Weber 38 DGAS : info + settings + tuning (1 Viewer)

[ErikinSC]

Drove Elsie home today; 35 - 45 in 4th gear took about 10 seconds. consider I have 33's and 3:70 gearing now - and I have not corrected the spedo setup. It could have been a 45-55 mph.

I ordered 140 & 145s today. It will be at least a week or longer before I can re-jet and comment. I'll be traveling & truck is getting a body TLC.

 

[Weber Sarge]

That isn't too bad considering the gearing - 35's and 3.70 gears is a bit rough and takes all it's torque to move it . 4.11's and 33's I can pull from 40-60 (on gps) in less than 5 seconds easily on the primary of the Trollhole . I'd love to have a solid , rebuilt engine and DCNF to play with again but it would have to be a one-off - not going down that road selling kits again .

Sarge

 

[Bluegrass40]

Great thread guys! I'll be walking through all of this on my rig soon, I hope!

 

[ErikinSC]

My set up :

'74 FJ40 with a replacement 2F (sn 882263) and what I was told is the F head (steel valve cover). I have a stock exhaust header and intake, but the truck has been de-smogged. I have a Weber 38/38 with cable throttle and gas pedle setup (from TPI - installed by the PO). Non USA vacuum advance distributor, points & condenser, and an aftermarket coil.

I have a mechanical fuel pump, 4psi O/P with a @Weber Sarge suggested CJ style 'vented' inline fuel filter, just before the carb :

View attachment 1083898

And I have the stock heat shield installed, less the insulator. I have a 2 piece aluminum mounting bracket for the weber, and Im holding 20in of vacuum.

View attachment 1083897

I am using a Toyota Non-USA vacumm advance dizzy, new points, condenser and rotor.... timing bullet is on the top side of the mark (@ 8* BTDC) on the flywheel window.

Just some feedback... and an update. I rechecked my timing, and adjusting the 'bullet' to BELOW the alignment mark, I would assume that it is now 10* BTDC

(Pic of Timing window - w/starter removed courtesy of @Slow Left )


It has helped my truck to run better.

 

[mags]

I just ordered a Petronix after I busted my points in my 1975 FJ40, which is a 3/75 build date. So I will be doing timing again soon. Can someone clarify that when timing, if the BB is lined up with the mark, that it's at 7 BTDC? Then if that is true, and I am running a Weber on a desmogged 2F, where abouts should the BB be to get between 10 and 12 BTDC? Do I send the BB above the alignment mark pictures in the previous post, or below it and about how far?

So when I set it about a week ago before I broke my points I had the BB well below the alignment mark in the site window, as in I sent the BB out of the site window. That seemed to be the spot where it ran best. Turning the distributor any more it started to bog and run rough so I turned it back to that point. I guess my question is am I doing this right? Is that about where 10-12 BTDC is? Any help is appreciated I am installing the Petronix Friday or Saturday and then I'm going to time it again.


Sent from my iPhone

 

[JohnnyC]

BB is lined up with the mark... yes... it's 7 BTDC

yes my weber 38 likes it at 10-12deg as well... i use a adjustable timing light

its not much further past the BB... you dont have an adjustable light?

 

[mags]

No I have a light that just turns on and off. No adjustability. So are you still able to see the BB in the sight window? Mine disappears below the window at what I believe is its best running state.


Sent from my iPhone

 

[ErikinSC]

This last time, I tuned mine using a Vac gauge with the timing light. When I adjusted the dizzy so that the BB was between the alignment mark and the bottom of the window, but still in the lower portion of the window, I watched to see where I had the best vacuum. When the vacuum reading peaked, that is where I set my timing.

 

[mags]

Ok that makes sense. Where did you plug your vacuum gauge in at?

On another note I had my timing set below the window so I am assuming maybe up to 14 or 15 BTDC if you can still be at 10-12 inside the window. I have been running it daily like this for about a week. Washed the truck Sunday night to include inside the engine bay. Parked it in the garage, which is not heated and temps are down to 0 degrees here in Northern NY. Opened up my distributor Monday to look at cap, rotor and points but didn't start it. Put it back together and when I tried to start it Tuesday it wouldn't fire. Cranked nice and strong. Just wouldn't fire. At the end of the cranking process you could hear the engine have huff like it was holding air and releasing. The question is now did I mess up my engine with having the timing set with the BB outside the sight window?


Sent from my iPhone

 

[ErikinSC]

I used a vac port off of the intake manifold, just below the yellow tabbed hose clamp in the pic below. You can measure vac from several places. * I had to be sure to remove & cap the vac line from the dizzy.

I wont say that you messed up the engine.... but if the timing is (advanced or retarded) off enough, you might not be able to get it to restart. Check the dizzy, loosen the bolt underneath so that you can adjust it back so the BB is visible in the window again when the ignition is firing. It should start now. At worst, you might get some pinging (if you can hear that in these rattle cans) or backfiring if you get the timing too far adjusted one way or the other. It sounds like maybe you are not getting the spark, or fuel to the carb, check everything around the dizzy, make sure all contacts are dried, and that you are getting fuel.

Be sure that you don't get water into the intake thru the carb.... Water won't compress and could prevent the motor from turning over properly - but I don't think that is your issue..... unless you washed the truck by driving it into a pool..

 

[mags]

lol! I washed it downtown and then drove it all the way home so I am guessing it's not the fuel. Bearing in mind that i took the distributor cap off to check some stuff I wonder if I got everything back on just right. You know rotor back on and seated fully dust cap not upside down, etc. anyway I got so crazy about the points that I removed them and subsequently broke it while inspecting it. Oh well needed an excuse for the Pertronix upgrade lol. Hopefully this beast will fire right up this weekend but we will see. I ordered new points for it just in case so before I upgrade I will put those in and get it running then do the Pertronix.


Sent from my iPhone

 

[mags]

Where did you get that external foam filter for your Weber? My main filter always gets pretty mucked up quick and that would be a good addition.


Sent from my iPhone

 

[JohnnyC]

They are called foam pre filter or filter foam wraps

UNI or K&N

TPI and MAF and Downey used to carry them AFAIK


You can also get green pre filters at lawn mower shops ... Cheap

 

[mags]

Sweet! Green filters cheap at one on the local mower places it is. Thanks JohhnyC!


Sent from my iPhone

 

[ErikinSC]

@JohnnyC is smarter than me.

The PO of my rig included a catalog from TPI 4x4 Landcruiser Parts and Accessories

They are in TN and were close to the PO. I ordered a K&N air filter and the TPI pre filter to fit the oversized air filter. I like that my clips are no longer a missle hazard when removing the air cleaner.

Cheap and green would have worked fine.

 

[JohnnyC]

@JohnnyC is smarter than me. I like that my clips are no longer a missle hazard when removing the air cleaner.

When I worked at GE GlobalR I was the stupid one for sure LOL

I hated those clips as well... got rid of them ... drilled it out and use studs/nuts happily for the past 20 years

 

[Weber Sarge]

Not sure what it would take these days to get one - but years ago I ran the Ramflo filters from Australia - these flow directly from the top which is how a Weber is designed to breathe and takes away the "up and over" issue with the top air horn on a DGV series . The foam is a very high filtration flame retardant type and washes easily , no oil required . Made by Lynx Corp. if they are still around .

Pictured is the triangle 1050cfm version . There was an importer here in the States but he never followed through enough to supply the demand I had for my custom builds so I had to drop the whole deal .
The engine was an insane 1.3L Suzuki Swift GTI engine with a stage 4 head from a 1.3L in my old Samurai - would bury the 8k tach easily - dyno on the ground was 165hp@6500 / 135ft/lb torque in a 3k lb Sami = fun to drive , lol .

Sarge

 

[JohnnyC]

@Weber Sarge I remember those ...always thought they were ugly... but... function over form

you might remember the Borg-Warner filters for the webers... it was also an all fiber filter with a metal pokadot cover

 

[JohnnyC]

looking around on brake i found a borg warner for sale on ebay LOL

and some here (copies):
75mm Chrome Rectangular Weber Air Filters - Weber Performance Carburettors

 

[Weber Sarge]

Any filter design the flows air in from the side on a Weber DGV is a problem - I've had the dyno research done to prove it years ago . That argument started on the OffRoad.com forum in a Toyota thread about 32/36 vs 38DGAS , which turned into an eye bleeder and ran for a couple years non-stop . At one time there was another company that made a top-flowing air filter that was actually better than the Ramflo - can't remember the name or find the pictures I had now , of course...argh . Their filter used a pleated dual-layer paper element that was cheap and easily replaced . The Ramflo's foam had to be washed and air dried .

I absolutely hate the K&N designed filters w/gauze - all it does is fill the air jets with oily dirt particles and on some series carbs it quickly alters the mixture rates . That oily crap is also a real pain to clean out of idle air circuits - had a lot of DGV's come here years ago that required removing the lead galley plugs completely to rod out the circuits , which cost the owners a lot of extra money and they went right back to using the same stupid filter . There is a paper element filter that fits that junk filter design that is 2-5/8" tall out there somewhere , not sure where we found it but some ran that and had better luck . Other option is run an adapter and use the round filter element and base/cover setup . Due to the Cruiser's hood vents , extreme rainfalls could end up dumping water into a top inlet filter - so keep that in mind .

All I can say is this - if you have to run a side inlet filter - get the tallest one possible so it at least has a chance to breathe correctly .

Sarge