280zwitha383 Posted July 20, 2007 Share Posted July 20, 2007 So I bought this '77 Corvette and threw a timing light on it (HEI) and there's no notch on the balancer (visible). Moved the distributor around a lot and found the notch. I set it to about 10 degrees and it started moving up a little bit and kept going. So I retarded it back to 10 deg. and it started going down in the same way. If I set it it will always move but the rpms seem to stay pretty constant. The weights were pretty worn out and it didn't really seem to return to where it should be (the mechanical advance part). So I replaced to whole assembly with a junk HEI and still the same. Please help! Quote Link to comment Share on other sites More sharing options...
jt1 Posted July 20, 2007 Share Posted July 20, 2007 Check to see if the mark on the damper is in fact at TDC, and that it isn't moving. I would also try another dist., a known good one if possible. It sounds like the weights aren't pulling the timing down correctly. John Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted July 21, 2007 Author Share Posted July 21, 2007 That's what I thought too about the weights. I guess I'll piece together another distributor like you say and give it a shot but shoot I replaced the shaft with the weights and mech. advance part with what seemed to be a better one. It couldn't be the module could it? I don't know what else to look for really. Quote Link to comment Share on other sites More sharing options...
lbhsbZ Posted July 21, 2007 Share Posted July 21, 2007 How far does it move up....it can't just keep going forever. Mark the pulley and the balancer, and run the car around the block a few times...see if the marks are still lined up or if they moved. Spun balancers are not uncommon, especially on a '77. How are the bushings in the distributor? Does the shaft wobble back and forth at all? How is the timing chain? You can check this by rotating the crank back and forth with the Dist. cap off....if there is any lag in movement of the rotor while you are turning the crank back and forth, the T-chain is toast. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted July 21, 2007 Author Share Posted July 21, 2007 You are right. My rubber was slipping.... I dripped a little white paint on the pulley when I marked it and wondered why it wasn't still lined up with the notch. I put another mark where the notch was and it moved again just by bumping it over with the starter. Found out I can turn it by hand pretty easily. This sucker needs a rebuild anyway from the looks of it because I've got my timing in the ball park and the carb is clean with atleast close to stock jets (floats are set right, gaskets look good, PV holds suction, blah blah) but it just doesn't have the power it should. I'll do a compression test and take the valve covers off and make sure all the rocker arms are even moving, much less adjusted. Someone put a Victor Jr on the thing so I hoped they had put a cam in and knew what they were doing. Anyway, thanks for the help. After I put a good distributor on it and it was still moving I was really starting to wonder what was going on. Quote Link to comment Share on other sites More sharing options...
lbhsbZ Posted July 21, 2007 Share Posted July 21, 2007 I'd just pick up a new balancer for the time being, and double check TDC so at least you'll know where the timing is set....thats probably why it has no power....because you have no idea where the ignition timing is actually set. Go for total timing between 38 and 42 degrees. And with a victor junior manifold, that thing won't make any power until you hit about 4000rpm. If it doesn't have a super lumpy cam in it, the cam is probably done making power by the time the manifold starts making power. Maybe try a dual plane manifold on it if the cam sounds pretty tame, I bet that will wake it up quite a bit too. I don't know what kind of carb you've got, but I've got an edelbrock performer manifold for a Q-jet that I'll sell for $50+shipping if you want to try it out. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted July 22, 2007 Author Share Posted July 22, 2007 You can set the timing pretty close by ear. I did a compression test today and one cylinder was at 85 psi. I only did the odds but 1 was 125, 3 was 110, 5 was 85 and 7 was 120. IMO the car needs a dual plane intake with the weight (3500+ lbs) and close to 3.00 gear ratio and the VERY tall tires. I don't know what the gear ratio is for sure but with the power the engine is making it won't hardly go into 3rd without letting off of the gas. If you barely try to accelerate it will kick down into 2nd. I would like to keep the thing street friendly and get some good gas mileage. Looks like I've got a new candidate for the 350 vortec... Quote Link to comment Share on other sites More sharing options...
lbhsbZ Posted July 22, 2007 Share Posted July 22, 2007 Yeah, I know what you mean about the gears....I just built a mild (325hp) street motor for my buddies '67 camaro....I also swapped out the powerglide for a TH350. I was scratching my head for a while after I got it together and drove it....until I realized that with the Powerglide, GM put 3.08 gears in it. No wonder it doesn't have any kick to it. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted July 23, 2007 Author Share Posted July 23, 2007 (edit: it might keep going into 2nd from 3rd because....) The kickdown cable on the thing is stuck I guess because it doesn't return to where it should be and if you pull it there's only maybe 1.5" of cable left. The transmission also leaks (a lot come to find out sitting in the garage) and the dipstick is broken off so who knows really how much fluid is in it. The dipstick broke off right before where it has that slotted bend in it I guess to keep it stable in the shaft. Anyway, I tried to use that as a reference point with another dipstick I had that was obviously longer (probably went on a truck) but it didn't seem to come out right. Me and the wife are going to put some old heads that I know are good on the engine tomorrow and see if the compression problem isn't in the valves (who would get that lucky). I'm pretty skeptical but since we got the Corvette I have actually been able to get her out and teach her some stuff about engines (read: she really likes Corvettes). I know what you're talking about with the gearing. This things actually does decent in 1st and 2nd but 3rd will just barely keep you at speed. Heck my truck used to have 2.73 gears in it and it really didn't have a problem with 3rd. 1st would go up to 55 pretty easily which was funny and it was fun to kick into second going 60 or 70. I actually wish I didn't put the 3.73's in it. That sucker is too heavy to race unless there's something serious under the hood and then it's kind of foolish to have it in there and not a much lighter car. With the corvette I think I'll enjoy it especially if I get the 350 vortec in it with the FI. If I can get close to 20mpg I'll sell my '81 280ZX and make the corvette my dd. ASSuming I can afford insurance for it Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.