diesel spam

[johnnyfive]

The 236 was fitted to a shed load of things with a very wide range of rated HP too, aside from pump and injector differences (& the presence of a turbo), I doubt there was much difference otherwise.

[johnnyfive]

When it seems like it's not delivering what it should up a hill, black smoke?

Aside from things like intake obstructions, the mongrel in me says to play with the pump until power happens 

[HighLUX]

Yeah I'd be checking fuel delivery pre injector pump. Blocked strainer where the fuel line runs to the injector pump if they even have one fuel filters etc

[johnnyfive]

Unsure if JCB application is the same, but the ones I know have strainers in the top of the mech lift pump, and a strainer in the top of the fuel tap on in the bottom of tank.

[Goat]

Has it been gutless since you got it? The PO could have messed up the injector timing when reassembling?
I'm sure its not some super high power beast, but it should make more and more power until it runs out of huff new full throttle right? 

• Filters and lines pre pump restricting fuel delivery
• Fuel shutoff in the pump (if its solenoid based, maybe its not fully disengaging)
• Not sure what style of pump they have, but is there something inside the pump limiting full throttle? Rack not extending all the way, but its spring loaded so it appears to be full throttle externally (struggling to articulate sorry)?
• Pump timing off a tooth (I take it it starts well? Not sure if they would start well if it was off a tooth)

[Rookie]

Does it have a hydostatic drive? I've driven a few Hydrema Dumpers and it is exactly what you discribe, full noise but road speed is highly dependent on load and inclination. Also have you checked in a manual to see how fast it should go? 25 kph seems in the ball park for an industrial machine.

[Unclejake]

Hi chaps, thank you and sorry for the slow response. Internet has been out here

The machine should do ~ 40kmph according to the factory. It has a conventional manual 4 speed gearbox, but that's mated to a torque converter shuttle system off the flywheel (forwarder and reverser) which seems to be working well. Transmission system filters are all new. When travelling along the flat everything seems sort of OK but go up a hill and the engine slows noticeably so I don't think it's a transmission problem.

Max RPM is about 2,200. I usually dig (using the backhoe) around 1,200RPM which is absolutely fine. There's at least adequate power for digging at those RPMs. 

At risk of sounding like a dick - I'm suspicious that the excessive exhaust noise has something to do with the lack of engine power. You can hear the machine literally half a kilometre away - even with a brand new 24 inch stainless packed muffler (admittedly a Coby muffler, but not a resonator). I only found that out a couple of days ago when I had a mate drive it. It sounds awful. Sort of an out of phase waffle. Not quite a running on three cylinder noise, but definitely an unpleasant sound and extremely uncomfortable without hearing protection

The machine has been noisy and slow since I got it. I got a bit ripped off TBH. It had a blown head gasket which I had a local 'mechanic' replace.

The engine should be about 82hp from factory, but it definitely has some blow-by out of the crankcase now so it's worn and probably burns oil (it leaks a lot too so hard to gauge how much it's burning).

I've done all the disposable fuel system filters but haven't investigated the strainer in the fuel pump. Thanks for that tip. I will look at that in the weekend... but I think we'll take the rocker cover off and check valve clearances as well. I'm thinking perhaps the exhaust valve lash is too tight and perhaps the valves aren't closing properly? I think that could explain the noise? Maybe?

There's a bit of black smoke under load but nothing significant. You have to look to spot it.  The engine starts well and idles well at about 700RPM (any less than that and idle is a bit lumpy).

There is also a rust hole in the air filter housing which will be contributing to engine noise. I'll sort that when possible.

 

 

[440bbm]

out of curiousity, if its running through a TC, whats the oil condition like? if the oils burnt to fuck it can cause further slip when in those moments. But youd just lose speed, engine revs or note wouldnt drop. Might be something else to check and try but I think as already been mentioned and what you're going to check are good starters.

[Unclejake]

Thanks. The ATF is bright red and smells good so I'm hopeful the convertor and associated pump is still OK.

Terrible weather here so no spannering today

[johnnyfive]

Tight/burnt exhaust valve?

[Unclejake]

20 minutes ago, johnnyfive said:

Tight/burnt exhaust valve?

That's what I'm thinking. Hopefully we can find out in the weekend if I can gather the right tools

[UTERUS]

J5 wrote what I was thinking. 

Sounds a lot like an exhaust valve not closing. 

 

I bought a cheap USB endoscope for peeking into impossible to see places, probably slim chance having one of those on the island though. 

 

https://a.aliexpress.com/_mLRaVpk

[JustHarry]

5 hours ago, Unclejake said:

That's what I'm thinking. Hopefully we can find out in the weekend if I can gather the right tools

Compression test will show that up real quick.

Or otherwise does it sound like it's catching all 4 conpessuons when cranking on the starter? If it's down a cyl it will sound like it's skipping.

 

Otherwise Perkins industrial motors are often noisy and not nice to be around. But they tend to go forever 

[Unclejake]

Hey chaps, to partly update the JCB saga, the fuel tank was pretty grubby, the sediment filter gross but lift pump, spin on fuel filter and internal filter in the injection pump all really clean.

We cleared as much gunk out of the tank and sediment filter as possible... but now she won't run for more than a few seconds so no chance to road test for power increase. I'll sort the new problem tomorrow as it'll be an assembly error (of mine) in the injection pump. 

 

[Mof]

Is there any right angle fittings between the pump and the filter, eg at the pickup to pipe on the tank, or into the filter housing. 

Older trucks had right angle fittings and gunk would get stuck in the tight bend of the fitting and then catch more gunk and block the fitting up.

They would be down on power, after a while drive for a bit then conk out, then not start.

[440bbm]

Sounds like it's got air in there somewhere still? 

[Unclejake]

It might be air in the lines ... but more likely the exact order of re-assembly of the teeny, weeny springs, poppet valves and diaphragm injector pump parts that sprung out onto the grass. Without warning. Like a pouncing menace

Puhuhuhuhu

TBH it wasn't that bad and nothing much got lost. I may have just put a poppet in on the wrong side of a spring. I have the electronic workshop manual so will check soon. 

[Unclejake]

1 hour ago, Mof said:

Is there any right angle fittings between the pump and the filter, eg at the pickup to pipe on the tank, or into the filter housing. 

Older trucks had right angle fittings and gunk would get stuck in the tight bend of the fitting and then catch more gunk and block the fitting up.

They would be down on power, after a while drive for a bit then conk out, then not start.

Untold fuel getting to the injector pump (using the manual lift pump) so I think we're clear on the pipe elbow scenario sir, but thank you for the thought.

[440bbm]

12 hours ago, Unclejake said:

It might be air in the lines ... but more likely the exact order of re-assembly of the teeny, weeny springs, poppet valves and diaphragm injector pump parts that sprung out onto the grass. Without warning. Like a pouncing menace

Puhuhuhuhu

TBH it wasn't that bad and nothing much got lost. I may have just put a poppet in on the wrong side of a spring. I have the electronic workshop manual so will check soon. 

ohhh u went THAT deep lol.   well good luck with that haha

[Unclejake]

Problem most likely solved my friends. 

Those suggesting fuel were correct. The lift pump body wasn't tightened down properly.  That and perhaps some restriction through the sediment filter was starving the engine of fuel. 

Noticeable power increase now, but I am still going to check valve clearances when I get a spare afternoon. 

Thanks all. Really appreciate the guidance. I am starting to like diesel engines. These old ones are refreshingly simple to work on once you understand them