Looks like your rear carb is too lean
Weber 32/36's - can't figure it out!
- Thread starter dang
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That's what I'm going to focus on. Which sync tool is most popular with Webers? Seems like some kind of foam spacer would need to be used to seal the top of the carb since it's not flat with the choke plate and linkage sticking up. A closed foam spacer would be nice, or do some just twist a rag around the top?
I'm wondering if I didn't put enough attention toward making sure the carb linkage was correct before moving on to the carbs themselves. I made linkage pieces, messed with the linkage rods, but all I did was make sure everything moved freely and the throttle arms on the carbs lifted up at the same time.
The best imo is the SK synchronmeter with the STE-40 adapter. You’ll be able to verify and sync airflow at idle and 3k rpm, and verify the secondary barrel settings:
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Agreed for idle, but at 3k rpm it’s difficult to hear.
Idle is a good place to start.
I too am a fan of the SK synchronizer. I have an ST-40 adapter you are welcome to borrow. I not longer have downdrafts, so its just sitting around.
As to linkage, I found you can do quite a bit by just observing closely how the various components of the linkage and throttle plates move. Look not only at upwards movements and what happens when you press the accelerator, but also what happens when you back off and the various springs come into play.
As to linkage, I found you can do quite a bit by just observing closely how the various components of the linkage and throttle plates move. Look not only at upwards movements and what happens when you press the accelerator, but also what happens when you back off and the various springs come into play.
For syncing carbs I use the setup as shown in these pics. It's a Synchro Test made by MotoMeter in Germany. And yes, that is an old Rain Dance car wax can modified to fit over the carb and a hole matching that on the meter. Seal doesn't have to be PERFECT as long as it's equal as you move from carb to carb. You're just ensuring the carbs are drawing equally.
Concerning that Facet electric fuel pump, I found it adequate when I had Weber 32/26s, but not when I switched to 38/38s. The Facet is high pressure / low volume, and the 38/38s wanted low pressure / high volume. I switched to a Carter P4070 fuel pump and it solved all my flat spots and jetting issues. I probably spent more on jets trying to solve what I thought were jetting issues than the cost of the Carter.
Concerning that Facet electric fuel pump, I found it adequate when I had Weber 32/26s, but not when I switched to 38/38s. The Facet is high pressure / low volume, and the 38/38s wanted low pressure / high volume. I switched to a Carter P4070 fuel pump and it solved all my flat spots and jetting issues. I probably spent more on jets trying to solve what I thought were jetting issues than the cost of the Carter.
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I had a cheap Facet ‘cube’ pump 37 years ago that kept up fine with triple 40DCOE’s on 3.3liter once I paired it with a FPR. It ran great even under sustained WOT.
Latest update... I used a hose and listened to try to sync the carbs. The more I did it the more I started to understand what to listen for to match the volume of air going through. I started with the linkage disconnected and carbs independent from each other and was able to get them sounding the same as far as volume, BUT, the rear carb sounded like a very smooth air flow and the front carb sounded like it was pulsating. I'm not sure which is correct, but after feeling better about the adjustment and also spending time getting the linkage adjusted a lot better than it was, no change in the way it ran. None at all.
So, I took the carbs off and put the 38/38's on from my coupe to confirm the 32/36's were the problem and the engine runs perfectly. I've decided to leave the 38/38's on the E3 with the 3.5L and rebuild the 32/36's for the coupe (2.8L). I have four carbs to make two good ones, you'd think I should be able to make that happen. Ha!
So, I took the carbs off and put the 38/38's on from my coupe to confirm the 32/36's were the problem and the engine runs perfectly. I've decided to leave the 38/38's on the E3 with the 3.5L and rebuild the 32/36's for the coupe (2.8L). I have four carbs to make two good ones, you'd think I should be able to make that happen. Ha!
Before you rebuild your 32/36’s shouldn’t you check the easy stuff, like how they are setup with various jets etc.? Would have been quicker than swapping in the 38/38’s
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See page 2.
@dang - Nice going. Sounds like an ideal solution. Although, who needs smooth running when you can spin the tires in 2nd??
I don't have other jets, plus trial and error time, so swapping the carbs took about an hour and now I move forward with it. My coupe is down right now with a brake problem and I needed to get the E3 moveable so that was my motivation. The 38's should be on the 3.5L anyway, at least versus 32/26's, but I have the choice of 32/36's or Zeniths on the coupe now.
To be honest, the underlying "swap it and move forward" attitude is because I have WAY too much on my plate right now and this was the best way to check it off my list.
I hear ya, but when I explained to the officer that I only have idle and full throttle he didn't believe me.
got it.
Now that your 32/36’s are “on the bench,” it takes maybe as much as 10min to se what MERs/etc they are setup with. The results of that 10min will help you decide if you want to keep them or go in another direction.
I'll have a better plan once I start working on them again but I have been scratching my head a little bit about where to start. I've had them apart so many times it just feels like I'm missing something obvious. Should air flowing through the venturi sound smooth or pulsating? The pulsating makes me imagine fuel spraying on and off like an injector.
Air pulsing sound : any chance you were hearing the cooling fan airflow or a worn/ intake valve seat?
Definitely not the fan and would be surprised if a worn seat since the head is a DOT-R and looks very new. Doesn't mean it couldn't be that though. Once I get the 38's all buttoned up I'll listen to them and see what they sound like for comparison.