I am still fighting with my fresh 302 and am running out of ideas. I am tempted to take it to a mechanic (say it isn't so... I am so ashamed that I can't figure this out!!!)
The thing has very low vacuum at idle (10 inches at 900 rpm) and runs pretty rough. I finally got the car on the road for the first time in a year last weekend and it felt like I was towing a huge trailer. It would not spool up at all.
It has classic symptoms of a retarded cam (low steady vacuum at idle) but engines with retarded cams usually wake up at higher rpms - mine does not.
Everyone I have talked to tell me that this is not likely and that they have never heard of an edelbrock cam or Cloyes timing set that was off more than a degree or two. If I rev up the engine slowly from idle (no load) it is rough to about 2500 rpm and then seems to smooth out a little - although on the road it won't pull at any RPM.
I have a balanced and blueprinted 302 bored +.030", Edelbrock performer RPM cam, intake and 600 CFM carb (Edelbrock Carter AFB). Stock ported heads, screw in studs, full roller rockers, long tube headers, stock rebuilt and recurved distributor (26 deg total advance at ~3600 rpm) with Pertronix ignition and coil, Cloyes timing chain/gears. I spliced around the resistor wire so the coil sees the full 12 volts.
I have tried rebuilding the carb, and a new fuel pump. I have checked the compression (~140 psi cold) and the leak down (all less than 7% cold). I used my inductive timing light to confirm that each plug was firing (placed the pickup on different wires as the engine ran). I sprayed carb cleaner on the intake gaskets to rule out a leak (can't check the side to the block though). I took the (2.25") exhaust pipes off to confirm that the mufflers weren't plugged. The engine ran differently but did not have any more vacuum. I have an old engine analyzer that I use to monitor RPM when I am under the hood and when it is hooked up to the coil the needle jumps around a lot.... as mentioned before, according to the timing light, all cylinders are firing.
I have not tried changing the needles and seats on the carb yet. The carb came off my buddies car that had a very similar setup to mine. It worked great on his car so I have left it as he had it (except for new gaskets, etc). The engine idles best when the idle needles are about 2 turns out (normal) so I don't think it's lean at idle. The mechanic I talked to thought the Carter's were junk and suggested I get a Holley (I have always heard the exact opposite).
It was also suggested that the valves may be to tight (I put 3/4 turn of preload on the hydraulic lifters as perscribed in the instructions but the mechanic I talked to said to back them off the 1/4 turn...). I have started to turn back the valves but have not finished yet. I don't think this is the problem either since the compression and leak down tests were good... and the car does not run worse as it warms (like tight valves would).
What the heck am I missing?
The thing has very low vacuum at idle (10 inches at 900 rpm) and runs pretty rough. I finally got the car on the road for the first time in a year last weekend and it felt like I was towing a huge trailer. It would not spool up at all.
It has classic symptoms of a retarded cam (low steady vacuum at idle) but engines with retarded cams usually wake up at higher rpms - mine does not.
Everyone I have talked to tell me that this is not likely and that they have never heard of an edelbrock cam or Cloyes timing set that was off more than a degree or two. If I rev up the engine slowly from idle (no load) it is rough to about 2500 rpm and then seems to smooth out a little - although on the road it won't pull at any RPM.
I have a balanced and blueprinted 302 bored +.030", Edelbrock performer RPM cam, intake and 600 CFM carb (Edelbrock Carter AFB). Stock ported heads, screw in studs, full roller rockers, long tube headers, stock rebuilt and recurved distributor (26 deg total advance at ~3600 rpm) with Pertronix ignition and coil, Cloyes timing chain/gears. I spliced around the resistor wire so the coil sees the full 12 volts.
I have tried rebuilding the carb, and a new fuel pump. I have checked the compression (~140 psi cold) and the leak down (all less than 7% cold). I used my inductive timing light to confirm that each plug was firing (placed the pickup on different wires as the engine ran). I sprayed carb cleaner on the intake gaskets to rule out a leak (can't check the side to the block though). I took the (2.25") exhaust pipes off to confirm that the mufflers weren't plugged. The engine ran differently but did not have any more vacuum. I have an old engine analyzer that I use to monitor RPM when I am under the hood and when it is hooked up to the coil the needle jumps around a lot.... as mentioned before, according to the timing light, all cylinders are firing.
I have not tried changing the needles and seats on the carb yet. The carb came off my buddies car that had a very similar setup to mine. It worked great on his car so I have left it as he had it (except for new gaskets, etc). The engine idles best when the idle needles are about 2 turns out (normal) so I don't think it's lean at idle. The mechanic I talked to thought the Carter's were junk and suggested I get a Holley (I have always heard the exact opposite).
It was also suggested that the valves may be to tight (I put 3/4 turn of preload on the hydraulic lifters as perscribed in the instructions but the mechanic I talked to said to back them off the 1/4 turn...). I have started to turn back the valves but have not finished yet. I don't think this is the problem either since the compression and leak down tests were good... and the car does not run worse as it warms (like tight valves would).
What the heck am I missing?
runs like it should.
on the propane trick.
