Help?

[r&h110125200]

Ok, so now that i'm on here, i guess i can ask yall for some help.... My 85 200x needeed a rebuild last year, so i decided to do it myself, I used a .50 over wiseco piston and put it all back together, and fired it up. It idles fine, but i got on it to take it for a spin, and started up our driveway, as soon as it was under a load, it started making a hammering noise and lost power. I can put it in neutral, and rev it up, and it is smooth as can be, but under a load it does the hammering thing, and screws up... What does this mean?

[ceaserthethird]

Did you take the Hammer out ? J/k

Check the Valve's ...

[r&h110125200]

they are fine, could it be something with the increased compression?

[Just_Randy]

Too much compression or too much ignition advance.

I don't know how to set the timing on those engines, but it sounds like the gas is igniting before TDC - either from ignition advance or low octane (detonation).

Run a higher octane gas and see if it improves any. Maybe get a can of octane boost. Be careful though, you can blow a hole in your piston. Did you get the valve timing exactly right when you put it together?

[r&h110125200]

I tried pj1 octane booster, maybe it is the timing, but it is just being a pain in the ass.

[Just_Randy]

did the boost make any diff at all?

[r&h110125200]

no, It runs the same, it just turns the plug red

[Just_Randy]

gotta be the timing then. Can you back the timing off some???