Oil Pump Knock?

[Dick Deegan]

Last winter I refurbished my engine. I removed the engine and adjusted clearances on mains and journals, lapped valves, deglazed cylinders, replaced rings etc. etc.

I have developed a significant knock in the engine in the middle around the oil pump, center main area. I checked the location with a stethascope. I don't think the knock is coming from the center main since I was very fussy when adjusting the clearances. The knock is very noticeable at idle and does seem to lessen or disappear when the engine is under load like going up a hill.

I do recall that the gears on the oil pump were a little sloppy. Would a worn pump create a knock?

Any other thoughts?

I am dropping the oil pan tomorrow.

Dick

[Special Coupe Frank]

Dick,

I'm not going to argue with where your stethescope seemed to locate the knock, but I myself can't figure-out what there is in the oil-pump / drive that would cause a knock...

I DO know that a stuck / failed cam plunger or spring in the timing cover will allow the cam to "walk" back & forth in the block, and THAT sounds like a really heavy bearing knock...

Before you drop the oil pan, try pulling the side-cover from the timing case and let the engine idle ( don't rev it, our you'll have an oil-fountain! ). Watch the cam gear and see if it moves fore & aft along the camshaft axis...

I may be wrong about not understanding how the pump could possibly be the source of a knock, but I know from my very own experience that failed cam plunger WILL cause a knock like a spent rod -bearing... and it's easier to check-out.

Good luck !

SC Frank

[Dick Deegan]

Frank;

Thanks for your reply. I did in fact check out the plunger and spring before and replaced both. I did drop the pan early this morning (before I got your reply). The oil pump seemed fine and I think that you are correct - there is nothing in the oil pump to cause a knock.

I think that I found the culprit - two loose journals. The worst one was #3 where I took out 0.006" from each side of the shims. #4 was also loose, but I only took our 0.003" from one side.

I'll button it back up this afternoon and see it the knock is gone.

Thanks again for your advice.

Dick

[Purdy Swoft]

A weak spring on the bottom of the pump may cause a knock. Ford didn't use a gasket under the bottom plate of the pump. The gasket is supplied with the oil pump rebuild kits to give clearance if the new gears bind on the bottom plate of the pump. Inspect the bottom plate for wear where the gears have made contact. If wear is noted on the lower plate, either turn it over or replace it. It is best to not use a gasket under the lower plate unless there is a bind. The pump will actually perform better and produce more pressure, without the lower gasket. I would check this out while the oil pan is off.

[Special Coupe Frank]

Regarding the oil-pump spring: inspect it VERY carefully with a strong light, after cleaning-off with carb or brake kleener.

Look for signs of acid pitting / corrosion.

I have a '29 engine pulled-down for inspection, and the pump spring broke right-off at the clamp when I accidentally snagged it with a rag; where the spring broke was all eaten away by crankcase acids.

New springs are cheap compared to a babbit job.


Keep us posted, Dick !

[Brian T]

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Just a thought, ---- you say you previously adjusted the rods and now find they are loose, make sure you have the rod dippers facing in the right direction.

[kelley's restoration]

did you put a new oil pump drive/dizzy drive in at the same time (gear off the cam)
these have been known to be poorly machined
tk

[Dick Deegan]

I did. All point towards the cam shaft.