The Stovebolt Site Forums The Shop Area Engine Shop Rattleing from the oil pan

I have just rebuilt a 1954 235 engine and everything is going well except for a rattling sound in the oil pan making a racket around 1300 rpm. The engine runs great with 40+ oil pressure and vacuum above 20 pounds
I checked everything on the bottom of the engine and everything is torqued properly and is solid except the oil pump screen pick-up. The oil pump is from a 1956 235 and has a movable screen that rotates freely through around 10 degrees.
I suspect this screen is causing the rattling .
Has anyone had this problem before?

I've never heard anything like that before but I'd pull that pan tout de suite. You don't want the oil pump falling off while you're driving.

Does it sound like something loose rolling around in there or is it a a vibration?

I have pulled the pan a couple of times looking for the cause of the rattle. Everything is to torqued and is solid except that oil-pick-up screen which will move freely up and down a few degrees. Is it suppose to be free like that?

Use the carburetor idle speed screw to set a steady fast idle speed that causes the noise to happen, and disconnect spark plug wires one at a time. I'd suggest pulling the wires at the distributor cap instead of the plug- - - -less chance of getting bit by high voltage that way. If the noise stops, or makes a noticeable change when a specific cylinder is disabled, go looking for a loose connecting rod bearing or a cracked piston at that position.
Jerry

Hi Jerry,

The engine is running on all cylinders and sounds great except for that rattle. I checked all rods and they are at torque and solid along with new pistons.

Is that oil pick-up screen suppose to be completely free through a few degrees like that? If so, wouldn't they make some noise?

'd still pull the plug wires one at a time and see what happens.

Any chance the baffle inside the block by the road tube has worked its way loose?

The oil pan was in bad shape when I started and the front baffle is missing. The rear baffle is solid.

The floating pickup is correct for some late model engines. I don't remember exactly when the change was made, but it was somewhere in the late 1950s, I believe. It shouldn't be rattling under any circumstances. Is the screen in the pickup able to flow oil freely at higher speeds (not restricted or clogged)? You could temporarily lock the floating pickup with a piece of stiff wire or a hose clamp to positively eliminate it as the source of the noise.
Jerry

I get strong oil pressure at all temps and RPMs so it is flowing oil freely.

I do have the engine on a stand and am listening to the engine very carefully. Maybe the noise is nomal. I will give it a shot to lock it down just to make sure thats causing the sound.

Thanks Jerry.

I found my problem. The timing was set too advanced.

I had used the vacuum gauge method to set the timing by :

-Run the engine to 2000 rpm

-Set the advance to max vacuum reading then retard the timing until the vacuum reading drops 2 lbs.

That certainly did not work for my engine. Way too advanced.

This came up to me when I was sleeping last night. This does not reflect well to me as I do my best thinking when I'm sleeping.

All is well again.

Setting ignition timing by vacuum is about as accurate as:

Measure with a micrometer
Mark with chalk
Cut with an axe!

An Innova delay flash timing light is well worth the one time cost, especially if you melt the pistons on a couple of engines making a SWAG on timing! On at least a dozen dyno runs, I've discovered that one degree too much ignition timing robs as much power from an engine as 5 degrees retarded from the "sweet spot".

Jerry

bosco24 - Glad you got it figured out! Some of my best thinking is done like yours. My problem is "will I remember it in the morning" - LOL!

Measure with a micrometer
Mark with chalk
Cut with an axe!

Yes , I learned that the vacuum meathod is not the way to do it. An Innova delay flash timing light is on order,

By the way, why does a 1954 235 have the timing mark at 2 degree after TDC verus 5 degree before TDC for 1956 and later 235s?

On your timing question, the factory timing is different between the years and also the location i.e., Canada. But there are other variables. First, is the flywheel original to the block? What part number is the distributor you are using?

By the way, 55-57 pass car oil pump pickups were generally not the floating type. Fixed to the tube. Always exceptions although I was always under the impression the floating type was earlier. 55-57 was one part number, 58 was another, 59-62 was another. I would have to check my 59 parts catalog to see if the trucks got different pans and pickups.