WIJohnDeere855
Member
Has anyone tried putting a JD 955 motor in a JD 855?
955 motor in 855
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beenthere
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Must be more to the story behind the question. :confused3:
OP
WIJohnDeere855
Member
My 855 I just bought is showing signs of low compression. It is going to the JD dealer to have them test if its rings or cylinder issues. Anyway I found a 955 being parted out and didnt know since the frames or the 855 and 955 are nearly the same if the motors would be a match.
RoyJackson
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I can't help you with the fitting question, but that would be a very nice increase in power if the engine does fit.
There's enough similarity between the 855 and 955 to justify buying the 955 as a parts machine.
There's enough similarity between the 855 and 955 to justify buying the 955 as a parts machine.
dfkrug
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Nearly the same? The quick way to check to see if the frames are indeed
the same is check your 855 parts book and compare the frame part #
to the one for the 955. Since you prob do not have the book for the
955, use JDparts.com.
I suspect the engine will fit right it, but I have not done it. 33hp in
a 1970 lb tractor is awesome.
OP
WIJohnDeere855
Member
I know it a little more power then I need but to pull the old motor have the block redone buy oversized pistons, gaskets then put it all back together I am looking at $2,500-$3,000 if it all goes perfect. I dont have much into the 855 and I can get the motor form the 955 for about $2,000 and I know it has 800 documented and maintained hours, so it just getting broke in. I will post my findings.
dsmau
Silver Member
Try to get the hydraulic pump off that 955 as well. You will enjoy having more GPM if you use a loader or backhoe. That and the front axle are the 2 differences I know of besides the engine on a recent 855 when compared to a 955. You can also increase the hydraulic relief from 2050 to 2500psi to match the 955. I did it and it is on a thread here on TBN.
Mechanos
Veteran Member
Having an 855 as a parts tractor for my 955, here is a list of the parts that are different that know of....
Transaxle (case is the same but internals are different, different gear ratios on ring and pinion, different low range gear ratios, more steels and frictions in the PTO clutch and PTO brake, etc.)
PTO delay relief valve (different springs for different operating pressures)
Rear final drives (955 has beefier planetaries and longer axle shafts)
Impelement pump
Entire front axle is different
Front and rear tire size
Front wheels are 6 lug on 955, 5 lug on 855
If the 855 is an early model with the fuel tank in front of the radiator, then there are even more differences. Fuel tank, radiator, radiator support, hood hinge rods, etc.
I don't see why the 955 engine wouldn't fit in the 855. I have a 3TNE88 (37hp) in my 955 instead of the 3TN84. It looks right at home there.
Transaxle (case is the same but internals are different, different gear ratios on ring and pinion, different low range gear ratios, more steels and frictions in the PTO clutch and PTO brake, etc.)
PTO delay relief valve (different springs for different operating pressures)
Rear final drives (955 has beefier planetaries and longer axle shafts)
Impelement pump
Entire front axle is different
Front and rear tire size
Front wheels are 6 lug on 955, 5 lug on 855
If the 855 is an early model with the fuel tank in front of the radiator, then there are even more differences. Fuel tank, radiator, radiator support, hood hinge rods, etc.
I don't see why the 955 engine wouldn't fit in the 855. I have a 3TNE88 (37hp) in my 955 instead of the 3TN84. It looks right at home there.
dfkrug
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I have bought the 0.5mm oversize pistons, but you can also get 0.25mm
O/S, and they will cost about $120 per hole for the piston/ring set. If
everything else is OK, you only need to buy a head gasket and pay for
boring service. I don't know who would rebuild it, but it is very straight
forward as engines go, and it sits on top of the frame for easy removal.
Of course, if this a 5000hr engine, you will want to do the head and
bearings.
$2000 for a used 955 engine is no steal, but it will make a better tractor, esp
if you also get the 2500psi pump as DSMAU suggests.
OP
WIJohnDeere855
Member
Very good info. I did notice the fuel pump needed to be used but never thought of the Hyro pump being able to be changed to 2500psi.
dfkrug: Where did you get the oversized pistions and rings? Are they JD parts? Do you have a part numbers? I found a shop that does Diesel engine machining so that might be a cheaper option. The $2,500-$3,000 came from the JD dealer. I haved worked on motors before so I might look at that option as well since this is a winter project.
dfkrug: Where did you get the oversized pistions and rings? Are they JD parts? Do you have a part numbers? I found a shop that does Diesel engine machining so that might be a cheaper option. The $2,500-$3,000 came from the JD dealer. I haved worked on motors before so I might look at that option as well since this is a winter project.