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RonDwyer82-931 · Joined: 10 Sep 2007 Posts: 35 Location: San Leandro, Ca.

Well, the oil issue solved by my moms' trusty old 1950's era cannister vacuum cleaner. the gremlin was reincarnated as a rough running issue that lent itself to solution by correcting the plug wire connections (amazing how it ran on 2 cylinders without backfiring). I am a little concerned about the smoky running now, it's still on jack stands in the garage. How long do most people experience smoky acceleration before the rings seat? My caterpillar bulldozer support group recommends tossing a handful of Bon-Ami cleanser into the intake, but that is vintage 1948 technology! I put in a fresh set of fitted Deves rings on the re-assembly, but I have a sneaking suspicion I got so excited to finish the project that I never broke the glaze on the bores. Duh. Anyone have any ideas short of getting a little rough on the beaver? How long does it take to ruin a catalyst with smoky exhaust? OK, so I'm a little on the nervous side. Actually not nervous, just thrifty after the divorce.

924RACR · Posted: Wed Sep 19, 2007 10:09 pm Post subject:

Well, you can't seat the rings without load. Revving in the garage does nothing, may in fact set back your efforts to seat the rings. You need to go out and drive the car hard, put it under load, and run it through the gears...
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Vaughan Scott
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'79 924 #77 SCCA H Prod racecar
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Chrenan · Joined: 15 Jan 2003 Posts: 3903 Location: Canada

I'm with Vaughn, the engine needs load to seat the rings, it can't be done while sitting. After I rebuilt my 924 engine, I only kept it running in the garage long enough to know it would stay running. Then, I was out in the evenings when the roads were empty, up and down through the gears, lots of engine braking, full throttle runs but only to a 4000 rpm for the first 1000 km. After that, I have driven it hard, redline at least a few times each drive, and it nevers misses a beat. Uses less that the factory recommended 1 litre of oil per 1000km.
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1987 951 - M193 Version for Japan

Paul · Posted: Fri Sep 21, 2007 11:29 am Post subject:

If you did not cross hatch the cylinder walls, the rings may never seat.

If you ran it for long on 2 cylinders, you have a lot of gasoline in the oil. This may have diluted the oil to the point that it is easily getting past your rings.
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White 87 924S "Ghost"
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Owned and repaired 924s since 1977
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RonDwyer82-931 · Joined: 10 Sep 2007 Posts: 35 Location: San Leandro, Ca.

I didn't run it long, and the oil has no smell of gasoline in it. I did research my invoices and did have it honed when I hot-tanked the block. A hundred miles of varying speed acceleration and mountain roads cleaned up the smoke thankfully. I'll go another hun in the morning for good measure!

RonDwyer82-931 · Joined: 10 Sep 2007 Posts: 35 Location: San Leandro, Ca.

Seems time cured this one. I'll settle for drips over smoke any day!