Just bought a 1972 Skylark that needs tuning?

[Timmy-Boy]

So i just bought this beautiful lark. I payed $3,000 for It. I'm about to turn 17 and this is basically my first car. The car is almost all original excluding the wheels and the interior has been redone. It has 79,000 original miles on it. Under the hood is a 350 with a 2bbl carb I believe to be a Rochester? Or whatever comes stock on them. The car runs good but It needs a good tune up. First thing is the car will bog when given to much gas to quick. I'm pretty sure its because of a lack of air. I also checked the spark plugs and they were pretty black which I'm pretty sure is a sign its running to rich? It seems to idle perfectly normal and when sitting if you give it gas it doesn't really bog. I need to figure out how to solve this problem so I can start driving her. I plan on doing an oil change, new plugs, belts, hoses, etc... Please leave me your thoughts on how to solve this problem and any other things i should consider doing to her before hitting the road.

[raycow]

For the black plugs, check that the choke is opening fully and the air filter isn't clogged. Bog on throttle opening is usually caused by too little fuel rather than too much. Check that the accelerator pump is working.

Besides the other maintenance items you mentioned, a 72 would still have distributor points if it was stock, so replace them if they look bad and check the dwell and timing. Don't forget to put a TINY amount of grease on the distributor cam. You might also want to attend to the grease fittings on the front suspension and steering linkage.

Had the car been sitting for a long while before you bought it or was it being driven more or less regularly?

Ray

[Timmy-Boy]

For the black plugs, check that the choke is opening fully and the air filter isn't clogged. Bog on throttle opening is usually caused by too little fuel rather than too much. Check that the accelerator pump is working.

Besides the other maintenance items you mentioned, a 72 would still have distributor points if it was stock, so replace them if they look bad and check the dwell and timing. Don't forget to put a TINY amount of grease on the distributor cam. You might also want to attend to the grease fittings on the front suspension and steering linkage.

Had the car been sitting for a long while before you bought it or was it being driven more or less regularly?

Ray

The air filter is defiantly not clogged. Judging from the how It idles upon start up I'm pretty sure the choke is opening fully. But ill double check that. Can the bogging also be because of a lack of air though?

What exactly is the dwell?

The car basically sat for about two years. The owner would start it up every once in a while and drive it around the block and that's about it.

[telriv]

Where do you call home????

[raycow]

Can the bogging also be because of a lack of air though?

What exactly is the dwell?

It depends on how you would describe the bog. If the mixture is too rich, the engine will run sluggishly and the exhaust will be smoky (black smoke), but it will normally keep on firing. With a too-lean mixture, the engine will stop firing, at least for a while.

Other possible reasons for a too-rich mixture are the carb float level is too high or the power valve is sticking open. The float valve could also be leaking, but then you would probably notice fuel leaking out of the carb.

Dwell is the number of degrees of distributor cam rotation that the points remain closed for each cylinder. A typical figure for an 8 cylinder engine would be about 30 degrees. It is inversely related to the point gap (more gap = less dwell).

A dwell meter was a fairly common shop tool when all engines had points, and some types of multimeters include a dwell function. It's not an absolute necessity though, and you can usually get close enough with a feeler gauge as long as the points are in good condition. With pitted points, a dwell meter is more accurate than a feeler gauge because a feeler gauge can't measure the actual gap (there is a metal build-up on one of the points and a corresponding depression or hole on the other.)

Ray

[Timmy-Boy]

Where do you call home????

Phoenix, Arizona

[Timmy-Boy]

It depends on how you would describe the bog. If the mixture is too rich, the engine will run sluggishly and the exhaust will be smoky (black smoke), but it will normally keep on firing. With a too-lean mixture, the engine will stop firing, at least for a while.

Other possible reasons for a too-rich mixture are the carb float level is too high or the power valve is sticking open. The float valve could also be leaking, but then you would probably notice fuel leaking out of the carb.

Dwell is the number of degrees of distributor cam rotation that the points remain closed for each cylinder. A typical figure for an 8 cylinder engine would be about 30 degrees. It is inversely related to the point gap (more gap = less dwell).

A dwell meter was a fairly common shop tool when all engines had points, and some types of multimeters include a dwell function. It's not an absolute necessity though, and you can usually get close enough with a feeler gauge as long as the points are in good condition. With pitted points, a dwell meter is more accurate than a feeler gauge because a feeler gauge can't measure the actual gap (there is a metal build-up on one of the points and a corresponding depression or hole on the other.)

Ray

So i should check the float levels, and power valve. Once I figure out what exactly that is lol.

So should i by a dwell meter? If so where could i find one and do you know about how much they are?

I don't wanna spend a ton of money on this motor. Cause I'm gonna build a 455 to swap into this car.

[raycow]

A shop manual with an exploded view of the carb will show you what the power valve looks like. As for the dwell meter, I would say forget about it unless you plan on owning a lot of engines with points.

If you are looking for things to spend money on, get the shop manual before anything else.

Ray

[Timmy-Boy]

A shop manual with an exploded view of the carb will show you what the power valve looks like. As for the dwell meter, I would say forget about it unless you plan on owning a lot of engines with points.

If you are looking for things to spend money on, get the shop manual before anything else.

Ray

Do you think It would be easier just to replace the carb thats currently on It? I found a new Holley 2bbl carb for about $150.
I feel that may be easier and probably more reliable.

[raycow]

If it were mine, I would want to make certain that the stock carb was bad before replacing it. Besides, I'm not sure that the Holley will bolt to your stock manifold without an adaptor.

Ray