timeing problems, lots of spark knock
Thread Starter
Safety Car
Joined: Jun 2005
Posts: 3,775
Likes: 4
timeing problems, lots of spark knock
69 350/300...
ok, first up, ill come right out and say it. i havnt even had a timeing light on this thing yet. god only knows where it is in the garage or basement right now.
the timeing has been heavily retarded, that much i can assure you. it was doing it pretty bad awhile ago so we got it home nice and gentle and retarded it quite aways. the problem seemed to have been taken care of but it came back again this afternoon.
im running 92/93 ocatane in it right now which should be just fine for this motor.
when the car has just started up and is still cool, i can floor that sucker and not have a bit of knocking. after its come upto operating temps itll start knocking for awhile if i get on it, but then itll back off quite abit as it warms up more. itll still SK if i really hit it, but nothing like it did when it got upto the normal operating temps.
im running out of ideas here, its so heavily retarded that i this shouldnt be causing any problems at all.
ok, first up, ill come right out and say it. i havnt even had a timeing light on this thing yet. god only knows where it is in the garage or basement right now.
the timeing has been heavily retarded, that much i can assure you. it was doing it pretty bad awhile ago so we got it home nice and gentle and retarded it quite aways. the problem seemed to have been taken care of but it came back again this afternoon.
im running 92/93 ocatane in it right now which should be just fine for this motor.
when the car has just started up and is still cool, i can floor that sucker and not have a bit of knocking. after its come upto operating temps itll start knocking for awhile if i get on it, but then itll back off quite abit as it warms up more. itll still SK if i really hit it, but nothing like it did when it got upto the normal operating temps.
im running out of ideas here, its so heavily retarded that i this shouldnt be causing any problems at all.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
You need to put a timing light on it so you can have a starting point for adjusting initial and total. Also, cheap gas or plugs that are too hot can aggravate the problem. Lastly, are you running vacuum advance?..and have ever changed the weights or springs that regulate mechanical advance?
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
first of all, if you haven't had a timing light on it than how do you know it's very retarded? first thing to do it put a light on it and see whatr the actual numbers are otherwise EVERYTHING is nothing but a pure guess and speculation.
second, it is probably detonating more once it comes up to operating temp as opposed to when it's cold because of higher cylinder temps.
find your timing light, get your initial timing amount, total timing amount and when it's all in by.
BTW, just as an off-chance thought that again at this point is nothing more than pure speculation or a sheer wild guess - if you touched nothing on the car and the problem came on very suddenly, you may also want to remove the cap off the distributor and see if the advance limiting bushing is still there. They tend to disintergrate over time and fall off. If that happened your mechanical advance travel can now be too great giving you significantly too much advance and too high of a total timing and therefore put you into detonation.
second, it is probably detonating more once it comes up to operating temp as opposed to when it's cold because of higher cylinder temps.
find your timing light, get your initial timing amount, total timing amount and when it's all in by.
BTW, just as an off-chance thought that again at this point is nothing more than pure speculation or a sheer wild guess - if you touched nothing on the car and the problem came on very suddenly, you may also want to remove the cap off the distributor and see if the advance limiting bushing is still there. They tend to disintergrate over time and fall off. If that happened your mechanical advance travel can now be too great giving you significantly too much advance and too high of a total timing and therefore put you into detonation.
Thread Starter
Safety Car
Joined: Jun 2005
Posts: 3,775
Likes: 4
thats about what i figured was gonna be said about the timeing light. the distributer has been turned back by hand quite aways.
vaccum advance is hooked up and working to the best of my knowledge.
never changed the weights or anything in it. bought a new distributer cap about 3 years ago and have never had to take it off since.
ive switched carbs out on this carb about 3 or 4 times now this year, but i cant say how suddenly the problem came about. ive probably only but 70 miles on it at most this year.
vaccum advance is hooked up and working to the best of my knowledge.
never changed the weights or anything in it. bought a new distributer cap about 3 years ago and have never had to take it off since.
ive switched carbs out on this carb about 3 or 4 times now this year, but i cant say how suddenly the problem came about. ive probably only but 70 miles on it at most this year.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
It can't be retarded very much or you wouldn't have any power, so "Flooring That Sucker" wouldn't do much. Dig up the light and figure out where you are, otherwise youe pizzin in the wind
