4010 diesel upper rap ('63 vintage)

There's a constant light rap seemingly consistent with a valve. It doesn't come and go.

meter shows 1586hrs, no doubt 2nd time around...

disconnected and ruled out water pump, alternator, fuel pump ... didn't try hyd pump yet but doubt it's that...

With stethoscope i can pick it up in the front timing cover, supposedly a ventilator pump in there, but it's more predominately heard in the upper engine area near the front... does not act like a rod bearing, no difference in sound whether engine under load or not, nor whether accelerating or decell... and doesn't sound like a bad piston wrist pin would...

reset valve rocker clearances per shop manual method, no difference... gaps were hardly off.
does that rule out a bad lifter or cam lobe?...

oil pressure 55-60psi at oil pump port, however, it took a few seconds for oil to seep from valve rocker holes when engine was started.. I've known engines to shoot an extreme amount from the rocker shaft (soaking everything within a few feet), and some engines have a lighter but obvious flow.. this 4010's rockers were hardly seeping at best, even at high rpm's.. Is this delayed & slighted flow normal for this engine? ...

I'm suspecting an oil passage blockage somewhere to the upper end.. Would like to get a test gauge up there but appears to be no port... But the sound & location is still a mystery and also what caused the sound in the first place...

oil/filter change about 30 hours ago, Deere dealer-installed 15W-40 diesel lube... no idea when previously done (recent purchase)nor what was in it before... have recently received an old original manual saying engine should have straight 30W. Is a dealership that would put 15W-40 in it looking for future engine failure?
At dusk I have noticed occasional sparks from the muffler.. at first believed it was old carbon burning off (tractor was light-duty work until now) but those sparks have been there for a few weeks now... Tiny pieces of valve? So far engine runs smooth as silk.

to recap, two questions asked...

1: is a hardly-noticeable seepage of oil from the rockers considered normal flow for these engines?

2: anyone else had or solved a similar mystery rap in their 4010/20? It's not as loud as a rod, but a little louder than the valve action..

Very reluctant to put it back to hard work, but I'm not finding anything

Have you tried using a stethoscope or wooden dowel rod to isolate where noise is coming from? Possible piston/liner galling problem.

Lifter? Don't think they have such. I never tore into my 10, but my 20 didn't have them. Cam lobe? 1500 hrs, doubt that too. But due to the age, you probably nailed it that it is a roll over.

On a cam lobe, it would be worn off on the top and the rocker for that cylinder wouldn't depress that valve as far as the one adjacent to it did. Other thing, if a lobe, with no lifter, when you set your gap, you set it to the worn lobe so I would forget that.

Might have a weak spring, crud on the valve stem/guide, or an irregular metallic interface that could be caused by the rocker and stem not being in proper alignment. The rocker would be the problem and the valve could slip off the ridge and smack the non-ridge and make a tick.

If interested I could walk you through the process for checking this out with the head intact.

Mark

(quoted from post at 08:33:38 07/06/12) Lifter? Don't think they have such. I never tore into my 10, but my 20 didn't have them. Cam lobe? 1500 hrs, doubt that too. But due to the age, you probably nailed it that it is a roll over.Mark

Click to expand...

Mark
If you're referring to a cam follower(parts key #23) as a "lifter" then yes both 4010 & 4020 engines have them.

Well, in the sense of self adjusting hydraulic lifters my answer
was no.

I realize that you have to have an interface element between the
rod and cam lobe, but we used to refer to these as "solid lifters"
requiring an adjustment screw on each rocker. On a solid lifter,
cam follower, if the end was beat in, then the variance should
have been compensated for in the adjustment process just as
the cam lobe variance would be.

Mark

yes did listen with a large screwdriver and also a stethoscope .. as with deisels, a lot of noise everywhere making it hard to pinpoint location...

going to bale with it today, perhaps 3 hours.... keeping a close ear and fingers crossed it doesn"t get worse before 1st cut is done ... 40 acres remain after today is done

It could be a broken wrist pin We had one break on 1 of our 4000 tractors.

nobody has answered about the very-low-flow of oil at the rockers ... is this flow amount normal? It took almost a minute for it to begin pooling