'76 Carrera 3.0 Mixture and Timing Questions
11-09-2008, 06:02 PM
#1
'76 Carrera 3.0 Mixture and Timing Questions
Thanks to everyone who helped with the mixture questions before, as expected I am now sifting through the can of worms I opened. At any rate, I figured on starting with the easiest and least costs checks before moving to the mroe expensive and difficult ones.
So here are my questions:
1. Does anyone know definitively if I am to have the timing at the 5 degree mark (BTDC) or TDC? When I checked the timing it was at TDC, so I adjusted it to 5 degrees to the right (where the 5 mark is). I then lost a lot of bottom power, not as snappy. I then adjusted it so it landed right in between TDC and the 5 degree mark. Somewhat better, not as snappy as TDC.
2. How about the idle mixture on the Carrera 3.0, does any have the definitve percent spec on that when using a CO meter?
I am having trouble finding these specs due to the Haynes manual being barely competent, and the Bentley manual covering 78+ SC. Any assistance would be greatly appreciated.
So here are my questions:
1. Does anyone know definitively if I am to have the timing at the 5 degree mark (BTDC) or TDC? When I checked the timing it was at TDC, so I adjusted it to 5 degrees to the right (where the 5 mark is). I then lost a lot of bottom power, not as snappy. I then adjusted it so it landed right in between TDC and the 5 degree mark. Somewhat better, not as snappy as TDC.
2. How about the idle mixture on the Carrera 3.0, does any have the definitve percent spec on that when using a CO meter?
I am having trouble finding these specs due to the Haynes manual being barely competent, and the Bentley manual covering 78+ SC. Any assistance would be greatly appreciated.
11-09-2008, 06:11 PM
#2
RL Technical Advisor
Hi,
1) Total timing at 6K is FAR more important than idle timing values. Set total timing to around 33-34 deg at 6K. Idle timing should be 5 deg ATDC at 900 RPM with the vacuum line connected.
2) Set CO to 2% at 900 RPM idle.
Thats a REALLY neat car,..
1) Total timing at 6K is FAR more important than idle timing values. Set total timing to around 33-34 deg at 6K. Idle timing should be 5 deg ATDC at 900 RPM with the vacuum line connected.
2) Set CO to 2% at 900 RPM idle.
Thats a REALLY neat car,..
11-10-2008, 11:15 AM
#3
Thanks Steve, one point of clarification. When you say ATDC, do you mean 5 degrees to the left of TDC as you are looking at the engine, or 5 degrees to the right? I have a notch in the pulley at 5 degrees to the right of TDC, and I believe another one at 25. But nothing to the left. Thanks for the props on the car, we have our work cut out for us, as every knucklehead has touched this car and we dont know where to start. I am still looking for a good shop in Orange County, CA to do some of the more complicated work. Any ideas?
11-12-2008, 12:52 AM
#6
OK, so I got myself a better timing light to have at it. Here are the specs, when I set the idle timing at 5 ATDC, the 6k RPM timing sits at around 40-42. When I back it off to be 36 degrees at 6k RPM, the idle timing sits around 3. Does that sound about right, as the Bentley manual says 5 degrees plus or minus 2? Man...I am realizing as I am reading this that I sound like such a noob. Sit me in front of a single bore 4 stroke dirt bike with a socket set and feeler gauges and let me have at it. These germans have me mixed up! Thanks again for the help!
