project with 302 needs exhaust....and future part list.

After lower hose R&R, went for a drive with distributor settings of: 10 initial, 9 manifold vac, about 25 mechanical all in by 3K. The difference is unbelievable. Part throttle power went from nothing to "do you wanna burn off from a 15mph roll with slight throttle?" I am still grinning. I also drove on a road with an incline that had a wall by the sidewalk to reflect sound through an open window, and accelerated from 30 to 40 in drive. no ping. A lean stumble upon cracking throttle is worse than before, But I may need some carb cams to fix it. The adjustment on the accelerator pump is practically zero lash, but not so tight that it wont wiggle easily. Top end may be on the lean side...

 

Ideally you would soften the spring and limit the mechanical sweep to about 10-12 degrees to allow bookoo initial spark lead(up around 25'ish) which pushes manifold vac up while sharpening throttle response from abrupt idle to wot throttle snaps. Then add another 8-10 degrees for vac assist. Tough to do without solder or welding the factory unit but these lite motors feel much bigger down low when you get closer to ideal.

 

Can one get away with 25* initial with iron heads? I am running a 160 Tstat, about 9.5:1 compression(?) (static pressure 165-170). Heads are 1968 2V heads with un-known work. I did have the intake off, and the ports lined up nicely. Both heads and intake (torker 289) have relatively small ports. I think I can solder a piece of brass into my distributor to limit the mechanical at the upper end; I just have to take it apart and see if that will cause it to bind....but I think I can figure a way to do it. Then I can leave the spring alone, as what will be left of the mechanical advance will be done by 2500 rpm. I may have to experiment with that 25 initial with some 1500 rpm engine loads to see if it will ping. I also may be running out of good weather, and it might have to all wait until spring. Such is the life of a true back-yard mechanic.

 

Depends on a few factors, gear ratio being a biggie.. but many engines can run completely locked timing of 36 degrees and have no issues. These carsare also lighter than many other models which helps improve engine accelleration rate to avoid lugging.

 

I took my distributor apart. It had a 13 and an 18 slot. I moved it to the 13 and soldered a piece of brass in the upper end of the 13 slot to take out 1/2 of the space used for the advance. I used a mini torch and some flux....it will never come out unless that part heats up to 350*. After re-assembly, my timing light said I had 12* of mechanical advance, all in at 2500 and no more after that. I set initial at 24*. The vac pot gives 10*. Didnt get do do a full battery of tests before my carb started acting up again, but it has got some angry grunt without even using the secondaries. TFI ignition is up next.

 

Too bad more people don't pay closer attention to posts like this. ^^^

As I've stated many times to various gearheads theough the years that there can be upwards of 40-50 lb/ft of torque gains in the lower rev ranges. And the dramatic effect it can have at the carb boosters ability to help the motor come up on the cam can make a motor feel bigger and much more responsive to the go pedal. Congratulations on opening your mind to learn things that some others never fully grasp in a lifetime of working with engines.

PS. Next thing to wrap your head around is how heavy ignition lead tends to lean out the carbs idle and cruise circuits to the point of lean musfire and surging.

 

The 302 that was the subject of this thread was replaced with a used roller 302. The 302 discussed in this thread was torn down, and the following discoveries were made: The heads had 68cc chambers, The pistons were .040 down the hole, and the gaskets were .050 compressed thickness. All added up, this motor could not have been any higher than 8:1, and everything was sooty including intake valves and ports all the way back to the intake. This is why it responded so well to electronic ignition, with so much initial and total timing. Also compounding its problems were the thermactor bumps in the exhaust ports, single plane intake, and a cam with a late exhaust valve closure. What a mess!!!!! The replacement engine has a dual plane manifold, GT40 heads, a cam with 210* @ .50 duration, .035 quench, 9.9:1 compression and has far less advance. It does not ping with 87 octane, gets 15 mpg instead of 10, and runs the smile meter much higher. I am learning alot as I go, and have accumulated a small stack of David Vizard books. Next up for my car will be a posi, and then some chamber work on the heads and a tighter LSA cam.....but posi first.