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Old 03-29-2005, 11:23 PM
rgnprof rgnprof is offline
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Join Date: Feb 2003
Location: Oklahoma
Posts: 1,073
'72 250 Crane/Zenith update

Just thought I would provide a brief update to the earlier post regarding my Crane installation. I was having trouble with the vacuum advance and emission switches, so at last report I had bypassed the smog stuff and was running vacuum directly from the front Zenith to the vacuum advance on the distributor. Thought things were better and ran it that way for several weeks - and it did run better at highway speeds but around town it was sluggish and I had an increasing problem with carb backfire. Convinced it was a timing problem I decided to totally disconnect the vacuum and plug the lines at the carbs, and set the timing to 10 degrees BTDC.

Result: No carb backfire at all (for the past week) and took it to Tulsa today (225 miles round trip, 70 mph) and got 18.5 mpg and car ran well, also got 14 mpg aroound town. Both are much better than usual. Checked the timing advance at 3000+ rpm and I'm getting almost 40 degrees, when I should be getting up to 54 (according to the manual), but I'm assuming 40 degrees is enough. I really don't think I'm going to get much better than 18.5 mpg on the highway. Still have a slight lurch off idle, but not too bad. Again, thanks for all the help and suggestions.

Ryan
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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE
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