Weber DGAVs - jets etc.

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tdgray

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So my engine came back from Korman with a new set of Weber DGAVs.

Paperwork states 135 main (no mention of secondary).

45 / 60 idle jets - this I have verified physically.

170 air… assuming they are talking emulsion tubes? Maybe it’s the secondary. Have not got in there yet

I cannot get a smooth idle for anything and I’ve had the air mixture all over the place… currently at 3 turns out but not smooth… just running. Getting some backfire every great once in a while. Idle speed screw is also too far in as far as I am concerned… about three and a half turns after contact.

No air leaks ( just did a round of spraying carb cleaner) although the amount of crap I have had to go around and tighten since the motor went in is slightly frightening.

Motor is a slightly hopped up 3.0 with a mild Schrick cam. When I rev it… nice.. real smooth. Timing is set at 22 btdc. And I used one of you guys 123 tune curve that I found here.

Question after that long winded summary… what are you all that have Weber DG’s running as jets?

I am of the opinion right now that at least my idle circuit is undersized but the whole thing could be wrong?
 
First impression is the cam might be adding to your struggle to get good idle?
I have a "happy" setup now for 3.5L and can provide setup info when I can access it later.

I struggled to get the old engine 3.0 running well thinking it was carb tune but found uneven compression across 6 cylinders, you might be in a different scenario with a fresh motor?
I have a Weber manual if you need to reference anything for setup.
 
This may help.
Simple Rules for low speed calibration
If the mixture screw is more than 2 1/2 turns out turns then the Idle jet is too lean (too Small). When the mixture screw is less than 11/2 then the Idle jet is too rich (too large). These assumptions are based on the fact that the speed screw setting is not opened more than 11/2 turns. If the speed screw has to be opened 2 or more turns then this is also an indication of a lean condition usually requiring greater change. At times it may appear to be showing signs of richness or flooding it is really a lean condition. See pictures and notes in the tech 2 article supplied in the kit instructions, view and please understand the need to keep throttle plate as near to closed as possible so as not to prematurely expose the transition holes. This is what causes the visible rich condition, and confirms the need to increase the jet size.

JET KITS are available if needed.

EXAMPLE: With the speed screw set at no more than (1 1/2) turns in after contact with the stop lever; and the best idle occurring with the mixture screw set at 3 turns from bottom, indicates the need for a larger Idle jet. Achieving the best idle at under 2 turns indicates the need for a smaller idle jet.

The secret to understanding the critical nature of the carburetor set up and the advantages of a WEBER over other carburetors is the Idle circuit. Referred to as the low speed circuit by Weber, this circuit is responsible for 80% of the driving operation. This is the reason that the Weber should give a fuel economy improvement over most factory carbs along with significant performance gains. In the worst case you should not see a significant fuel economy loss over stock, while improving HP & Drivability.
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https://www.yotatech.com/forums/f120/proper-only-right-way-tune-weber-32-36-a-240521/
 
I’m pretty familiar with Webers. They truly are simple little things. When dialed in they are pretty much bullet proof.

Just interested in seeing what others are running before I start ordering crap randomly…. Well not randomly but you know what I mean.
 
Hey Todd, I see you are getting closer. I run a couple 32/36DGAV Webers. I will preface this by saying whatever jets are inside work well here...at sea level. Coast of British Columbia. Few years ago I went through these 2 carbs and cleaned and purged all of the varnish out. Then I adjusted the valves many many times until I was certain I was within spec, plugs, ignition wires....and so on. Then I could tune carbs. Best it has ever idled and performed on the highway. So....in answer to your question, my mains are front ( nearest radiator) both 130, back by firewall, 127. That is just how it is in my car. I have no complaints. These Webers are infinitely adjustable and I am sure you will dial in the correct jet setup for your car and area.

BTW, excellent interview with Mike Pierce, Weber whisperer through Hagerty. Attached here.

Good luck with the tuning!

Mike

 
Thanks Mike. Had not come across that one. Great read.

Coincidentally, I ordered jet sets from Pierce last evening. Starting off with the recommended 6 cylinder kit.

I still can’t understand why Korman jetted this thing the way they did. It seems totally backwards.

Will report back when I get these in.
 
tdgray said:
I still can’t understand why Korman jetted this thing the way they did. It seems totally backwards.
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That's pretty disappointing. I thought Korman dyno tested their engines before returning them. Hard to imagine that they did that and having it run so badly...
 
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