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Waste Motor Oil / Re: Wmo
« on: February 28, 2011, 04:36:51 AM »
[quote author=DRDEATH link=topic=5574.msg67004#msg67004 date=1296937201So back to the auto industry I remember in the 70's when unleaded gasoline came out everyone said it would not work in vehicles not built for it. That was a hoax just to get people to trade. We used it in vehicles that had always used regular gas. [/quote]
Induction-hardened cast-iron valve seats did not hold up well to the removal of lead.
I've had to have several cast-iron heads machined to accept hard seats. The engines would have decent compression, but the rotating valves would wear the seats down so far that the valves would become shrouded in the head, and little airflow could occur. They'd run, but poorly, and the compression numbers wouldn't tell the whole story. Rebuild the heads, new seats, and bingo! Back in the saddle.
Engines with aluminum alloy heads have hard seats already, so little change was noticed with the removal of TEL, but I was seeing only about 40-80k miles on cast-iron heads on unleaded before we'd have to pull them and install hard seats.
So, it's not a complete fallacy that going to unleaded caused more wear. I know it was a good move, to substantially reduce the lead in our environment, but there was a mechanical downside.
Induction-hardened cast-iron valve seats did not hold up well to the removal of lead.
I've had to have several cast-iron heads machined to accept hard seats. The engines would have decent compression, but the rotating valves would wear the seats down so far that the valves would become shrouded in the head, and little airflow could occur. They'd run, but poorly, and the compression numbers wouldn't tell the whole story. Rebuild the heads, new seats, and bingo! Back in the saddle.
Engines with aluminum alloy heads have hard seats already, so little change was noticed with the removal of TEL, but I was seeing only about 40-80k miles on cast-iron heads on unleaded before we'd have to pull them and install hard seats.
So, it's not a complete fallacy that going to unleaded caused more wear. I know it was a good move, to substantially reduce the lead in our environment, but there was a mechanical downside.