -- thanks!

I don't know why it was idling so high this time. Usually it's idling around 900. But usually I don't get to drive it long enough to warm up much.

I fought with mine when I first set them up. Make sure that the linkage on both cars are symmetrical. The rods that attach from the linkage to the arm on the carb should be the same angle... otherwise one carb is going to open at a different rate than the other. You can operate the linkage with the car running manually to check the flow at higher rpm. I try to hold it at 2500 rpm and compare one carb to the other to ensure the linkage is working correctly. Set the idle with one side disconnected and then reconnect and make sure that there is no change in rpm when you reconnect... adjust the rod if you have to so that the rpm doesn't change.

I noticed in your photos that there is a spring on your throttle cable. I have never seen that before. My carbs have springs built in to the throttle shaft. That extra spring may be causing your idle to change with engine temperature. I have my cable adjusted so that there is a little bit of slack in it so that as the engine heats up it doesn't pull on the cable and change the idle. You might try eliminating the spring on the cable.

Maybe this will help you:

https://www.youtube.com/watch?v=5tigMg-Fn94


He doesn't go into making sure the linkage is set up correctly or how to check it at rpm. It is a simple explanation of how to set the idle.

Yeh that throttle cable spring is intresting

And id say idle speed varies a little bit
But 1200 is on the high side

Once again ive heard dellortos
Are the smoothest as far as partial throttle is concerned

Back the pass side idle speed adj screw off of the stop. Does the engine stumble or a marked change in the idle? Using the driver's side, pass side off stop, turn the idle up to 1.3k. Now measure the flow on the front venturi of both carbs. You want a stable needle on the flow measuring tool. Now you can control/increase the idle speed with ONLY the driver's side ISAS. Matched at idle means nothing if the flow measurements change when the linkage is working. You don't want to be dropping a c-note + per hour for a linkage problem or needs carbs rebuilt "diagnosis".

When idling, filter tops off, and you glance down the carbs do you note any fuel dribbling?

You don't need to spend $ on an additional flow measurement device.

I have a 2270 with 45 Dellortos and a Mallory Unilite distributor. I had a similar experience as you have with a off idle stumble. When taking off slow from a stop it would jerk around a little before taking off unless I took off fast. I played with the everything from timing, jetting, float levels, accelerator pump, clean carbs, and coils. It did get a little better but it was still there a little so I thought thats how it is coz I tried everything I thought. One time I was cleaning the carbs and noticed some of the auxiliary venturis were a little loose in the bore so I tighten them up until all the wiggle was gone. I would always try to make sure these were tight but they would loosen up. This time I notice that a couple of the set screws would not go all the in and would stop at a certain point so I retapped them. When I tighten them I wiggled them until they were tight in the bore. When I got it all together and drove most of the hesitation was gone and thought wow this is nice. I also learned that the transition from low to high circuit was lower than I thought and leaned the accelerator pump and that removed the rest of the hesitation. That's been my experience. After thinking about it I thought if the venturis were loose then maybe some air was getting between them and either delaying the high circuit or leaning it.

I hope another newbie question is appropriate. I noticed this intake manifold gasket is deformed. Is this caused by overtorquing? Will it leak?

I have not removed the carbs yet -- still afraid of messing something up.

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I've never seen one like that. Neoprene? If you want to investigate just remove the 8 nuts, cable and fuel supply line. Then you can lift both carbs at the same time preserving the current settings. Nyloc nuts? That's a new one too.

Holy cr#p never seen base caskets like that,WAY too thick if they are overtightened you could bend the carb bases...seen it before ,thick cork gaskets can do the same.
The correct gaskets are only 1mm thick and usually high temp material,I have an Italian Dellorto kit in front of me now.
The OP needs to go right through this whole setup and start again from scratch,every problem or potential issue needs to be sorted before trying to tune them afterall.

One thing at a time.

Any VW/bug shop in the Seattle area will have the proper gasket.

IIRC those are CB performance gaskets, I think they called them "dellorto doctor".
Dellorto's have a weird notch cast in the throat that makes an annoying whistle, the gaskets have a molded part that stick up into the notch to stop the whistle. I believe they are a hard plastic.

This is all going from memory from back in the 90's.

My carbs had some thick gaskets somewhat similar to that. They have a built in raised portion that fills in a boss/void in the bottom of the body of the carb. I used them till I wore them out...I was never able to find a source for them. The raise portion keeps the carbs from whistling or chirping. If they aren't leaking I would leave them alone. In fact if you aren't planning to rebuild the carbs I wouldn't remove them.

Just googled I was thinking dellorto "Jet Doctor" which was made to solve a dell jet issue,

Below is the gaskets I'm talking about, MarkV here's where you can get them and many other dell parts.

http://vwparts.aircooled.net/Dellorto-DRLA...stle-gasket.htm

Link to the dell parts

http://vwparts.aircooled.net/Dellorto-DRLA...-Jets-s/933.htm