Oil pump fit to block

gilitos

gilitos

Senior Member
I'm chasing a low thumping knock that comes and goes. It mostly shows up under load in high gear when cold, but it's not always there. So I'm reviewing my bearing clearances, etc. The new Burlington crank and babbit only have a few thousand miles on them, installed by (the late) Herm Kohnke. I have suspected that the sound may be related to the distributor drive (although I'm checking everything I can think of). I notice that the oil pump fits rather loosely into the block. When fully seated in the block it can wiggle back and forth a couple of millimeters (measured at the end plate). Is this much play normal? Seems mighty floppy to me an I could see it as a source of noise.
 

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The whole dist./oil pump gear set up is a tad loose normally I think. But it generally will just up and down which is what you may be hearing. My car has a drum at 47/48/49 MPH. I think it is pretty well locked in front to back. Just my 2 cents. Also, check your water pump to make sure it is not loose front to back.

Mike
 
Is the locating pin on the base of the pump still there ? Without it in place the pump could rotate enough to make a noise
Don S
 
The spring holds the unit in place the side clearance is a negligible factor. a weak spring can cause a noise maybe.?
 
Regarding the possibility of a loosely attached oil pump consider removing the pump locating pin and drilling it out for a machine screw. Drill and tap the pin hole in the block to accept a screw. My Burtz engine uses this method for attaching the pump. It also eliminates the need for the spring.
 
CT Jack said:
Regarding the possibility of a loosely attached oil pump consider removing the pump locating pin and drilling it out for a machine screw. Drill and tap the pin hole in the block to accept a screw. My Burtz engine uses this method for attaching the pump. It also eliminates the need for the spring.
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Wow that's a great idea and I wish I had seen this post before I ordered a new pump today......I mic'd the block and the hole for the oil pump was right at 0.937-0.938 (basically unworn) but the pump housing was ~0.930 and not round. A rather loose fit. But I should have just installed a retaining screw rather than spend >$200 for a new pump!!
 
gilitos said:
Wow that's a great idea and I wish I had seen this post before I ordered a new pump today...... >$200 for a new pump!!
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Don't toss the old one 'cause there is really nothing wrong with it. The pin is just there to keep it from spinning.
 
did you use a stethoscope to locate the area of the knock?
soo many things in there to make that noise.

if you make a fitting with a bolt through it and install at the external oil gallery of the block, (i think they actually sell something like that to hold the pump so i doesn't fall out when pulling the oil pan). that may anchor the pump.
but
Replacing the locater pin with a bolt is a good idea and easy to do now the engine is out.

And what about the cam gear set, are they new?

ps. that is a nice looking engine.
 
one more thing.
you say mostly under load in high gear.
is there a chance it may be a ****** or drive line noise.
did you drive it with the floor boards out?
 
My first thought was spark knocking which occurs under a load , BUT the op has the engine out of the car ! Many things can cause spark knocking
 
CT Jack said:
Regarding the possibility of a loosely attached oil pump consider removing the pump locating pin and drilling it out for a machine screw. Drill and tap the pin hole in the block to accept a screw. My Burtz engine uses this method for attaching the pump. It also eliminates the need for the spring.
Click to expand...

I would consider drilling a hole through the head of the machine screw and using safety wire.
 
You might want to know why Ford used a spring instead of a bolt. It would have been cheaper to build without the spring and retainer. I was told by an older fellow that the spring acted as a pressure relief in cold weather with thick old oil. I don't doubt there was some good reason for it.
 
J Franklin said:
You might want to know why Ford used a spring instead of a bolt. It would have been cheaper to build without the spring and retainer. I was told by an older fellow that the spring acted as a pressure relief in cold weather with thick old oil. I don't doubt there was some good reason for it.
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I recall a previous post regarding a thumping sound that came from an "A" engine under varying conditions that was traced to an oil pump spring that was weakened by rust. The spring was replaced and the thumping went away. The pump will move up and down due to fluctuations in oil pressure and the spring controls the movement.
 
Echoing "ursus'" suggestion, years ago a friend brought me a 1929 Tudor he had recently purchased that had a knock in the engine at all speeds, especially at idle. It sounded for all the world like a loose rod bearing. Down came the oil pan. A disgusting, messy job if you haven't done this yet. Laboriously adjusting the rod bearings resulted in only a modest decrease in the knocking in this supposedly rebuilt engine. I pulled off the timing gear side cover and hand-cranked the engine over to inspect the timing gear teeth during the gear's 360 degree arc. Nothing wrong was noted, no broken teeth and the gear was tight on the camshaft. After checking other traditional causes of engine knocking, I finally pulled off the valve cover. While "ursus" recalled reading about a weak oil pump drive housing spring causing a knocking noise, I found no spring whatsoever! NONE!!! Zip. Zero. Nada. Nichts. Gone, Baby, gone. Grumbling, I replaced the missing spring and guess what! The engine didn't knock anymore. How could anybody be so stupid as to leave out this all-important spring when assembling the engine? It's not exactly something one could overlook in a box of left-over engine parts, such as a small headlight socket adjusting spring. It's BIG!!! I mean, didn't a previous owner hold the spring in his hand after the engine had been assembled and wonder where in the heck that came from? What did he do? Toss it because he didn't know where it was supposed to go? Brilliant! Yeah - All these years later I'm still a little p*ssed because of all the fruitless and painful work lying on my chronically sore back I had to do to find the source of the knocking - and it all came down to stupidity and ignorance at the worst and lack of attention to detail at best. Good grief! Saints protect us from idiots "restoring" Model A's!
Anyway, grousing aside, if all other sleuthing efforts to uncover the source of the engine knock fail, take the time to pull off the valve cover and make "ursus'" and my day by verifying our mutual experience with the distributor drive gear housing spring. You can make something foolproof, but you can't make it damn foolproof!
Marshall
 
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Hey everybody: I love the ideas and comments.


I first opened up the motor to check bearing clearances. There's only a couple thousand miles on new babbitt. (Herm Kohnke poured and fit them). Rods, front and center mains were all at 0.0015" via plastigage. Rear main was between 1.5 and 2 thou. So I didn't mess with the shims.


First picture shows the locating pin pressed out of the pump (0.250" diam.) next to the hole in the block (0.280"). 0.030" difference in the diameter. I turned a new one of the right diameter (next photo) so the slop is gone and we'll see what happens when the motor is back together and installed.


The cam plunger spring was too weak to reliably return the cam to its rearward position so I replaced it. Let's see if some combination of all of this has an effect on the slight knock I was hearing.

The third photo is for you, Marshall! Upon disassembly I did find the spring installed.
 

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old ugly said:
one more thing.
you say mostly under load in high gear.
is there a chance it may be a ****** or drive line noise.
did you drive it with the floor boards out?
Click to expand...

Dang I love the suggestion to drive with the floor boards out to help locate the noise source. As part of this 'exercise' I rebuilt the transmission and confirmed a good U joint and splines.
 
i am disassembling a 1930 engine rite now. guess what i found? the engine rebuilder made a shim that fits in beside the oil pump to take up the issue or too much clearance.

i find it strange that we just start talking of this issue and it shows up rite on my shop floor. if i remember i will post a picture tomorrow of how that shim was in there. weird.

one more thought on the oem spring, i am wondering if ford did not want that pump in there solid, some movement, maybe why a spring was used. just thinking out loud.
 
I had same issue, the combination of a installing a new oil pump spring and I made a brass bushing to take up the difference between the pin diameter and the hole in the block ( was .060 difference). Noise completely gone.
 
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