Thread: Common Sbc Myth's

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Why do you think there are a lot of aftermarket parts made for it????

There ya go..............

I have heard of the term dwell in regard to time at tdc on a cam, but not for years... Schneider and Lunati used to play with it some on their roller cams. Now cam science has gone so far beyond dwell and do more engineering in the cam opening and closing ramp rates. When time at TDC was the rage, lots of the chebbie guys were boring their lifter bores out to use the Ford lifters so they could have the point of the lobe, thereby the dwell, longer. Nobody is wrong here, just some of us are a lot older then others......

If Tech comes along, I'm sure he could explain all the differences in cam engineering over the years if he were inclined to write a book. I still do it the easy way, call one of the engineers at Comp Cams and get one ground. Got to remember, years ago we didn't have all the long rods to keep the piston at the top longer, and the emphasis was all on the cam designers to make the engine work. This was also when flow benches were rare, and everyone thought bigger was better on port and runner size.....

Originally Posted by DennyW

Actually, the cam lobe dwell should be longer than the piston dwell, as to get the flow going to fill, or empty the cylinder quicker. Along with a modified lobe ramp to speed up the sealing of the valve.

Denny, this goes back to an old discussion we used to have to kill time running countless miles towing the sprinter around from track to track...... Does scavenging the cylinder make the engine think it has a blower on top, or does scavenging increase the velocity of the intake charge so much that it doen't atomize the mixture properly and give the cylinder a false rich condition and kill a good burn across the piston top....????? The tow from Rapid City, SD back to the shop was 380 miles, we did it every Friday night (aka Sat. AM) for a couple years. This was the topic on a number of those trips!!!!! Not sure we ever resolved the issue, or if anybody ever managed to convince the others that his viewpoint was right!!!! And no, I'm not even going to say which side of the argument I was on!!! You don't even want to know what some of the other topics were!!!!

Oh yeah, we were running methonol, too. And sometimes somebody would sneak by and toss about a 4% load of nitromethane in the tank.... Made the discussion even more lively on the way home.....

PS---at 10% in a 40 lap main on a 1/2 mile dry slick track, the piston tops resemble crispy critters!!!!!

Dwell means to stay in a place for a certan amount of time. Bob is right. When refering to points dwell is the amount of time the points stay open, same as with piston staying at TDC or BDC for x amount of time, same with lifters.

I stand corrected, the amount of time points closed.