Kubota RTVX900 w/ Hydrolocked Engine

[CowboyCarpenter]

Hi all,

New to the forums here. Looking for some advice and information sources. I recently drove our RTVX900 through a flooded creek and hydrolocked the engine. Took it to the dealer and they are recommending a new engine at about $10k out the door. The service manager said they pulled the glow plugs and found a little water, ran the compression test and all three cylinders failed. Probably bent connecting rods.

I am interested in rebuilding it myself. I've never rebuilt an engine before, but my buddy and I have done lots of work on vehicles and are pretty mechanically inclined. I'm looking for some recommendations on sources of information for doing this properly as well as any tips you all may have from doing this before or things to watch out for.

Thanks

 

[North Idaho Wolfman]

Get the WSM and follow it.
It will cover teardown and all the parts to check along the way.

Look at the envelope on the top right of your screen.

 

[Runs With Scissors]

As a former auto mechanic, I rarely saw a “significant savings” in rebuilding an engine.

Most of the auto/truck ones I have had to replace in the past were purchased from places like the dealer or rebuilders like Jasper (or someone like that)

There is a lot of machining/measuring/general nuances to be aware of.

I regularly rebuilt/overhauled transmissions and axles, however when dealing with engines, its tough to beat the “big guys”.

Now if you are doing it “for the experience” thats an entirely different story…..That would be a cool project, albeit not a “financially smart” one (usually).

Maybe tractors are different, but I doubt it.

Good luck though

 

[North Idaho Wolfman]

As a former auto mechanic, I rarely saw a “significant savings” in rebuilding an engine.

Most of the auto/truck ones I have had to replace in the past were purchased from places like the deal or rebuilders like Jasper (or someone like that)

There is a lot of machining/measuring/general nuances to be aware of.

I regularly rebuilt/overhauled transmissions and axles, however when dealing with engines, its tough to beat the “big guys”.

Now if you are doing it “for the experience” thats an entirely different story…..That would be a cool project, albeit not a “financially smart” one (usually).

Maybe tractors are different, but I doubt it.

Good luck though

If it was a worn out engine i would 100% agree with you.
But for this Physically damaged engine, it's an easy parts swap job.
In and out.
I would change pistons, rings, connecting rods and rod bearings.
You could forgo the pistons and rings if they look in perfect condition.
Keep all parts in the same location and orientation.
The pistons and rods are directional.
Mark them with a paint pen when you remove them.
And Install the new rods Exactly the same way as originals.
I wouldn't even pull the gear case (timing cover) and mess around in there.
Oil pan off head off and parts swap and back together.
3 gaskets and a few parts and your back up and running.
Check the head for cracks while you have it off (you will be able to see the cracks if they are there).
And get new glow plugs.

 

[Russell King]

@North Idaho Wolfman
Is it IMPOSSIBLE to have damaged the valves on that engine? Just curious since you make no mention of them.

 

[CowboyCarpenter]

If it was a worn out engine i would 100% agree with you.
But for this Physically damaged engine, it's an easy parts swap job.
In and out.
I would change pistons, rings, connecting rods and rod bearings.
You could forgo the pistons and rings if they look in perfect condition.
Keep all parts in the same location and orientation.
The pistons and rods are directional.
Mark them with a paint pen when you remove them.
And Install the new rods Exactly the same way as originals.
I wouldn't even pull the gear case (timing cover) and mess around in there.
Oil pan off head off and parts swap and back together.
3 gaskets and a few parts and your back up and running.
Check the head for cracks while you have it off (you will be able to see the cracks if they are there).
And get new glow plugs.

Thanks for replying. I've read some of your posts on similar threads and you seem knowledgeable on the subject. I'm assuming I would purchase standard pistons and rod bearings, not the oversized options? We bought this unit new and I'm positive the engine hasn't been touched.

I usually order parts either from the dealer or off of messicks. They have the connecting rods and glowplugs, about a grand for those total. Weaver's compact tractor parts has a rebuild kit with pistons, rings, bearings, gaskets etc. for about a grand as well:

Original OEM Kubota D902 Engine Rebuild Kit Standard Specs - Weaver's Compact Tractor Parts

Complete rebuild kit for engines in Kubota tractors, utility vehicles and zero turn mowers. Rebuild Kit includes: gasket kit, std pistons, std rings, std rod bearings, std main bearings, thrust washer kit. Pistons are available in std, .25mm. Rod & main bearings are available in .2mm and .4mm...

compactractorparts.com

Is there anything I would need apart from these in order to do what you're suggesting? If I go that route do I need to worry about matching the pistons and rods together?

 

[North Idaho Wolfman]

@North Idaho Wolfman
Is it IMPOSSIBLE to have damaged the valves on that engine? Just curious since you make no mention of them.

Never seen that happen.

 

[North Idaho Wolfman]

Thanks for replying. I've read some of your posts on similar threads and you seem knowledgeable on the subject. I'm assuming I would purchase standard pistons and rod bearings, not the oversized options? We bought this unit new and I'm positive the engine hasn't been touched.

I usually order parts either from the dealer or off of messicks. They have the connecting rods and glowplugs, about a grand for those total. Weaver's compact tractor parts has a rebuild kit with pistons, rings, bearings, gaskets etc. for about a grand as well:

Original OEM Kubota D902 Engine Rebuild Kit Standard Specs - Weaver's Compact Tractor Parts

Complete rebuild kit for engines in Kubota tractors, utility vehicles and zero turn mowers. Rebuild Kit includes: gasket kit, std pistons, std rings, std rod bearings, std main bearings, thrust washer kit. Pistons are available in std, .25mm. Rod & main bearings are available in .2mm and .4mm...

compactractorparts.com

Is there anything I would need apart from these in order to do what you're suggesting? If I go that route do I need to worry about matching the pistons and rods together?

If that is an OEM kit, that's great, and not a bad price.

Yes you need to absolutely make sure you replace the rods in the proper direction (look for the cast part number) and replace the pistons in the same direction.
If you think there is any wear on the engine (lots of hours, blow by, oil consumption, low compression (before bent rods) Hard starts, blue / white smoke) you might want to pull the head first and get a cylinder dimension reading to see if you need oversized pistons and rings, normally you don't.
Note: Some model engines have one different piston, I don't know if yours does or not, normally it's a skirt difference.
Also Note: The rings are also directional

 

[whitetiger]

The compression is low on all 3 cylinders?
What were the compression readings?
I find it hard to imagine all 3 rods bent.
I have repaired several and never found more than 1 bent. I guess 2 bent is possible.

I would perform another compression test, then, if confirmed low, remove the cylinder head and measure the piston-to-block height.

It could very easily be a faulty tester gauge.

 

[North Idaho Wolfman]

The compression is low on all 3 cylinders?

It could very easily be a faulty tester gauge.

Or a faulty tester gauge reader!

 

[whitetiger]

Or a faulty tester gauge reader!

I have actually seen that happen!!!! He now repairs truck service beds.

 

[Runs With Scissors]

If it was a worn out engine i would 100% agree with you.
But for this Physically damaged engine, it's an easy parts swap job.
In and out.
I would change pistons, rings, connecting rods and rod bearings.
You could forgo the pistons and rings if they look in perfect condition.
Keep all parts in the same location and orientation.
The pistons and rods are directional.
Mark them with a paint pen when you remove them.
And Install the new rods Exactly the same way as originals.
I wouldn't even pull the gear case (timing cover) and mess around in there.
Oil pan off head off and parts swap and back together.
3 gaskets and a few parts and your back up and running.
Check the head for cracks while you have it off (you will be able to see the cracks if they are there).
And get new glow plugs.

Good to know!

I was originally thinking of a “total rebuild”.

But if you can just swap a few parts, then thats exactly what I would do.

 

[Motion]

How long was it in the creek? How deep? Electric system, diff, trans, CV's, etc. should all be checked

 

[CowboyCarpenter]

If that is an OEM kit, that's great, and not a bad price.

Yes you need to absolutely make sure you replace the rods in the proper direction (look for the cast part number) and replace the pistons in the same direction.
If you think there is any wear on the engine (lots of hours, blow by, oil consumption, low compression (before bent rods) Hard starts, blue / white smoke) you might want to pull the head first and get a cylinder dimension reading to see if you need oversized pistons and rings, normally you don't.
Note: Some model engines have one different piston, I don't know if yours does or not, normally it's a skirt difference.
Also Note: The rings are also directional

The engine seemed pretty healthy to me before the damage. Not sure exactly on the hours, probably around 1500.

The compression is low on all 3 cylinders?
What were the compression readings?
I find it hard to imagine all 3 rods bent.
I have repaired several and never found more than 1 bent. I guess 2 bent is possible.

I would perform another compression test, then, if confirmed low, remove the cylinder head and measure the piston-to-block height.

It could very easily be a faulty tester gauge.

Cylinder 1 - 350 psi
Cylinder 2 - 200 psi
Cylinder 3 - 210 psi

According to the dealership

How long was it in the creek? How deep? Electric system, diff, trans, CV's, etc. should all be checked

It was in the creek for probably a couple hours. Not very deep, I almost made it across. I think the water splashed into the intake, the intake was not submerged. The only thing submerged while it was sitting would have been the suspension components.

 

[SDT]

As a former auto mechanic, I rarely saw a “significant savings” in rebuilding an engine.

Most of the auto/truck ones I have had to replace in the past were purchased from places like the dealer or rebuilders like Jasper (or someone like that)

There is a lot of machining/measuring/general nuances to be aware of.

I regularly rebuilt/overhauled transmissions and axles, however when dealing with engines, its tough to beat the “big guys”.

Now if you are doing it “for the experience” thats an entirely different story…..That would be a cool project, albeit not a “financially smart” one (usually).

Maybe tractors are different, but I doubt it.

Good luck though

Agreed.

 

[CowboyCarpenter]

If that is an OEM kit, that's great, and not a bad price.

Yes you need to absolutely make sure you replace the rods in the proper direction (look for the cast part number) and replace the pistons in the same direction.
If you think there is any wear on the engine (lots of hours, blow by, oil consumption, low compression (before bent rods) Hard starts, blue / white smoke) you might want to pull the head first and get a cylinder dimension reading to see if you need oversized pistons and rings, normally you don't.
Note: Some model engines have one different piston, I don't know if yours does or not, normally it's a skirt difference.
Also Note: The rings are also directional

Another question: would you pull the engine to swap those parts?

 

[North Idaho Wolfman]

Another question: would you pull the engine to swap those parts?

If you can pull the head and the oil pan, then no reason to pull the whole engine out.

 

[CowboyCarpenter]

If you can pull the head and the oil pan, then no reason to pull the whole engine out.

I figured so. Thanks.