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| Gas mileage for a flathead Willys Jeep; MPG's for Willys Jeeps | |
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| Tweet Topic Started: Dec 15 2012, 08:46 PM (2,069 Views) | |
| mikec4193 | Dec 15 2012, 08:46 PM Post #1 |
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Hi Everyone I am about waist deep in a 1947 Willys CJ2A rebuild and it is going to be totally stock when finished. I really want to run this vehicle to my day job (daily if possible)which is about 11 miles from my house. I think I have stock gears in the rear end also. What kind of MPG's should I be looking at when it is all said and done?...Motor is totally rebuilt and the transmission will be too when reinstalled in the next couple of weeks. Any insight would be wonderful. Thanks everyone. MikeC |
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| Bob | Dec 16 2012, 11:31 AM Post #2 |
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Bob
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A good guess is anywhere from 15-18. The low gears and low power of the motor contribute to this. |
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Bob 1953 CJ3B 1965(?) CJ5 1949 Jeepster 1947 Cj2A 2004 Kubota l3400 | |
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| oldtime | Dec 16 2012, 03:18 PM Post #3 |
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Mike, Welcome to the CJ-3B Bulletin Board !Seems perfecrtly reasonable to me if enroute posted speeds do not exceed 55 mph. 1947 should have a Dana model 41. This particular axle was only manufactured with 5.38 final drive ratio. No aftermarket gears are available for the D41. Realistic sustained top speed without O.D. is about 50 mph. Driving 45 mph will yeild better mpg due in large part to jeep not engineered for aeroynamics. Expect slightly less mpg than the F134 equivilant. With 10% ethanol fuel figure about 16 MPG. Personally I gave up on the Go-Devil engines after the national speed limit increased above 55 mph. That was back in the early 1980's. The Hurricane only provides 12 more HP but that's a large percentage compared to the Go-Devil's 60 HP. The Hurricane provides just enough power that I can maintain 60 mph on the steepest Missoiri Interstate grades at wide open throttle (W.O.T.) My current one and only daily driver, a 1962 CJ-3B is set up with 5.38 final drive, 29.5" tall tires and Warn O.D. |
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Currently building my final F-134 powered 3B . Rock Crawler using factory parts from the Willys Motors era (1953-1963) http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new | |
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| johnrb | Dec 17 2012, 11:54 AM Post #4 |
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You notice Ken (oldtime) mentioned overdrive. That's the easiest upgrade you can do to an old CJ. Simple bolt-on. It'll give you a little better gas mileage and it'll give you a little more top speed. Nothing major on either front. But the real advantage is that it lowers your engine RPM 25%. Those engines were red-lined at 4,000 RPM but you probably don't want to push those 65 year old connecting rods that hard. I feel most comfortable keeping my 3B's F-head at 3,000 RPM or below. The F-head's torque curve peaks at 2,200 RPM so that's a good target. Overdrive is great for that. And it turns your 3-speed into a 6-speed. I love more gears. Used Warn / Saturn overdrives can be found but it's a crap shoot as to their condition. You can get a nice, shiny, new one from Herm http://hermtheoverdriveguy.com but it's not cheap - $1,000 I think it's worth every penny and Herm's "tech support" is priceless. If you do find a use one for cheap, you may end up having Herm rebuild it before it'll work. Might as well save the hassle and get a new one. Or you might find a "whole" CJ with overdrive in it. I bought a totally rotted out 3B for $900 that had a good, running engine, sound drive train and a working overdrive. It was a bargain. I got my money's worth on that one. |
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John Burch - west burbs of Chicago 1946 2A - now I have one older than me 1949 - me - no longer older than all my vehicles 1954 3B - mostly stock - fun driver and snow plowing 1957 - 6 cyl Station Wagon - hope for the future past Willys 1954 3B - no tub | 1959 3B - engine in pieces in a box past addiction - VW 1969 Bus | 1970 Westfalia Camper | 1984 Westfalia Camper | |
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3:46 AM Jul 11