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Fuel pump
Posted: Tue Apr 29, 2025 5:45 pm
by Duaneb
I'm having trouble finding a 63/69 fuel pump, all the listings say one pump fits 60/69. The 60/62 1/2 have a longer rod on the pump itself. Clarks is out of stock. Duane
Re: Fuel pump
Posted: Tue Apr 29, 2025 9:40 pm
by Lane66Monza
A longer shaft pump can be used in a LM engine requiring the short shaft. But it is either opening up the pump and swapping in a short shaft or trimming the shaft.
I have a long shaft pump that Bill Pritchard checked out this weekend and he said it was a good pump. He also mentioned it is a Delco pump. It is for sale, as I only use electric pumps. Ad to be posted as soon as I get it out of the trailker and take photos. I have to get the failed ones out to get the short shaft out for supplement to pump, if needed.
The fix for my pump to fit LM engines needing the short shaft is easy: grind the stem down a bit, until it is about 0.15" long from housing stem casting. But I can also supply a shaft from a frozen up LM short shaft pump, I will be scrapping.

- LM Fuel Pump Shaft Length.jpg (37.47 KiB) Viewed 219 times
Re: Fuel pump
Posted: Wed Apr 30, 2025 4:11 am
by jimbrandberg
I believe any aftermarket mechanical fuel pump you can find for sale today will be flawed. Internal leaks, external leaks, no locating hole and too much pressure are the top problems. I could be wrong.
Clarks is supposed to be coming out with one soon but we've been waiting for a few years.
Re: Fuel pump
Posted: Wed Apr 30, 2025 4:50 am
by Lane66Monza
I forgot to mention that Bill said the long shaft pump I have is a Delco pump. I will correct the other post.
Re: Fuel pump
Posted: Wed Apr 30, 2025 4:53 am
by toms73novass
Helped a club member try to install the available mechanical pump you can find now. Shortened the pump shaft, one lasted 2 days the other a week. Put the leaking original back in and it lasted till he had a electric one installed. New mechanical pumps are garbage....Hopefully Clarks pumps work out.
Re: Fuel pump
Posted: Wed Apr 30, 2025 5:13 am
by Dennis66
I believe I saw where Clark's now has them available - check with Clark's. However, a mechanical pump still leaves you with the carb bowl evaporation problem today's ethanol has. Because our carbs are vented to the atmosphere, the fuel in the bowls tends to evaporate after afew days, this means you are trying to start your car on empty carbs, meaning excessive cranking with a mechanical pump. For this reason, you might consider an electric conversion as many feature a priming feature or it can easily be added.
As a side note: Not being familiar with your car, you want to make sure there are NO rubber fuel lines in the engine compartment.
Re: Fuel pump
Posted: Wed Apr 30, 2025 10:20 am
by RexJohnson
If you need to shorten the rod coming out of the pump I would probably measure from the dimple, if it has one. If they can't make the rod the correct length, what are the odds they got the height from the dimple to the bottom of the casting correct?
Re: Fuel pump
Posted: Wed Apr 30, 2025 3:58 pm
by Wittsend
With the thought of, "Don't raise the bridge..., lower the river," it would seem some simple spacer rings would solve the "too long" rod problem. And it would make the "dimple" a moot point. Install the pump tighten the bolt (to mark), remove pump, drill indent. Even have a cardboard "Go/No Go" gage to determine the size (or number of) spacers. It seems so simple I'm surprised there isn't a "Sticky" for it.
I know, I know..., if it was THAT easy why haven't I done it? Ahhh..., electric fuel pump is also easy and as already mentioned solves the fuel evaporation problem.
Re: Fuel pump
Posted: Wed Apr 30, 2025 5:36 pm
by Lane66Monza
Or change shaft with a known proper shaft from failed short shaft pump.
Re: Fuel pump
Posted: Wed Apr 30, 2025 10:12 pm
by Frank DuVal
Or change shaft with a known proper shaft from failed short shaft pump.
Shaft is crimped to the rubber diaphragms, so changing the shaft means using the failed rubber diaphragms.
Re: Fuel pump
Posted: Thu May 01, 2025 4:47 am
by Lane66Monza
Thank you ,Frank. I didn't know the insides of a good pump. The pumps I scrapped, the shafts were not attached.
Now I don't have to look for the frozen pumps in the trailer I took to Helen. Just have to locate the good long shaft pump in one of the bins in the trailer.
Re: Fuel pump
Posted: Thu May 01, 2025 9:20 am
by RexJohnson
When it takes just a couple of minutes to measure and grind off the rod why would you to do it any other way?