Ok, I've about had it with the Mopar Performance distributor/ignition

[moparedtn]

I had an edelbrock 800 AFB carb once had a weird stumble at a certain RPM, no matter how many combinations of rods and springs / jets I tried which was every possibility it just wouldn't fix the issue, a new QFT 850 was good, I use a QFT 780 vac sec now for just cruising but have the 850 for fun time point is maybe it's just a bad carb out of the box? I still think its electrical though

Thanks for hanging in here with me, JB.
Electrically everything is new, including the coil, ECU, heck man short of pulling the new MP distributor, I'm at a loss there - and I'm darn close to picking up a regular ol' rebuilt stock electronic distributor and tossing it in there just to eliminate THAT possibility.

Oh, I got a response from Holley. Not sure what to make of this:
"Thank you for contacting Holley Performance Products.
I would suggest dropping to a 5.5 power valve and blowing out your high speed air bleeds with compressed air. Sounds like there may be a bit of varnish in the bleeds. See it that takes car of you. If not, let me know and we will go from there.
Sincerely,
Jeff Teel"

I'm confused about the power valve suggestion - isn't the purpose of the power valve to aid with the initial demand for lots more fuel when you step on the throttle?
Guess it couldn't hurt to take the new, shiny carburetor off and blow out all the orifices with brakleen...
but something is telling me I got the junior member of the tech support team at Holley.

 

[69Runner]

Initial demand for fuel when you step on it is from the accelerator pump/ shooters. The power valve opens at the rated vacuum which depends on engine rpm, throttle plate position etc. But if its lean then a 75 would be the way to go, assumimg 65 is in there now. What is your vacuum at idle?

 

[moparedtn]

Vacuum @ idle is 11-12hg, so I figured the 65 power valve was in the ballpark, given the old "divide by 2" bit.
Since the power valve is a "transition" helper of sorts, at worst I'd figure the carb would be a little off on the timing of the boost of fuel the power valve gives, but then the carbs' regular circuits (primary/secondary) would take over the demand for the additional fuel flow, right?

 

[moparedtn]

UPDATE:
I took the Holley off the car and tore it down, blowing out all orifices and shooting them with Brakleen.
I took the opportunity to put 75 primary jets in there as well, also verifying (and actually raising a little) the fuel float levels as well just to make sure I was maxed out on fuel levels.
Everything, as you'd guess, checked out spic'n' span in there. Replaced carb on motor.

Hooked up timing light, set timing at an INDICATED 0*TDC this time (down a couple degrees from before) once the engine was warmed up.

Results:
Pretty much the same results. Wringing it out in each gear, by the time I got to 3rd and went over 4k, RAPITA RAPITA RAPITA (heard in the exhaust more than anywhere else) with the accompanying falling down surging/dying/surging.
If I stayed in it, or ever "reloaded" the throttle, at that point, it would even attempt to die out.

No gains, in other words....yet I dared to rev it HARD in idle once I got back, to an indicated 6k, and the engine mechanically sounds really good going up there with no load. Seemed REAL happy to rev, in fact.
Reckon it's breaking in real well.

PS - the engine still does not like the vacuum advance hooked up. Acts all jittery at even lower speeds with it. Plug it off and the car is pleasurable to drive in most normal conditions, very smooth throttle in fact - until it's hammer time, at least.

PPS - I have verified the secondaries are free when installed on the car - no binding at all.

Conclusion: The car is flat running out of SOMETHING when under heavy load over 4k RPMs.

I'm ready to conclude the carb is ok as long as it's fed and I've had the timing everywhere from an indicated 15*BTDC to now 0*TDC. Other than crispness of response at lower speeds, the timing adjustments haven't made much of a difference at all - seems like I could run any timing I want within those parameters, with just a simple idle speed adjustment, as long as I don't hook up the vacuum advance.

What now? Fuel pump?

 

[dieseldazzle]

Fuel delivery.

 

[SlinktRR]

Fuel delivery.

Yep. If you can rev to 6k at idle that suggests the ignition is ok. But there is no load so fuel demand is really nothing. Plus when you're accelerating the fuel system has to fight g's while pushing the gas forward...not so sitting in the garage.

Try putting a gauge on there and see how it does wide open.

 

[moparedtn]

I'm very appreciative to see other folks thinking what I'm thinking.
Now, question is - what pump? I'd think a new stock one would suffice, but of course the urge to get a higher volume one is eating at me. Can I put one of the old school Carter street/strip mechanical ones on there without worrying about a regulator, for example?

 

[dieseldazzle]

I'm very appreciative to see other folks thinking what I'm thinking.
Now, question is - what pump? I'd think a new stock one would suffice, but of course the urge to get a higher volume one is eating at me. Can I put one of the old school Carter street/strip mechanical ones on there without worrying about a regulator, for example?

Pull your fuel pump pushrod out and inspect it as well. You may find a shocking suprise.

 

[moparedtn]

Pull your fuel pump pushrod out and inspect it as well. You may find a shocking suprise.

I had already sort of figured on buying another, even though this one looked fine when I did the cam swap very recently.
Do you know the answer to my question?

 

[dieseldazzle]

Yes you can is the answer to your question. I had one on a mild 383 with a Holley it worked flawlessly

 

[moparedtn]

Great. Now, WHICH Carter? Seems Mancini has two, one of which makes me slightly nervous because of the pressure output.

 

[bigmanjbmopar]

Depends on your needs for your application the basic one with 120 GPH 5.5 to 6.5 PSI should be perfect


http://www.manciniracing.com/cabheen5psis.html

Fits: Big Block

The product specialists at Mancini Racing worked directly with the Federal-Mogul/Carter Fuel Systems brand team in bringing back these highly sought after mechanical fuel pumps that Mopar enthusiasts have been requesting for some time.

Both the Carter M6902 (small-block) and M6903 (big-block/Hemi) have the following features and benefits:

• 5.5 to 6.5 PSI

• 120 GPH flow rate

• Tough lightweight aluminum silver cast finish body

• Large full-flow valves

• Anti-float springs for high RPM operation

• Heat treated lever

• ¼” NPT inlet and outlet

• Housing is positioned for the many popular Chrysler O.E. fuel line routing but can also be rotated to accommodate different inlet and outlet locations

• Perfect for stock or modified Mopar muscle cars requiring additional fuel delivery while maintaining a stock appearance under the hood





http://www.manciniracing.com/brbhemen85ps.html

Fits: Big Block

Fuel Pump, Mechanical, Strip Super Series, Chrysler, Dodge, Plymouth, Each

Free Flow Rate: 43 gph

Maximum Pressure (psi): 8 to 9.5 psi

Inlet Attachment: Female threads

Inlet Size: 1/4 in. NPT

Inlet Quantity: One

Outlet Attachment: Female threads

Outlet Size: 1/4 in. NPT






http://www.manciniracing.com/bhefupu6psi.html

Fits: Big Block

We have a limited supply of mechanical fuel pumps that were built for Holley Performance Products.

The pumps are made to Holley's specs. Same as the 12-440-11 big block high performance fuel pump.

Free Flow Rate: 110 gph

Maximum Pressure (psi): 6.5 to 8 psi

Inlet Attachment: Female threads

Inlet Size: 1/4 in. NPT

Inlet Quantity: One

Outlet Attachment: Female threads

Outlet Size: 1/4 in. NPT

Outlet Quantity: One

Gasket Included: Yes

 

[moparedtn]

UPDATE:
Bit the bullet and got on the horn with Mancini. Seems they are having Carter (Federal Mogul) reproduce the (famous?) M6903 hemi fuel pump, which has the proper pressure and of course, tons more flow than the 440 ones:


Once he assured me of no need for a regulator, done deal on that. It's on the way, along with the Comp Cams fuel pump pushrod #4626, made specifically for flat tappet cams.
Dieseldazzle was dead on the money with his comment on these - seems todays' cams eat fuel pump pushrods if they don't have a proper tip on them like this unit does.

I'll have to do some adapting of fittings once it gets here (pump has 1/4" female inlet and outlets), but no worries there.
I'll update once I get these in and on the car.
Thanks y'all!

 

[dieseldazzle]

Good choice. I like this one because with 1/4 npt you can get a fitting for 3/8 hose barb. I didnt like mine because it was not rebuildable and was only 5/16 hose but it flowed 33gph which was more than enough for my mild 383.

 

[moparedtn]

Depends on your needs for your application the basic one with 120 GPH 5.5 to 6.5 PSI should be perfect
http://www.manciniracing.com/cabheen5psis.html

Hey looky there, we were posting at the same time. Yep, JB, the Carter M6903 is the exact one I just ordered, you're spot on!
Pump ought to last forever on this motor. Not making gobs of power here with the stock 440 magnum.
Thanks!

- - - Updated - - -

Good choice. I like this one because with 1/4 npt you can get a fitting for 3/8 hose barb. I didnt like mine because it was not rebuildable and was only 5/16 hose but it flowed 33gph which was more than enough for my mild 383.

Yeah, the flow with this one is ridiculously more than I'll ever need, so I'm figuring it's likely to last forever.

Look, you guys have stuck with me through this whole thread (that started out about ignition LOL) and I deeply appreciate it.
This whole project wasn't likely to happen to begin with; I was supposed to be dead by now, after all, so I'm really into it, chewing on it like a steak. To have found this site and folks like you all to help me along the way is a blessing, really is, and I'm in your debt.
Not only am I still alive (54 years today, in fact!) but the car is almost done to boot.
Can't complain about any of that.
Thanks, y'all.

 

[bigmanjbmopar]

Cool beans hope it resolves that issue

 

[69Runner]

While you are waiting for the fuel pump to arrive, another thought. How tight is the clamp on the hose feeding the existing fuel pump? Or even at the fuel pickup? Good luck getting to the bottom of this issue.

 

[moparedtn]

While you are waiting for the fuel pump to arrive, another thought. How tight is the clamp on the hose feeding the existing fuel pump? Or even at the fuel pickup? Good luck getting to the bottom of this issue.

Oh, everything is snug as a bug. Just went through all that with the install of the new tank, sending unit, et al.

Anticipation of pending arrival of new Carter "hemi" high volume fuel pump & pushrod from Mancini.
It's still cool to be waiting on goodies in the mail.
Took her down to the local cruise-in tonight. Perfectly normal operation as long as I don't beat on her past 4500RPM, always gets lots of compliments when we take her out.

Oh, the guy from Holley tech is adamant I change the power valve before helping me any further.
I'm starting to think they put the resident 20-something Honda enthusiast on the tech line over there...
"Hey, Junior, the number on the power valve indicates WHEN it opens, not how much it flows."
Oy.

Appreciate the words of encouragement! Worst case, I pull off the vacuum secondaries/metering plate and replace them with the guts of a double pumper. Couldn't hurt, I suppose.

 

[moparedtn]

Well, the pump looks great on the car and sure enough, the old pump pushrod had been eaten on some - I'd guess about a tenth of an inch, seems like. Probably not enough to matter, but glad I bought a new one just the same.
Job's not done, however...
1. Ethanol has managed to eat on my couple year old 3/8" rubber fuel lines already. Sheesh. That stuff is such garbage.
2. Parts store hose clamps ain't worth a damn the 2nd time around, apparently.
I did go ahead and re-route the fuel line out from under the alternator over to the frame to make future filter changes easier, since I was replacing hoses anyways.
The rest will have to wait until I get over to the store in the morning, hopefully to find some GOOD hose clamps (Gold Seal comes to mind - do they still make those?).
Sigh...and so it goes.

 

[bigmanjbmopar]

Well at this point you are still not sure what the cause is?

What I know / did about fuel lines / clamps

I bought this stuff to update the 5/16" factory line just to make sure delivery was on par and since the car was 44 years old and I could not look inside I just upgraded it, if you shop around you can find it cheaper I paid $25 forgot where free shipping I think.
http://www.jegs.com/i/Moroso/710/65330/10002/-1


As far as clamps go I switched to these for fuel, yes they are size specific but they work! and works well, I didn't buy from this place this is just an example I think autozone or orileys sells them.

http://www.karishmasteels.com/Galvanised-Hose-Clamps.asp


http://www.mcmaster.com/#standard-hose-clamps/=yir0lk

http://www.directindustry.com/prod/mpc-industries/product-65240-719197.html


http://www.kartek.com/Product/3228/JAMAR-Black-Aluminum-Hose-Clamps.aspx