Well there's also the rebuilding the pump part since there are no remanufactured Hemi fuel pumps to be found. But I do have a FBBO member who has offered to help me with that task. So we will see how it goes.
Removing Fuel Pump on GTX
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Daves69
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There was a thread here a while back that possibly had a link to a rebuilder. The rebuilder would adjust the pump output to your specification. I haven't been able to find the thread. Maybe someone else can recall.
I think the parting line eight screw diaphragms are a bit scarce. (4824)
R413
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Lots of confsion.
Fuel pump pushrods have different wear on each end. Put it back in the same direction it comes out.
Back both attaching bolts out 3-4 turns, if the pump is loose then the cam is in the right place. If the pump is tight then it’s on the cam lobe so rotate the engine a bit until the pump is loose. Then remove it. Now you know it will go back in easily.
Then and now automotive has the rebuild kits, how many do you need? not scarce. The parting line and non parting line diaphram is the same.
Fuel pump pushrods have different wear on each end. Put it back in the same direction it comes out.
Back both attaching bolts out 3-4 turns, if the pump is loose then the cam is in the right place. If the pump is tight then it’s on the cam lobe so rotate the engine a bit until the pump is loose. Then remove it. Now you know it will go back in easily.
Then and now automotive has the rebuild kits, how many do you need? not scarce. The parting line and non parting line diaphram is the same.
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If you don't feel like rebuilding it, these look about the same. https://www.yearone.com/Product/challenger-cuda/af89/#prettyPhoto
I'd disconnect the battery because of removing alternator. Push rod is around 3.20" correct me if I'm off.
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3.22 is correct for RB as well.
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Au contrare, mon frere:
Carter Mechanical Fuel Pump
It's a good pump. I run one on my 440 - and yes, just like the original, it uses the same rebuild kit (which Mancini
also has).
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Sorry, I was not referring to you. I was commenting about the guy that thought the pushrod could fall out when you pull the pump. It is immediately evident once you pull the pump that it cannot come out on it's own.
I think these kits fit these 8 bolt pumps...
Mancini Racing Fuel Pump Rebuild Kit
Mancini Racing Hi-Volume Fuel Pump Rebuild Kit
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Buy the rebuild kit from Then and Now so you're assured to get a spring that's not too heavy, causing too much pressure. Give him a call so he can talk you through it. Or better yet, put it in a box and send it to him to rebuild. His turn around time is pretty good. He's a member here.
Removing and installing the pump...
You want to remove pump then remove the plug then remove the pushrod. Measure the pushrod for wear. 3.220 or close is what you're looking for. If alls good reinstall the pushrod, hold it in with your finger and rotate the engine by hand and feel it travel in and out. When it is in as far as it goes then you can install the pump. You can tell if the arm is in contact with the end of the pushrod by feel or by looking in the plug hole.
I like to use a remote starter button to bump the engine around to find the shortest stroke of the pushrod. Just install the rod and while holding it against the cam lobe bump the engine until it's in as far as it goes. It makes it so much easier to install the pump not having any pressure on the fuel pump leaver.
A little sealer on the gasket and stick the bolts though just a few threads before installing. Most gaskets will hold the bolts for you.
All buttoned up.
Removing and installing the pump...
You want to remove pump then remove the plug then remove the pushrod. Measure the pushrod for wear. 3.220 or close is what you're looking for. If alls good reinstall the pushrod, hold it in with your finger and rotate the engine by hand and feel it travel in and out. When it is in as far as it goes then you can install the pump. You can tell if the arm is in contact with the end of the pushrod by feel or by looking in the plug hole.
I like to use a remote starter button to bump the engine around to find the shortest stroke of the pushrod. Just install the rod and while holding it against the cam lobe bump the engine until it's in as far as it goes. It makes it so much easier to install the pump not having any pressure on the fuel pump leaver.
A little sealer on the gasket and stick the bolts though just a few threads before installing. Most gaskets will hold the bolts for you.
All buttoned up.
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P.S. the plug (if still the factory one) has a goofy size to it. Might want to make sure you have a tool
to fit it before you begin.
to fit it before you begin.
Goofy size? Every one I have seen is just a standard allen wrench.
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Yep..
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It's an allen, all right - but not one in the basic el cheapo set.
Ask me how I know.
MTBRider
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Definitely recommend sending it to Now and Then, they rebuilt mine and returned it within a few weeks. Very easy to ruin the diaphragm putting it back together.
Highly recommend to verify the pushrod length, mine was over 1/4” short!
Highly recommend to verify the pushrod length, mine was over 1/4” short!
mopar 3 B
Well-Known Member
Small blocks have an eccentric cam the pump arm rides on. No rod, no plug.
Nevada dan
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I’ve never took the time to grease the rod just took the wires off the alternator and the adjuster bolt out, rolled the alternator up, used my finger to hold the rod up and put the pump in
Quick and easy job
Guess I could take longer now that I’m retired
Quick and easy job
Guess I could take longer now that I’m retired
Dragon Slayer
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Let me know when you get it off. Can get it taken care of and have pumps that are built already also.
Dragon Slayer
Well-Known Member
I did not enter the discussion a while back about the fuel pump rebuild, but several things to think about. I disagree with then and now on the spring. Their spring choice is too soft. It works, but Carter designed the original to operate with the check valve springs and designed for the carburetors in use.
Yes the pump is a constant volume pump, but there is a velocity element to the stroke provided by the spring and that does effect the volume of fuel delivered especially at higher rpms. The pump arm pulls the diaphragm up primes the chamber with fuel, BUT the now compressed spring delivers the fuel through the check valves to the carburetor. Just like valve springs and cam design matter based on engine performance so does the fuel pump spring. At higher rpm the softer spring will not deliver the same volume and you also wind up closer to vapor lock on a hot engine when pump pressure is much lower.
There is information in the service manuals
Pumps are not hard to rebuild and it is Not easy to damage the diaphragm as stated, but there is a procedure for doing it. Also, I do not use the brake rivets as check valve. The umbrella seals had vapor escape holes drilled in them on certain pumps.
If you have an original Carter pump you can recover the spring and use it. I have extensively documented the cast part numbers, volumes, spring dimensions etc... for the various mopar original pumps. I really wish the current Carter would provide rebuild kits for the 8 screw pumps build to orig spec. But they don't and won't. I asked.
Then and now kits are good and do work, but they are not the same as originals.
Don't believe me. The 6903 and 4862 are the exact same body components with one exception. The spring rate. They have different volume rate. Not just pressure. There is a hell of a lot more technical stuff that went into the design to control spring harmonics and check valve flutter, etc.. Even the plates below and above the rubber diagram are sized and shaped by design of carter. They had a patent on it back in the day. I am sure the Chinese ignore all that and cut corners when making the current crop of pumps, but it mattered.
Yes the pump is a constant volume pump, but there is a velocity element to the stroke provided by the spring and that does effect the volume of fuel delivered especially at higher rpms. The pump arm pulls the diaphragm up primes the chamber with fuel, BUT the now compressed spring delivers the fuel through the check valves to the carburetor. Just like valve springs and cam design matter based on engine performance so does the fuel pump spring. At higher rpm the softer spring will not deliver the same volume and you also wind up closer to vapor lock on a hot engine when pump pressure is much lower.
There is information in the service manuals
Pumps are not hard to rebuild and it is Not easy to damage the diaphragm as stated, but there is a procedure for doing it. Also, I do not use the brake rivets as check valve. The umbrella seals had vapor escape holes drilled in them on certain pumps.
If you have an original Carter pump you can recover the spring and use it. I have extensively documented the cast part numbers, volumes, spring dimensions etc... for the various mopar original pumps. I really wish the current Carter would provide rebuild kits for the 8 screw pumps build to orig spec. But they don't and won't. I asked.
Then and now kits are good and do work, but they are not the same as originals.
Don't believe me. The 6903 and 4862 are the exact same body components with one exception. The spring rate. They have different volume rate. Not just pressure. There is a hell of a lot more technical stuff that went into the design to control spring harmonics and check valve flutter, etc.. Even the plates below and above the rubber diagram are sized and shaped by design of carter. They had a patent on it back in the day. I am sure the Chinese ignore all that and cut corners when making the current crop of pumps, but it mattered.
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