ok, could this be my problem?
Thread Starter
Race Director
Joined: Feb 2000
Posts: 12,431
Likes: 1
From: CT
ok, could this be my problem?
i recently posted about how i think my car is running out of gas on the top end. i may have found the problem, what do you think.
while at my friends shop today i decided to check my timing, with his 200 dollar timing light. at idle i am at 14 deg. that is what i always got with my 50 dollar light. but this light can also tell you the advance of the motor at all rpms. it showed 57 deg. at 5500 rpm!!!!!!! what the f*cK>???? what should i do about this? how can i fix it. shouldnt it be at like 28 deg? my friend says that since i am running a stock 79 Hei distrubutor in a moded vette, the distrubutor may be all wrong for the car.
what should i do? any help much appreciated. i am triing to get this fixed before the covette challenge on saturday. thanks.
ps, im starting to hate cars
while at my friends shop today i decided to check my timing, with his 200 dollar timing light. at idle i am at 14 deg. that is what i always got with my 50 dollar light. but this light can also tell you the advance of the motor at all rpms. it showed 57 deg. at 5500 rpm!!!!!!! what the f*cK>???? what should i do about this? how can i fix it. shouldnt it be at like 28 deg? my friend says that since i am running a stock 79 Hei distrubutor in a moded vette, the distrubutor may be all wrong for the car.
what should i do? any help much appreciated. i am triing to get this fixed before the covette challenge on saturday. thanks.
ps, im starting to hate cars
Le Mans Master
Joined: Oct 2000
Posts: 8,897
Likes: 1,353
From: Santa Ana CA
Re: ok, could this be my problem? (Vetteboy)
Did you remove and plug the vacuum line to distributor when using the dial back light? Try this and set the total timing to about 28 degrees. If the idle timing is still over 10-12 degrees, you're alright. If its too low, you must put a "stop" on your centrifugal advance to keep from overtiming the engine. If the idle and full timing are OK, but the vacuum is causing too much advance, you can change the vacuum advance mechanism. These are available in diffentent advances. Some aftermarket makers even make adjustable units that are tuned using an Allen key in the port. Another way to reduce the amount of throw of the vacuum unit is to put a "stop" in the path. I use one of these on my '64 and it actually has various indentations relating to different degrees of stop. Around 45-50 degrees of total advance is usually OK with the vacuum unit connected. Remember, you only get this much timing when the engine puts out vacuum. WOT essentially disables the vacuum advance.
Thread Starter
Race Director
Joined: Feb 2000
Posts: 12,431
Likes: 1
From: CT
Re: ok, could this be my problem? (toddalin)
toddalin: im pretty sure that this timing was done with the vacume hooked up while reving the motor to 5500. is 57 deg. way to much with this hooked up? i am going to try it again on monday with the vacume advanced unpluged. what should i look for?
you said that WOT disables the vacume advance. what does this mean if the timing is 57 while reving the motor to 5500??? is something major wrong?
how does a machanical dist. work. would purchasing an msd billet mach dist. be a good investment? and how do you set these dist. to where i need it?
you said that WOT disables the vacume advance. what does this mean if the timing is 57 while reving the motor to 5500??? is something major wrong?
how does a machanical dist. work. would purchasing an msd billet mach dist. be a good investment? and how do you set these dist. to where i need it?
Melting Slicks
Joined: Apr 2001
Posts: 3,399
Likes: 278
From: Olmsted Falls, Ohio
Re: ok, could this be my problem? (Vetteboy)
52-55 deg is about right with everything hooked up and at max rpm.... Why do you think it's a problem? Other symptoms causing you to wonder about this?
Instructor
Joined: Apr 2001
Posts: 199
Likes: 0
From: Guyton, Ga.
Re: ok, could this be my problem? (KenSny)
I would think 40-45 degrees would be right for max advance. the MSD dist. works well, I run 14 deg. initial, with 21 mech. adv. and 12 vac. this was all done with a lot of trial and ERROR it seemed more error at times but it now works for me.
Thread Starter
Race Director
Joined: Feb 2000
Posts: 12,431
Likes: 1
From: CT
Re: ok, could this be my problem? (KenSny)
here is my original post. i know this doesnt sound related but im kinda stumped:(
http://forums.corvetteforum.com/zerothread?id=155639
http://forums.corvetteforum.com/zerothread?id=155639
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Re: ok, could this be my problem? (Vetteboy)
After reading your original post I would say fuel also. The ignition curve goes away very gradually. The fuel could be clogged filters or floats. I had a Camaro years ago that the fuel pump was not keepig up. The pump was not that old just could not flow enough fuel. I replaced it with a high performance pump and it ran great. It was doing just what you say. Laying over at the top end. At about 80+ mph it just ran out of power. Sounds like fuel starvation.
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