How much advance am I supposed to run on my 305tpi 88 Iroc? I just installed an Accel cap and rotor, Taylor Spiro pro wires, and regular ACDelco plugs. I set the base timing at 12* before TDC, but it seems like it's knocking. I read somewhere thats a safe point to start from. Timing was previously RETARDED to about 4-8* after TDC. No wonder it was running like crap.

What should I do about the knocking? I can't really hear it but there is a slightly metallic sound from the engine when I press the gas pedal in third gear. Doesn't really sound like knocking to me, but I don't want to take chances. I'm using 93 octane gas.

Should I retard timing a little bit? I've read about people running 14* advance w/o any problems. Am I just hearing things? Probably...

Anyway, changing the plugs and wires, and setting the timing really woke the car up. Starting is so much easier, and there a helluva lot more power on tap.

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'88 IROC 305 TPI
Gutted airboxes
160 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel
Ram-air setup coming soon
Flowmaster muffler

 

Your waaaaaay to advanced, especially if your still using a chip. If you're using a chip, it is supposed to be set at TDC, since that is a reference point for the chip. But it is safe to set it up to about 8*. depending on how much of a lobe you have on your cam, you could probably set it higher, but I wouldn't recommend it...

 

Shiytes!! Better back the timing down. Don't want to bust anything in there.

Can excessive advance produce a ticking sound from the motor? I can hear it and it's RPM sensitive. It wasn't there before I adjusted the timing.

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'88 IROC 305 TPI
Gutted airboxes
160 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel
Ram-air setup coming soon
Flowmaster muffler
Taylor SpiroPro wires
Accel cap and rotor

 

BACK THE TIMING OFF!!! I have herd as much as 10 degrees btdc but that requires good octane boost...

 

The most I have heard people use is 8*.. UI wouldnt go much above that unless I was running a carb =)

One thing I founf out about timing is that each car is happy at one spot.. So play around with it till the car likes where it is at.. For instance my car is happy with it 4* advanced =) Oh yeah and it doesnt knock (detonate)at all with 89 octane either.

Kat

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90 RS 305 TBI A4
Dumb ***/**** poor/orginating memeber of the infamous NE Crew
Time to see, believe this in me,This pain that i feel deep inside

 

Yup I backed it off to 8* but the car doesn't feel ready to take off like it did before. No more knocking, but it does make this weird ticking sound thats RPM sensitive. It wasn't there when the timing was retarded to like 4* ATDC before the tune up. I checked the sound out and it seems like it's coming from the injectors. Used screwdriver with my ear on one end for this. It's definitely with the injectors and at exactly the same rate. Funny thing is it's not that audible with the hood open but i can easily hear while driving. I know its nothing to do with the con rods or valvetrain, basically no part of the rotating assembly. I've seen timing changes drmamtically alter the engine sound but i just want to rule out any sinister causes.

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'88 IROC 305 TPI
Gutted airboxes
160 degree T-stat
Advanced base TPS voltage
Relocated IAT sensor
Momo steering wheel
Ram-air setup coming soon
Flowmaster muffler
Taylor SpiroPro wires
Accel cap and rotor