I notice that what seems to be a knocking noise between 2200 and up with accel. As soon as take my foot off the gas it goes away. Is it rocker arm or exhaust leak? I can't hear the noise when the car park and rev. up. Only under load and mostly 2200rpm - 3000rpm, cruising speed. It appears to be getting louder.Any ideas? its driving me crazy!!

If its under load, it might be detonation. Have you tried some better fuel ? Hard to tell otherwise without hearing it.

Well I am using 92 ocatane and it almost sounds like it's coming from the drivers side. But the wierd thing is you don't here it as much on the street. Mainly when I am crusing down the freeway. Now would detonation only happen at certain rpms? Would it happen going through all the gears for example if you keep in low drive up to 2500rpm. I dont here it as much, sometimes, when I keep it in 1st or 2nd drive, manily in third and crusing.

I am thinking detonation. 3rd gear puts a lot more load on the motor then other gears. The reason is because you don't have the benefit of torque multiplication like you do in other gears. If you only have the problem at part throttle and not full throttle, then the primary side of the carb maybe too lean. Try upping the jets on the primary side and see if it helps.

Steve

OK so I pulled all of the plugs on the driver side and everything looks to be ok. I checked my intial timming with the vacummed pulled off and plugged( not the carb side). and it was 8 btdc. Now I am not sure if I did the total advance right. I rev the motor up to 2800 rpm, still had vaccum line plugged, So I move dial indicator on the back of the timimng light so that the marker on the balancer is at Zero on the tab. And the degrees on the back of the light was at 19 degrees. Is that right for total advance? Well I connected the vaccum back to carb. Then timming jump to 42 degrees. I know did something wrong.help!


Addendum: I checked the timing again with the carb side vacummed pluged and it was 18 degrees. Rpm 2700.

OK I set intial at 12degrees. with the carb vaccum plugged. NOw I increase the rpms to 3000 and adjusted the dial indicator on the timing light to 36 degrees. turn the hei dist until the balancer line was at zero. NOw I am assuming that is total timing of 36 degrees? But not idle was much higher. adjusted the idle screw couldn't make come down lower than 22 degrees of timing at idle. now base timing is 22 degrees is that to high? Mind you that this with the vaccun line plugged.

22 is too much. 16-18 on a big block is ok. You have to set timing at idle, vacuum advance disconnected. If you don't have enough 'total' advance, 36-38 by 3000 rpm then you need to look at your centrifugal advance. You can buy a kit, don't recall but they're pretty cheap, to rebuild the advance. It has the weights, nylon bushings and several sets of springs. You may need a lighter set of springs to get the total advance you want.

Try 22. I run 22 on my 305 with zero problems. I have 180PSI cranking pressure and zero problems on 87 Octane. The more timming I put in this motor the faster it goes. I wouldn't worry too much about the number, try and and use what the motor likes.

Steve

Well messing with the timing didn't change the problem with the weird knock, unfortunately. I actually went to an area where there was no cars and listen for the sound with door open. I put it in low drive got the rpm up past 2k and the noise kicks in. Someone said it might be lose pin on a piston. A lose rocker or lifter does it make that noise under load and with no load,park? I can rev the car all day in park but no noise. Any ideas?

Has anyone posted a sound clip before?

your running an automatic? it could be a cracked flexplate