Originally posted by 1991 318is
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That's the only one he really uses, but he'd seen another mechanic stick straight acetone in a crankcase, run for 20 mins, and drain the oil and change. I don't know the quantity used, but I wouldn't guess much more than a cup if it was a 5 quart oil system. He said that worked for freeing sticky lifters.
As a cocktail, since I was in the refineries, I'd get one of my friends research grade toluene which is 120 octane, and what they run in the test motors in the refineries to get the final octane value of gas blends they send out. He used it in his wifes' v-tec Prelude since she was running it down at SIR.
I now use the following toluene formula where, since I no longer am in the refineries, have to use standard grade which is 114 octane.
So since toluene is 114 octane, use this to figure what octane you get:
( Gallons_of_gas * Octane_of_gas ) + ( Gallons_of_toluene * 114 )
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Total Gallons
Toluene isn't as cheap as it used to be, but still cheaper than buying retail high octane gas. Roughly $8.50/gallon a few months ago.
I used to get to 100 octane and run my old Corrado on that from time to time, and I'd stick a cup or mineral spirits in too, used to really wake up that VR6.
It seems like anything over 100 was overkill, since you never had the knock sensor retard the timing, that being my goal with the Corrado. Same thing though with my old YZ250 dirt bike, and my current YFZ450 quad. My BMW never got the toluene treatment when it had the S14, so I don't know what benefit would come from it there.
Something I personally did when I got my Landcruiser was to pop the plugs and I put ~1.5 ounces of 2/3 mineral spirits / 1/3 laquer thinner in each chamber, let sit overnight, and fired it up and ran for 15 minutes. I did this 2 more times and got quite a bit of laid down carbon off my pistons. After the 3rd time I changed my oil to be on the safe side, since I'm sure some got past the rings. Worked quite well, I borrowed a bore scope and was able to see almost all but a really thin layer had broken up and blew out.
Another mechanic I trust who was a lead mechanic for a Saab & Porsche dealership, and raced Viggen(SP?) Saabs, said a whole bottle of Redline fuel system cleaner in 5 gallons super unleaded does a lot of good, despite the Redline bottle saying to add a full bottle to a 20 gallon tank of gas.
Funny sidenote, we used to get those fuel system additives (Techron, Clean System 5, whatever Shell called theirs too) in 4' x 4' x 3' plastic totes, maybe 200-300 gallons. That stuff in pure form was very corrosive to all but the stainless ball valve & teflon gasket. Anything else in constant contact was in pretty poor condition down there. I thought it was funny.
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