4020 Deisel engine

So I have a 4020 and I think a rod is knocking,
has many hours on it and the knock shows up at PTO speed. I only put a bout 50 hours a year on the tractor a year and wanted to wait another year before a major overhaul.

Is it possible to do a the bottom end with out taking the engine out ?

Thanks Robert

In many cases, yes. All depends on what is actually doing the knocking, and why. If it IS a rod bearing, and the rod journal still looks relatively good, a new standard bearing, or a .002" undersize may work fine. The .002" under bearings are made just for this purpose, i.e. tigthening things up without a proper rebuild. Deere still sells them.
Obviously, if your engine already has an undersize crank in it, you can't do this. There are .002" under bearings to be had, but I've never seen a ,.012", or .022", etc.
We've fixed a lot even then the crank-pins were scored and a little out of round. Cleaned up with emory cloth and installed a undersize bearing. But, it cannot be excessively out of round or gouged. Check clearnace with Plastigauge when you assemble.
One other note. Look at the rod end carefully, once the bearing is out. If it looks as though the bearing-shell was moving a big in there, the rod needs to come out and get resized. High-hour 4020s with loose bearings tend to knock the big-ends of the rods out-of-round. When that happens, they have to shaved, closed up, and honed back to OEM size.

That all being said, you might have a loose piston pin and not a rod bearing. If so, there's no way to fix without a tear-down.

You sure it isn't the hydraulic pump drive coupling ?They can sound like a rod knocking if very bad.

JD,

I gotta cry "hogwash"! :>)

I saw a feller try that one time on a car. Only he just put in .001" undersize "to take up the slack".

Tried to tell him, but he just wouldn't listen. Said, "My grandpa told me how to do it." :>(

Anyway, she made it 16 miles before the old car thru every rod in the engine. :>)

The methods used to "fix" the old Model A(s) just do not work on an inserted engine because the oil clearance is only a thousandth or so to start with.

Ya cancel that out with an undersized bearing shell and you have absolutely NO lube cushion whatsoever. Metal to metal just doesn't last too darned long.

Allan

JD,

I gotta cry "hogwash"! :>)

I saw a feller try that one time on a car. Only he just put in .001" undersize "to take up the slack".

Tried to tell him, but he just wouldn't listen. Said, "My grandpa told me how to do it." :>(

Anyway, she made it 16 miles before the old car thru every rod in the engine. :>)

The methods used to "fix" the old Model A(s) just do not work on an inserted engine because the oil clearance is only a thousandth or so to start with.

Ya cancel that out with an undersized bearing shell and you have absolutely NO lube cushion whatsoever. Metal to metal just doesn't last too darned long.

Allan

This has little to do with Ford Model As (1st or 2nd versions).

If a person knows what he and she is doing, .001" and .002" under bearings can often work out fine.

If they haven't worked for you, then obviously you did something wrong. I can't answer that "unknown."

I've done many engines, where complete teardowns weren't wanted. In fact, I've got a Deere 450 crawler(202 engine) in the neighborhood that lost several bearings 15 years ago, when a sleeve leaked coolant into the oil and siezed the engine. We used emory cloth on every journal and had to use some .001" and .002" bearings from Deere to get clearance within specs. No journals were more then .001" out-of-round.

That was 15 years ago and it still runs fine. It's a limited-use farm crawler. Note, I also did the same with my Ford 4000 Industrial with a 172 engine.

Allan, when you make such a sweeping statement i.e. "hogwash", how about some actual specifics. What did you try to fix, and why exactly did it fail?

The ones I did worked out fine, and your's did not. I wonder what made the difference?
A journal not severely out-of-round, with proper clearance and oil pressure, is going to work regardless if standard or any undersize. Please explain why you claim to the contrary.

A few more of my comments on your"s.

4020 Deere rod bearing clearance range is .001" to .0045"", not just .001" as you claimed.

If a engine suffers a failed bearing, and once the journal is cleaned up and relatively round- very often a new standard bearing will allow too much clearance. If you"ve got one assembled that mikes up to .005", and you stick in a new .002" bearing, it brings it back to allowable specs. Some companies sell .001", .002" and .003"

As I said, works fine when done properly.

Your anecdotal story proves nothing except there are some Bozos out there turning wrenches.

So, "Clem" sticks a undersize bearing on a good standard crankpin, and it locks up. And that means "hogwash" to all situations, Allan?? I"m surprised at you.

I'm with you. I know of this being done many times. Just takes patience. Mike

Yes, and the ability to eiter use a micrometer, or some Plastigauge.

But, according to Allan, one idiot does it wrong, and therefore nobody can do it??

My cousin once did this on an 800 h.p. pulling tractor. The tractor ran for years after the rod spun. Mike

I'm not gonna stand here and argue with ya, JD.

Spent too damned many years working as a factory trained tech and have rebuilt engines by the Gawd-awful trainloads.

Allan

There's a difference between "arguing" and "explaining with specifics." I suspect you cannot support your claim.

You certainly are not the only person on these forums with a strong background in mechanics.

Note that I never asked for any argument. I stated some easily verified facts in response to a question. You called them "hogwash" with NO facts to support your negative claim. And, you won't because you are incorrect.