Well, I'm not a Buick guy so I guess I should have seen this coming. I have a friend with an 82 Olds Cutlass with the 3.8L V6 with computer controlled carb and distributor. Engine needed a rebuild so he wanted to turn up the wick just a bit while we were at it. I rebuild it just like stock with the following exceptions:
1. Compression. Stock was 8.5 with heavily dished pistons. I put in a set of Hypereutectics (Federal Mogul) with much less dish that brought it up to 9.5:1 with a 30-overbore.
2. Cam. Replaced with a very mild Crane cam with 202/210* duration on a 112* LSA. I was trying for good torque, which I did not achieve.
3. Heads. Mild pocket porting just the clean up the nasty sharp edges and casting flash, etc. Installed springs designed to work with the cam.
It idles and runs beautifully- just like the stock motor did. And that's the problem- It's got nothing more than the stock configuration power-wise. I was hpoing for a substantial bump in low end torque but I got nothing.
I have timing set at 15* initial (stock setting) and I rebuilt the stock computer controlled 2bbl carb (which really had nothing wrong with it to begin with). Mixture control solenoid and TPS both work fine as does everything else on the motor- even all the smog stuff is working as the factory intended. Computer says everything is working correctly, sane readings on the O2, mixture control solenoid, etc.
My only possible point of concern is the computer controlled distributor. It doesn't have any computer-supplied advance at idle. If you rev it up in neutral you can see it stay at 15* until you get to about 1500 RPMs and then it jumps immediately WAY up to probably 35* or so- way off the top of the scale. If I unplug the distributor from the ECM the timing stays constant at 15* until you reach 1500 again and then it DROPS instantly down to about 10* and then holds constant until you bring it back to idle again. Very odd. I'm wondering if the distributor is supposed to work like this. I thought it would hold constant timing regardless of RPM if I unplugged it from the computer, like similar Chevy stuff I have worked on. Could the electronics in the distributor be shot?
I can manually bump up the initial timing to 18, 20, 22, 24* or more and the engine keeps making more and more power every time I bump it up with no apparent detonation. I can take it up so high you can't even start the engine becuase the spark is so far advanced and it still wants more, more more.
Also, wondering if this is normal for a Buick- the mixture control solenoid in the carb does not make that clicking noise when you turn the key to the run position (engine still off) like a similar Chevy application does. The solenoid is definitely working when the engine's running, but it won't click if the engine is off (unless you put the computer into diagnostick mode by jumpering the ALDL terminals- then it will click without having the engine running). Again, this is different than similar Chevy stuff I have worked on in the past, but maybe this is how it's supposed to work with Buick stuff.
Any guidance would be appreciated. I think the basic combo is sound but somethings out of whack somewhere.
1. Compression. Stock was 8.5 with heavily dished pistons. I put in a set of Hypereutectics (Federal Mogul) with much less dish that brought it up to 9.5:1 with a 30-overbore.
2. Cam. Replaced with a very mild Crane cam with 202/210* duration on a 112* LSA. I was trying for good torque, which I did not achieve.
3. Heads. Mild pocket porting just the clean up the nasty sharp edges and casting flash, etc. Installed springs designed to work with the cam.
It idles and runs beautifully- just like the stock motor did. And that's the problem- It's got nothing more than the stock configuration power-wise. I was hpoing for a substantial bump in low end torque but I got nothing.
I have timing set at 15* initial (stock setting) and I rebuilt the stock computer controlled 2bbl carb (which really had nothing wrong with it to begin with). Mixture control solenoid and TPS both work fine as does everything else on the motor- even all the smog stuff is working as the factory intended. Computer says everything is working correctly, sane readings on the O2, mixture control solenoid, etc.
My only possible point of concern is the computer controlled distributor. It doesn't have any computer-supplied advance at idle. If you rev it up in neutral you can see it stay at 15* until you get to about 1500 RPMs and then it jumps immediately WAY up to probably 35* or so- way off the top of the scale. If I unplug the distributor from the ECM the timing stays constant at 15* until you reach 1500 again and then it DROPS instantly down to about 10* and then holds constant until you bring it back to idle again. Very odd. I'm wondering if the distributor is supposed to work like this. I thought it would hold constant timing regardless of RPM if I unplugged it from the computer, like similar Chevy stuff I have worked on. Could the electronics in the distributor be shot?
I can manually bump up the initial timing to 18, 20, 22, 24* or more and the engine keeps making more and more power every time I bump it up with no apparent detonation. I can take it up so high you can't even start the engine becuase the spark is so far advanced and it still wants more, more more.
Also, wondering if this is normal for a Buick- the mixture control solenoid in the carb does not make that clicking noise when you turn the key to the run position (engine still off) like a similar Chevy application does. The solenoid is definitely working when the engine's running, but it won't click if the engine is off (unless you put the computer into diagnostick mode by jumpering the ALDL terminals- then it will click without having the engine running). Again, this is different than similar Chevy stuff I have worked on in the past, but maybe this is how it's supposed to work with Buick stuff.
Any guidance would be appreciated. I think the basic combo is sound but somethings out of whack somewhere.
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