E4ME Jet Size

[LannyL81]

Anyone happen to know what size the jets are in the E4ME?

 

[RC81]

I sure would like to know too. The secondaries can be changed, but I dont think the primaries can be. Wonder if the jet sizes are the same for all E4MEs, or does the Corvette have specific ones?

 

[LannyL81]

I do not have my E4ME carb apart at this moment, but why would the primaries not be able to be changed? Are they not the normal screw-in used on all QJets?
I also just assume that the meterring rods could also be changed, but may be these are special to the E4ME....will have to do more research I guess.

Anyone have a spare E4ME sitting around?

 

[6880 Mike]

I've seen a chart listing the jet sizes. I think the chart is in Doug Roe's QuadraJet book, but don't quote me on that.

 

[damoroso]

Actually the primary jets on the E4ME are integral in the tubes that the meetering rods ride in. These tubes basicall hold the meetering rods in place and are screwed in howerver and can be removed but to my knowledge nobody makes different sizes of these things. If I remember correctly, you can't remove the secondary jets (but I could be wrong).

 

[Peer81]

The primary jet and rod are different from other years like Damoroso says so not interchangeable. But it could be that other type cars with a E4ME used different sized primary rods and jets. On the other hand, I don't think you really need to change them any way. The M/C solenoid is trying to get the mixture to 14.7:1 but you can change the upper and lower stops so you can for example screw the upper stop a little higher to enrich the mixture if it's a little lean on little acceleration.

The secondary jets are fixed (pressed) into the fuel bowl floor and the rods and hanger are interchangeable. I'll look tomorrow what the OEM jet and hanger sizes are.

Greetings Peter

 

[Sensei]

Like everyone has said, the primary jets and rods are unique. They only come in one size that I am aware of, which I believe is 72 (I quit looking at them years ago when I figured out they were all the same). The good news is that the E4ME primary metering system can flow plenty of fuel when it needs to. The secondary rods and hanger are standard Q-jet stuff, secondary jets are not removable.

God bless, Sensei

 

[RC81]

Have any of you guys changed your secondary rods or hangers? I played with mine a bit but couldnt feel much difference. Almost need a dyno to tell for sure.

 

[Peer81]

I'm about to!
I still need to fix some problems I have with my carb but after that I'm going to do the fun part to tune the carb the best I can with this thing.

(also look at Hib's wideband topic in the tech section).

At this moment my carb is still running lean at idle and running far to rich 10:1 at 3/4 to full throttle. ;squint:

Greetings Peter

 

[GerryLP]

I'm about to!
I still need to fix some problems I have with my carb but after that I'm going to do the fun part to tune the carb the best I can with this thing.

(also look at Hib's wideband topic in the tech section).

At this moment my carb is still running lean at idle and running far to rich 10:1 at 3/4 to full throttle. ;squint:

Greetings Peter

Hey Peter,

Are the graphics on the box simulated? Or is it reproduced by the screen as sown on the image?

Also, If you re-call when I had Gail on the dyno, she was running rich at WOT or near that...remember?

Well, I am not sure if you are using your thermac, but that's what I found was causing the rich mixture...a vacuum gage showed how the snorkel flaps would be open at idle after the temperature near the carburetor's intake caused the thermac switch to open the snorkel flaps, but then at power, the vacuum signal alerted me to the flaps closing at near top end rpm's.

Replaced thermac switch and problem solved.

GerryLP:cool

 

[Peer81]

Hello Gerry,

Great to hear from you
Yes, the readout is as shown. But the exact numbers on the readout are going to fast up and down at this point so can't use that right now. The digital graph is good to use for overall fine tuning. When you're near perfection (if you'll ever get there with a carb) the numbers for change so fast so you can use them.

Thanks for the headsup on the thermac. A few months ago I found out I switched the vacuumlines that connect to the thermac so one flap was connected to intake vacuum all the time and alway closed.
After my vacation I'll continue my search

Greetings Peter