The Stovebolt Site Forums The Shop Area Engine Shop Adjusting to the Rockies

If all goes well and I can get my 53 panel put back together, I hope to go to Colorado Srings and the high mountains of Colo. this Fall. I remember as a kid that when we went west on the great family vacation my Dad stopped somewhere near Denver and had the carb on our 53 Plymouth "adjusted for the altitude". I have a H/W 2bbl on my 261. I live in TN at about 800'. How should I adjust my carb for "altitude"? Will I need to? Don
P.S. Ya think I should bring an anchor for added braking?

I'd suggest an 8-ounce ballpeen, and hit it medium-hard on the float chamber. That will do about as much good as any adjustment you could attempt. The only thing that's adjustable on that, or any modern carb is idle mixture. Evervthing else that affects mixture is deep down in the works, and is not adjustable, things like main jets, air bleeds, metering rods, etc. As the altitude goes up, a carb runs richer due to the thinner air, and a leaner main jet or a larger air bleed would have to be installed to compensate for the lighter-weight air. An ideal air:fuel mixture ia 14.7:1 BY WEIGHT. Aircraft carburetors have aneroid-type mixture compensation for just that reason, or they have adjustable mixture for altitude compensation. Cars don't have that option, unless they have computer-controlled fuel injection. You might be able to lean out the idle mixture for a smoother idle, but that's all you can do externally.
Jerry

That makes sense.Could it be that mechanics in the late 50's were scamming the poor flatland tourists?!?!! I'm going to be taking the Blue Hwys. and smaller roads so slow going up will be ok. Slow coming down is always good too.
I get the hammer concept; got alot of big ones for fixing things in my shop! I believe in the bigger hammer theory of smithing! Thanks, Don

Where is Kelso? I've got a farm halfway between Pulaski and Fayetteville, in Lincoln County. I work in Nashville, and commute to the farm on weekends.
Jerry

Jerry, Kelso is on Hwy. 64 about 4 miles east of Fayetteville. I'm about 4 miles south of Kelso (postal address) and 3 miles east of Park City. The closest wide spot with a store is Corders Crossroads.
Don

Hey, we're almost neighbors! I'm on the west side of the county, close to Dellrose. Let's get together for a coffee, or something stronger, whenever it's convenient!
Jerry

Jerry, I have sent you an email.

What about advancing the timing? I'm sun cooked today, so I forget how many degrees per 1000 ft..... We're about 6500 ft here, maybe something to check into.

Be careful with timing advance. Some dyno tests we ran several years ago determined that one degree over-advanced robs as much power as retarding the timing 5 degrees from the best setting. Too-early timing also promotes detonation, and severe piston and ring damage. On one full-power dyno run on a Dodge 440 tractor-pull engine, less than 5 seconds of detonation at full throttle burned a 2" hole in the top of a piston. Of course, the engine was developing over 700 HP at 6,500 RPM at the time!
Jerry

I moved to the mountains in 1970, was driving a carburated V8..All I had to do was change the jets, and it made it up Pikes Peak..Good Luck, but don't try to make it more than it is..Steve

I think you'll be OK going up in altitude although you might notice a little loss in power. Of course, the steepness of mountain roads might be the primary culprit.

When we lived at 7200 ft. in Laramie, WY, our car tuned for that would start to knock at Baker, OR on our way to sea level. I'd just use a mixture of regular and ethyl until be got back to Baker.