310 valve lifter does not rotate

I discovered I have a valve lifter not rotating on my 1855. It's right behind the cover were the fuel pump would go. It's free and goes smooth I can spin it by hand when the tension is off. However it will not spin when running. Lifters are new from AGCO, the cam was used but checked and polished by a local shop. Engine has 17 hrs on it with 30wt break in oil. I just changed it to 15-40 synthetic. Should I worry about it or just run it? I did find a few metal specs in the filter and didn't find a source.
 
I can't specifically address that engine, but the lifter not rotating would concern me.

Here's a quote from Crane Cams...

"Lifter rotation is created by a taper ground on the cam lobe and the convex shape of the face of the flat tappet lifter. Also in
some cases, the lobe is slightly offset from the center of the lifter bore in the block. If the linear spacing of the lifter bores in the block
is not to the correct factory specifications, or the angle of the lifter bore is not 90 degrees to the centerline of the cam, the lifter may
not rotate.
Even if the engine you’re rebuilding had 100,000 miles on it and the cam you removed had no badly worn lobes, this still doesn't mean
that your block is made correctly. It just means that the break in procedure caused everything to work correctly. Be careful to watch the
pushrods during break in to verify lifter rotation. Don't assume everything will work correctly the second time."

Below is a link to the entire document, (which is geared toward automotive engines, but I would think the same principles would apply here).
Why cams fail
 
IF IT WAS MINE, I'd worry about it. The top of the lobes of a camshaft are not parallel to the base of a camshaft, they taper down so that the lifter will spin. I would recheck the lobe.
 
I'd worry about it. Without proper rotation, the cam follower interface won't develop proper hydrodynamic lubrication which will gutter the follower and ultimately lead to failure.

The quote that was posted is spot on...there needs to be proper crown on the follower and taper on the cam.

The polishing is interesting, but would be pointless if the taper has been worn away. I suspect your cam was worn flat or had a slight dish to the lobes. Couple that with new followers which have crown and you'd have a lack of rotation. Note that your cam may still have proper lift but no taper. The taper is very slight.

I've had very good luck with Oregon Cam Grinding. Might want to hit them up to have them grind your old cam. You'll want to evaluate the condition of the follower that didn't rotate, but if it was my engine, I'd just replace it.
 
I will tear it down again and get the cam rebuilt or hopefully I can find a new one. That lifter will be replaced if not all of them again and recheck the lifter bores. There could be other lifters not rotating, I can only see 2. Oil started bleeding out the turbo elbow tonight. Turns out the turbo bearing went bad. Probably the source of some of the metal specks in the filter. It was good or at least it felt good 17 hrs ago. Now to determine what caused that. The turbo never did sound quite right. Thanks
 
Adam,
How would you know that the lifter is not rotating? you cant even see that thing down there.
Just because the push rod might not be rotating don't mean the lifter doesn't.
Maybe the push rod has a wee bend in it or the ball insert in the bottom of the rod is loose and rotates in the rod.i would check that first.
If the cam lobes are within specs and polished and the lifters are new i would not worry about it.
 
There were problems with the original design of the camshaft and a change was made in the camshaft. The failures would occur in the area you are talking about. I would have though by now if the early cam was going to fail it would have failed before now. Do you have a good shop that can grind cams and or resurface lifters near by?
 
I was changing the oil and found metal specks in the
filter. So I started inspecting any thing I could
see in the crank case with a scope. I pulled off the
cover where the little mech fuel pump would mount (
this engine does not have that pump) and can see 2
lifters. I started the engine with that off and
discovered it. This cam was inspected by the same
shop that inspected the other cam and that has me
worried. Did you ever find a good cam?
 
This is the later cam. Looking for a shop now. May just go with the one listed. Don't know when I will get it out. Need to get the combines going first.
 
(quoted from post at 06:37:08 09/11/14) I was changing the oil and found metal specks in the
filter. So I started inspecting any thing I could
see in the crank case with a scope. I pulled off the
cover where the little mech fuel pump would mount (
this engine does not have that pump) and can see 2
lifters. I started the engine with that off and
discovered it. This cam was inspected by the same
shop that inspected the other cam and that has me
worried.[b:59c642fe3e] Did you ever find a good cam?[/b:59c642fe3e]
dam, i never found a good camshaft, all the shafts i found at the wreckers had one or more worn lobes.
So I had both mine and the cam i got from you rebuild by Oregon cam grind in WA at a cost of $250 a piece incl freight both ways.
I still have to put the engine together though.

The other cam may come in handy someday when i do the much needed rebuild in my other tractor.
 

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