How dumb can you get
 

As some of you already know I drive a sixty mile trip every Sunday. Well some of the trip is going up and down 8% mountain grades. For some reason I have always had trying to go faster on my mind and never retarded the spark while going down these grades. I always slow down and shift down to first gear as two of these declines are almost a mile long. Yesterday I just moved the spark up all the way and I could feel an enormous difference in the engine holding back. I've been driving model A's since 1958 and never tried or heard anyone comment on this. Is this something everyone knew but me and does this do any kind of harm to the engine? :o

Re: How dumb can you get
 

JUST REMEMBER THE RULE OF THUMB what ever gear you go up in . come down the other side in . ( or lower ) and there at your speed you will be running is where you need the spark. have fun modelAtony tony white Lafayette, LA

Re: How dumb can you get
 

It has been mentioned here before, not often but it has.

Dumb would be knowing about it and not doing it. Your actions all these these years were not dumb at all!

Guess the saying about old dogs is not true after all.

Re: How dumb can you get
 

I am not sure how good an idea this is. You would retard the spark some under severe load going uphill.
But full retard going down is making the motor run very late and prone to overheating. It is holding the car back because it is so retarded. But that ain't necessarily better.

If you must I would not fully retard it

Re: How dumb can you get
 

I doubt there would be much combustion heat going down hill with retarded ignition.

Re: How dumb can you get
 

Re: How dumb can you get
 

It will NOT over heat !!..:rolleyes:

Re: How dumb can you get
 

It may not cause overheating, but I agree with tbirdtbird that full retard going down hill is probably not good practice. The throttle is closed, there's very little fuel/air charge in the chambers, compression will be very low--normally conditions under which you want spark advance.

Do you notice any difference in backfiring?

Re: How dumb can you get
 

i heard it helps but i thought it would bur my exhaust valves.

Re: How dumb can you get
 

"It will NOT over heat !!"

This statement needs to be backed up with engineering data.
The engine will NOT be at idle since the downward incline will impart torque and RPM to the crank
There is no precedent for this or capability for this in any other automotive situation.

Re: How dumb can you get
 

It will not overheat! the throttle is closed going downhill. It is fire that heats an engine.

Re: How dumb can you get
 

Retarding the spark going down hill is no advantage at all. It won't cause overheating but will cause popping. As a kid I would rev the engine and retard the spark to cause backfire or retard the spark to make it pop while decellerating ,going down hill. It had a straight stack back then and still does now. now.

http://i193.photobucket.com/albums/z...rld/Sept-3.jpg

Re: How dumb can you get
 

Let me see,

One mile downward slope
Driver wants to go slow, what is slow? Lets say 30mph.
Driver retards the spark at the very top of the hill and advances it again 1 mile later.
Auto has 30MPH air running through the radiator.
One mile at 30 mph is two minutes

The car will over heat during the two minutes?

Re: How dumb can you get
 

well well well....
as I have stated we need engineering data.

1 mile may not be much of a test.
But what else is going on with this contrived condition:
1. slow revving engine is also not turning water pump very fast, 30 mph air at radiator or not.
2. There will be no internal cooling effect from intake air entering the chamber via the intake valves.
3. It is well documented that a late motor will run hot. Maybe not in 1 mile.
Anyone want to research this further? Anyone want to go down Pike's Peak like this?
Maybe I am wrong. But I think we need more than opinion. Some interested points have been raised.
My suggestion was to leave some advance applied.

Re: How dumb can you get
 

But one mile is EXACTLY what he is talking about!

Re: How dumb can you get
 

This just seems like a bad idea. Not scientific, no mechanical tests done, just my gut feeling.

Re: How dumb can you get
 

Let's ask the experts in these matters:

http://throwinwrenches.blogspot.com/...py-ending.html

Re: How dumb can you get
 

Just to add a new dimension to this, What does a car with automatic advance do when going down hill? If it's an advance that works on centrifugal weights,the advance retards with the lower engine speed. If it's a vacuum operated advance, The vacuum (As a force) goes up and the wipers run really well and the spark advances. Conclusion, It makes no difference.
Terry

Re: How dumb can you get
 

haha Roccaas sends us to a Three Stooges blog for an answer. Maybe that is what it will take:
Strap the 3 Stooges in an A and send them down Pike's peak with the advance lever broken off in the retarded position and see what happens to the car when it reaches the bottom

Re: How dumb can you get
 

One of these grades that I descend is long and winding. I always shift down to first gear at the top and never let it over wind. I have never had an over heating problem. I have a "thermo quail" radiator cap and I can see the red come up on inclines about I/2 an inch but it never comes up in sight going down.