Looking for weber jet numbers

[ddhacor]

Hi Guys.

I've searched a bunch and can't seem t get a good answer for what I'm looking for...

What jets are you runing in your 32/36 on an L20 (78 620)?

 

I pulled a 32/36 off a 240Z and rebuilt it, installed it on my new/rebuilt w58 peanut head. Stock cam. Pistons +50. GM ignition mudule. New coil (not a High perf).

 

From the JY it had:

55 50 Prm/Sec Idle

130 145 Prim/Sec Main

 

I've changed to:

60 55 Prm/Sec Idle

145 130 Prim/Sec Main

 

I increased the jet size because I was backfiring on decelleration and occasionally on accelleration.

After the change, I'm still backfiring on decelleration, especially when the secondary had been open. Acceleration is good if I hammer it, but sucks if I'm gradually trying to go faster.

I'm also backfiring those little mini backfires when i'm just running it in idle in the driveway (setting it up per the weber specs). The thing is, my muffler is toast so I may not hear those mini's if I had a functional muffler.

I'm thinking that going t a 65 idle jet is too much maybe, so I wanted to check with you guys to see what your thoughts were...

 

Timing is good and I tried two diff dizzys with same result.

 

Thanks,

Bob

[banzai510(hainz)]

I would think 50-60 on the idle jet will be fine

 

the primary of 140 should be OK and 135 secondary or a little less But maybe the timming chain is just worn. Ck the cam timming set up

[ddhacor]

Timing chain checks out good. I've also double checked the dist. spindle.

When you say 50-60 on the idle jet, do you mean 50 primary/60 secondary?

[reese]

L18 = 125/115 mains

 

Here is some good Weber info:

 

http://www.bleachgarage.com/620tech_mech.html

 

http://www.nwde.org/extras/forum/forum_posts.asp?TID=3467&PN=1

[banzai510(hainz)]

I have run 50 thru 60 and notice no real difference

 

 

Intake tight?

 

I have bolted a 38DGES to a L16 and had not proplems and that was over jetted(for a 6 cyl landcruiser).

[Phlebmaster]

I am going through a similar thing with my Weber.:D

 

Not sure what my jetting is yet but I have noticed it is acting like there is not enough manifold pressure to pull fuel from the primary sometimes??

 

I have a man choke and what I do for now is pull the choke until the backfiring stops and then let it back out once I am where I want to be on the throttle. This works;)....not a solution but may help until you figure out the fine tuning. If you get it fixed please keep us updated.

 

I am running an L16 and the Weber I have came off an L18.

[ddhacor]

Thanks for the info guys. I put my 55/50 idle back in and I'm gonna start from scratch with new plugs. I'll pull the plugs an go that route to see if I'm rich or not.

With the 55/50 in there, I can real gradually bring the throttle up high and let go with no backfire. It's when I do it quick that I get all the noise when I release. I'm taking that to mean that my issue lies in the main jetting. I'm gonna bring those way down to reese's 125/115 and go up. Maybe start at 130/120 since I've got the L20.

When I figuire this crap out I'll let you know.

[banzai510(hainz)]

I assume your adjusting the mixture screw(the one with the tension ring)

turn it IN/OUT till it runs smoother

 

I would think 140 135 would be fine for a L20. I think your waisting you time but let us know.

 

Maybe the eleltrical choke is not adjusted correctly? Get rid of it if not working right. just my 2 cents

[reese]

Anyone got any extra Weber DGV jets they want to sell? I need 115, 120, 125, 130 mains.

[yello620]

Sorry, i dont have any that are that small. Curious what you are installing that small of main jets on.

 

Factory Weber settings are very generic, but they work good for an L20

 

Primary main 140

Secondary main 140

 

Primary air corrector 170

Secondary air corrrector 160

 

Primary emulsion tube F50

Secondary emulsion tube F50

 

Primary idle jet 60

Secondary idle jet 50

 

Pump jet 50

 

 

Thought that some of this info would be good to just have archived. This info was taken off the Weber link form the racetep.com website for those of you that want more detailed info that site has lots of very good weber tuning info.

[reese]

My 510 with a L18 ran best with 115/125 mains..

 

Putting another Weber on the truck and want to start there again, its got 140/150 in it now.

 

What would you recommend for a L18 620, all stock?

[yello620]

Not sure what all of my jets are with my L20, but i do remember that the mains are both 140 and the idles jets are both 50's.

 

The jets numbers just seemed a little small for a L16 even, but if you have had them work good for you in another motor then you have more experience with them than me.

 

Jason

[phatdave]

http://forum.ratsun.net/showthread.php?t=2013

[reese]

There is always a rebuild and performance jet kit from Top-end:

http://www.racetep.com/rebuildrejet.html

 

Then read and follow this:

http://www.racetep.com/webjettune.html