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Engine Specific Info and Questions => IDI Engine => Topic started by: levi20AE on February 28, 2011, 10:21:42 pm
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I did a compression and leakdown test tonight and the numbers seem awfully positive (maybe overly high).
500 550 475 500
7% 4% 6% 8%
The motor is a 1.6NA in a 1982 Caddy. The approximate mileage is 207,000. I have taken great care of it and the oldman before me was the OG owner(he had another caddy with 1,250,000mi). This truck was his "garage truck". I did the tests cause it has always put out alot of grey/white smoked since i have owned it. Under zero load it does not smoke at all but under moderate load there is a noticeable amount of grey/white smoke. Under full load the normal black smoke is present. I have recently found a K24 turbo, intake and exhaust manifolds. The fuel economy has gotten better with the turbo at very mild boost (5-7 PSI) and the smoke is "maybe" less but not that noticeable. My question is what other factors could be causing the white/ grey smoke? The performance is there but the smoke concerns me. The only hint of a leak during the leakdown was occasional tiny bubbles past the lifter buckets but nothing consistent. Would replacing the valve guide seals reduce to white/grey smoke?
Thanks,
Levi
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Those compression numbers (assuming your gauge isn't blatantly lying) are indicative of a very well maintained and broken-in engine hitting its prime... congrats!!
Leaky valve seals cause oil to drip down the valves and then burn.. generally noticeable as a puff of blue smoke when first starting the engine after it has sat overnight. Doens't sound like your story.
White smoke is generally unburnt fuel...worn/misfiring injector(s) a possibility but most commonly retarded timing. What timing valve are you set to? Do the injectors have 207K miles on 'em?
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I should have mentioned that I just had a set of 130bar injectors rebuilt to 155bar, after installing the K24. The new injectors netted another 2 mpg gain! Still smoking though???
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Are you running a td pump? And where is your timing set?
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What timing valve are you set to?
One a turbo engine you can safely be in the 1.00 to 1.05mm range.
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It's still an NA pump ( that's why the pressures are so conservative) set at .039" (.991mm). Should I try a less aggressive setting?
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If you are running turbo injectors (155/150 bar) use the turbo timing spec 1-1.05 as Vince indicated.
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I will try that tomorrow then. Thanks!
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set the injection pump timing to 1.05 tonight and it did seem to reduce the light colored smoke some. I also found that the junkyard turbo is pretty unhealthy. There is a good amount of oil blowing by the compressor and into the intake manifold. This is likely another cause of light colored smoke.
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set the injection pump timing to 1.05 tonight and it did seem to reduce the light colored smoke some. I also found that the junkyard turbo is pretty unhealthy. There is a good amount of oil blowing by the compressor and into the intake manifold. This is likely another cause of light colored smoke.
ive never seen a turbo that was COMPLETELY CLEAN..
my VNT cakes my charge piping with engine oil..
i bet your turbo is fine. if its bad, it makes the engine run away.
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I was also did a boost leak test so I had the silicone hose that runs from the turbo to the intake manifold off. I started the truck without the hose or the airfilter to see just how much oil is coming from the turbo while the truck was running. I was surprised to find that the turbo wasnt spinning at idle until the truck had been idleing for ~ 5 minutes. Even then it was easy enough to just touch the but on the turbo lightly and it would come to a stop. No oil was streaming from the compressor outlet which was my fear but I am very concerned with the journal bearings in the turbo. I have a healthy K26 from a previous project. Does anyone know if the bearings are compatible?
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I just had my K14 and K24 apart and they had different size turbine shafts. This doesnt really help but my guess is that they would have different size journal bearings. The K26 has a different flage compaired to the K24. You could easily make a adaptor to make it work.
Maybe just try out the k26 and see how it works, it might spool really late though.
Here is a ton of info on the K26 all depending on what vehicle it came off of. Hope this helps.
http://www.924board.org/viewtopic.php?t=15595 (http://www.924board.org/viewtopic.php?t=15595)
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if your idle is very low, and the oil pretty cold, your turbo may not spin till you get some into some rpms..
i can stop my VNT with one finger, and its far from worn out.
does your turbo still boost? does it make any odd noises? maybe the smoke you are experiencing is from valve seals? my old rabbit used to smoke blue from bad valve seals.
always thought the turbo was where my engine was losing its oil, but i put the turbo on a different engine and it hardly burns any oil..
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Im starting to think the smoke is valve guide seals as well after the good compression and leakdown results. The turbo whines more than I'm used to hearing. Also when going 65 on the freeway if I floor it only make 5 lbs. I can get it to make more by increasing fueling. Has anyone had dealing with rebuilds from the Gpop shop?
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Gpop shop is good.. GeeBee backs then whole heartedly. he doesnt do that for someone unless they deserve it..
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one of the car club guys just had his grand national turbo come back from gpop. They do very good work.
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I just had a 2.5" exhaust made for the downpipe back yesterday and the spool is still horrible. I knew that a bigger exhaust was gonna be necessary down the road so I stung for it this week before the road trip next week. I'm driving from Las Vegas to San Fransico and then down to LA before coming back to LV. I'll plan on replacing the valve guide seals when we get back. Turbo blows but is still better than nothing.