Ok I have a 71 with a rebuilt 350 with oversize valves, ta intake, headers, small cam, tci street fighter tranny, 2000 stall convertor and 3.55 posi. Heres the problem, the car really feels like it has no power, cant even roast them off the line so I know something is really wrong here. It kinda bogs and stumbles then picks up a little power as the rpm's go up. My first thought was the carb, so for kicks I threw on a freshly rebuilt Quadrajet from Carmen Faso. It did nothing. Then I went to the ignition, noticed the vaccum advance on the hei was busted so I just took the whole damn thing out and put in a "high performance distributor" from Postons adjusted the timing to 12*, even put new plugs in all around. Car ran much better at idle not as rough but I took the car out and yup it still sucks. Car seems to run better when cold just like the motor I had before with 200,000 miles on it. This motor has only about 1000 miles on it and everything is pretty much new except the old fuel pump which I took from the blown motor because it was an a/c pump. The car really stinks of gas through the exhaust no matter what carb I try. Any tips or suggestions would be great.Thanks Pete
You said it was a "small cam" so I'll pass on the "cam too big" guess. My next guess would be cam timing. I've heard of more than one Buick cam being ground "off" and having to be degreed to work correctly.
What are your plugs gapped at? new wires? It may be one cylinder throwing things off, at idle, unplug each cylinder on at a time. If any of them doesn't drop the idle, that cylinder is problamatic. I'd do a compression check to, possibally something didn't go together right when rebuilt. Good Luck, and I hope it's nothing major.
Pete, Check your lifter preload. You say it runs better when cold. You may have too much preload and when things expand it leads to valve sealing problems. If the motor was rebuilt, and you don't have an adjustable valvetrain, that might cause a problem. A compression check is in order. Just a shot in the dark.
Hi Pete Does the exhaust stink of raw fuel or rich burned fuel ? Have you checked the engine vacuum at idle with a gage ? Did the engine ever run ok after the rebuild ? Cam break-in was the engine run at a minimum of 2200 rpm for the first 20 minutes ? Just some questions before the next round of ideas.
Hi Pete Does the exhaust stink of raw fuel or rich burned fuel ? Have you checked the engine vacuum at idle with a gage ? Did the engine ever run ok after the rebuild ? Cam break-in was the engine run at a minimum of 2200 rpm for the first 20 minutes ? Just some questions before the next round of ideas.
Double check the advance weights in the distributor, they CAN get a bit rusty and stick in the advanced position or not advance at all. You might try advancing your initial timing up to 16 or 18 degrees to see if that makes any difference. Another thing is the distributor may just be worn out, causing alot of timing variation. The vacuum advance will have no effect on intial acceleration, thats what leads me to believe that theirs something wrong with the initial timing or the distributor itself, or cam timing. Hope this helps, Mark:beer
Pete, Did you use the same exhaust system that was on your car with the old motor? I had a muffler go bad once and it made the motor weak as can be. Turned out a baffle had collapsed in the muffler and was blocking it. Cause the exhaust gas to back up on one side and wreck havoc. Did you try it with the headers open? Seems to me it has to be something that was not changed when the old motor was still in the car. Exhaust, converter or fuel system. Give me a call, you have my #. Mark
Thanks for the replys everyone,Iv'e been away from the computer for quite sometime and real busy at work(have to work 12 hour shifts) Anyway I am starting to think the problem lies within my car itself since my old motor before acted up in the same way. Vacuum advance was bad on the hei it came with so I put the Postons hei that Carmen Faso built which is fine. New plugs all around. Timing is good,wires in order, can't remeber what my buddy gapped the plugs to. Even put on new carb that Carmen also rebuilt. The motor came with a non a/c pump so I used the one from my old motor. Since it was acting up like my old motor did I figured it had to be a bad pump so for kicks I replaced that with a new carter pump and problem is still there. Exhaust does smell rich. Mark suggested I check the fuel lines for kinks and to also drop the tank to check that nylon sock which I am doing today. Also exhaust is brand new, headers, mufflers and pipes. If I cant get this thing figured out today I am just gonna have to bring it to John Csordas when he gets back. Thanks for all the help guys. Pete
