GRN69CHV
Mar 9th, 06, 7:19 PM
Beautiful day here - finally. Was able to get some time with the new motor today and definitely have some issues to address. I'll list them in a numerical order, so feel free to offer up some input wherever you can. My guess is these are similiar issues that others have experienced and resolved.
Refresher - 460CI, 10.3/1 CR, GMPP(Ede)ovals, Air Gap, 870SA Carb, Carter mech street pump, Summit HEI w/ V1862 canister added.
1. Hot starts are a problem. Starter is a Powermaster 9000, worked great on the 9.5/1 408 motor, not cutting it with full timing on the 460 motor. Pull the timing back and it's fine, but it does not want to crank this motor with the initial at 20 (more on this later).
2. HEI, I have installed 1- heavy/1 light spring to tighten up the advance curve, may have to tighten this even more. Best I can tell is I am only getting about 16 mech advance from the HEI. In order to get the motor to turn over hot I need to set the timing to 8 - 12 initial max, which sets my total way down. Set the timing to 36 total and my idle timing is off the tab (most likely the HEI has about 18-20 in it and I may be getting a few degrees advance at idle as this motor does not want to idle below 900 - 950. Either way, I see this as a problem. With the vac advance installed on man vac, the advance at idle is probably close to 36+ total (V1862 canister is listed as 8* dist/16* crank). Setting it like this I was getting flame through the carb off idle, so this will not work. I suspect the HEI needs to be reworked or replaced with something that will allow me to run 36 total with no more than 6-8 initial to allow hot starts, then run manifold vac at idle to get a decent idle quality.
3. Off idle stumble. As I shut it down tonight, the idle is set about 900. Total timing is down to about 30*, initial is about 10-12, but I am running ported vac advance and getting about 20 at idle, which indicates that I am past the idle circuit. Thinking I may need to drill the primaries to get the carb back into the idle/off idle circuits. I did play with the pump shot and got most of the stumble out, but it is still there, right off idle.
4. Getting a distinct metallic tap, that I am sure are the Crane Energizer (Silver)rockers just tapping the baffles in the valve covers, this is defintely not valve lash. Thinking these may be a little thicker than the Golds or Har-Sharpe. Tall valve covers may be in order.
5. The rear water ports on this intake are still leaking, this is growing old. Going to try some different plugs as a last resort, if that doesn't work, this intake goes in the recycle bin.
Refresher - 460CI, 10.3/1 CR, GMPP(Ede)ovals, Air Gap, 870SA Carb, Carter mech street pump, Summit HEI w/ V1862 canister added.
1. Hot starts are a problem. Starter is a Powermaster 9000, worked great on the 9.5/1 408 motor, not cutting it with full timing on the 460 motor. Pull the timing back and it's fine, but it does not want to crank this motor with the initial at 20 (more on this later).
2. HEI, I have installed 1- heavy/1 light spring to tighten up the advance curve, may have to tighten this even more. Best I can tell is I am only getting about 16 mech advance from the HEI. In order to get the motor to turn over hot I need to set the timing to 8 - 12 initial max, which sets my total way down. Set the timing to 36 total and my idle timing is off the tab (most likely the HEI has about 18-20 in it and I may be getting a few degrees advance at idle as this motor does not want to idle below 900 - 950. Either way, I see this as a problem. With the vac advance installed on man vac, the advance at idle is probably close to 36+ total (V1862 canister is listed as 8* dist/16* crank). Setting it like this I was getting flame through the carb off idle, so this will not work. I suspect the HEI needs to be reworked or replaced with something that will allow me to run 36 total with no more than 6-8 initial to allow hot starts, then run manifold vac at idle to get a decent idle quality.
3. Off idle stumble. As I shut it down tonight, the idle is set about 900. Total timing is down to about 30*, initial is about 10-12, but I am running ported vac advance and getting about 20 at idle, which indicates that I am past the idle circuit. Thinking I may need to drill the primaries to get the carb back into the idle/off idle circuits. I did play with the pump shot and got most of the stumble out, but it is still there, right off idle.
4. Getting a distinct metallic tap, that I am sure are the Crane Energizer (Silver)rockers just tapping the baffles in the valve covers, this is defintely not valve lash. Thinking these may be a little thicker than the Golds or Har-Sharpe. Tall valve covers may be in order.
5. The rear water ports on this intake are still leaking, this is growing old. Going to try some different plugs as a last resort, if that doesn't work, this intake goes in the recycle bin.