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HS 2.8 TGV engine problems


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Hi All,

Have one of these engines in a crop sprayer coupled to auto box. The other day the turbo blew, turned out some of the compressor blades were not the shape they should have been, I assume this put the the shaft out of balance and swiftly destroyed the bearings/seals.

So I put a new turbo on, cleaned intercooler/pipework inlet, fresh oil/filter. Had a devil of a job to get it to start, when I did it smoked heavily (dark brown/black) which led me to believe that the intercooler wasn't as clean as it could have been of a restriction in the exhaust. Once running however it would tick over/drive just with plenty of smoke.

I suspected that a piston had picked up on the bores and the rings were knackered, so took the head off for further inspection. The bores were fine if a little glazed, no sign of foreign objects in the bores, valves looked fine no sign of contact with the head. The one think I did notice was that the tappets were very loose when I took it apart. I didn't compression test it as didn't have one at the time. I did however sit the pistons half way down the bores and tipped neat diesel in, it sat there for a good 10 mins and didn't drop (in level).

Put it all back to gather again, again a sod to start (always used to start first turn) but once running, still smoked, blue/white I assumed oil.

Took it for a spin, it showed signs of dark brown/black smoke on any throttle setting, I gave it some beans and it seemed like it wanted to run away with me, fortunately it didn't.

I have checked the pump timing (this lines up perfectly with the front piston at TDC) so discounted that. I have managed to get a compression tester for tomorrow so will see what they read, this hopefully will exlude any ring issues.

Other than I am struggling where to go, it did try and run on again when I stopped in a field, revved it up slightly and off she went, fortunately I managed to put my hand over the inlet and stop it. Rocker cover oil filler when removed was shoving plenty of smoke out, but then I am not sure how much is too much. It just seems to be running very rich, lots of black smoke, even on start up and once running, once the boost comes in it goes like a rocket.

I am leaning towards injector pump if the compressions are ok and then I guess cam timing. this engine has only done 280hrs use (I would guess less than 10,000 miles in car talk)

What sort if any problems do these pumps give? checked the return gauze filter in the back of pump, was clean.

Anyone any sensible ideas???

regards Chris

It has no EGR valve and it all old school. pushrods are fine, rockers, fine, pads, fine

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does the engine breather recirculate into the intake? is it using oil now at all? do you know what the boost levels are now? im guessing the boost should be around 11psi standard?

i can't see it being the fuel pump if you have only changed the turbo, did you retrieve all parts of the old turbo? does the wastegate work ok on the new turbo? sounds to me like its overboosting, and maybe the pump is compensating so much that it is smoking?

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There's no wastegate as such (VNT), but I think discomikey is probably on the right lines. Boost should be around 15psi stable but as it's mechanically controlled it can spike much higher.

I have seen the boost nailed at 25psi for a few minutes after leaving it parked outside for months without use. Jumping on and off the throttle a few times fixed that, and it never recurred.

Is it possible the VNT shape is 'stuck' so as the engine comes off idle the turbo isn't able to get the boost under control?

I'd check the boost compensator bulb on the pump isn't full of oil (miketomcats was after his turbo blew a seal the other day).

Then I'd try running it with the boost pipe from turbo to pump removed to see if it still tries to run away.

With no boost feed, it shouldn't be able to rev up in quite the same way, and you should be able to get a gauge on and check the boost level. It should be around 15psi when loaded but not trying to accelerate.

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Yes the turbo inlet is connected to the oil breather system. Have run it with intercooler and exhaust excluded from the system, it ran but smoked badly from both exhaust compressor wheel and also compressor side of turbo also. I do suspect it is possible that a faulty seal maybe an issue with the turbo?? After all where can it get oil to run on?

There does seem to be pressure within the crankcase system, but not sure what is normal, I know most engines breathe but cannot fathom that an engine can "run away" on crankcase fumes??

The intercooler/turbo/pipes were spotless, cleaned using Carb cleaner, so I can rule that out as a source of oil for the engine to consume. Upon dismantling this morning they were full of oil, circa an egg-cup full in the pipework leading to the intercooler.

I did do an oil pressure check, 50psi cold and it dropped down to 40psi idle so suspect the knocking I heard was diesel/oil knock?

Compressions were down (if going by the manual) with 280/280/220/220, the bores are glazed but I am trying to figure out if this low compression is bad enough to blow oil out of the breathers and into the turbo inlet?? Thereby this would negate turbo oil seals but cannot think this is possible, a) in such a short time of running with new turbo, 10 mins b) the correct oil level is in the sump c) it was a mist coming from the rocker cover breather.

I think I will have the sump off, pop the rods/pistons out and see what state the rings are in, compression is obviously low'ish so best Glazebust the bores and pop some rings in. Meanwhile I will get the Turbo looked at, bearings seem fine but would like to know if the seals are faulty.

I am afraid I don't know what the boost levels it's running, I don't have a boost gauge, it was certainly boosting when I drove it up the farm track as it went like a scalded cat around 1200/1300 rpm.

I am leaning towards your thoughts re not the injector pump, I will also check the boost membrane on top of the pump to see if oil is in there also, did check the pipe and it was clean at the banjo end but will take the cover of and see if anything is in there.

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Yes new Turbo is a re-furbed Garret. Popped the rods/pistons out today and rings are shot, noticeably the top compression ring, can see where oil has been getting past the top 2 rings no sign of it further down the piston skirt. I think maybe a possible combination of worn out rings and faulty oil seal. Will get the rings in, Big Ends looked fine but will bang in a set while its apart, try the turbo again and go from there.

Its been an interesting little saga so far, hope we're not in for any more surprises!!

Many thanks for your suggestions, will post when and if I know it all works.

regards Chris

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smoking from the compressor side of the turbo is a bad bad thing. is that with the breather connected to intake?

Yes, stupidly I didn't remove the breather to the intake before I took it apart, if I had we could have eliminated the turbo seals if no smoke.

On further inspection the rings are shot and there is a 0.2mm step on the top of the bores (using a feeler gauge), I need to measure the bores correctly and work out what size overbore to go, it needs re-boring.

I would like to take the engine out (not a simple job on this machine) but due to time and needing the machine am going to look at getting it rebored in situ, have found a company in Stockport, will have a word today and see what they say, it maybe that the bores are past limits and it'll need sleeving. Need to get hold of a bore gauge and see how bad it is.

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The mobile borer from Stockport does an amazing job. We have just used him on a DAF 55 LF 6 cylinder engine that had been running for 6 months with no air filter. He did it all in situ, took him a couple of hours to bore and reline. Was remarkably cheap too.

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Kellands make crop sprayers, called an Agribuggy, this uses the TGV engine (I assume they get them from M&D). I bought mine from a scrap yard (it had burnt out) and completely re-built it. I guess if you keep a look out on the agg salvage sites you may come across one or phone Kellands, they were offered mine one but they weren't interested as they thought it too bad. They often hear of ones that are written off and might know of such.

The engine mine came with was so bad it had melted the alloy injector pump but I still have the scrap engine, head, block, crank/rods etc sat in the corner of my workshop. They also have some pretty trick gears in the reduction drive due to us using 48 inch row crop wheels, flat out we do 50kph on the road, so you can see it's geared down a fair bit.

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