I messed some more with my carb and dizzy....

[big2bird]

Just to be sure, we are talking part # 7501 (manifold) that uses Gask #7201 , .060" (Gasket)?

 

[big2bird]

One more item. WITH the .060" gasket in place, and the manny just resting there, insert the dizzy and see it it seats all the way down. You should NOT be able to insert a feeler gauge. If so, you need to shim it till it does not with nylon shims, and THEN add a gasket.
AND, if you really want to be perfect, coat the gear with prussian bluing, and spin the crank a few times to see where the gear ends up riding.

 

[mrvette]

It's sitting on .070" shims on the corners. The bolt holes almost line up. The current plan is: I'll try using a standard .060" intake gasket (MRG 101) and elongate the holes in the intake slightly to make them fit.

I remember doing that in your pix there some years ago, with the original set of iron heads I had on this engine, they were angle milled heads, it turned out, so they did never seal on the bottom of the Edel intake, until it was shaved 20 mills/side changing IT's angle to agree better, I never found it with the feeler gauge, dunno why, just was....drove me crazy for a while, finally just had it done and everything was fine then, now when going with either set of aluminum heads, using the exact same mani did NOT give my any leakage on top of it, never did have any issue with bolts lining up or gasket thickness....

if your China wall leaks a bit on a install, I have a little trick to fix that with, sure worked for me some time ago...

:smash::surrender:

 

[MYBAD79]

OK, I used a .060" gasket and the distributor sits all the way down. I then added the gasket.

I did not find anything wrong so I just cleaned up everything and reassembled with a new thinner gasket and fresh RTV on the china walls... the holes line up better than with the old manifold - I did not have to elongate them to fit the thinner gasket.

Test run is scheduled for tomorrow....

 

[big2bird]

OK, I used a .060" gasket and the distributor sits all the way down. I then added the gasket.

I did not find anything wrong so I just cleaned up everything and reassembled with a new thinner gasket and fresh RTV on the china walls... the holes line up better than with the old manifold - I did not have to elongate them to fit the thinner gasket.

Test run is scheduled for tomorrow....

Look at the bright side. The dizzy will be happier now.

 

[MYBAD79]

Dizzy all the way down:



.
With .060" gasket there's roughly .100" at the china walls:

 

[mrvette]

Been watching this thread on the dizzy height aspect of this install....
how much variance is allowed in the dizzy on that cam???

I have a suspicion on the oiling for the drivers side due to dizzy setting too high...

anyone??

:fishing:

 

[big2bird]

Your in good shape Karsten. :yahoo:

 

[big2bird]

Been watching this thread on the dizzy height aspect of this install....
how much variance is allowed in the dizzy on that cam???

I have a suspicion on the oiling for the drivers side due to dizzy setting too high...

anyone??

:fishing:

For the oil passage? I would imagine as long as the passage way is blocked off top and bottom, a-okay. Probably as much as 1/4" would survive. My concern would be insufficient purchase of the oil pump drive extension. Too little with a high volume pump and "snap."

 

[big2bird]

If your not done Karsten, put a groove in the dizzy housing from the oil passage down to the gear with a triangular file. .010" is fine. Also, check all plug wire resistence. Should all be within about 20% of each other. (X ohms pre foot).

 

[mrvette]

[QUOTE=big2bird;45996]If your not done Karsten, put a groove in the dizzy housing from the oil passage down to the gear with a triangular file. .010" is fine. Also, check all plug wire resistence. Should all be within about 20% of each other. (X ohms pre foot).[/QUOTE]

What that do???:suspicious:

 

[MYBAD79]

If your not done Karsten, put a groove in the dizzy housing from the oil passage down to the gear with a triangular file. .010" is fine.

That was done 3 years ago :thumbs

I'll check the wires but that reminds me of my MSD wire disaster: the resistance of the stock wires on my Z28 (LS1) was over 300, the new MSD wires were at 28-32.
Think the engine ran any different than before the swap ?? NO.....

But the red wires looked pretty

 

[mrvette]

These daze I dunno of anyone listening to AM radio anymore, so why in the world any wiring maker messes with resistance wire, or plugs is still a mystery to ME.....

I would go solid core wire and REAL plugs if I could find it cheep enough....

 

[big2bird]

[QUOTE=big2bird;45996]If your not done Karsten, put a groove in the dizzy housing from the oil passage down to the gear with a triangular file. .010" is fine. Also, check all plug wire resistence. Should all be within about 20% of each other. (X ohms pre foot).

What that do???:suspicious:[/QUOTE]

Gets oil to the dizzy gear.

 

[big2bird]

I'll check the wires but that reminds me of my MSD wire disaster: the resistance of the stock wires on my Z28 (LS1) was over 300, the new MSD wires were at 28-32.
Think the engine ran any different than before the swap ?? NO.....

But the red wires looked pretty

It's not about the ohms per foot, it's about them all being the same per foot.
I.E., If the wire is 100 ohms per foot, a 3' piece should read 300 ohms.
If it's 10 ohms per foot, 3' piece is 30 ohms.

 

[big2bird]

These daze I dunno of anyone listening to AM radio anymore, so why in the world any wiring maker messes with resistance wire, or plugs is still a mystery to ME.....

I would go solid core wire and REAL plugs if I could find it cheep enough....

Some of the HEI and aftermarket systems need more resistence(wires), or they burn up the modules. Ask Kevin.

 

[MYBAD79]

All I can contribute at this point: I am not an electrician

.

 

[BangkokDean]

All I can contribute at this point: I am not an electrician

.

Now I see your problem those plug wires don't look like they will fit your spark plugs correctly.................:tomato:

 

[mrvette]

These daze I dunno of anyone listening to AM radio anymore, so why in the world any wiring maker messes with resistance wire, or plugs is still a mystery to ME.....

I would go solid core wire and REAL plugs if I could find it cheep enough....

Some of the HEI and aftermarket systems need more resistence(wires), or they burn up the modules. Ask Kevin.

THAT is interesting, I can't see why, wonder what I forgetting??, coil shouldn't draw more current on the dwell/'points' closed/energizing portion, current draw should be the same, but on the secondary side putting out 30+ kv, I can't see a silly 300 ohms as doing anything at all to decrease loading....

now that I thimk about it, wonder if the coil heats up enough to change the primary inductance?? anyone???

:shocking:

 

[mrvette]

All I can contribute at this point: I am not an electrician

.

Now I see your problem those plug wires don't look like they will fit your spark plugs correctly.................:tomato:

I"m shocked but not surprised....looks like he bent over to unplug a wire with the engine running.....:hissyfit::gurney::shocking:

 

[MYBAD79]

It runs a lot better, I was actually able to drive it for 2 miles today

It still hesitates and misfires under full throttle at lower rpm - f.e.: 4th gear, 2000rpm, full throttle.... it does not like it at all....

It runs perfectly fine in neutral, great throttle response, no more nasty fumes....

I have the DV1838 vacuum canister and the 928G spring kit on order, it'll be here Tuesday/Wednesday... until then all I can do is play with the carb some more... maybe adjust the secondaries so they open later ?? I have the springs for the metering rods and still have to read up on what I'm supposed to do with these springs.... I think without a vacuum gauge it's pretty much a hit and miss.....

 

[Arthur Brown]

I've been following this since you installed the intake and the carburetor, did you adjust it again today ? Any update ?

 

[Twin_Turbo]

Didn't read it all but did from your last reply, sounds like it needs more pump shot. As you open full throttle manif. vac. drops to close to zero (better, manif absolute pressure climbs to atmos!) , fuel flow from idle and sec. system drops down (no manifold vac and little or no venturi vac. due to little flow) fuel drops fall out of suspension, that's why you need the pump shot to make it through this transition phase so the engine gets enough fuel (it's starving for fuel) and pick up RPM -> flow -> venturi vac -> fuel flow picks up and booster does it's job of dispersing atomized fuel. This condition is not there, or hardly in P/N no load on engine.

You can do 2 things, move the acc. pump rod to the other hole in the lever (I have drilled additional holes for these things in the past, not an issue at all), this will icnrease total fuel delivery. You can also change the acc. pump squirters for a diff. size. Smaller will change the delivery duration to longer, larger will shorten the delivery, in other words, the pump shot is all squirted in faster. They are easily removed, they are bolted down between the 2 barrels, do keep an eye on the spring and the little check ball underneath.

 

[MYBAD79]

Arthur,
yes, I've been messing around with this pretty much all day. :********:

Marck,
at about 1PM today, after the third adjustment on the secondaries and the second metering spring it was running somewhat acceptable... I was still pissed because it ran smoother with the old carb... went to Starbucks and met Bob (RTJ at DC) ... talked Corvettes and he said the same thing: give it more acc pump, it's starving for fuel.... I did and it improved quiet a bit.

I will try the stock metering rod size next... right now I'm lean acc to the manual.

Now that I see some success it's actually sortof fun tinkering with this carb....wish it was down in the 70's... this is no fun at 100F...:bs:

 

[MYBAD79]

Carb adjustments seem to have little effect, I moved the pump rod one more hole and it's somewhat acceptable but it still stutters at low rpm acceleration....

I installed the AR12 vacuum can and the golden springs from the MRG 928 kit.

Timing is at roughly 12 degrees advanced at idle (with vacuum connected) and at roughly 36degrees advanced at 3000 rpm.... that's just eyeballing the dampener marks... 45 degrees is easy to spot, my advance is a lot less....

This vacuum can really pulls less advance than the old one... now my ignition is set and I have to tinker a little more with the carb... maybe go to .110" jets (that's between the stock .113 and currently installed .107).....

oh boy this is fun......

 

[Twin_Turbo]

So your issue is only @ low rpm?

 

[MYBAD79]

So your issue is only @ low rpm?

Yes. It runs fine in neutral and it revs easy without any misfiring or stuttering.... only when accelerating it stutters... not easy to describe...

Let's say I'm driving in 3rd gear at 1800-2000 rpm and open the throttle it will hesitate. If I open the throttle slowly it won't do it as much but still a little....

If I keep the rpm up and let the clutch slip more then it's fine, above 3000 it pulls hard up to 6500 - full throttle is no problem, just the transition from cruising to accelerating.

Unfortunately this means it runs like **** in 5th gear on the highway, at 65mph I'm way under 2000 rpm.

 

[Twin_Turbo]

If you open slowly you're using the transfer slot, if you open quickly not. Slowly you also won't be using the accelerator pump (it bleeds off). What you need to do is tune the raising of the metering rods and for the rapid throttle down you'll need to tinker with the pump shot some more if the adjustment of the metering rod opening doesn't help there. What you have is a "hole" in your fuel delivery transition. The engine will run fine with no load (revving in P/N) like you said, it's when there's a load on it that the problems arise.

 

[mrvette]

If you open slowly you're using the transfer slot, if you open quickly not. Slowly you also won't be using the accelerator pump (it bleeds off). What you need to do is tune the raising of the metering rods and for the rapid throttle down you'll need to tinker with the pump shot some more if the adjustment of the metering rod opening doesn't help there. What you have is a "hole" in your fuel delivery transition. The engine will run fine with no load (revving in P/N) like you said, it's when there's a load on it that the problems arise.

Lars has supported in some other post, as I recall, the information I have about that off idle transfer slot in there, they feed up through the top of the Qjet via two of those brass tubes....the smaller ones, and so a fellow who rebuilt a carb for me years ago, told me the tubes were drilled some numbers larger to pass more gas under that I remember as similar problems to what you got Karsten.....I had sent the carb off to California ....

:surrender:

 

[Twin_Turbo]

Karsten has an Edelbrock carb, not a Q jet. The transfer slots are fed through the emulsion passage just as the idle jet does. The adjustment of the idle screws in front adjusts the air vs emulsified fuel (air/fuel mixture) and as such also influences transfer slot, since it's the same output as the idle jet but is only active when the throttle blade is open far enough to expose the slot to manifold vacuum. It only sees manifold vacuum at limited throttle pos. Anywhere after that it sees nothing, fuel is metered by the main system via the booster (bernouilli venturi principle) but the transition between when opening the throttle quickly is done w/ the pump shot. Since Karsten has issues w/ both that lead me to believe his transfer slot is not giving enough fuel, either due to the incorrect idle setting (but unlikely) or the metering rods open too slowly. As manifold vac. drops the metering rod raises, if the spring is too weak it may raise too slowly.

As for the emulsions system (which is very simple in these carter/edelbrock carbs, you can't adjust the air bleeds and there are no emulsion tubes to swap out - if you want a carb where you can change that all..get a weber side draft, or better the dellorto which has much more increments in jets, air bleeds and emulsion tubes) it's a sort of fuel brake system. fuel is mixed with air as the air is drawn by manif. vac. or venturi vac (depends on what throttle pos. - which delivery system is operating) through the emulsion passage where it mixes with fuel. More air is also introduced to regulate the emulsion flow. This is adjusted with those idle set screws. Emulsifying is just a pre mixing of air and fuel.