davek
Well-Known Member
congrats on the find,is the new pump in ? How does it sound?Ticking/knocking after warm up
- Thread starter PlymCrazy
- Start date
congrats on the find,is the new pump in ? How does it sound?
Measure the fuel pump pushrod while you're in there
no new pump yet.
Don,
Is that to make sure it’s long enough to reach the cam sufficiently? Can you elaborate please? Am I measuring anything internally from the opening on the side of the block with the pump out as well?
The pushrod should be 3-1/4" long. There is a pipe plug you need to remove to install or remove the pushrod. An eccentric on the cam drives the pushrod which actuates the pump arm. It seems as though all the newly manufactured rod wear. The original rods seem to hold up well
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Ok. That makes sense. I was confusing the fuel pump rocker arm with the push rod. Very clear to me now with the explanation and illustration. I’ll check that out as well. Thank you.
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So I measured the fuel pump push rod and it measured 3.22" with no significant visual signs of wear. The old fuel pump has no manufacturer label on it however it looks similar to many of the high volume models I see listed on Jegs, Summit, et al. I want to order a new pump but there are many options. I currently have an Edelbrock AVS 1806 650cfm carb on it. Without knowing much about the build on the motor, is there anything that would be recommended to put back in there? I see 110/120gph pumps vs 20gph pumps and pressures from 4.5psi to 9psi. Lot to to choose from...
davek
Well-Known Member
is you pump like this
or this
davek
Well-Known Member
go with stock specs and you should be fine,your not racing just cruising.
My existing pump is like the latter of he (2) you posted, with the threaded outlets. Looking at my existing one that broke it has far less quality of construction than the Carter. In particular the hinge pin on the pump actuator arm. On mine it has the pin pressed in and doesn't pass through the body like the Carter. If that hinge pin on mine was installed like I see on the Carter there would would have been a far less chance of the arm separating itself from the unit like it did.
The pump you have pictured is an M4862. I see some prefer the M6903. From the specs I see on Jeg's and Summit, the M6903 ranges from 5.5 to 7.5 psi. The M4862 ranges from 8 to 9.5 psi. I have an Edelbrock 1806, 650cfm carb and heard they can be finicky with pressures much above 6psi. Can you recommend one pump over another? Am I overthinking this? I work in a trade where these pressures would barely move the needle on our gauge LOL.
davek
Well-Known Member
I would go with the 5.5-7.5 pump. I believe I bought the M6903 this year but havent had time to install.
I was leaning that way. Just waiting for confirmation and that’s all I needed to hear. I’ll pull the trigger on that in the next couple days hopefully. Thanks Dave.
New pump is in hand ready to go in. Came with (2) gaskets and got me thinking…
Is this thing supposed to have a spacer between the fuel pump and block mounting surface? If so, it would make sense why the old pump arm pin popped out as it wasn’t installed with a spacer.
Is this thing supposed to have a spacer between the fuel pump and block mounting surface? If so, it would make sense why the old pump arm pin popped out as it wasn’t installed with a spacer.
davek
Well-Known Member
I would think not,I never had a spacer on any of my BB.
Ok. Thanks. I dry fit it with the push rod on the low spot of the cam. The pump flange fit flush. I’d agree with no flange as well. Let you know how it sounds after it’s all buttoned up. Thanks again Dave.
Fuel pump replaced. It was definitely the culprit. Engine noise is gone. Thanks everyone for your input.
davek
Well-Known Member
glad you got it Nick and now go smoke them tires 
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