I have the Edelbrock power pkg. #3702 Edlbrock Cam and heads. I have to run 89 OCT, because of being in Mexico. My question with the wire disconnected, what should I set the timing at BTDC. I am reading 0,4,8. I am guessing 4 degrees and see how it runs with this great gas we have here.
I'm fairly sure that base timing should be at 0 degrees on your truck.
Elbert
4 BTDC is what spec is. (I run more than that on my 89 TBI) Did you also use the Eldebrock intake manifold? The stock GM one does not flow too good.
I have a 89 4x4 burb with that engine and it is 4 BTDC. Myself I run
10 BTDC but I never use 87 octane either (I use premium) and I consistantly get 17 to 18 MPG of highway if I keep it under 70. If I run stock timing with 87, the best I could ever get was 15 to 16 MPG and it did not run as well either. Been doing it this way for years.
My factory sticker under the hood says 4 BTDC with wire disconnected. With cam, heads and intake I would use at the very least 89 octane or better and 8 to 10 degrees of spark if you want to get the most out of that combo. If you retard spark to run low octane fuel it will not live up to its potenail.
if you've got edelbrock's complete power package and the chip for it, run the advance they tell you to.
-Bret
I have a 1992 K 1500 with 350... the sticker is gone from under the hood but I thought it said 0 degrees for base timing...i see others are saying
4....I've swapped radiator shrouds and I guess the timing sticker went out with the old shroud. There may be a differece between the 89 and 92 models?
I do know my truck is very picky about the setting, just a little bit off and it pings or runs like crap..
Elbert
My 89 burb was that way when I got it new. If you retarded the spark enough to limit it, power, response and MPG was lacking. I switched early onto plus during cooler months and premium in summer month reset timing and it still runs like a champs. I took it to South Carolina a few weeks ago and got down there on one tank (560 miles and it has a 40 gallon tank) with gas to spare and got 17.1 averaging 70 to 75 on way down and coming back doing 75 to 85 (I was in a hurry) I got 16.7 again on one tank. It never did anywhere near that on 87 nor had the power either. Also when I take it out to Colorado I set timing to 14 to 16 BTDC while out there in thin air and it helps a lot as with stock timing it sucks in thin air as computer cannot dail in enough spark to make up for it on old TBI engines. It has been about
15 years since that truck has had a tank a 87 in it and with 9.5 to one compression you have to retard spark to control knock. I have a old Jeep with a 360 and 8 to 1 compression and I used to use 86 in it when sunoco sold it and it never knocked once and ran great on it too.
I have a 1990 Suburban 5.7L TBI and it runs great on 87 octane gas. The setting listed on the emissions sticker is zero degrees BTDC. If you advance it above this, you will gain power and fuel mileage but you may need a higher octane gas. We used to run the older small blocks (pre ECM) at 4 to 8 degrees advanced with few if any problems and I used to run mine slightly higher. When checking/setting the timing, remember to unhook the sensing wire to the distributor.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% There are two classes of pedestrians in these days of reckless motor traffic - the quick and the dead. ~ Lord Dewar 1933 ~
Climbing into a hot car is like buckling on a pistol. It is the great equalizer. ~ Henry G. Felsen 1964 ~
You do not know what you are missing because it will run a lot better with better gas and more spark. Also, back in carb days a lot of GM truck with manuals were timed at TDC while one with automatics were usually around 4BTDC or so. The TDC setting was to enhance of idle torque which is not needed with a automatic.
Tried 0,4,6,9 degrees. Runs very well at 9 Degrees BTDC. Anything below that, I had lack of performance and a flat exhaust note. Thanks
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.