Bizarre question, I know, but ...

Last week I had new axle shafts installed in my 160K 1987 560SL. I also had the oil and filter changed with a quart of Risilone to see if it would quiet down the lifters. Now I have a rattle on light acceleration that sounds to me and the tech who did the work like pinging.

It only occurs on light acceleration when there would be high vacuum - like coasting at 35 mph and giving it a little gas. It does not occur under heavy load or hard acceleration.

The timing is showing 14 deg BTDC with vacuum, which is in spec. I have no reason to believe that the timing has changed. The rattle continues after a fresh fill-up with high-test.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

I don't know. When I was a kid and was putting gas engine's back together I'd dip each part in 1:1 reg motor oil / Risilone. Mostly on faith I believed as I was told that Risilone "stuck" to parts a little better, ensuring the engine was "well" lubricated on first start-up when the pump was first gearing up. It almost sounds like, since you haven't changed anything else, that perhaps the Risilone is pre-igniting. Personally, I'd change the oil back to straight what you were using before and see if you lose the "ping". I'd think it would ping at low vacuum too, so that's kind of evidence against Risilone causing an ignition problem. Perhaps, a long shot I know, a lifter is going through a "freeing-up / sticking phase", though again, the phenomena only heard at low vacuum / moderate to light load sounds like the Risilone is pre-igniting, though, from the 1960's, I don't recall anyone ever having this problem. Geez, that was a long way of saying "I don't know". I'd look at some of the Mopar sites and see if you can come across anything similar.

I did a light search on my own of Risilone and really didn't see anything wrong with it as an additive. A few Master Techs said it was great for quieting lifter's. But, they also said if the rings were gunked up it'd clean them fast. Maybe it's dissolved ring gunk that's pinging.

i had a buick and i decided to do the risoline thing on it..

I put it in the oil... ran the engine for 5 mins then drained the oil and
changed it and the filter.... that very instant the engine started making
a bottom end noise... and it went out...

lost an engine on account of rislone..

the fellows at the gas station said it was just kerosene anyway

Hmm. Normally I would not have even tried this, but I did personally see/hear the stuff stop the ticking in a friend's 560SEL. Think I will do an oil change tomorrow, and I will report.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe