No longer a young mans problem (premature detonation)

[rooster57]

Well i have a clattering problem that i thought was my flexplate. I installed a new flexplate and same porblem. I was at the tues night roundup and an old hotrodder suggested to slow my timing down a bit and see what happens he thought it was a premature detonation issue. I did back the timing off and the problem is much improved but the car doesnt seem to run as well. i need some advice please it is a 94 chev 305 with an edelbrock 600 all stock. any and all advice will be greatly appreaciated

 

[old round fart]

High timing WILL give more power AND detonation. The low octane in today's gas will not support the high compression and performance we had in the past. Backing down the timing and going to high test gas is about the only thing except lowering the compression I know of to take care of that.

 

[rooster57]

i wonder where i should set my timing at????

 

[old round fart]

Put in high test gas and back it down 'til it quits rattling. How is your water temp? Heat has something to do with it too. Can you have carbon build up in the combustion chamber? May try some Z-Max or something like that to clean it up in there.

 

[rooster57]

Temp is good never gets over 195, motor is new less than 200 miles, it does seem a bit better after its warmed up but not much.

 

[putz]

What is timing currently with vacuum advance unplugged and hose plugged off.

 

[rooster57]

I will need to check again ive been tinkering with it kinda on the move.

 

[Screaming Metal]

Yep....the guys got ya a going in the right direction.........here's a little something that you might want to try. Water injection.......if you look around....you'll find a few systems that are pretty cool and totally adjustable.

BACK IN THE GOOD OLE DAYS OF DECENT FUEL.....we had a substance called lead....it lubed the valvestems, upper cylinders....and yes....it polluted. We can send probes to Mars but we can't bump up our octane without poisoning ourselves......go figure........

They make additives........but are expensive........Rooster, your a prime canidate for a good ole roots blower.......

 

[Rick]

Put a blower on it and then you can put the dancing chicken up and out of retirement.Sure to put a BIG smile on your face(not to mention the wardens)

 

[Screaming Metal]

YEA..........what RICK said!!!!!!!!

 

[rooster57]

I would love a blower but i think if i spend anymore money right now the warden will revolk my parole and i will have to serve the rest of my sentence at hard labor. I am refering to the dreaded (home remodeling sentence) . So i will work on her but for now their must be another way carb spacers, higher octane ,retard timing, I am using a stock HEI could i move up to something that would help.

 

[Rick]

Yea a FORD:rofl:

 

[old round fart]

Yea a FORD:rofl:

I'd rather have the detonation.

 

[Rick]

To each his own.I have no problems with the 351 at all.
[ame=[media=youtube]yjmSXwfrC2w[/media] - Winter Time in Detroit[/ame]

 

[409T]

This is admittedly remote, but I had a Dodge once with the same problem and solved it by replacing the distributor cap. It was explained to me that as the rotor arcs to the terminals, microscopic particles of metal or carbon, depending on the composition of the terminals, are launched into the air. If there is any oil inside the cap, be it from a finger print or something faint like that, some of these particles will get trapped in the oil, and eventually build up to the point of causing a portion of the spark to also be conducted a different terminal. If that happens to be the next one in line, you have pre-detonation. I know this sounds far fetched, but changing the cap did solve the problem.

 

[rooster57]

The cap came with the distributor from hotrod usa so i will replace it. Thanks 409

 

[Brucer]

If its detonation, put an msd ignition on it and it will be solved..

 

[RUN-NE1]

How much total timing are you running base and centrifugal also how much vacuum advance? Some vacuum advance pods you can adjust how much advance there is available you might just need to back it down if you have 15 degrees so you can keep your low rpm timing and WOT timing.

An aftermarket distributor would help your problem with the adjustablility they offer. Trust me I have a Mag...

 

[Ted Brown]

Roost, You set your timing by driving the car, at about 30 - 35 step down on the pedal, it should ping maybe once just before it down shifts... Vacuum advance is for gas mileage, as it only advances when there is real good vacuum... and that is at crusing speed. Do you have a lower tin cover on the tranny that covers the bottom of the flex plate, check it to be sure the flywheel and or the converter is not touching it anywhere, look for a shiny spot, or take it off all together, till you locate the problem, could also be a broken valve spring, Do you have a good vacuum gauge hooked up? or hook one up temp, with a 1/4" line to check that out, if a higher RPMs it flutters, that could be your noise, you can use a DR's stethoscope to listen to the valve covers, as a broken spring or top cup can drive you crazy... Just some thoughts.. Hope you find it over the load exhaust?? :ciao:

 

[Wild Mango]

Leaner mixtures detonate easier too.

You didn't mention the static compression ratio, if its over compressed it'll rattle like a couple of skeletons going for it in a tin bath.

E85 has much higher RON number, a few guys here make their own with Methanol and C12 race gas. Just you use almost twice as much which cuts your range down.

Or Ted might be quite right, something loose and not the dreaded pinkers at all. Wouldn't that be nice??