Volvo L120C lack of power and excessive smoke

[Pralhad Birdi]

Hi everyone,
I've got a Volvo L120C wheel loader that's lacking power and smoking excessively. Bought this machine from a quarry, so it was pretty poorly when it came to us, with a hard start and blow by from the breather. We stripped down the engine, new liners and rings, ground the valves and put it all back together. I should mention at this point that someone had messed with the timing gears and injection timing was out. I couldn't find any reference material, so after a few tries, we settled on 20 BTDC which gave us half kick start on the bench.
Put the engine back in the machine, and noticed it was smoking grayish smoke at idling. Tested it under load, and got thick grey-black smoke.
Got the injector nozzles replaced and the pump tested, as I thought it might be an overfuelling issue. Hasn't made the slightest bit of difference, plus the machine still lacks power and is running a bit warm as well. It does however start right on the key.
I'm really not sure what to try next as I've piled money into this with no return so far. Any help/ideas would be greatly appreciated.

 

[komatsukid]

Boost?

 

[funwithfuel]

20° BTDC, you're probably going to have to pull the heads for inspection of the pistons. Timing is 9°. Having it that hot probably caused issue immediately. I'd perform a compression test. For a "new" engine spec is 377. Good luck.

 

[Pralhad Birdi]

Thanks mate, I'll try setting the timing to 9 degrees first and see what happens.
Cheers

 

[Pralhad Birdi]

So I tried setting the timing at 9 BTDC today. Machine refused to start. I'm going to reconfirm the timing tomorrow again, but I'm pretty sure I got it right. Any ideas on why it would behave this way? At 20 BTDC it started on the key by the way.

 

[funwithfuel]

Are you reading the marks in the flywheel with the pointer in place?

 

[Pralhad Birdi]

Yes the pointer is in place.

 

[funwithfuel]

Have you got a dual indicator? I think it's time to verify TDC. There could be a lot of slack in the gear train. Figure true TDC and go from there. That doesn't explain the smoking, unless it's grey/white smoke, that could be retarded timing.

 

[funwithfuel]

And i just read what i wrote and it makes no sense. The flywheel is marked, there is no gear train. It's crank and flywheel. Back to my earlier statement. Compression test, if it fails, teardown and inspection.

 

[Mbar]

I built a Volvo a awhile back and had the same issue. New turbo, injection pump, injectors. Pulled heads again verified correct pistons. Timing was spot on as it was a in frame. Double checked Timing. Pump only bolts up one way or the other way it’s 180 off. Never did found the cause and it still bothers me. The truck fired rite up and sounded great just heavy smoke. Let me know what you find.

 

[funwithfuel]

Did you remove, clean and test your aftercooler?

 

[Pralhad Birdi]

Okay I'm going to have to make an embarrassing admission, because although I'd set the timing at 9 BTDC, I was 180 degrees out of phase.
Corrected that, machine does start, but still a lot of smoke and no power.
I'm going to do the compression test tomorrow, but before I do, I'm going to swap the turbo out with a spare one I have, as I noticed a bit of whistle as we were testing it today.
Cheers

 

[Pralhad Birdi]

It doesn't have the aftercooler the holes have just been blanked out, we bought it like that. Does that potentially have a big effect?

 

[sfrs4]

If its had some bit's tinkered with (like the inlet cooler being removed) , are you 100% the injection pump is the correct injection pump, there are different pumps available for the TD73 across the range, i'm just wondering if someone has just thrown whatever cheap parts they could find on it to keep it working and one of them is the pump, i know you've had it tested but if it's working good but not the right way it could explain a few things

 

[Pralhad Birdi]

That's a really good point. So I've had a look, and as far as I can tell, this pump is off of a Volvo NL12 lorry. What sort of effect do you reckon that would have?

 

[sfrs4]

So going back to my original point, do you know if the complete engine is from the loader or the truck? whats the serial number of the loader? I'll tell you what should be in there and then work from there

 

[Pralhad Birdi]

Hiya mate, sorry for the late reply I've been out on site. I'll check the serial number tomorrow and post it on here. Thanks

 

[sfrs4]

I am off on annual leave again 23-31st august, and will be in the islands off Scotland, so doubt i'll get much signal and no access to my Volvo data, so bare with me until then if you can.

 

[Pralhad Birdi]

The engine serial is TD73KE 12085207. Sorry for the delayed reply, and hope you have a great break!