I'm starting to think my fancy "hemi" mechanical fuel pump is eating pushrods

[moparedtn]

So y'all know I'm running one of the Mancini-sourced reproduction "hemi" fuel pumps, the kind you can take apart and rebuild, right?
I think it's eaten another pump pushrod. Pressure gauge is only showing 4psi at the rail at idle and the thing is starving on top end in 3rd gear under spirited driving.

I'm starting to think the spring pressure in the fuel pump is excessive - that or they just don't make pushrods like they used to? This one is the fancy Comp Cams one and this pump ate a stock pushrod before that as well.

Thoughts?

 

[khryslerkid]

Do you know the part number of the pump?

I bought a Carter M6903 and they state the pressure is suppose to be 6 - 7.5 Well it runs 8 lbs at idle. Good thing my Edelbrocks have the larger needle and seats. It does perform ok without any flooding.

Ed, Id check your float level. Also check plugs for a lean condition. If they look ok then maybe check what springs and rods that you have.

If the pressure is less than what it use to be, pull the pump before it gets any worse and measure the pushrod. 3.220 is the measurement.

 

[Darter6]

I remember reading about some push rods being of inferior material,meaning China. Try to find a 50 year old factory one.Bet it solves your problem.

 

[moparedtn]

Do you know the part number of the pump?
I bought a Carter M6903 and they state the pressure is suppose to be 6 - 7.5 Well it runs 8 lbs at idle. Good thing my Edelbrocks have the larger needle and seats. It does perform ok without any flooding.
Ed, Id check your float level. Also check plugs for a lean condition. If they look ok then maybe check what springs and rods that you have.
If the pressure is less than what it use to be, pull the pump before it gets any worse and measure the pushrod. 3.220 is the measurement.

Yep, that's the one.
Floats and plugs and such ain't got much to do with low fuel pressure, obviously - and that's what I'm after right now -
but to answer the question yep, this carb has had the full Ed treatment, including buying the tuning kit and changing out the
incorrect jets and rods the previous "reman" company totally effed up on it. Seems to work ok now.

Yep, I guess I gotta figure out what size hex that plug is and go after the dang thing....again.
I never seem to have the right one?
Sadly, I know that rod measurement all too well....

 

[moparedtn]

I remember reading about some push rods being of inferior material,meaning China. Try to find a 50 year old factory one.Bet it solves your problem.

I'm thinking you may be right there. The one in there is the pricy Comp Cams one with the brass on one end,
which I tried after a "standard" parts store one got short real quick-like.
Hope the dang pushrod isn't actually eating the cam lobe!

 

[Darter6]

Doubt the cam. I have one new in the bubble pac that has the "Tipped" ends. I think it's going to the next swap meet.

 

[PurpleBeeper]

Yep, that's the one.
Floats and plugs and such ain't got much to do with low fuel pressure, obviously - and that's what I'm after right now -
but to answer the question yep, this carb has had the full Ed treatment, including buying the tuning kit and changing out the
incorrect jets and rods the previous "reman" company totally effed up on it. Seems to work ok now.

Yep, I guess I gotta figure out what size hex that plug is and go after the dang thing....again.
I never seem to have the right one?
Sadly, I know that rod measurement all too well....

3/8" hex I believe

 

[440+6]

I bought one from Rick last year at half the price, (he must be getting low on them) but this is what you need, I would think they are around at a more reasonable price.

https://www.ebay.com/itm/NOS-Mopar-...mp+pushrod&_from=R40&rt=nc&_trksid=m570.l1313

 

[moparedtn]

I bought one from Rick last year at half the price, (he must be getting low on them) but this is what you need, I would think they are around at a more reasonable price.
https://www.ebay.com/itm/NOS-Mopar-Hemi-Max-Wedge-FUEL-PUMP-PUSHROD-Hardened-440-426-383-Dodge-Plymouth/223073308477?epid=1029939718&hash=item33f0348f3d:g:dUcAAOSwbbdbK6ud&_ssn=rehrenberg&_sacat=0&_nkw=Mopar+fuel+pump+pushrod&_from=R40&rt=nc&_trksid=m570.l1313

Woah, pricy for sure. Thanks!

 

[khryslerkid]

I'm thinking you may be right there. The one in there is the pricy Comp Cams one with the brass on one end,
which I tried after a "standard" parts store one got short real quick-like.
Hope the dang pushrod isn't actually eating the cam lobe!

The bronze tip pushrod is for use with a roller cam (steel camshaft). This is the one I'm useing.

 

[moparedtn]

The bronze tip pushrod is for use with a roller cam (steel camshaft). This is the one I'm useing.
View attachment 632306

Well dang, you'd think their parts description would say such a thing, sheesh.
Thanks much!

 

[oldbee]

I remember reading about some push rods being of inferior material,meaning China. Try to find a 50 year old factory one.Bet it solves your problem.

Thank you Lord, my original pushrod(86000miles) still going. You guys all make me nervous at times!

 

[moparedtn]

Thank you Lord, my original pushrod(86000miles) still going. You guys all make me nervous at times!

Sorry sir, didn't mean to start any worries. It just appears to be yet another case of parts today being inferior in quality,
sort of like most commodities in our world these days.
I've found a couple of Mopar ones on sites of dubious natures besides the $$$ one Professor Ehrenberg offers.
Might just have to roll the dice on a NAPA one or something. Becoming a regular replacement wear item anymore, sheesh.

 

[Paul_G]

This thread got me thinking. I have a 78 440 motor home block at the machine shop right now. The engine had 50000 miles on it. Very little wear at tear down. I went and measured the fuel pump push rod, measured 3.221. I have no reason to believe it is not original.