Fuel Pump Push Rod not Pushing

[drolston]

I usually prime with the electric fuel pump and run on the mechanical, just so I don't have to listen to that buzz. While testing the rebuilt 59A/B recently reinstalled back in the car I found that it would not keep running on only the mechanical pump. Running at idle, I listened to the pump with a long screw driver; no pump cycle sound. Cranked the primed pump with the fuel line off; zero flow. The pump spring compressed when I installed the pump, and decompressed when I took it off, so the push rod is the correct length (8.75"). The same manifold and push rod worked fine on this engine before the rebuild.

Is it really possible that Schneider Cams forgot to grind the eccentric for the oil pump! Is there anything else that could cause this problem?

[flatjack9]

Remove the fuel pump and crank the engine to watch for movement. It only moves .20 inches.

[51 MERC-CT]

As stated, The pushrod should move appox. .200" in one revolution of the cam.
If it does then you most likely have a bad fuel pump.

[drolston]

Should have mentioned: With the pump off I cranked the engine with my finger on the push rod. No movement. Not even a vibration.

[JSeery]

Originally Posted by drolston

Should have mentioned: With the pump off I cranked the engine with my finger on the push rod. No movement. Not even a vibration.

That should answer your question.

[FlatheadTed]

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Remove it and try a longer rod like 1/4 stock Ted

[drolston]

The rod is the right length. It worked before on the same block and manifold. I had to compress the pump spring when tightening down the pump to the manifold. With the fuel pump off, I turned the pushrod upside down to be sure the rod wasn't bottoming on the flare thing. Still no motion when cranking.

Is there anything else besides no eccentric on that fuel pump lobe on the cam?

[FlatheadTed]

Use the rod like I said and put your ear to it.Ted

[51 MERC-CT]

Originally Posted by drolston

The rod is the right length. It worked before on the same block and manifold. I had to compress the pump spring when tightening down the pump to the manifold. With the fuel pump off, I turned the pushrod upside down to be sure the rod wasn't bottoming on the flare thing. Still no motion when cranking.

Is there anything else besides no eccentric on that fuel pump lobe on the cam?

Being "recently rebuilt" sounds like (but hard to envision) the push-rod may be hanging up on a misaligned cam bearing.
As previously stated use a smaller dia. rod that will go past any obstruction to test for movement.

[flatheadmurre]

If it´s stuck on the cambearing it should be way up...groove plus bearing shell must be a bit over 3/8 would be a pain to install the pump that way ??
I agree with previous poster, get a smaller rod and test for movement.
With the fuelpump stand and oiltrap out you should be able to look down into the pumprod bushing to see if there´s anything odd.

[Bored&Stroked]

Either the pump rod is too short, or it isn't going all the way down (due to the cam bearing being incorrectly aligned), or the cam has no eccentric ground into it. Should be easy to figure out the issue - though you may not like the results!

[Kube]

Originally Posted by FlatheadTed

Remove it and try a longer rod like 1/4 stock Ted

...

[51 MERC-CT]

Originally Posted by flatheadmurre

If it´s stuck on the cambearing it should be way up...groove plus bearing shell must be a bit over 3/8 would be a pain to install the pump that way ??
I agree with previous poster, get a smaller rod and test for movement.
With the fuelpump stand and oiltrap out you should be able to look down into the pumprod bushing to see if there´s anything odd.

Did a check and found that when the pump lobe is at it's highest point the push rod end resting on the lobe on an 8BA is 1/4" from the OD of the bearing.

[drolston]

Thanks for the suggestions. It turns out that the cam bearing is intruding into the fuel pump push rod hole by about 3/32". Cranked it with a slim screwdriver down the hole and it moved up and down as expected.

John at the machine shop was worried that the rear cam bearing may have spun in its housing and slipped aft. That raised the specter of oil not getting to the rear main, but then we remembered that the rear main gets its oil directly from the pump, versus from the center and front mains which get oil from around the corresponding cam bearings. Great pains were taken with the cam installation to be sure the front and center cam bearing holes were exactly aligned with the main bearing oil passages. Do those ever slip out of alignment, once installed? Is there any way to check?

The oil pressure gauge on the dash is reading low (20 PSI at Idle, 25 at higher rpm), raising fears that something went radically wrong between the test stand and the 30 break-in miles logged so far. So, I re-checked pressure with a mechanical gauge. The mechanical gauge showed 40 psi on the starter motor and 80 running. Whew!

Unless someone on this forum thinks having the rear cam bearing a bit too far aft is a big concern, we are going to turn down the diameter of the bottom 3/4" of the pushrod by about 1/8" so it can get past the cam bearing to the fuel pump lobe on the cam. Thought of just flattening one side of the push rod, but I think the rod is supposed to rotate, same as lifters.

Clearly I have an 80 PSI oil pump (46-53), versus 50 PSI (35-42). The oil pressure indicator on the dash has 50 PSI as the top reading. Should I order the 80 PSI sender, or the 50 PSI. I am thinking 50, so the dash indication is correct, but worry a bit that the indicator will spend a lot of time pegged at the high end. I don't suppose that will harm the instrument.

Do I need to worry about the other cam bearings?

Comments? Advice?

[JSeery]

The only one who knows how well the rear cam bearing was aligned when it was installed is the one who installed it. He is also the only one who knows how snug the cam bearings were in the block and likewise how free the cam was when it was installed. All of this is a little difficult to determine now.

[flatjack9]

I have never seen a cam bearing move. I think it is clearly improper installation.

[drolston]

Will consult with the shop regarding how the bearings and cam went in.

In the mean time, is there any downside to running with the rear cam bearing a bit aft, if the front and center were properly aligned with the oil passage holes?

[JSeery]

I would say no, one method of blocking off that area is to deliberately rotate the rear cam bearing on install

[Overkill-F1]

When I disassembled my C1BA block, the camshaft would not pull out. The rear cam bearing was installed a couple of degrees out and it was partly blocking the push rod. The PO must have hammered the push rod down because he bent a bit of the cam bearing into the space between the two rear journals to make way for the push rod.
...Terry

[51 MERC-CT]

If the engine was out of the car it may be possible to remove the rear cam cover plate and idler gear. Then using something like an old cam bearing with it's OD slightly turned down (for loose fit in block), hammer the miss-aligned bearing forward.
Turning down the push rod is at this point the simplest solution to the problem. (but don't recommend it.)