timing problems?

[project250x]

Well recently i took my cylinder in to be bored .5mm over bore and have a wiseco 12-1 comp piston installed. I was talking to my brother who is a big dsm car lover and he was telling me that i'm going to have to change my timing and find a way to retard my spark. I know he knows what he's talkign about but i probably didn't write it correctly but i was wondering if its true that i need to change my timing and any other mods i would have to do to keep it from falling apart.

[Screamin440]

Originally posted by project250x
Well recently i took my cylinder in to be bored .5mm over bore and have a wiseco 12-1 comp piston installed. I was talking to my brother who is a big dsm car lover and he was telling me that i'm going to have to change my timing and find a way to retard my spark. I know he knows what he's talkign about but i probably didn't write it correctly but i was wondering if its true that i need to change my timing and any other mods i would have to do to keep it from falling apart.

There is no way to retard your timing with the stock ignition. What you'll possibly need to do is get a cooler plug and/or run high octane fuel.

Both of these steps are taken to reduce detonation, commonly called "pinging". This happens whenever the temperature inside the cylinder is too hot for the level of octane fuel you're running. The pre heated cylinder causes the fuel to ignite prematurely and you have a bunch of small explosions inside your cylinder instead of one big explosion which occurs in a normal combustion cycle.

[project250x]

So will i have to change the timing on it?

[Screamin440]

You cannot change the ignition timing. The only timing that can be adjusted would be the cam timing but I don't see any reason to do that.

What you'll want to do is get some high octane fuel, 94 should be sufficient for this test. Get a stock spark plug, I believe an NGK DPR9Z is the correct stock plug number. Run this combination of fuel and this plug for an hour or two while listening for any pinging(it can sound like marbles in a can). Let the motor cool back down and pull the plug. If it looks white or chalky then you need to step down to one plug range colder and try it again. What you're looking for is the plug needs to be a nice tan color with no discoloration or hot spots.

[mojoe2878]

Originally posted by Screamin440
You cannot change the ignition timing. The only timing that can be adjusted would be the cam timing but I don't see any reason to do that.

What you'll want to do is get some high octane fuel, 94 should be sufficient for this test. Get a stock spark plug, I believe an NGK DPR9Z is the correct stock plug number. Run this combination of fuel and this plug for an hour or two while listening for any pinging(it can sound like marbles in a can). Let the motor cool back down and pull the plug. If it looks white or chalky then you need to step down to one plug range colder and try it again. What you're looking for is the plug needs to be a nice tan color with no discoloration or hot spots.

like he said.
you dont need to change anything on the timing. just make sure you run some good fuel with the 12:1 piston. if you get any pinging with 94 octane (which you shouldnt) then mix some octane booster withh it to make the octane rating a little higher.
i would also run a flexi steel type head gasket instead of the fiber one with the high compresion.
if theDPR9Z is too hot of a plug then switch it to a DPR8Z.

[sickmojave]

Originally posted by mojoe2878
if you get any pinging with 94 octane (which you shouldnt) then mix some octane booster withh it to make the octane rating a little higher.


Do not use that crap! if you have to spend the money on race gas.

[mojoe2878]

Originally posted by sickmojave
Do not use that crap! if you have to spend the money on race gas.

it true that its not the best, but some people dont have easy access to race gas. its easy to get around here but i dont know if it is where he lives.

[Aceman]

11-1 compression is borderline for 93 octane. If you have a 12-1 piston I would definitely run at least a 50-50 mix. The few extra dollars spent on fuel is well worth keeping your engine from blowing up.