Detonation explaination needed

[danman6677]

Hi, I have a stock 350, with ACDelco plugs, timing was checked yesterday its correct 0degrees, i run reg fuel but on my way to victoria it would detonate bad on the hills, isnt detonation from running low octane fuel on a higher compression motor? ive tried running half 91 octane, idles better but still sounds like a diesel when on hills.

 

[sewlow]

Sounds like the distributer gear may be worn. Pretty common. It'll run fine until you put a load on it, then due to the worn teeth, you're not getting full advance.

 

[redneckchevy90]

that's the mine is. cruising no sound what so ever. the second I hit the gas it sounds like a freaking deisel. my question is how much would just a reg dizzy cost. my truck is mostly stock and I don't plan on hoping it up

 

[sewlow]

I just bought a new distributor. IIRC it was under $150.00. Re & re'd it myself.

 

[danman6677]

Awesome thank you, ill order my new one from ebay, $80 shipped

 

[STEBS]

another note to consider...


idk how many miles ur sbc has or the type of driving conditions its been suceptible to, but when u checked the timing (with the esc disconected if its tbi), if the indicator on the crank was iratic, that could indicate a worn timing chain aswell

 

[MazingerZ]

Hi, I have a stock 350, with ACDelco plugs, timing was checked yesterday its correct 0degrees, i run reg fuel but on my way to victoria it would detonate bad on the hills, isnt detonation from running low octane fuel on a higher compression motor? ive tried running half 91 octane, idles better but still sounds like a diesel when on hills.

I am experiencing these symptoms, did you get around fixing the issue? please advice.

 

[someotherguy]

Possible causes for detonation when using correct fuel grade for engine (87 is correct for a TBI), pretty much in order of likelihood:

- Incorrect base timing (original poster is at zero though which is correct)
- Bad EGR valve (non-functional)
- Low fuel pressure due to clogged filter or failing pump
- Overheating
- Carbon deposits in combustion chamber (not very likely)

Richard