Distributor Question (2 Viewers)

[brian]

That's what I am looking for. I still have my old 38 / 38 and going to replace the idle jets to start. The smoke is black at idle, and the fuel mileage from the main jets is around 7 - 9 MPG.



But, there is no bucking, hesitation.

This will be a new job for me, never jetted a carb before. Need to balance performance and mileage. I do not even know what jets are in there.

Boaf

Idle jets are easy.
They go right in the side of carb fron the outside under two brass caps.

 

[Boaf 32]

Folks on the Nissan forum run the 38/38 on the tiny 2.4L 4 cylinder (nearly half of the displacement as a 2F) with as good of fuel economy as I get with my 32/36 (which is actually undersized without tweaking for my 720 minitruck here at 6,800' to 10,000' above sea level). A big carb can run less throttle and smaller jets, but a small carb will be challenged at idle and wide open throttle for getting a proper mix of air.

The range of sizes of jets listed from Pierce Manifolds should be adequate. Do yourself a favor and see if you have the same overall shape, not size, of the primary and secondary idle jets on the 38 synchronous. On the 32/36, one is different from the other, and it only is specific to the manual choke DGV, not the DGEV, iirc.

So it's easier to go smaller with a bigger carb than to go bigger with a smaller carb. The shape of the 38 / 38 is the same. The 32 / 36 is the manual choke. I'll try and read the Idle Jets and move forward.

Boaf

 

[brian]

I had 45s in the idle....and I'm sure those were the smallest I readily found.
They made the biggest improvement as I believe that there were 55 or 65s in it.
But honestly the best thing I did was put a non USA OEM carb on both my 2fs.

 

[Boaf 32]

Re-installed my 38 / 38 Weber. Found a torn O-ring on one of the Idle Jets. Replaced it and no more black smoke at idle. Took it for a short ride, still have a bit of bogging down when trying to accelerate hard but nothing like before. And so far, no carb backfire. Will keep testing. May still need to re-jet, but one step at a time. Thanks for telling me to "go Big".

Boaf

 

[Boaf 32]

Well still have a back fire and no power on the climb of a hill. I will reset to spec (2 turns out on the mixture) and re-tune. Two quick distributor question:

1. When re-assembling my distributor, I notice that the cam can fit 2 ways: one side of the cam says 18 degrees. The other side says nothing. Are there 2 settings by rotating the cam and re-seating it, or is it just a single 18 degree cam?
2. Where do most of you hook up the automatic electric choke? I know to an ignition source but which one?

Thanks,

Boaf

 

[Dizzy]

The + positive side of the coil? Isn't there a wire somewhere around your valve cover, from your stock carb idle cut solenoid?

Turn the idle mix screws in 1 turn out from seated to start, no more than 1.5 tuns or the idle jet needs to be drilled or replaced. Use a light touch to find where it is seated.

 

[Boaf 32]

The + positive side of the coil? Isn't there a wire somewhere around your valve cover, from your stock carb idle cut solenoid?

Turn the idle mix screws in 1 turn out from seated to start, no more than 1.5 tuns or the idle jet needs to be drilled or replaced. Use a light touch to find where it is seated.

Weber indicated 2 for a 38 / 38. Either way, I'll count when I tune. Thanks Dizzy, greatly appreciate all the help.

Boaf

 

[Dizzy]

38 DGAS Tunning

 

[Boaf 32]

38 DGAS Tunning

My 38 / 38 only has a mixture screw on the Choke side. I read the same instructions from CU Weber but it said start at 2. Clearly there are differing tuning specs on the web. Huh, imagine that . I will look at the idle jets to see what size they are. I'm thinking that may be the first place to start. This Weber came with the truck.

Interesting, when the carb was running rich, never had a problem, just black smoke and crappy fuel mileage. Now that the o ring is fixed, it's not running well. We'll get it. Patience is key...

Thanks Dizzy, I'm gonna put you on speed dial.

I have a DGES (electric choke). It has a Weber decal on it, but only a single mixture screw. Starting to wonder if it is a real Weber.

 

[Dizzy]

Brian posted pics of the two idle mix screws, above.

 

[Dizzy]

They have compression springs and a knurled head, on the very base of the carb.

 

[Boaf 32]

Brian posted pics of the two idle mix screws, above.

I am pretty sure there is only one. It makes sense that there should be 2 with synchronous carb, but what makes sense anymore? . I will check again this morning and take pictures. Thanks.

 

[brian]

pictures go along way

 

[Boaf 32]

Back to you in about an hour after coffee

 

[brian]

Yes coffee..good idea

 

[Boaf 32]

Well, @Dizzy, Think we have a winner. Attached is the carb and guess what is wrong with this picture. I am correct, I only have one fuel mixture adjuster. But look closely, looks like the other one is broken off. I will see if I can get an extractor to pull it out. Sound right to you?

I the mean time, what size is the factory mixture screw? I'll check the other one and get the same, but my eyes are not what they use to be and damn that writing is small.

Boaf

 

[brian]

The two piece adapters probably are not doing you any favors either.
The fasteners for top plate need to be carefully checked.
They historically are a thread or two too long. They bottom out before truly tightening up the gasket.

 

[Dizzy]

Don't use a conventional drills, get a left-hand-drill (counterclockwise) for extraction.
Maybe your 38/38 carb hit the floor, literally and/or figuratively?

Call Pierce Manifolds, Monday.

 

[Boaf 32]

The two piece adapters probably are not doing you any favors either.
The fasteners for top plate need to be carefully checked.
They historically are a thread or two too long. They bottom out before truly tightening up the gasket.

Thanks Brian, seriously considering replacing the carb, but will try my extractors first. I would be worried if the seat is damaged...

Boaf

 

[Boaf 32]

Don't use a conventional drills, get a left-hand-drill (counterclockwise) for extraction.
Maybe your 38/38 carb hit the floor, literally and/or figuratively?

Call Pierce Manifolds, Monday.

I'm thinking the PO had it out and muffed it. May consider a new one, but will extract first and see if I can get a new fuel mixture screw.