[Vincent]

My go to has been air die grinders. Here's a 73 intake ported for my 38 dges .

 

[opelbits]

That's a lot for a Dremel, but a cheap die grinder from Harbor Freight, a rounded carbide bit and some sanding rolls are pretty cheap.

 

[RallyBob]

Hmm, what's the most painless way to accomplish this?
I wonder if a fly cutter mill bit could be used. I'd have to find out one to work.

if you’ve got a mill and appropriate tooling, that would be the fastest way.

I use an electric Foredom die grinder and single-cut carbide burr to grind it out.

 

[oblvnnwtnjhn]

Great thread! I too found it searching for tuning help for my 38 on my 61' Willys CJ5 with 2.3 F-134 inline 4. Shaved 0.60 between head/block, .060 bore, Isky camshaft grind 240/238, 2" free flow exhaust. Of course I am looking for max torque vs horsepower. My kit, K380 from Redline, shipped with 145 main jets, 55 idle, 170 air corrector. I installed a wideband yesterday, too rich at idle, 15+ at 1.5 turns, I could smell and feel that beforehand. Landed at 40 idle jets, 1 turn, close to 14.7, changed the air correctors to 180 (most 38's I see ship with 185's?) definitely cleaned up the mid range which is where I run most when trail riding, as I don't yet "crawl" much until I install lockers front and rear. When I floor it, shoots to 10+ and spitting bog down until it clears.

Reading through the threads until the last one, it's recommended to change to F66 emulsion tubes for a cleaner response? Also the throttle bearing upgrade looks/sounds to be worthwhile.

I have a Prestolite IAY 4401 distributor rebuilt/recurved by Jeff Schlemmer at Adavanced Distributors, he sent it back with suggested 12-16* degrees of dynamic timing, I am maxed physically at 12*, I need to flip/adjust the collar plate to gain the additional adjustment.

In talks with a custom electronic distributor source to convert a IAY to one of his units to gain more control/flexibility.

 

[Autoholic]

Reading through the threads until the last one, it's recommended to change to F66 emulsion tubes for a cleaner response? Also the throttle bearing upgrade

I don’t know if you saw this other thread, but it has a lot of resources you can download that can help with tuning and rebuilding a 38 DGAS.

The Weber DGV Carburetor Series

Thread Table of Contents (to be updated as thread continues) Intro to DGV Carb Series: post #1 (with posts #7-13 for corrections and discussion over general info) Exploded Diagrams (documents to download): post #2 Tuning & Troubleshooting Guides (documents to download): posts #3 and #31 DGV...

www.opelgt.com

 

[RallyBob]

Reading through the threads until the last one, it's recommended to change to F66 emulsion tubes for a cleaner response? Also the throttle bearing upgrade looks/sounds to be worthwhile.

This is really only a thing we do for smaller short-stroke 4-cylinder engines.

The standard F50 emulsion tubes were originally designed for a European Ford V6 (2.5 or 2.8 liter) and they should be closer to what you need.

 

[oblvnnwtnjhn]

This is really only a thing we do for smaller short-stroke 4-cylinder engines.

The standard F50 emulsion tubes were originally designed for a European Ford V6 (2.5 or 2.8 liter) and they should be closer to what you need.

Thanks for the info and clarification Bob and Auto. One other item I read on this thread did not point out, you tune from the main jets back to the idle?

Lastly, best source for Weber jets in the US? My regular source, Pegasus Racing is out of stock of the 185 air correctors, I have the regular and high altitude kit, but 185's aren't included and would like those on hand since that's what they ship with from the factory.

 

[RallyBob]

Thanks for the info and clarification Bob and Auto. One other item I read on this thread did not point out, you tune from the main jets back to the idle?

On the 32/36 and 38 mm downdrafts, the mains feed the idle circuit. So yea, get the mains close first.

I made the mistake early in my jetting days of dialing-in the idle jets and idle mixture screws first. Then I changed the main jets and I had to start all over!

Lastly, best source for Weber jets in the US? My regular source, Pegasus Racing is out of stock of the 185 air correctors, I have the regular and high altitude kit, but 185's aren't included and would like those on hand since that's what they ship with from the factory.

Tons of US and Euro sources out there. I used to get all mine through Interco back in the day. Also Redline, Weberjets.com, Cannon Industries, etc.

If you need 185 airs, I have tons since they came stock in our Opel Weber kits. Usually I’m jetting performance engines so I remove them. I probably have 30 or so.

 

[oblvnnwtnjhn]

On the 32/36 and 38 mm downdrafts, the mains feed the idle circuit. So yea, get the mains close first.

I made the mistake early in my jetting days of dialing-in the idle jets and idle mixture screws first. Then I changed the main jets and I had to start all over!



Tons of US and Euro sources out there. I used to get all mine through Interco back in the day. Also Redline, Weberjets.com, Cannon Industries, etc.

If you need 185 airs, I have tons since they came stock in our Opel Weber kits. Usually I’m jetting performance engines so I remove them. I probably have 30 or so. View attachment 459524

The 145 mains definitely seem too big, if I floor it, the wideband shoots past 12 to 10 and below, makes a spitting/bog before it picks up. As it shipped to me from Redline, it has always been rich. Curious why the K380 kit ships with 170 air correctors when most 38's seem to leave the factory with 185's.

I'll put it back to as shipped, see where I am, start from mains and work my way back properly. I can't figure out how to shoot you a PM regarding the 185 air correctors as I would like to have them on hand to add to my jetting kits.

I was also curious if I could get more timing into it, would it cure the rich WOT, I am currently stuck at 12* physically, I think I can flip the distributor collar to gain more adjustment as it was returned to me from Advanced with 12-16* written on the bag. I almost always run 90 non ethanol as my understanding pure gas burns more completely than ethanol blends.

 

[kwilford]

...I can't figure out how to shoot you a PM...

MODERATOR'S NOTE:

New members have to post ten times to send a PM (aka Conversations) on this site. I believe that Bob can PM you, though, and then you can respond.

 

[oblvnnwtnjhn]

Update: 140 mains, 200 air correctors, PULLS and PULLS! Hitting my AFR targets, so on 3rd base, headed to home!
Innova 5568 and generic dialback, confirmed 16* of timing (rebuilt/recurved IAY 4401), the engine sounds right, smells right. Verified correct float height. Still a little intermittent spitty when I flog the pedal down, may be the power valve but will spend some more time driving and butt dyno, observing, check vacuum etc.

I cannot recommend this book enough for those new to Weber carburetors, even something for those with prior experience. It really brought the design into focus for me, helping me to understand the circuits and the interactions between them.

I also ordered a parts genuine 32/36 to try the progressive mod on my 38.

 

[Autoholic]

Does that book specifically cover the DGV carb family?

 

[oblvnnwtnjhn]

Does that book specifically cover the DGV carb family?

Yes it does. $23 on Amazon

 

[Young Gt Lover]

Update: 140 mains, 200 air correctors, PULLS and PULLS! Hitting my AFR targets, so on 3rd base, headed to home!
Innova 5568 and generic dialback, confirmed 16* of timing (rebuilt/recurved IAY 4401), the engine sounds right, smells right. Verified correct float height. Still a little intermittent spitty when I flog the pedal down, may be the power valve but will spend some more time driving and butt dyno, observing, check vacuum etc.

I cannot recommend this book enough for those new to Weber carburetors, even something for those with prior experience. It really brought the design into focus for me, helping me to understand the circuits and the interactions between them.

I also ordered a parts genuine 32/36 to try the progressive mod on my 38.

View attachment 459661

I need some help on my webers. I might just have to buy this book.

 

[Vincent]

I did a change up on my 38 dges Weber after years of running my 2L with 145 mains, I swiched to 140s even though my air fuel ratio gauge indicated jetting was damn near perfect already. No other changes other then bringing in the idle mixture scews maybe another 1/8 turn to lean out the idle a touch further.

I'm happy I experimented further with my set up. The overall engine responce across the RPM range improved and feels crisper .

On hot days my engine no longer loads up with prolonged idling at stop lights, or construction zones as before. Also the occasional run on after shutting off the ignition is gone.


Point of this post is even with all the additional knowledge an air fuel ratio gauge provides ( in my case priviously showing ideal numbers) , there are always benefits to continually experimenting with different tuning set ups. Nailing the last little bit of fine tuning is indeed a sweet feeling.

 

[oblvnnwtnjhn]

Also, do not run the restrictive rectangle air filter the 38 kit comes with, I am running the following:
1. Filter: ITG JC20S "Sausage" Racing Air Filter Element Only, each - Pegasus Auto Racing Supplies
2. SVK velocity stack: Low Profile Velocity Stack (Air Horn) for Weber DGV or DGAS - Pegasus Auto Racing Supplies
3. baseplate adapter: ITG Baseplate only for JC20 Air Filter, Weber 32/36 DGV - Pegasus Auto Racing Supplies

 

[RallyBob]

Just an FYI, since I recently re-discovered this in my notes. Jetting a 38 DGAS for a stock high compression 1.9.

This was my jetting on a bone-stock high compression/solid lifter 1.9. It was on my Kadett wagon with automatic transmission and 3.18 gears. It had about 95,000 miles on it with all stock ancillaries except the 38 DGAS and a Pertronix w/Bosch red coil.

Idle jets: 40
Main jets: 130
Air corrector jets: 155
Emulsion tubes: F66
Float level: 41/51 mm

Driveability and throttle tip-in was awesome, which isn’t easy to achieve with an automatic, especially with taller rear gears!

Anyway, I’d expect a low compression stock engine to have to be richened up a bit due to combustion inefficiency. Airflow requirements would generally be the same however.

Any deviation from stock airflow requirements…ported intake, header or Sprint exhaust, larger main exhaust, small cam change…these would necessitate re-jetting.

 

[hrcollinsjr]

Any deviation from stock airflow requirements…ported intake, header or Sprint exhaust, larger main exhaust, small cam change…these would necessitate re-jetting.

If it doesn't require re-jetting then you probably wasted your time doing the mod.

Harold

 

[oblvnnwtnjhn]

All, do any of you have 74403.047 and 74409.047, Primary and Secondary idle jets. Appear to be uncommon Stateside and having a hard time finding a drill bit this size to make my own. I am really close to being dialed in near perfect, 50 are just a wee bit too large, 45's are too lean. Wanting to try a .047 to see if that's the magic sweet spot.

 

[The Cub]

I found the .045 to be a tad lean, the .050 too spongy (rich) as well. It seems you’re awfully close to what I ended up with. I could drive with either but wasn’t satisfied.

If no one has them here, try these links:
77409.047 lg. idle jet
or
77409.047 lg idle jet
77403.047 small idle jet

The .047 was a bit lean for me too.
Grainger also has a very good selection of micro drill bits, I found the .048 size to be ideal they have the .047 size as well.

HTH