I was just wondering if a colder or hotter plug would reduce how much my engine pings...?
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Kyle - '68 Volvo 142 w/71 b20b and m40...

Today when I drove my car around, it seemed to never get up to operating temperature... Maybe it just looked that way because it's low on fluid... Better top that off, I'll report if the engine is all of a sudden running cooler... It is colder outside, but it should still get hottish. I'll check it out.
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Kyle - '68 Volvo 142 w/71 b20b and m40...

Well, Today I drove it around a bit more, topped off the coolant, and yeah. I guess in this 40 deg. weather it just runs COLD. For example, normal temp when it's getting decent amounts of air is just before or just at the white line on the temp guage. It starts pinging when it starts to go above that. Well, while driving around today, the temp guage barely registers anything, unless I sit for a little bit at a light. After letting it sit and idle for a while(~5 minutes, to get as hot as i could) it would get up to the line where it normally is. It probably would've gone higher with more time, but whatever. So I guess with my current intake setup, and just in general, it runs cold in these cold temperatures outside...
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Kyle - '68 Volvo 142 w/71 b20b and m40...

Fit a warmer thermostat. But then it will ping again! What fuel do you use? Her in New Zealand you can get only unleaded, but some stations have 98 which is a must for my Stromberg B20B. If I use 96 then the engine diesels almost every time I turn it off. And the only other option is 91 or converting to LPG which is equivalent to about 105 or so.

Have fun...

Unless the spark plugs you have now are the cause of the pinging, then no. Use an NGK BP6HS at about .030 inch, and that's it. The pinging is more than likely overadvanced timing, and possibly carbon build-up in the combustion chambers. You should be using the best gas you can find.
Rhys

Whelp, I've been using 76 91 octane, which is premium... Timing is about 10deg... And I have the 6's... I've done the water "injection", as in pour (slowly) water into each of the carbs and let the black smoke billow out the back... If there's still black smoke coming out does that mean there's still more carbon? Or will there always be black smoke even when you've gotten rid of all the carbon? Cause I put a lot of water in there and then stopped, just because I thought I had done it long enough... But if the smoke is supposed to stop being black, then I have some more to do. But I've already tried that. Maybe the head has been shaved? who knows. I was just wondering if there was a quick fix. It's not that big of a problem, and I don't drive it much any more, being illegal and all.........
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Kyle - '68 Volvo 142 w/71 b20b and m40...

I don't use water to remove carbon, I squirt ATF into the carbs. The smoke is blue, dense, and huge. Environmentalists will surround your car and heap abuse at you. Small dogs and children will run from the sight. Helicopters will appear overhead and you will hear amplified voices shrieking at you.
But the combustion chambers will be clean and spotless, and the pinging will be gone if it is due to deposits.....

Haha, sounds like fun... But how does that work? Water theoretically is able to disolve carbon deposit and flush it out, but does that also aply for ATF? I would tend to think it would actually deposit even more carbon. Just curious.

Cheers, ben
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P131, '65, B20B+M47. P131, '69, B20E+AW71L+LSD. (www.tinustechniek.tk)

I was under the impression that (since oil and water are largely incompressible) you were temporarily raising the cylinder pressures to very high levels and "shocking" the carbon off... The smoke is understandable as you are adding oil and making it very hard to burn the fuel properly.

Mike!

If you pull the head off an engine that is burning oil past the rings, you will notice the tops of the pistons are clean where the oil comes up. Usually a crescent shape on one side or the other. The oil combines with the carbon and sets fire to it essentially. Years ago with leaded fuel the occasional domestic V-8 would get a piston knock, the result of a flake of heavy carbon coming loose and getting pinched in the quench zone of the head. Half a litre of ATF and the carbon dissappears as the engine is revved. Always impressed me. I have also done this trick before tearing an engine down for rebuild, to see the cleaning action. Very impressive. It is just that the smoke produced is extreme, and far too much for any engine with an O2 sensor or a cat. Of course modern engines don't produce heavy carbon internally anyways.
Water works more slowly, and doesn't hurt anything, but it softens the carbon rather than burns it out.

I always just tweak the timing until pinging is gone or at an acceptable level...

-Matt
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-Matt '70 145s, '65 1800s, '66 122s wagon, others inc. '53 XK120 FHC

Well, the pinging is gone, unless the car sits for more than a minute at a traffic light or anywhere else, the temp will go up as it sits, and it'll go up just enough(not necessarily that much) that it'll ping (not under light loads) until it cools back down... So basically it's on the verge... Which is annoying considering it's only at about 10 degrees advanced...

Do the older motors have different cooling systems at all? Like this 71 compared to my 74? I know that my new motor has quite a bit higher compression, so that would account for most of the heat increase, but it seems like a bit much, but maybe not. I might just not be used to the higher compression?
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Kyle - '68 Volvo 142 w/71 b20b and m40...

same cooling system, try using a colder thermostat in the system. should keep the temp down. my engine has 10.5 to 1 compression. if i leave the summer 180% thermostat in in the winter my car never gets to operating temp, and if i leave the winter 195% thermostat in in the summer it will get too hot at lights. i also have an e-fan witch rarly comes on in the winter and only when stoped in the summer. if you have a cooler thermostat in then maybe you should flush your system. maybe try some water wetter if all else fails. best of luck