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.)

[flatheadmurre]

Just don´t make it to narrow...wear will fast become an issue if the surface gets to small.

[Bored&Stroked]

Well - at least you found it! I've seen this a few times myself - which is why I always check the cam bearing alignment when I get a block back from the machine shop. I have a cam bearing installation tool, so I just ensure they are in the right spot.

I would not worry about the cam bearing spinning - the problem was caused by installation at the machine shop - most likely the bearing is too far back. Also, I would not worry about the other cam bearings - you're probably just fine.

Since you don't want to pull the engine and 'fix' it, I guess your method of grinding the fuel pump push rod will have to do. I would probably grind a flat on the one side - so you can leave as much of it as possible contacting the cam. I doubt that the shaft actually spins - as I've seen patterns worn in the tops of them quite often. The only down side is that you'll obviously wear a funny pattern into the cam eccentric and the push rod might wear a bit faster than normal. Heck, give it a try and maybe check it after 500 miles and see what it looks like . . . you can always decide to pull the motor and 'fix' it later on - if you don't like what you see.

Good luck!
B&S

[Charlie ny]

Not easy to say but I'd pull the motor and return it to the shop. Grinding is not an
option as far as I'm concerned. That push rod must SPIN not just go up and down.
To clear the 3/32 you'll have reduce the WORKING end of the push at least 3/16.
Charlie ny

[Capt Kirk]

As Charlie said, if the intrusion is 3/32, you'll need to reduce the pump shaft diameter by 3/16...that's a lot. I'm not sure what the normal shaft diameter is but if it's 3/8" diameter and you reduce it by 3/16, you'll end up with a 3/16" wear surface on the rod. I'd be nervous about that. With the cam bearing misaligned by 3/32", the oil hole may be reduced resulting in less oil to the bearing. It would be a shame to spend your days driving the car with a constant thought about if/when something is going to go wrong. There is the right thing to do and the easy thing to do. The right thing to do would be to have the shop fix their screw up and enjoy worry-free driving. The easy thing to do would be to install a good quiet electric fuel pump and leave the rod out.

[Bored&Stroked]

On second thought, I should have read your last post a bit better . . . as I was thinking 1/32. If it is really 3/32, then the hole is about 1/4 covered up already . . . so there will be a lot of grinding and how much of the pushrod end will be left? I'm sure it will wear a lot faster . . . and it will ruin the eccentric lobe on the cam - such that you'll NOT be able to ever put the correct pushrod on this particular cam. Also, will it wear at a fast rate and maybe sluff of metal filings into the engine? Who knows. The more I think about it - the more it seems like a problem waiting to happen.

Since you paid a machine shop to build the engine, they should fix it for you -- it is not your problem (so why take it on). Truth be told, they should pull the engine for you and fix it.

The other option is to go to a Plan B and run an electric pump and NOT run the mechanical. I'm sure the machine shop would like this approach (and they should pay for the pump if you go this route) - but it is an option.

If it was mine, I'd probably have the machine shop fix their work.

D

[Frank Miller]

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This is not the place to come looking for the easy answer when you know the hard one is right. Charlie said something about the pushrod needing to turn. Not sure it does but if it is inclined to and can't you just created a wear point where metal of some sort will be deposited to your cam bearing. I am not a fan of electric pumps but admit there are advantages. I just like original even though I caved with electronic ignition when I got two bad condensers I paid top dollar for.

[JWL]

I'll say this for what it is worth----I have found more than one engine where the cam bearing was slightly misaligned and "someone" hammered the pushrod through to contact the camshaft. In all cases it did NOT seem to be a problem except for me when I tried to remove the camshaft because a small lip was bent over in the bearing I.D.

[drolston]

The shop turned the end of the rod down by .07" diameter, leaving .314" diameter contact surface on the cam. Pretty sure the cam surface is very slightly inclined to impart a rotating moment to the push rod. I will index the push rod on the skirt and run it to see if it rotates.

I figure the worst thing that can happen is the push rod wears down faster than normal. My push rod probably has over 100,000 miles on it ant it still exactly the specified length of 8 7/8". That rod is pretty hard stuff; it took a carbide bit on the lathe to cut it.

Thanks to all for the advice. I will report to the forum if this solution turns out to be a problem.

[supereal]

The rear cam bearing has holes in the top and the bottom of different sizes. If the push rod doesn't drop into the hole, it is likely the bearing was installed upside down, easy to do when the engine is upside down on a stand.