Weber or Mikuni?

[SaxMachine]

Hi all, looking for a little advice on carburetors here. I have a 1982 Dodge D-50 Royal. 2WD, 2.6L, 5spd manual and my Mikuni 32-35 DIDTA carb is toast. I do not have to pass emissions and am trying to decide whether or not to buy a Weber* kit or a rebuilt Mikuni from Rock Auto. Also, I'm having trouble trying to find what Weber would even fit my truck. It doesn't look like they are available through Redline and I don't trust eBay or Partsgeek. Any advice would be appreciated.

I love that little truck and just want it to run well. My father bought it new in 1982 and it was my first vehicle when I was turned 16. It was the first vehicle I ever worked on and it got me interested in wrenching. All maintenance and repairs have been done by my father and I. Below is a list of what has been done to it...

• Full engine rebuild and new head
• Aftermarket exhaust header (Pacesetter I believe)
• Custom air cleaner (thermostatic valve removed and vacuum line capped)
• CAT removed
• New clutch
• Fully rebuilt transmission
• New NGK plugs, Bosch wires, ignition coil
• New fuel tank, fuel filter, fuel pump, fanbelt, all rubber fuel and vapor lines, hard lines blown out
• Check valve tested, two-way valve replaced
• Charcoal canister rebuilt and filter replaced
• Carbon cleaned intake manifold
• EGR valve cleaned/tested
• Distributor tested
• New radiator, coolant hoses, thermostat
• Rebuilt front end

[SubGothius]

No question, get a Weber 32/36 DGEV or DFEV, included in Redline kits K610 or K614 respectively.

Looks like Redline doesn't offer online ordering, but you could call them to order, or just order online from their distributors:

Pierce Manifolds:

• Kit K610
• Kit K614

Carbs Unlimited:

• Kit K610
• Kit K614

The DF-series (K614) and DG-series (K610) are mirror-image designs, tho' the DG is a newer design derived from the DF and thus somewhat more refined. Having just completed a DGEV conversion on my '87 2.6L, IMO the DFEV (K614) is probably the better choice, as that easily allows orienting the fuel bowl in front with stock throttle cable routing and easy access to the adjustment screws. That said, most folks seem to do the DGEV (K610) and put up with either having the fuel bowl in the rear or the difficulty of finagling adjustments and cable linkage with the bowl in front. Having the bowl in front means it goes slightly lean with braking and slightly rich on uphill inclines, whereas a rear-oriented bowl makes it slightly flood on braking and may stall when coming to a stop unless you jack up the idle to compensate.

You will also want to convert to an electric fuel pump, as the stock mechanical pump puts out a bit more pressure than the Webers like (which can force fuel past a closed needle valve), and putting a pressure regulator on it leads to premature failure of the pump. I like the Carter P90091 pump for Weber applications; it's got the right native PSI and delivers a smooth, even flow, so no regulator needed. See this thread for pump wiring w/ relays and related tips.

[geezer101]

^good advice from SubGothius. Make sure you get a genuine Weber as there are knock-offs (licensed copies) of Webers on the market and they are a death spiral of grief to work with. There is another carb option that has become popular which is the Weber 38DGES. This is a similar but newer design of the 32/36 with 38mm throats. If you want to lean more towards performance it will suit the 2.6L better than the smaller 32/36 and is set up to function the same way. There are other modifications you may want to think about when doing the Weber swap like deletion of the EGR valve, tap and threading a grub screw into the coolant port hidden on the mating surface of the manifold to prevent coolant from coming up under the carb gasket. Using a sealed air cleaner assembly is preferred. The after market open air filters will pull hot air from the engine bay and rob the engine of torque. I'd wrap the headers in thermal tape to keep engine bay temperatures down and aid exhaust gas scavenging (hot gases move faster) which will allow you to be a little more aggressive with tuning.

[xboxrox]

Hello SaxMachine ~ I rebuilt my Mikuni carb runs good but need to now figure out which screw to turn to lower the idle RPM another 75 RPM or so ~

The fastest & easiest & about the same price as other alternatives is too just buy a rebuilt Mikuni from Alan @ https://www.carbtech.us/automotive.html

He is located in Tacoma ~ I only spoke to him over the phone several times but his advice is 100% AOK

WELCOME here & Aloha
George

[SubGothius]

Buying from Pierce Manifolds or Carbs Unlimited should ensure you get a genuine Weber made in Spain; they don't appear to list any "economy grade" versions that would be a troublesome clone. Just for the record: the genuine article has the Weber name/logo and "Made in Spain" cast right into the carb body, which has a rough/dull casting finish, whereas the clones just have Weber on a decal or ink-stamp and a smooth/bright finish. The electric choke housing can also be a clue, as genuine ones have an off-white plastic cover while clones have a black plastic cover, but it's not a dead giveaway as these can be mismatched (e.g. to upgrade a water choke to electric).

I don't think the 38 DGES is any newer of a design than the 32/36 DGEV; I'm pretty sure that dealer tech who said it was a newer design than a 32/36 was referring to the mirror-image 32/36 DFEV design there, which is indeed older. Aside from the larger and same-size throats on the 38, it also has a synchronous linkage meaning both barrels open simultaneously, whereas the 32/36s are progressive meaning the larger secondary barrel only starts opening past a certain point in pedal travel, but driving with a lighter foot keeps it on the smaller primary barrel for better fuel economy.

Speaking of that grub screw to block the coolant port in the manifold, I'd recommend tapping that port just deep enough for the screw to clear the carb mounting face when screwed in tight, and be sure to use thread sealant (e.g. Permatex 59214).

[SaxMachine]

Thanks for all the great advice! I was on the Mikuni/Weber fence for awhile but I decided to go with the K610 Weber kit. It seems like I'll have an easier time with the Weber down the road. I've had a really hard time tracking down parts for my truck in the past (good luck finding a new thermo valve) and I'm pretty happy to eliminate the EGR system.

I'll be picking up the Weber tomorrow from Carbs Unlimited and I have an electric Carter fuel pump in the mail. Once I install the Weber, is there anything I should do with the gas vapor line going back to the tank or just cap it off?

Thanks again.

[geezer101]

Do not cap off the vapour return/vent line. It 'may' cause vapour lock in warmer weather and it'll be hard to diagnose the fault due to it being a minor mod that doesn't seem to have any real ramifications. Keep the charcoal cannister connected as this the safest way to vent vapour into the intake. Cap off the fuel return line though*. This will prevent any risk of moisture or junk entering the line and possibly making it's way back to the tank.

*depends on what variant of Weber you end up installing. The majority of Webers do not have a return barb fitted to them, but if you have salvaged a used unit from somewhere it may have a return on it...

[xboxrox]

Here's a sorta thread stealing question: IF SaxMachine had decided to go the rebuilt Mikuni route ~ then in the future, those hard to find parts that might fail like theremovacuumvalve EGR valve etc etc ~ my Question is IF THEY FAILED ~> in a non smog state, can a Mikuni be made to run without every gadget attached to it (?) just plug the vacuum connections not used on removed parts but leave the computer O2 sensor & carb selenoids & air cleaner thermo valve temp sensor in place... Will it work..? I am asking coz this senario could be in my future too...

[geezer101]

It'll run sans EGR (probably run better too lol) I neanderthal tech'd a 32-35 with a couple of microswitches instead of the throttle position switch and the carb computer (this Mikuni had 3 electric solenoids on it and was horrid to work on). I installed a toggle switch in the centre console that would allow the carb to 'sort of' function as eco or power mode - so it can be done. If you have AC I think it'll be more difficult to rig up unless you're happy to ramp idle speed to compensate for rpm loss when the AC is on. Without the computer, the O2 sensor is just dead weight but then you can hook up an EGO meter to eyeball the air/fuel ratios (which is what I did You could hunt down a Mikuni Solex carb and install that instead. Guys bitched about them being no good, but they aren't nearly as hard to work on as the Mikuni 32-35. Problem is if you do find one, it'll need to be re-bushed as I can almost guarantee the through holes for the butterfly shafts will have worn out. Biggest grief with Mikuni is the wax pellet choke (new or old Mikunis...) You got a fighting chance to replace a bad secondary vac solenoid, but the choke assembly -

[xboxrox]

Hmmm SANs the Weber ~ Thanks Doc

[SubGothius]

The majority of Webers do not have a return barb fitted to them, but if you have salvaged a used unit from somewhere it may have a return on it...

Or of course you could just add a return barb to the Weber, just threads right in, or put a tee inline before the inlet barb with one branch going to the return line. That said, a return is probably not necessary unless you get vapor lock, which I haven't experienced here in Tucson even in midsummer, so prolly unlikely to happen anywhere else.

[boozehero]

Coming to this party a little late, but...
No mention of the improved performance the Weber conversion provides.
The only draw back is the racket the intake sound makes.
It's LOUD!!
I installed a Weber on my 79 D50, the Mikuni/Solex was so miserable, it was almost not driveable when cold.
It now flies (much quicker) by comparison to the other carb, and when cold, pump gas twice and the engine idles. No stalling.
In another life, I installed these kits on so many vehicles, I don't remember how many.
Everyone who I did the conversion for was almost shocked at the overall improvement.
Post pix if you did the conversion. If you know the difference between a pair of pliers and vicegrips, you can do the swap easily.