John R Murray Posted December 16, 2015 Share Posted December 16, 2015 My car is relatively new to me and I am thinking that it's mileage (<9 miles per gal.) may indicated the need to do a range of things, e.g., rebuild carb, rings, spark plugs. What should I be expecting for mileage? Recommendations for the order for things to fix if I should be concerned would be appreciated.. Thanks for any help. Link to comment Share on other sites More sharing options...
Daves1940Buick56S Posted December 16, 2015 Share Posted December 16, 2015 Start with a compression test. That will tell you loads. Cheers, Dave Link to comment Share on other sites More sharing options...
FLYER15015 Posted December 17, 2015 Share Posted December 17, 2015 John,Sounds like you need a "tune up".In the old days this was set the valve lash, set the points set the timing, clean the plugs, tune the carb, usually in that order. Dave's idea of a compression test would fit right in with clean the plugs. Oh, and when you set the points, clean the contacts in the dist cap and the rotor, and apply some vacuum to the little fitting at the base of the carb and see if the dist plate moves. It may need some lube. This also checks the line and the advance diaphragm. Either one could be leaking, and that ruins mileage. Ring us back with some MPG figures when these are done, and then we'll talk about setting the float level in the carb, (carby for Danny and folks down under). Mike in Colorado Link to comment Share on other sites More sharing options...
DonMicheletti Posted December 17, 2015 Share Posted December 17, 2015 My '38 Roadmaster gets about 12 mpg on the highway at a pretty good clip. However it weighs more than your Century and the Century has a better rear end gear ratio. That being said - you should get better mileage than you are getting. There are lots of things that can be wrong from those mentioned to a choke not completely opening and a bad vacuum advance itself on the distributor. Link to comment Share on other sites More sharing options...
John R Murray Posted December 17, 2015 Author Share Posted December 17, 2015 Thanks everyone. Good ideas. I'll start tomorrow and let you know how I make out in a week or so. Best regards, John Link to comment Share on other sites More sharing options...
danhar1960 Posted December 17, 2015 Share Posted December 17, 2015 "Ring us back with some MPG figures when these are done, and then we'll talk about setting the float level in the carb, (carby for Danny and folks down under). Mike in Colorado" Bugger !!! I thought carbs were something you avoided to stop getting fat. :) How's it hanging these days cobber ?? Danny 1 Link to comment Share on other sites More sharing options...
Mark Shaw Posted December 17, 2015 Share Posted December 17, 2015 My 38 special gets around 12 mpg. Link to comment Share on other sites More sharing options...
Larry Schramm Posted December 20, 2015 Share Posted December 20, 2015 One suggestion is to only do one or two items at a time and then go out and drive it. If you do it all at once and then it will not run properly it might take you some time to sort out what would now cause the car not to run properly. By doing only one or two items at a time and driving after each change, you can easily know where to look. Just a thought and from others experience of "doing it all" and then the car will not run. Can take a long time to sort it out. 1 Link to comment Share on other sites More sharing options...
DonMicheletti Posted December 20, 2015 Share Posted December 20, 2015 AMEN! to Larrys comment Link to comment Share on other sites More sharing options...
FLYER15015 Posted December 21, 2015 Share Posted December 21, 2015 "Ring us back with some MPG figures when these are done, and then we'll talk about setting the float level in the carb, (carby for Danny and folks down under). Mike in Colorado"Bugger !!!I thought carbs were something you avoided to stop getting fat. :) How's it hanging these days cobber ??DannyFat n sassy mate.We just got 12" of snow up here in the high country, so it looks like a white Christmas for sure.The "baby" is tucked away in her trailer, just waiting for spring. I heard recently that that tiny island just east of you is getting a new flag with a palm tree in the corner, in place of the union jack.Won't Grant be proud ?Maybe they will get a 2nd amendment.You know. Like the one they are trying to take away from us.Only a year to go.............Till regime change, I hope.Be well. Mike in Colorado Link to comment Share on other sites More sharing options...
FLYER15015 Posted December 21, 2015 Share Posted December 21, 2015 My car is relatively new to me and I am thinking that it's mileage (<9 miles per gal.) may indicated the need to do a range of things, e.g., rebuild carb, rings, spark plugs. What should I be expecting for mileage? Recommendations for the order for things to fix if I should be concerned would be appreciated.. Thanks for any help.John,Are you sure you are talking about the '39 Buick and not the '65 Riv.I had a '65 Riv, and on a trip from Iowa to California and back I only got 9 MPG.I left Ca. with a $20.00 bill and an American Express card.Back then only Sinclair stations took A.E. so we got gas at every one we could find.What a trip................. Mike in Colorado Link to comment Share on other sites More sharing options...
carbking Posted December 22, 2015 Share Posted December 22, 2015 In order: (1) compression test If poor compression, decide on if you wish to do an engine tear-down. If good compression (2) place the car on jack-stands, and check the bearings for grease and the brakes for drag. On to the engine tune-up. If an electronic gadget has replaced the points, make sure the generator was upgraded to an alternator. Check performance after each step. (3) SEE NUMBER 8, OUT OF ORDER FIRST. Then check the condition of points, and the dwell; replace points if necessary (4) Check operation of vacuum advance (5) Adjust the timing (note to do timing AFTER dwell). (6) Check the spark plugs (7) Check the spark plug wires (8) SHOULD BE NUMBER 3 - check the engine ground connection. (9) Check fuel pressure (10) If necessary, dig into the carburetor and rebuild Jon. 2 Link to comment Share on other sites More sharing options...
JamesBulldogMiller55Buick Posted December 26, 2015 Share Posted December 26, 2015 Make sure the brakes aren't dragging Link to comment Share on other sites More sharing options...
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