Hill grades, altitude, and power

[alhnelson]

Hi: After lots of tweaking of our new engine (440), our Clipper is getting closer to what seems to be normal power. One of the problems I found was lack of timing advance as the old distributor was not giving sufficient mechanical advance. Replaced it with a Mopar performance distributor and orange box ECU, which made a noticeable improvement. Now have the timing (initial+mech advance) at 35 degrees BTDC(assuming the timing mark is accurate).

The Clipper still has to work hard to climb one section of Boulder canyon which is at about 7000' elevation and a long 10 percent grade. I can make it up in 2nd gear but speed drops down to under 30 mph. I've done, lots of theoretical calculations regarding power (torque), weight, hill grade, with adjustments for altitude and drive line loss and it may be that I am just expecting too much from this heavy a vehicle. I've also read the various posts about Clippers cruising over Mt. passes with a towed vehicle behind.

I would love to know what experiences you all have had with steep grades, especially at altitude, what grade hills and in what gears, and at what RPM. Like to especially hear from those of you in Colorado and other mountain areas, and from those who have towed vehicles over passes. I may eventually put on a set of Thorley headers but want to first establish a baseline level of performance from which to work.

Thanks in advance for your input.

Al

[Charlie]

Al,  The only experience I have had at that altitude is Donner Pass in California going to Lake Tahoe area, it is 7200 feet at the summit and a real good grade going west from Tahoe.  My Clipper is a 1979, 21 ft., with a 440 at 72,000 miles.  Almost all stock except for the Carter AFB carb I installed.  Just went over the pass about two weeks ago, it slowed down starting up but was maintaining 50 mph the last mile to the top.  I wasn't pulling a trailer but, I did have a cargo rack with two trail bikes on it, maybe 400 pounds.  You might want to replace the harmonic balancer if the timing marks are showing 35 BTDC, that would indicate something wrong to me.  I replaced mine because I found that the outer part of the balancer had shifted about 3/4 inch.  They cost around $100.

[alhnelson]

Charlie, thanks for the feedback. As to the timing at 35 degrees, I was not referring to the initial setting which is at 10 BDTC. I was referring to the measured timing combination of initial setting plus the mechanical advance at between 2000 and 2600 rpm. This does not include the additional vacuum advance which would go away under load anyway. Vacuum was disconnected and plugged at the time of measuring. The recommended (initial + mechanical), for the 440 engine is up to 38 degrees BTDC which with a good distributor would probably put initial back at 8 to 10 degrees.This is suggested by published specs for the engine and also by the literature that came with the Mopar performance distributor as well as by the engine rebuilders.  Total timing with vacuum advance also included at mid RPM can come up to about 52 degrees. This can be fine tuned by adjustments within the vacuum cannister but again is less critical as the vacuum advance is lost during heavy load. Too much vacuum advance would be a problem if pinging is occuring in which case, the vacuum advance can be adjusted back. Based on this, I have no problem if initial plus mechanical is really at 35 degrees. I am however planning to still check the harmonic balancer timing mark in the event the rubber bushing has slipped and in fact my real timing is actually below the 35 degrees advance. As now set, I have no problem with engine cranking or pinging so there is always a slight possibility that the timing might still not beadvanced enough.
Thanks, Al

[uncleleroy]

My Clipper is a '78 440, about 75,000 miles.  I live on the Oregon coast, but travel to the midwest regularly.  My rig runs fine until I get into the "gasahol" country - just when I need the most power, I can't get gas without an alcohol mix, and driveability goes sour.  Not so much climbing power as poor starting and frequent vapor-locking. Problems disappear as soon as real gas is available.   Re: timing - don't forget most 440 bellhousings have a sight hole and timing mark right on the top, making timing a whole lot easier than using the damper pulley marks.