fuel pump push rod stroke

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Jumprun
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fuel pump push rod stroke

Post by Jumprun »

Does anyone know how much total stroke the fuel pump pushrod is supposed to have? this is the rod driven off a cam in the engine.

Thanks and Regards, --Tom in So Cal.
Timo
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Re: fuel pump push rod stroke

Post by Timo »

I don't, but if accessible, you might try to measure the offset travel of that pump drive lobe on camshaft.
Timo
Jumprun
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Re: fuel pump push rod stroke

Post by Jumprun »

I have already measured the stroke on mine but I was wondering if anyone knows what the specification is or even what theirs is.
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tyang
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Re: fuel pump push rod stroke

Post by tyang »

I've measured a bunch, and found 2.5-3mm of total travel. Not a lot of mechanical advantage, so making sure you're using every bit of it is crucial. On the 330s the mechanical pump pushrod is operated by an eccentric cam driven off the oil pump gear.

Tom
'63 330 America #5053
Jumprun
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Re: fuel pump push rod stroke

Post by Jumprun »

Thanks Tom, the travel on mine is exactly 2.5mm, it also seems to cycle at half the crankshaft rotation.

I had an interesting failure after doing some work on my mechanical pump that developed a minor leak. I also needed to flatten the warped mounting flange and phenolic spacer by sanding flat and parallel, this must have removed too much material because when I re-installed it the pivot pin snapped in half! I would have thought that the pivot plates would bend first. I also observed that this pin that broke was hardened steel but my original one was mild steel, so I replaced it with a mild steel one and used a slightly thicker gasket on the flange. This fix seemed to work after a vigorous test drive but it's difficult to trust something that has such a narrow operating tolerance.

Tom in SoCal
Jumprun
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Re: fuel pump push rod stroke

Post by Jumprun »

To clarify, the push rod seems to cycle once for every 2 crankshaft rotations.
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