Ok so I rebuilt my sbc, 305 heads aluminum intake Edelebrock 4 bbl carb summit racing cam, and it runs fine but has no power, could I have installed the cam wrong? I just lined up the dots and figured it would be right. How do I check for correct cam instalation, or is it something else I screwed up?
what Summit cam? what did you use for timing chain? some of those that have advance/retard built in with a few crank keys slots can get very confusing
Sometimes it helps to use a straight edge, line it up with the centerline of the crank and cam, the dots should fall in line. If you just eyeball it you can easily be one tooth off. Hook up a vacuum gauge, it will tell the tail.
did you time it with a light? got the correct timing pointer that goes with the balancer? take out the spark plug look in the hole and bring number one piston up to TDC. your timing mark should be at zero. that's what I would do first.
What cam? If this is a stock low-compression 305, and you put in a big cam, I wouldn't expect too much from it.
saeger, if you followed the manual you will find that your distributor is off 180 degrees. Just pull it out and turn the rotor to point at #6 and it'll be right. the same typo exists for big Dodges as well, they've shown the same mistake since 1955.
Ive never seen a motor run 180 off. I have seen it try to start(and pop through the carb) but never run. If it throws a fireball out the carb I always know its 180 off. Try rotating your distributor back and forth very slightly and see if this raises the idle. I would also check your carb and needles. Also check the compression!
It's timed right and runs smooth and sounds mean, but it just doesn't want to go like it should, I know for sure that I lined the dots up right, but I never bothered to check it with a degree wheel. If I get a vacuum tester what readings would I be looking for?
it's a 307 by the way, I put 305 heads on it to raise the compression. I bought a compression tester on eBay for $13 and it just had a rubber cone you put in the spark plug hole and the compression just blew past the cone so the tester is useless
Probably not, it runs best is nowhere near the timing scale. It runs best with the mark nearly straight up and down instead of at 2 o'clock where the timing scale is.
Hopefully you didn't cheap out and drop an old cap and rotor in there with used plugs. A buddy just went though this and spent a ton of money chasing fuel problems, only to find a cracked HEI cap, dead coil and what looked like 100 year old wires! Worth a quick look.
The vacuum gauge I have is marked with an area that says "late valve timing", a**** other things. Petty neat diagnostic tool. If the motor in question is just not performing like you thought it would, maybe you need to look at the combination of parts. Take those heads for example, they raise the compression, but they don't breathe. Some time with a die grinder could improve the ports a bit, but I don't imagine they'll ever flow any better than a power pack, which ain't **** compared to a stock 350 or 327 head, might not even be as good as the 307 head. A combination like that would have good low end, but run out of breath way early.
Would the cam being a tooth off explain the lack of power or would that also make it run rough? I think I might just swap the 307 heads back on and see if it runs better. But I would like to have some insight on what could be wrong before I start tearing things apart.
307 timing mark is strate up and down and you look though the waterpump if i reamber correctly. does it run better when you give it more timing. what carb do you have and is the advance working on the dist. you may need to put a 307 timing cover on it to get the timing correct or swap ballancers with a 350
you changed the heads? yeah i would go back and try the 307 heads you had on it..than go from there..you may have canged too much at one time and not be able to track down the root cause.. maybe the set of heads you have on there now are ****? (meaning the valve job, springs etc..)
It's the original 1968 307 timing cover, the balancer is off a later 327 or so I was told. And the advance is working. Oh and It's an Eddlebrock 1405 600cfm carburetor.
No I gave up after testing 2 cylinders with most of the compression blowing past the tester (****py rubber cone type). I might have better luck with the tester with the old heads because of the larger old style spark plug holes.
some of those comp. testers you can pull the cone off and replace it with a hose and an old sparkplug, but i'm guessing its the timing, heres what i would try, get the motor warmed up, shut it off for about 30 seconds, then start it again, if it rolls over fast and fires then shut it off and advance the timing a little, what you want it to sound like when its rolling over is a rump...rump..rump a few times before it starts, once your there then turn the timing back till no more rump...rump...rump, then your timing will be close and you dont have to worry about timing marks.
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