Fuel Pump!!

[ejoedirte]

What in the heck is that little lever doohickey sticking out of the back of the mechanical fuel pump! My Challenger has a Holley 'lectric fuel pump that's louder than God, so I want to downgrade(sic) to a mechanical unit that mounts where the block off plate is now at the front of the engine, behind the pulleys. I'm almost afraid to look behind the plate for fear of boiling oil or molten lava spewing out of it disfiguring me for life! Are there any other apparati I need for this (pushrod,etc.) or does it simply bolt to the block. What drives the damn thing?
At a loss-Thanks in advance for filling in the gaps!

[Mills]

You can replace your electric pump to a mech. no problem. Rip off that block off plate, install the fuel pump 'pushrod' (which requires you to take out the hex cap in the block), and put on your mech. fuel pump.

Personally, I would just buy a different electric unit; they are much better then the mech. units.

[charger_dan]

The lever you're referring to is the pump arm lever. During operation, this lever receives a lateral force from the fuel pump lobe on the rotating camshaft. The outboard end of the lever connects to an internal diaphragm, which actually pumps the fuel in an out of the pump body. An internal return spring forces the pump arm lever back the other way, keeping the arm in contact with the lobe. It's the same on big blocks, except there's a small pushrod that runs between the cam lobe and pump arm. Same operation. Installation is pretty basic, though you'll need to deal with some new fuel line plumbing. No big deal.

Other than the noise, are you happy with your current pump?
Is the pump mounted solid to the frame? Isolate it with some rubber mounts or bushings. I'm sure other fellas on this board have done this successfully.
Where is the pump mounted? Up front, pulling, or in the back, pushing?

I'd first try and fix the noise problem, before shelling out for a new pump and fuel line.

[ejoedirte]

Thanks for the quick info! What I have now is yer standard Holley Black fuel pump which pushes at I don't know what PSI (alot), and its gonna be a bit much for the carb i'm putting on eventually ( Eddy 750 performer from a Holley 750, just like 'em better). Performance wise no probs, but the Whirring noise and vibration is truly phenominal. This car has some monster torque and horses, and has led the last three years of its life as a drag car. I'm in the process of returning it to street duty and trying to reduce the current draw on Uncle Jethro's wiring setup. So im ditchin' the 'lectric pump, the line lock circuit, auxillary gauge circuits (in lieu of a rally cluster if I can find one) and whatever else I can find that I don't need for trips to the store for milk. The mechanical unit should pull no more than 6 psi (as per instructions that came with the Eddy 750) and will bolt on to my 340 just fine. From the sound of it a small block needs no additional hardware?
Thanks Fellas!

[charger_dan]

As for mechanical fuel pumps, I've had pretty good luck with Carter.
Their street pump M6902 for SB Chrysler flows 120 gal/hr @ 6psi.
The Strip pump M6270 flows same 120 gal/hr but @ 7.5-8psi. There's about a $5 difference in price from Summit.

Either way, it's a good idea to plumb in a regulator between the pump and carb, as these pumps tend to have a range of psi, not a stable psi rating, and a regulator helps ensure the carb stays happy with a nice steady rate of fuel.

Small blocks need no additional hardware for mounting a mechanical pump, unless your fuel pump eccentric is damaged or missing. Fab some good fuel lines from thickwall steel 3/8" tubing, add a regulator and pressure gauge, and you're good to go.

Best of luck.

[mtrv8n]

I suggest the Carter hp pump, it fits better than the Holley unit, and flows the right psi for an Edelbrock carb.

[dirty dan]

Originally posted by ejoedirte
What in the heck is that little lever doohickey sticking out of the back of the mechanical fuel pump! My Challenger has a Holley 'lectric fuel pump that's louder than God, so I want to downgrade(sic) to a mechanical unit that mounts where the block off plate is now at the front of the engine, behind the pulleys. I'm almost afraid to look behind the plate for fear of boiling oil or molten lava spewing out of it disfiguring me for life! Are there any other apparati I need for this (pushrod,etc.) or does it simply bolt to the block. What drives the damn thing?
At a loss-Thanks in advance for filling in the gaps!

Remove the plate the push rod should be in there waitting for you.
If not any big block rod will work.
As they are all the same.
If you put a peice of rubber between the holey pump braket and the mounting surface,it will make the pump a lot Quiter.

[pishta]

Joe , your using a Holley "black" for a 5.5 PSI Edelbrock? Sure hope you plan to neck it down a few, that is a 14 PSI pump that'll fill a toilet bowl in 26 seconds. Go get yourself a Carter Mechanical and make sure still have an eccentic on the end of your cam, install it with a gob of assembly lube on the pump arm and turn your stereo down.

[deadhorse66]

Whatever you do, make sure there is a pushrod in there! I don't know about a small block Chrysler, but on a big block, if you take that pushrod out, you uncork one of the oil galleries. That will result in an oil pressure of ZERO! Stick with some type of electric if you can live with it, they are just plain better in every way if you asked me. A carter pump will usually make a little less noise than a Holley.

[ejoedirte]

Thanks guys! There's some info I can use!!

[cuda66273]

How fast is this car?
What's you estimated HP?
What's the cam duration at 50?
Are you sure that Eddy 750 will be able to read the manifold signal?

Have you looked at the BG HR220 pump, it sounds to me like your gonna need more that a 120 GPH pump...and a 750 Eddy????

Why would you want to go slower?

Just curious............

[ejoedirte]

Glad you jumped in here Cuda! The recommended PSI of the Eddy Performer is no more than 6 PSI. Does that jive with your experience or is that a conservative requirement? Tha car has a big hydrolic bumpstick for racing but beyond that the guy I bought it from couldn't say. Was race car, I need a street car so I'm making changes to it with fuel economy and streetability in mind. Its plenty fast, believe me and I would surely be asking for trouble on my way to get milk with the car as it is. Also I have wiring headaches, so in the interest of simplicity and reliability I'm trying to eliminate a circuit or two-hence the mech. fuel pump. Maybe you can recommend a good one for that carb combo. Oh yeah, the Eddy will sit on top of the Victor 340 that is now occupied by a Holley 750!
Thanks Moparites!!

[cuda66273]

Driveability starts with Manifold vacuum and Idle quality...by decreasing the fuel and choking the air flow all your going to do is make it worse.

You need to tune the motor down, a cam change would really be the way to calm it down for streetability. This will enable you to reduce the idle speed, decrease cylinder pressures and reduce initial timing for ease of starting and low end throttle response would be drastically improved.

It's kinda like smearing the peanut butter on the bread board and then rubbing the bread on it...

You need to know what cam is in that motor either by research or by measuring it...

..one more thought.....it may not be so much the cams fault it mat even be just a real bad tune-up.

Bring it over and let me check it out....

[DartGT66]

On a hydraulic cammed 340 with a 750 carb, the mechanical HP pump should be able to deliver all the fuel needed and then some. It's basically the same pump that fed the 426 Hemi with dual quads, so it should be enough. You have a Victor intake in that thing? It's not known about it's idle quality. An Edelbrock or a regular Holley; it doesn't make much difference. They are bulk "universal" "one fits all" carbs and work somewhat in almost any application you put them on. There is a tremendous difference between a good carb and those what comes to idle quality and driveability. You will not believe it unless you have tried. Even a hot hydraulic may be a little "small" to take the advantage of a Victor intake. If you intend to change in to a smaller cam, loose the Victor too. Depending of your intended rpm range, use either a RPM or a Performer style dual plane intake instead.

[BakedMopar]

Originally posted by deadhorse66
Whatever you do, make sure there is a pushrod in there! I don't know about a small block Chrysler, but on a big block, if you take that pushrod out, you uncork one of the oil galleries. That will result in an oil pressure of ZERO!

I took mines out. I got oil pressure? I am kinda new at this so what exactly goes on here. I don't want to ruin my motor.

[DartGT66]

In a BB the fuel pump rod does not go in to any oil galley. You can well leave it out without any harm if you have an electric pump, no problem. SB's do not have that kind of rod, their mechanical pump is actuated by a separate eccentric that goes under the cam sprocket bolt, and that actuates the pump lever directly.

[ejoedirte]

Bitchin: Two page Thread!