Carburetor Identification? (Pictures Included)

[Mike Phillips]

Carburetor Identification? (Pictures Included)

 

This is an update to this thread.

 

Swapping a L20B into a 1974 Datsun Truck with an L18

 

I have the L20B and Automatic Transmission installed into my 1974 truck. I'm ready to install the intake, carburetor and exhaust manifold.

 

I would like to use the carburetor and intake that came with the L20B because overall it looks a lot less complicated and it also has a manual choke which I like on my old school style cars and trucks.

 

I removed both carburetors from their intake manifolds and found I need to replace the spacer and gaskets that fit between the intake manifold and the Carburetor.

 

This one,

 

 

I can't find any identifying numbers on either carburetor to enable me to order a rebuild kit to hopefully get the replacement spacer.

 

Can anyone identify these carbs?

 

A = The carb and intake that came on the L20B

B = The carb and intake that came off the original L18 in my 1974 Datsun Truck.

 

And again, I want to use the "A" components unless someone can make the case that the "B" components have more advantages.

 

 

 

 

 

 

 

 

Here are the intakes...

 

 

 

Thanks for any help and information...

 

 

Mike

[moparvwfreak]

part #s help alot in identification. it SHOULD be on the right side of the float bowl.

 

also if you decide to use carb B, SWAP float bowl fronts. the one with the big window is the better one to use since you can actually see the float level without being Superman.

[dat521gatherer]

carb a is a dch328 and carb b is a dch340. as stated these model numbers will be printed not stamped on the right side of the float bowl. if there is no printing then they may be rebuilt. the printing comes off easy.

[Mike Phillips]

carb a is a dch328 and carb b is a dch340. as stated these model numbers will be printed not stamped on the right side of the float bowl. if there is no printing then they may be rebuilt. the printing comes off easy.

 

Thanks.

 

I looked very carefully before making my post and cannot find any identification numbers printed or or stamped anywhere, so thanks for the clarification.

 

Anyone have any opinions of either carburetor? Is one any better than the other?

 

The DCH328 is definitely a lot less complex looking with less doo-dads.

 

 

Mike

[Phlebmaster]

I like the DCH340 personally.

[datzenmike]

Looks like they are reversed. B looks like it's off a '75-'77 L20B, carb and manifold. A has manual choke.. don't think any L20Bs were manual.

 

Carb A and intake are less complicated so is off an earlier motor maybe L16? Does it even have an idel cut solenoid? Not an L20B carb.

Edited October 8, 2008 by datzenmike

[Mike Phillips]

Carb A definitely came off the L20B engine I bought used.

 

Carb B definitely came off the L18 I removed from my 1974 Datsun Truck.

 

 

Could be these carbs were never the original carbs off the engines I have now in my possession in 2008, know way of knowing.

 

Carb A does have a Idle Cut-Off Solenoid, not sure how to wire it up? Toggle Switch on the dash?

 

I took lots of pictures of how the original carb was hooked up, where the wires went etc.

 

Carb A only has the Idle Cut-Off Solenoid wires whereas Carb B has 3-4 different wires and of course matching wires on the harness that I'll have to do something with.

 

Going to try to get it running this weekend. Hardest thing I have to do right now is get the collector studs out of the exhaust manifold as they all broke off when I unbolted the collector from the exhaust manifold.

 

Mike

[Mike Phillips]

B has manual choke.. don't think any L20Bs were manual.

 

Double checked just now, Carb B has an automatic choke and Carb A has a manual choke.

 

Kind of like manual chokes, anything to get a knob or toggle switch on the dash is good.

 

:D

[SickDrift]

Carb A does have a Idle Cut-Off Solenoid, not sure how to wire it up? Toggle Switch on the dash?

Mike

 

The way mine is wired is using one of those 12v wires that is only energized when the key is in the on position. I combined it with the electric chokes power.

[Mike Phillips]

Well off to NAPA to order a carb kit and pick up my exhaust manifold. They wanted $100.00 to remove the broken studs out of the exhaust manifold so I'm going to take a stab at it myself with a drill and a hand full of drill bits and some easy outs.

 

Are there "new" exhaust headers available for the L20B is I can't get this exhaust manifold back into working condition?

 

:)

[pl521sss]

Carb A definitely came off the L20B engine I bought used.

 

Carb B definitely came off the L18 I removed from my 1974 Datsun Truck.

 

 

Could be these carbs were never the original carbs off the engines I have now in my possession in 2008, know way of knowing.

 

Carb A does have a Idle Cut-Off Solenoid, not sure how to wire it up? Toggle Switch on the dash?

 

 

Mike

 

 

Carb A (DCH328) is not for L20B motors, someone else swapped it before you. It's from L16 motors like 510 or 521

Check the throttle lever, that's how you can tell.

 

Carb B (DCH340) did came on L18 and L20B motors.

 

 

Would recommend using DCH340 carb for your L20B.

Automatic carbs is also different with the addition of dash pot on 510's.

Not sure about the other carb for dash pot.

[Mike Phillips]

 

Carb A (DCH328) is not for L20B motors, someone else swapped it before you. It's from L16 motors like 510 or 521

 

Check the throttle lever, that's how you can tell.

 

 

The throttle lever is different between carbs, I already switched them to run Carb A and use the same throttle cable.

 

 

 

Would recommend using DCH340 carb for your L20B.

 

Automatic carbs is also different with the addition of dash pot on 510's.

Not sure about the other carb for dash pot.

 

Is a Dash Pot the same as the Cut-Off Solenoid? I know it's to keep the carb from running on after turning the ignition of correct?

 

I'd really like to run Carb A as it's a whole lot less complicated looking. I want to keep things as simple as possible with this project.

 

Thanks for all the help guys...

 

 

Mike

[Phlebmaster]

The DCH328 is simpler...but you will suffer for performance I would think. The best choice is what works best for you. Let us know how it works out. :cool:

[pl521sss]

Mike

 

The throttle lever is different between carbs, I already switched them to run Carb A and use the same throttle cable.

 

 

 

Is a Dash Pot the same as the Cut-Off Solenoid? I know it's to keep the carb from running on after turning the ignition of correct?

 

I'd really like to run Carb A as it's a whole lot less complicated looking. I want to keep things as simple as possible with this project.

 

Thanks for all the help guys...

 

 

Mike

 

 

Check this thread also

Has exploded view of DCH328 if your going to use it.

And links to DQ article for Hitachi carbs.

http://forum.ratsun.net/showthread.php?t=6595

 

 

Good luck

[Mike Phillips]

After reading a little about the DCH340 it's reading like a much better carburetor, so if I decide to run the DCH340, does anyone see any problems with running it with the other manifold I have?

 

Just to note, this truck is smog exempt.

 

So this carb with this more bare intake?

 

 

 

If not, is there anything on this system that isn't necessary?

 

 

 

For example, what's this thing? Is it necessary?

 

 

Thanks for the help...

 

:)

[pl521sss]

After reading a little about the DCH340 it's reading like a much better carburetor, so if I decide to run the DCH340, does anyone see any problems with running it with the other manifold I have?

 

Just to note, this truck is smog exempt.

 

So this carb with this more bare intake?

 

 

If not, is there anything on this system that isn't necessary?

 

 

 

For example, what's this thing? Is it necessary?

 

 

 

Thanks for the help...

 

:)

 

 

 

Those are smog stuff (EGR....)

L20 manifold is bigger but more crap on it.

Posted the question to Mike if he ever finish that L20 manifold.

Here's that manifold thread.

http://forum.ratsun.net/showthread.php?p=86777#post86777

[datzenmike]

As SickDrift said the idle cut and the electric choke can be wired together and run to a fuse on the ignition ON only side of the fuse box.

 

A dash pot prevents sudden closing of the throttle plate which can lead to stalling. The Idle cut allows fuel into the idle circuit when the key is ON. When the key is turned OFF this shuts off fuel and prevents the motor 'running on'.

 

I would use the L20B manifold, it's got larger ports and runners. It also has an obvious PCV valve, don't see it on the L16 intake, must be under the vacuum port. If you aren't running EGR just leave disconnected. If you remove the EGR plug the holes, If you remove the EGR and it's little manifold, you'll have to make a block off plate. Make sure you put the PCV valve back on it.

Edited October 10, 2008 by datzenmike

[bonvo]

make a block off plate for the l20 manifold the runners are bigger no need to have it portmatched its already done from the factory

[Mike Phillips]

 

I would use the L20B manifold, it's got larger ports and runners.

 

 

If you aren't running EGR just leave disconnected. If you remove the EGR plug the holes,

 

Where can a person get metric plugs? Nut & Bold supply store? How about NAPA?

 

So far I'm not having much luck removing the lower fitting from the manifold. I have it soaking with some WD40 right now.

 

 

Hate to just cut it and crimp the tube just in case someone out there has to Smog their truck and need this manifold/tube.

 

 

If you remove the EGR and it's little manifold, you'll have to make a block off plate. Make sure you put the PCV valve back on it.

 

Down the road might do this, for now I'm going to leave the manifold bolted up as it also provides a place to mount the throttle cable bracket to hold the sleeve portion of the throttle cable.

 

Thanks for all the help everyone, hoping to try to get the engine and tranny plumbed and wired enough to test fire this weekend. I have Saturday and Sunday off so should be able to get there as long as no major problems come up.

 

:)

Edited October 11, 2008 by Mike Phillips

[Mike Phillips]

Also, when I removed the fitting in the intake manifold that hooks up to the EGR tube, it came out with a struggle and now most of the threads are creamed out.

 

 

 

Was thinking about finding a brass or steel plug that's a close fit and using the plug with some JB weld to seal it up for now.

 

:confused: