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Engine Specific Info and Questions => IDI Engine => Topic started by: GTD_MK2 on June 23, 2010, 11:28:11 am
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Hi!
I've got some Problems with my TD,
When its cold, it starts good with or without the advance, but gives a little bit white smoke in idle and part throttle.
When its warmed up the smoke in idle is gone, but there is still a little bit of white smoke in part throttle and more under WOT .
Also when im on WOT and rev it over 4k RPM, regardless of fueling, it has a very high egt (up to 1750°F), and even when i turn the fuel up more, i cant get more than 25 psi Boost
I've got New GTD Nozzles, varied the timing, tried 2 other pumps, and changed from the KKK K14 to the K24 turbo, but the problems are still the same...
My biggest problem are the massive EGT's, so has anyone an idea how i can get them down ?
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Is the probe pre or post turbo?
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Oh ,i forgot ;)
Its a pre turbo egt.
The smoke under WOT is something like a mix out of white/grey and Black... and smells like unburnt diesel ...
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How many mm of advance are you running?
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From my understanding 25psi is well out of its efficiency range, so therefore it will run hot. If you are already getting EGT's into 1750F why would you try and turn the fuel up? What do you have for exhaust? If i were to guess with the limited information you have given i would say its a combination of, too much fuel, too much restriction in the exhaust, and fuel timing is out. Since you dont need the cold start to start it i would say you are too advanced. And with that high of boost pressure an intercooler or water meth wouldnt hurt.
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last time i saw a car with mysterious white smoke it ended up being a blown motor with burnt pistons and many other problems
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I cant say how many mm timing i run , because my dial indicator adapter doesn't fit into the 10mm Head that i fitted into the pump...
The pump mods are : 10mm head, Governor main spring shimmed completely, timing advance piston shaved to get more advance.
So i have timed it by ear and warm start cranking time for the moment...
If i retard the timing i have to crank it 5 to 7 seconds to get a warm start.
But i dont think that the timing is the problem, because i tried it with 2 other pumps that were completely stock except a gov mod, and tried timings of 0.95, 1.0 and 1.05 but that only changed the warm start cranking time, not the high egts or the white smoke...
Downpipe is 2.25", exhaust is 2.5" .
Intercooler is a Stock 80HP GTD unit.
I just upped the fuel to see if its too low to get more boost.
Before the k24 i had a k14 on it with the wastegate disabled, and had the same egts (at this time i thougt the egts are made by the restriction of the way too small turbo)
Another thing that i mess about is that it now only runs 160kph, 2 months before it used to run almost 200kph.
the engine has 270k miles on it and got some blow by (Oil filler cap dances a bit but doesnt fall down when i open it and lay it on its hole )
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Have you tried advancing it?
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Yes i already tried advancing it , but a little more advance and its going to make lots of noise (clatter/marbles), and still gives the white smoke. so now i timed it to the point it makes good warm starts (about 2-3 turns) wich is short before its going to clatter too much.
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Any chance you have some gas in fuel?
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No, there cant be any gas in the fuel, thats for sure.
Fuel filter is new.
But now, as you said gas in fuel, which color of smoke makes bio diesel/RME ?
Because here in germany the normal Diesel can contain up to 7% biodiesel....
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Check the cam to flywheel timing marks.
You may find they are out just a touch.
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Thanks for your help so far...
I've got no air in the IP, and the other pumps , the one i ran for about 2 weeks (about 400-500km) and the other for 4 days, and both showed no air bubbles in the return line.
Injectors are brand new GTD Nozzles (DN0SD274) in the 1.6 single stage injectors.
The Problems i have were the same , no matter wich pump tried.
I've also did a small test drive with timing advanced to very much clatter, but the problems are still the same...
Compression, that could be a factor, i can't say exactly how much it has, but with the right IP timing it starts real good, hot and cold.
Cam timing could also be a problem , because i fitted a lightened gasser 210mm flywheel, and i had the feeling the TDC mark is not exact now...
I think i will check the TDC mark on the flywheel and re-time the engine.
BTW, is the cam timing really so sensible that it cause those problems, when it's for example 1mm out on the flywheel?
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I'm not the best with math but here are my calculations.
If the flywheel measures 10"(254mm) and I'm not sure what the diameter actually is since I don't have one infront of me, but you can measure it and plug in the numbers.
Circumference=pi•diameter 3.14X10=31.416
Now we need to find how far one degree is at 10 inches 31.416/360=.0873"
Converted to mm .0873/25.4=2.217mm
So 1 mm is about 1/2 a degree at the pointer? And the cam turns half as fast as the crankshaft so it's about a 1/4 of a degree? Doesn't seem right but maybe it'll get a discussion going...
I do recommend resetting your tdc mark though, google the "dropped valve" method of finding tdc.
Hope this helps, good luck!
Aaron
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I had no time for doing this today, but i think tomorrow i will do it.
Thanks for your calculation ;)
I also did these , but im not sure about how much problems something like a half degree can cause...
But i think if it would be not such a sensible thing, wich other reason should be there for the adjustable sprocket from factory.
Because gassers do not have this, it's a diesel only thing...
So i will give it a try and will do it as exact as i can, then i will know for sure where my timing is set.
The dropped valve method seems to be the easiest way to do this...
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it has a very high egt (up to 1750°F)
Thats about 950C, which should have the manifold glowing yellowy orange! :P
That IS hot, are you sure the gauge isn't telling lies?
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There isn't a spark plug hole to drop a pencil down is there.
You could remove the injector closest to the tranny and drop a long stick down the prechamber hole and rotate the crank until the stick is at it's highest point. As such you would with a pencil through a spark plug hole. You just need something thinner and a new heat shield to put the injector back in.
The pistons 1&4 and 2&3 move together.
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Eddy, that is what is being recommended, only using a valve. Let the valve drop onto the piston (near TDC!) and measure the valve to determine tdc.
GTD:
IIRC, It has been measured that the gasser flywheel marks are about 5 degrees different from the diesel flywheel marks. I do not have a gas one to compare to, so I can't confirm that, but 5 degrees may be enough to cause you issues, in at least one case it was the suspected cause of (repeated) valve piston contact.
I agree, start by confirming TDC, then double check the cam and IP timing to the crank. However, I am not certain that this problem would give you white smoke, and in fact I think that timed by ear, or trying multiple timing points should have resolved the white smoke even if the cam/crank timing was out a little.
I'll be paying attention to what you find, so please do update us when you find a problem/solution.
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I cant say how many mm timing i run , because my dial indicator adapter doesn't fit into the 10mm Head that i fitted into the pump...
The pump mods are : 10mm head, Governor main spring shimmed completely, timing advance piston shaved to get more advance.
So i have timed it by ear and warm start cranking time for the moment...
If i retard the timing i have to crank it 5 to 7 seconds to get a warm start.
But i dont think that the timing is the problem, because i tried it with 2 other pumps that were completely stock except a gov mod, and tried timings of 0.95, 1.0 and 1.05 but that only changed the warm start cranking time, not the high egts or the white smoke...
Downpipe is 2.25", exhaust is 2.5" .
Intercooler is a Stock 80HP GTD unit.
I just upped the fuel to see if its too low to get more boost.
Before the k24 i had a k14 on it with the wastegate disabled, and had the same egts (at this time i thougt the egts are made by the restriction of the way too small turbo)
Another thing that i mess about is that it now only runs 160kph, 2 months before it used to run almost 200kph.
the engine has 270k miles on it and got some blow by (Oil filler cap dances a bit but doesnt fall down when i open it and lay it on its hole )
To check true blowby, at idle, squeeze the cam cover vent to stop the vacuum effect of the engine. True blowby pressure will become apparent. If the white smoke is a new issue and other pumps do not cure it, then you have a compression issue.
Probably rings, but possibly a valve not shutting properly....
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Eddy, that is what is being recommended, only using a valve. Let the valve drop onto the piston (near TDC!) and measure the valve to determine tdc.
Yes, i know that's what is being proposed. I just find it much easier to remove an injector than a valve. That's all i was saying. But i suppose a valve would be much more precise as it is straight on to the piston face.
I'm one of those "do it cheap & easy ... c'mon it's a vw" kind of guys. But then again, my build DID throw a rod so :P there is something to be said there. And i think it is, "don't listen to smokey eddy. he's a moron."
ps. I'd also be terrified of being 180 degrees WRONG and losing the valve into the cylinder. What a disaster that would be...
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No need to remove a valve - to "drop" a valve you simply rotate the camshaft. Works just like a piston stop... :)
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No need to remove a valve - to "drop" a valve you simply rotate the camshaft. Works just like a piston stop... :)
Nice, I wish I'd known/thought of that before. Oh well. Thank you for the hint.