Been seeing more and more of these older Mercedes both 4,6 and 8 cylinders with blowby problems. I had a very nice 560 SEC come in the other day that was very bad. It was so bad in fact that when you took off the oil fill cap you could acually see and hear the blowby. The crank case was so pressurized that pressure control system was unable to keep up, plus there was a big problem with the air flow sensor plate being coated with oil, messing with the idle quality.
While most of the V8 engines in the W126 were aluminum, its not very supprising that they develop this condition. There is a lot of information out there about how cylinder walls are supposed to look. More times than not on high mile engines consuming oil its the piston rings and walls that are causing the problem, not the valve seals.
Fixing blowby is a very expensive problem as it ultimatly requires a complete engine overhaul. Depending on the condition of many other componets on these engines, that can get very expensive, very fast. Just ask Teutone the moderator of the monkey house "BenzWorld.org", ask him if blow-by is good news to him! LOL
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What is to give light must endure burning -- Viktor Frankl
Regretfully I've had very little to do with the reconditioning of these aluminium MB V-8's, as they've been pretty well proven to be reliable, and when the "big-bang" problems have occured from a customers neglect, the repair has usually been a change-over motor from a crashed donor vehicle etc etc. Like the Sates, Oz has very few places that have the Sunnen K-10 machining facility, and so re-manufacturing the cylinder bores etc has yet to be realized, at least from what I've heard, though I've been out-of-touch with this side of things for a little while now...However...From a performance point of view where engine-life has been deemed less important than performance...Wouldn't one of these worn 560's with blow-by trouble be a perfect performance donor engine ? I would have thought that if it was possible to re-finish the cylinder bores by honing, ( or whatever process is required for these motors ), the fitting of a fresh set of piston rings ( pistons in reasonable condition of course ) would see the engine perform quite well, at least for say 20,000 miles since the internal friction of the pistons to bore clearances would now have much less drag etc that would enhance HP out-put due to reduced internal friction ? * This could possibly make for a great Drag-Car motor... Have you ever had the opportunity to re-fresh one of these babies with just say new rings and bearings ? If you have, what were your results ? Thanks mate !
Cheers,
Rastus
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"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together". Dwight D.Eisenhower.
I have not yet run into anyone with deep enough pockets for a full on M117 overhaul.
Many top halfs, chains, ect. but no full on overhauls with the exception of the one I plan on doing for myself.
You have to figure a full R/I + Overhaul done right with all new or reman parts would be upwards of $15,000.00 from start to finish (includes R/I engine of course) and it could be higher depending on what kind of parts you go with.
Book time alone is almost 60 hours! Do the math on that and then figure in parts cost and there you have it.
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What is to give light must endure burning -- Viktor Frankl
