ignition timing

[spikebot 81]

Just brought home my new 81. I knew the engine was not origanal. Owner showed me repair recept for new rebuilt long block installed with 10k. I did a search with the stamped block numbers on right front of motor. It looks like the engine came from a 71 C10 truck. Could anyone tell me what the ingnition timing should be set at?

 

[6880 Mike]

Point type distributor? Set it a 4 BTDC to get it running, then tune until she idles the best.

Begin your serious tuning from that point.

 

[minifridge1138]

Timing process i use:
1) Fill up the tank with whatever octane gasoline you plan on using.
2) Then set the timing at 4 degrees.
3) Drive on the interstate. If you have no spark knock under heavy acceleration, go to step 4. If you have spark knock, go to step 5.
4) Advance timing 4 degrees. Repeat step 3.
5) Retard timing 2 degrees.

At this point, you will having your timing set for the octane rating of gasoline you used.

Note: if you start using a lower octane fuel, then you may develop spark knock.

 

[spikebot 81]

Thanks alot Mike and Mini. That helps me a bunch. Mark

 

[6880 Mike]

The nice thing about the old point type distributors is that you can dial them in in the drive way with a point tool and a dwell tach.

Get a good curb idle and proceed from that point.

 

[gmjunkie]

The nice thing about the old point type distributors is that you can dial them in in the drive way with a point tool and a dwell tach.

Get a good curb idle and proceed from that point.

Yeah but is it a Point Type?? In 1975 HEI became standard equipment on Corvette!!1981 Corvette all went to Chevrolet's Computer Command Control system which was used on 1980 California Corvettes became standard equipment on 1981 Corvettes!! The system automatically adjusted ignition timing and carburetor air/fuel mixture!!

 

[6880 Mike]

...Yeah but is it a Point Type??...

I asked about that. He says it's a 71 engine.

 

[spikebot 81]

Thanks guys, The block stamp suffix number tells me the engine came from a C10 1971 truck. All origanal equipment is in place. I guess my question is do I tune this motor to 1981 specs or use the 1971 timing data. I do plan to remove computer, carb, distributor and related smog equip.

 

[gmjunkie]

Thanks guys, The block stamp suffix number tells me the engine came from a C10 1971 truck. All origanal equipment is in place. I guess my question is do I tune this motor to 1981 specs or use the 1971 timing data. I do plan to remove computer, carb, distributor and related smog equip.

You would time it to the 1981 spec's!!Why remove and change parts?? If it ain't broke,Don't fix it!!

 

[spikebot 81]

Gmjunkie, I too follow that motto but this qjet needs help and I don't Know much about these carbs. When I brought the car home 3 weeks ago I stoped at a light and did alittle footfeed test. The motor reved ,the tires spun, the car died. Wouldnt start. I popped the air cleaner and found this very small tappered plug laying on the secondarys. I put it in my pocket looked down into the manifold its full of fuel. Car wont start. Had to have a tow. Well after i got home, went to the library and found a qjet manual, showed were the plug goes. I installed it per instuctions engine fired right up. But now it dies after driving a couple of blocks. Wait few minutes fired up same story again Dead. So this carb has got me worried Read lots of posts here on engine mods for 81 smog cars and I think its time for 600cfm edle 6014. Ive had some good luck with carter afb carbs years ago. Ive been told this is basicaly the same carb. What do ya think MR. Master Mechanic?

 

[gmjunkie]

Gmjunkie, I too follow that motto but this qjet needs help and I don't Know much about these carbs. When I brought the car home 3 weeks ago I stoped at a light and did alittle footfeed test. The motor reved ,the tires spun, the car died. Wouldnt start. I popped the air cleaner and found this very small tappered plug laying on the secondarys. I put it in my pocket looked down into the manifold its full of fuel. Car wont start. Had to have a tow. Well after i got home, went to the library and found a qjet manual, showed were the plug goes. I installed it per instuctions engine fired right up. But now it dies after driving a couple of blocks. Wait few minutes fired up same story again Dead. So this carb has got me worried Read lots of posts here on engine mods for 81 smog cars and I think its time for 600cfm edle 6014. Ive had some good luck with carter afb carbs years ago. Ive been told this is basicaly the same carb. What do ya think MR. Master Mechanic?

Well,I think Eldebrock 6014 will never be as Good as a Good ol Carter AFB!! (Carter AFB is hard to beat!!)
I used to be a die hard Holley man till I burned the wiring and Hood off of my 68 427 Roadster!!:eyerole:eyerole:eyerole When I was younger,I was under the impression if you had a Good Q Jet leave it alone,if you had a Bad Q Jet throw it away and buy a new one!! But now since I'm not in a hurry to get it on the road to chase T&A,I sat down and figured them out!! A Q Jet is no big deal and if you pay attention there easy to make them right!!! Your problem is probly a gas logged float that is sinking under fuel pressure at the needle and seat!! $20.00 kit, $15.00 Float 2-3 hr's cleaning and checking things out reassembly and a few adjustments and you'll be good to go!! The directions is in the kit,familiarize yourself and just do it!!

PS be sure and check the lead plugs in the front bottom side of the float bowl, there bad to dribble and leak!! If there real!y clean when you take it off,there probly leaking!! You can usually peen them with a flat punch!! But sometimes you'll have to clean them good and seal them up with JB weld !!
Feel free to call me,my toll free # is on my Web Sight ext 1,2 or 5!!

 

[spikebot 81]

GM, Thanks a million.

 

[gmjunkie]

GM, Thanks a million.

Before I forget check the wiring plug on the front of the carburetor,and make sure it is getting a good connection!! I've had some problems there, with them not getting a good connection after warm up and Dumping the fuel to'em!!

 

[6880 Mike]

Excellent stuff here.

 

[spikebot 81]

Before I forget check the wiring plug on the front of the carburetor,and make sure it is getting a good connection!! I've had some problems there, with them not getting a good connection after warm up and Dumping the fuel to'em!!

Junk, I checked the timing per instuctions under the hood and found system was advanced off the scale with 4 pin dist. unpluged 500rpm in drive per spec. Reset to 6btdc added 2 degees to smooth out allittle. The big find was the fuel mixture solenoid connection. Read a post yesterday that said a rapid clicking sould be heard on engine start up. Ive never really noticed that before. The connectors locking tab was broke off and seemed loose. A short zip tie worked great. Took the car around the block a couple 100 times. Couldnt make the car fail. It runs darn good for smog car. I think the combo of both problems was causing the rich condition. I did pull #5 plug, nice golden brown color. Thanks for all your help, and thanks to all others for their input also. Mark

 

[gmjunkie]

Junk, I checked the timing per instuctions under the hood and found system was advanced off the scale with 4 pin dist. unpluged 500rpm in drive per spec. Reset to 6btdc added 2 degees to smooth out allittle. The big find was the fuel mixture solenoid connection. Read a post yesterday that said a rapid clicking sould be heard on engine start up. Ive never really noticed that before. The connectors locking tab was broke off and seemed loose. A short zip tie worked great. Took the car around the block a couple 100 times. Couldnt make the car fail. It runs darn good for smog car. I think the combo of both problems was causing the rich condition. I did pull #5 plug, nice golden brown color. Thanks for all your help, and thanks to all others for their input also. Mark

My bet is that someone had the timing Jacked Up to get it to run!!! Faster Timing will Lean it out some, Now you've saved some Coins,Some Work and your Ride isn't "Bubbafide"!!:L:L:L Glad to have helped "Corvette Brother"!! :cool