John Deere 4300 complete rebuild

[mjncad]

It's a John Deere Christmas! At least until the Discover card bill comes due.

The only thing rivaling that box of goodies is an order from McMaster-Carr!

 

[dfkrug]

OK, now for the engine assembly. I will not show every step here----just
some of the more unusual tasks you may not run into every day.

The first photo shows the block, bored and honed. You can see that the
wear did not completely clean up in the bore/hone process. The lighting
shows lots of contrast (see arrow), but you can not feel any differences in
level there. The ridge is still detectable, however, but I think I will be OK.
We will see. (I sure wish I could have gone with the .50mm oversize!)

At this point, I wash everything very thoroughly with soap and water to
remove all remaining hone grit. You can NOT count on a machine shop
doing this for you! A bit of rust patina forms up very quickly, so I blow-
dried everything and I oiled the machined surfaces well.

The 2nd photo shows me filling the bores using a ring compressor, and the
handle of a hammer to tap the pistons in.

Now to check the oil clearances. An engine like this with low hours and
not starved of oil will probably have in-spec bearing and journal diameters
and clearances, but I will check anyway. This method is called Plastiguage,
which is a plastic string that you squish under the bearing to determine the
clearance. The 3rd photo shows the guage before I put the bearing insert
and cap on and torque down. The final photo shows the squished guage,
which I then compare to my handy chart. This one shows 0.003" clearance.
The spec is .002-.003, and the limit is .006. I checked the rod journals and
the crankshaft main bearings, too. All well within spec.

Coming up next: the cylinder head.

 

[flusher]

OK, now the engine is on its stand and the head is off. This one is very
different from the pre-EPA engine (also a 3TNE84) from my last JD955. The
oil pan is a heavy cast stressed member that the subframe bolts to. The
955 was a full frame tractor with sheet metal pan. The front gear case had
a crap-catcher plate bolted to it....that is why it looks so nasty...it was
packed with dirt.

The water jacket design results in a fairly thin-walled cylinder. So only a
.25mm (0.010") oversize piston is offered by Deere. All three 955s I did
were bored for 0.5mm O/S pistons. Since I do not have a 3-4" inside
micrometer, I made a guage from a steel rod ground down to a point at
each end, and made to the wear limit of the O/S piston bore. At the worst
wear areas, I am right at the limit. Boring for liners would be the only other
option to save this block, if I can not make do with .25mm.

The head is pretty nasty, so I had it hot-tanked after removing the valve
train. I will be lapping to clean up the seats, but no seat cutting. The
valves are in nice condition. Getting the injectors out is often very hard.
One gave me particular trouble, so I removed one stud for better gripping
access. I will reuse these very expensive FI units.

Man, what an excellent thread! Congrats on your progress on this project.

I'm following in your footsteps. I picked up a 1951 Minneapolis Moline BF wide front tractor last Jan and am completely restoring it. More info in this thread

http://www.tractorbynet.com/forums/...nneapolis-moline-bf-restoration-progress.html

It's a 27-hp (engine) gasser with a 4-cyl Hercules engine (similar to an old Jeep engine). Hope to get the engine pulled soon. Been diverted into other jobs for the past month and am anxious to get back to wrench turning on this project.

 

[scott_vt]

The first photo shows the block, bored and honed. You can see that the
wear did not completely clean up in the bore/hone process. The lighting
shows lots of contrast (see arrow), but you can not feel any differences in
level there. The ridge is still detectable, however, but I think I will be OK.
We will see. (I sure wish I could have gone with the .50mm oversize!)

.

Good Afternoon Dave,
This is really a great thread, and thanks for all the pics and associated posts !

Dave you note on the first block pic that the honing process did nor entirely clean up the cylinder wall, Im just curious if you or the engine service took the time to put an inside mic on that section of the cylinder wall ? If its only .0005 then probablly not an issue, but if its more then its worth thinking about, just an observation on my part !

In any event thanks again for putting this whole thread together !

 

[WilliamBos]

I agree, Thank you.

Will this tractor be sold once done?

 

[dfkrug]

Dave you note on the first block pic that the honing process did nor entirely clean up the cylinder wall, Im just curious if you or the engine service took the time to put an inside mic on that section of the cylinder wall ? If its only .0005 then probablly not an issue, but if its more then its worth thinking about, just an observation on my part !

I am glad you guys are finding my project interesting.

Scott, back in post # 49, I noted that I could not make bore measurements
very precisely, due to not having an inside mike. The machine shop, of
course did have the right tool, and the machinist and I discussed this at
length. I knew that the bores would not completely clean up before the
machining commenced. The spec for the standard bore is documented, along
with the wear limit. The O/S bore spec is documented, too, but there is no
specified wear limit. The bore/hone job takes me out to the bore spec, but
not to the extrapolated wear limit. The few places that did NOT clean up
are up to, but not over the extrapolated wear limit. I hope that makes
sense. There were no surprises here.

 

[dfkrug]

OK, now for the cylinder head.

I had it hot-tanked at the machine shop, but the EPA-approved citrus-
based cleaner only did a fair job. I had to do some more cleaning to get
off some of the black gunk that built up in the exhaust ports. That's
what you get with incomplete combustion due to low compression.

Before I did any assembly on the head, I was going to lap the valves
to assure good sealing. You can get some minor pitting of the seats or
valves if you get any water in the cyls and it sits. When I lap the valves,
I first use a coarse grit, and I finish up with a fine grit. Instead of using
a stick with a suction cup on it, I chuck the valve stem up in a cordless
drill and turn the valve from the top side (2nd photo). This method works
great, and you can easily control the speed and pressure. All of my valves
and springs were in spec, but I did have to replace the seals since they
get damaged if you remove them. I washed everything with soap and water
to get every trace of grit out of there.

Anyway, these engines turn at less than 3000 RPM, so the springs are
pretty soft and they can be very easily compressed. No need for a C-clamp
style valve spring compressor like you have to use with gas engines. You
can compress these springs with your thumb, but I rigged up a little bracket
to get the keepers (locks) in and out. All valves were re-installed in 15-20
minutes.

 

[ampa]

Did you have to reverse the drill direction or do you keep in one direction, I know when lapping valves with the suction cup, you rotate the stick back and fourth, I first heard of using a drill about 6 years ago when I had to lap valves in a gas engine, I had already put it together so I did not get to try this new way of lapping the valves,the engine did not run too good, it would never pass an emission test, so I scrapped it, this was in a Ford mini van, I do own an ISEKI tractor, but so far the engine runs great, this using an electric drill is very good information,so I'll keep this in mind for the next time I need to lap the valves, thanks and do take care......Ampa

 

[Wayne_H]

DFKRUG: Thanks for sharing this great thread with us. And I thought I've taken on some basket cases...

But.. I have a 4400 with 500 hours that runs great. I looked under the hood tonight and I can see part of that hose that split on your machine. What caused that to split in the first place? I can only see a small part of mine, but I can't tell what might cause it to split like yours.

I also wonder if there is a way to test if the hose is split, for instance blowing air in or pressurizing the air intake, and seeing if you can hear a leak out the where the intake manifold it? At one point in the engine cycle I imagine all the valves are closed?

thanks again for the great pics and great posting!

Wayne

 

[Kyle_in_Tex]

I think I might just check my hose as shown in post#21 too! Hopefully, there is no split but I'll check it to make sure it isn't weak either.