Keep Dellorto DRLA 45s and Bosch 009? Options

[IronHillRestorations]

There's usually only about a half turn on that.

[MarkV]

Needle nose pliers or small set of vice-grips. Put it back together and leave everything loose and then wind up the spring and get it in place last before you tighten the nut.

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[98101]

Needle nose pliers or small set of vice-grips. Put it back together and leave everything loose and then wind up the spring and get it in place last before you tighten the nut.

(IMG:style_emoticons/default/confused24.gif)

Following Mark's advice, and considering Perry's experience that half a turn is enough, I managed to get the spring this far. I don't have a fish scale to measure the exact force, but it snaps back smartly and intuitively feels like the right amount of force for throttle return.

Per the CSP instructions for Weber IDF, I torqued the SW11 throttle control shaft nut to 4 ft/lbs. I'm guessing the right number for DRLA would be similar, and doubt the previous owners bothered with a torque wrench anyway. The lock tab wasn't done up before. I guess I should do that.

Maybe you tall guys could do all this with the carbs in place on the engine? I don't see how I could have done it without pulling the carb.

[98101]

I had to use more like 8 ft/lbs of torque (twice the amount in the instructions) to get the SW11 throttle control shaft nut to align with the lock tab. I hope The Maker will forgive my transgression.



UPDATE: I found this picture of "properly installed tab washer" online. I do not see how my tab washer can perform its function on the CSP throttle lever, and wondering if I should just replace it with a conventional washer.

(Or ignore this as a trivial issue and keep going with the CSP installation since it's taking longer than I expected.)

[98101]

In your carb pic the vacuum advance port isn't capped off ??

It turns out porschetub was right. The distributor vacuum port was NOT sealed internally as I'd assumed. Also my water-spraying vacuum leak test hadn't detected this.

Perhaps someone felt the need to drill it out in the past. What's the best way to cap this off?

I never would have found this with the carb in situ. Would a mechanic have found it?

[98101]

I unscrewed the pushrod (why is it called that when it actually pulls?) and attached the little ball socket to the CSP lever, using 8mm and 7mm spanners. I guess the next step is to put this left carburetor back on the engine and pull the right one.

[rhodyguy]

On a set of 45s I have, that open port has a small brass tube inserted in it with a rubber(?) cap on it. Big time vacuum leak below the throttle plate on yours.

[Mark Henry]

I'd look to see if I could find a brass tube to fit, maybe off of an old carb.
If you have a vac advance dizzy that's the first place I'd try to pull vac from. I'd also tee it with the one from the other carb.

[IronHillRestorations]

A thin 8mm open end wrench is the thing to snap off the ball ends. You want to take both long rods and adjust them so they are the exact same length. There are two different ball socket ends, left and right threads. It's made like that so you can turn them when installed. When you get them installed,put a sharpie mark on the top of both pull rods so you can count the turns if you have to adjust, remember you have to turn them both the same number of turns.

As long as you've got a tab bent up to keep the nut from backing out, you're good

[98101]

If you have a vac advance dizzy that's the first place I'd try to pull vac from. I'd also tee it with the one from the other carb.

Yes, good idea. I have a 123 Tune+ (Bluetooth), currently not using the vacuum advance. In the 123 group buy thread I've discussed hooking it up, and no one there seems to understand why I think it would be a good idea.

My one reservation is that I think I'd rather have the manifold vacuum signal, as I've read the port vacuum signal won't be strong at idle. As I understand it this was done to make combustion hotter at idle to reduce emissions. But this is probably still better than no vacuum advance at all + two carbs with 3.5mm vacuum leaks.

There's also an inop vacuum gauge in the dash. I haven't investigated what it's connected to, if anything. I'm assuming it would be difficult and painful to run a vacuum line from the engine compartment to the gauge.

[914_teener]

If you have a vac advance dizzy that's the first place I'd try to pull vac from. I'd also tee it with the one from the other carb.

Yes, good idea. I have a 123 Tune+ (Bluetooth), currently not using the vacuum advance. In the 123 group buy thread I've discussed hooking it up, and no one there seems to understand why I think it would be a good idea.

My one reservation is that I think I'd rather have the manifold vacuum signal, as I've read the port vacuum signal won't be strong at idle. As I understand it this was done to make combustion hotter at idle to reduce emissions. But this is probably still better than no vacuum advance at all + two carbs with 3.5mm vacuum leaks.

There's also an inop vacuum gauge in the dash. I haven't investigated what it's connected to, if anything. I'm assuming it would be difficult and painful to run a vacuum line from the engine compartment to the gauge.

Yes, good idea. I have a 123 Tune+ (Bluetooth), currently not using the vacuum advance. In the 123 group buy thread I've discussed hooking it up, and no one there seems to understand why I think it would be a good idea.



Never said it wasn't a good idea, I was wondering if it was necessary or worth the trouble porting a bunch of hoses around the engine.

If there are vaccum leaks in FI or carburetors, fixing those would be first order of business.....linkage....sync....jetting.....timing. More or less.

I'm just wondering that with a programmable dizzy....why augment the curve with vaccum when you can put it on a dyno and program it with your phone.

Am I missing something here?

The 123 I have has the vaccum advance port hooked onto the dizzy and it does work. There are two ports for the stock throttle body that were discussed. The model for D-jet is switched only so I can't use blue tooth to change it. Basically it is pre-programmed.

Do both and see what happens.

[98101]

I'm just wondering that with a programmable dizzy....why augment the curve with vaccum when you can put it on a dyno and program it with your phone.

Am I missing something here?

If a distributor ignores vacuum, the only information it has is RPM. This will work, but not as well as possible for street use. The best time to fire the sparkplug cannot be determined only from RPM because an engine running at 2000RPM at cruise benefits from an earlier spark and an engine running at 2000RPM at WOT -- with more stuff going into the cylinders -- benefits from a later spark. Manifold vacuum can give the distributor additional information it cannot get otherwise. Turbo guys take this even further by retarding the ignition sensitive to boost pressure.

The phone app cannot tell the distributor how much load the engine is under, but through the programmable MAP table it can tell the distributor how to respond to that load.

I have to do *something* about these open vacuum ports on the carbs, so running them to the distributor and setting up a MAP curve seems like an interesting experiment. I'm off to the hardware store with the carb to make sure they give me the right size.

[98101]

For some reason the right carburetor wasn't as covered with muck like the left one was. I still tried to clean it up a little with carb cleaner, aka wife repellent. Next time I would probably buy brake cleaner instead.

The right side was way easier since I didn't make the mistake of undoing the spring.

I noticed the other (front) end of the throttle shaft had an unlocked lock tab.


So I locked it. I'm curious how often these have actually fallen off.


The kit for IDF had another feature I didn't seem to need, as far as I can tell.


Engine compartment is much tidier without the hex bar. (I'm still wondering why there's oil spewed all around the filler.)

[rhodyguy]

Cork gasket under the fill Tower assembly? You can change out the carb filter bases now. No need for the ones with the cross bar pivots.

[98101]

I didn't try adjusting the CSP linkage until the next day. I used both the fingertip technique I learned from you guys (touching one while looking at the other), and also tried using paper as a feeler gauge, like a zero-lash valve adjustment. From the photo you'll see I used the CSP installation instructions for paper. This was the only use I got from the instructions, as they were written for IDFs not DRLAs.

When I tested with the air-flow meters later, the left and right carb were more in sync than I had ever gotten them before. (But there were other, much worse problems I'll describe next.)

[98101]

Once the linkage was dialed in, I started the car, looking forward to it running better than ever. Instead, it ran worse than ever. It wouldn't idle, and sounded like it was running on two cylinders. I was alone (without a remote starter), so couldn't get up from the driver's seat to view the engine running after starting it. The iPad was within reach from the driver's seat, so out of desperation I tried the "TUNE" button on the 123 Ignition app.

I was surprised to discover it *would* idle (though not very well) when I bumped the advance from 12º (at 1000RPM) to 20º.

BEFORE (wouldn't idle):


AFTER (would idle):


Later I found it idled even faster with the advance at 1000RPM at 40º!

[98101]

I couldn't see how changing the linkage and adjusting it better than it ever had been before would cause these problems. Maybe I had messed something up when I had the carbs out, using carburetor cleaner on the jets (should I have used brake cleaner?), trying to get the muck off of the exterior, or installing the new throttle arms? Or had I altered the mixture when I closed off the vacuum advance ports that had been wide open before? Had I knocked a spark plug wire loose?

The weirdest thing was the airflow into cylinder #3. It had always been slightly less than #4 on the same carb. But now it was *very* different. I believed it wasn't just a measurement error because spraying carb cleaner into #3 had much less effect than spraying into #4. Note that #4 was perfectly in sync with #2 on the other carb.

[98101]

The next morning I limped the car (with frequent bangs from the carbs and sometimes the exhaust) to a VW shop that had been recommended by a 914World member. When I showed the owner the picture of the mismatched throats he expressed his opinion the carburetor was damaged, possibly by a backfire. He also didn't think the mismatch was bad enough to explain how awfully my car was running.

We spent a couple hours fiddling with the tuning. We noticed that all four air bypass screws were open. Closing them had no effect though. Re-open the vacuum ports... no effect. Inspected all the jets. Checked the jet sizes -- they were the original ones that come with the carb. We even tried changing back to the Bosch 009 distributor. No effect. Tamper with the CSP linkage.... no effect. The engine would idle (with soft pops every few seconds), but wouldn't run at 2000RPM. At open throttle it would run faster than 2000RPM though. At higher throttle settings I noticed gasoline splashing and sputtering from the left carburetor -- the leaky one that's generally covered by muck, not the one with the mismatched airflow.

The shop owner admitted that he was stumped. I thought that he would want to open up the carburetors to see what was happening inside, but I guess he sends them to another shop for that.

He did have *another* pair of DRLA 45s, new old stock. We installed those, made a few adjustments, and the engine idled more smoothly than I had ever heard it. At this point we had worked through lunchtime into the afternoon. Once I heard that new-car idle, I had zero desire to put my old scratched, dented, leaky carburetors back on. He called his contact at CB Performance for pricing advice, and suggested he'd sell them for $750. (No, he didn't have any new Webers lying around.) It took me about half a second to decide: YES.

I'm pretty sure y'all will give me some flak for this decision. I'm 80% sure my leaky left carb and my bent right carb could have been fixed, slowly by me, or quickly by a carburetor shop. But I really feel I'm done with those old carbs. The previous owner was using those foam air filters, letting everything in around the edges. He'd left two vacuum ports and four bypass screws open. He had them mounted on deformed gaskets. In one case there was a paper gasket stuck on top of the squishy one. In my care they'd experienced at least a thousand explosions. Who knows what hell these carburetors have been through in their life?

(However, my carb problems weren't over yet! Continued next post ....)

[98101]

The Road Test

VW shop owner asked me to drive around to test the new carburetors in action. At first it seemed great. It drove smoothly out of the parking lot and pulled hard when I floored it pulling onto the street. A few blocks later I noticed popping sounds and sneezes! But only in some conditions, typically cruising around 3000RPM. Not wide open. And much less often than before. Idle was still perfect. He looked really sad and confused when I told him. I suggested we call it a day.

Today (Tuesday) I wondered how to find out what was in the exhaust at cruising speed. I don't know how hard it is to run the wires for a wideband air-fuel meter, or whether I'd like a gauge that doesn't match the others. I called a local dyno shop (with a sniffer) and found out they weren't very busy. I suggested I should drive the car on the dyno because an ordinary person cannot operate my linkage and worn syncromesh. The car was backfiring even while driving onto the test stand. While setting up, a technician noticed that the left carb's main jet stack was just flopping around in its holder, not screwed in! They screwed that in properly, and I don't think I've heard a backfire since. That was the problem I'd gone there to solve.

We did some dyno tuning, as you can see here (or in the other thread I started). Air/fuel ratio was lean on the first run and OF COURSE they didn't have Dellorto jets, so I asked him to ream out the existing 165 main jets. (I see that CB Performance sells them.) They had never seen a Bluetooth tunable distributor before. We advanced the overall timing a bit from what I had, which improved the bottom end but detracted from the top end. So we backed down just the top end. I really like the 123 distributor. We didn't explore using vacuum advance to improve drivability... still think there's a lot of potential here since this style of dyno run is only optimizing for wide open throttle.

Car ran fantastically while driving home. Unfortunately it's really raining here so didn't get to play with it.

According to another thread, this dyno result isn't impressive and now it's time to fix the clutch.

[mobymutt]

Thanks for sharing this! I'm also in the midst of hooking up a CSP linkage on a set of old carbs, but the -30C weather has stopped progress.