Compression Testing

FatLuckFarmer · Jan 18, 2019

Hi all.
I just bought a '82 L345DT with ~2600 hours showing on the meter. I bought it from a neighbor who lives about 2 miles away so I was able to drive it home.

However, I wasn't able to drive it in top gear. It would happily drive along in 7th but if I tried 8th the engine bogged down and nearly stalled. Going down a hill I was able to use 8th but as soon as the road leveled out the engine didn't seem like it could pull the weight. I m thinking the engine might be tired and I should do a compression test. I haven't done one on a Diesel before but I assume I can do it by using the glow plug port for each cylinder (I hope I have an adapter that will fit that thread). My compression gauge goes to 500psi so I'm assuming that will work too. Has anyone done a compression test on these engines? Does it sound like I'm barking up the right tree? Any Tips?

Thanks

Pete~

85Hokie · Jan 18, 2019

Pete,

you are in the right tree - and IF you have the correct fitting, the glow plug will be a good place to test the compression.

If you find that you do NOT have the correct fitting, go by Harbor Freight if you have on in your local area.

here are the specs on your engine:

412- 469 PSI considered "Good" 327 PSI low limit.

GeoHorn · Jan 18, 2019

Another possibility is your fuel injection pressure/volume in insufficient, dirty fuel filters, failing pump, etc. ...or if you're lucky a fuel pump adjustment may take care of it. When shifting into 8th does the exhaust blow black smoke (indicating good fuel delivery) or not...

North Idaho Wolfman · Jan 18, 2019

Are you 100% sure the engine was slowing down RPMs, and not just the tractor?
Because what you are explaining sounds like the clutch is slipping.

200mph · Jan 18, 2019

Compression could be down, but it might be worth investigating fuel delivery and air delivery as they both can contribute to lower power.

Fuel: Quality of fuel (h20, bacteria, dirt, etc...), fuel filter, fuel flow to filter exit, etc...

Air delivery: Restricted filter(s)

Congrats on the new tractor ownership!

FatLuckFarmer · Jan 19, 2019

Thanks all,
Definitely not a slipping clutch.

I ran it a bit today and tried the 8th gear again. When the motor bogs at almost full throttle, there is very little black smoke. So, Geohorn may be right thinking its a fuel delivery problem. I'll replace the fuel filter for good measure and before I go pulling injectors I'm going to check the valve clearances and do a compression check. That should be a fairly fast way I can rule out bad piston rings and or valves.

Do the injectors use single use crush washers to seal like some diesels? I don't have a parts book yet.

Thanks

Pete~

thepumpguysc · Jan 19, 2019

A quick search shows they are "pencil" type injectors..
They can be a real SOB to remove & they make a special tool to remove them.. slide hammer & a special end that slides into the cut-out on the side of the inj..
They bend real easy, so be careful if u don't buy the tool{130.00}

D2Cat · Jan 19, 2019

FatLuckFarmer, you probably have all kinds of fabricating tools, so here's a picture of the tool to pull pencil injectors. I made it from a piece of SS scrap. The open space on the bottom has to fit the flat groove on the injector. Weld a nut on the top to match your slide hammer.

Not pretty, but I refuse to pay $140 for a tool that I seldom use.

007kubotaguy · Jan 19, 2019

Hello
A few more things I would check. Be sure that the bleed screw is closed on the side of the injection pump. Clockwise is closed. If it is open under a full load the tractor will lose power. Also remove the fuel line from the fuel pump and be sure it is pumping. This tractor will run with a bad fuel pump because the fuel tank is above the engine. It won’t run its best. Very common problem with the fuel pump is the small plastic check valves inside crack and break. Also as others have said remove the fuel filter and be sure you have a good flow of fuel from the tank. How much blow by do you have out of the breather tube?This tractor when new did not have a lot of power in high gear. The injectors screw into the head. Side note. Don’t water the front tires. Will cause problems with the steering. Great tractor. Good luck Lance

North Idaho Wolfman · Jan 19, 2019

thepumpguysc said:
A quick search shows they are "pencil" type injectors.

Where are you doing your searches?

You might wanna start doing your searches on Kubota.com

The L345DT takes standard injectors, and yes they are one use soft washers.

thepumpguysc · Jan 20, 2019

I just Googled L345 & was surprised as u were.. I would have thought that they would be the screw in type like in your diagram. I don't ever remember seeing pencil injectors in a Kubota..
I guess the poster will have to verify.??

North Idaho Wolfman · Jan 20, 2019

thepumpguysc said:
I just Googled L345 & was surprised as u were.. I would have thought that they would be the screw in type like in your diagram. I don't ever remember seeing pencil injectors in a Kubota..
I guess the poster will have to verify.??

My L3450 has Pencil injectors, Kubota did use them.

CobraTom · Jan 21, 2019

North Idaho Wolfman said:
My L3450 has Pencil injectors, Kubota did use them.

Anything that is Direct Injection uses pencil injectors, Anything that is IDI uses standard Kubota injectors.

JohnDB · Jan 21, 2019

CobraTom said:
Anything that is Direct Injection uses pencil injectors, Anything that is IDI uses standard Kubota injectors.

CobraTom - that's useful, is that a general rule for all diesels of this sort of size (small industrial/agricultural/automotive) or just Kubota diesel engines?

CobraTom · Jan 21, 2019

JohnDB said:
CobraTom - that's useful, is that a general rule for all diesels of this sort of size (small industrial/agricultural/automotive) or just Kubota diesel engines?

This is specific to Kubota's. All IDI Kubota's have screw in injectors and a short glow plug that meets in a pre combustion chamber. Direct Injection Kubota use a long pencil style injector that is bolted down with a bracket, and have a long glow plug as they both meet in the combustion chamber.

And then there is new style Direct Injection Common rail which use a larger injector and have a solenoid attached to it. They are bolt in as well.

North Idaho Wolfman · Jan 21, 2019

CobraTom said:
Anything that is Direct Injection uses pencil injectors, Anything that is IDI uses standard Kubota injectors.

This is simply not true, they used standard injectors for DI engine too, I own one..

They only used pencial injectors for a short time period then that went back to standard injectors, I don't know why.

CobraTom · Jan 21, 2019

North Idaho Wolfman said:
This is simply not true, they used standard injectors for DI engine too, I own one..

They only used pencial injectors for a short time period then that went back to standard injectors, I don't know why.

Uhm.. That is not possible. What engine do you own that uses standard injectors on a direct injected engine?
Even Tier 2+ V2203 use a pencil style injector (a bit fatter pencil), and that is clamp down, not screw in. They require the length as a DI engine injector injects in the middle of the cylinder..

North Idaho Wolfman · Jan 21, 2019

Well it looks like I have egg in my face, not the first and not the last.

Kubota lists some of their E-TVCS engines as being DI engines, and parts lookups do the same thing.

I have always wondered why they (now knowing mistakenly) called them DI engines, when they were prechambered?

So back to the drawing board on what I think I know.

Also went out and looked at my V2203 DI thats in my bobcat, I was in such a rush to get it back up and running when it blew up the V1702 IDI that I didn't spend much time with it, and yes it too does have pencil injectors.

Thanks for correcting me.

CobraTom · Jan 21, 2019

It's no worries. Kubota E-TVCS actually stands for Three Vortex Combustion System, which references the pre combustion chamber. No idea where they would list Direct injection.

Many of the IDI engines are offered as DI alternatives (V2403, V2203, V2003, etc.) and they always have a DI in the engine variant ex. V2003-M-DI-T

JohnDB · Jan 21, 2019

CobraTom said:
Many of the IDI engines are offered as DI alternatives (V2403, V2203, V2003, etc.) and they always have a DI in the engine variant ex. V2003-M-DI-T

Great info thanks CobraTom and Wolfie. I had no idea that anyone offered essentially the same engine in IDI and DI variants - I'm living 'n learning.

Compression Testing

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