Hey,
i Was wondering if you were able to help. I have been rebuilding my datsun 240z and have finally completed it. however the first time i ran it it ran smooth and nice but when i tried to start it again the next day the pistons are hitting. i have no idea what is wrong, the timng is all correct.
Thanks

 

if the pistons are hitting the valves/head, your camshaft timing must be off, or something went awry internally. when you ran it at first, did you actually drive it? is it a new engine? is it modified?

 

hey,
no we didnt actually drive it, we ran it for about 15 mins, the head is new but everything else is older, the pistons have been carved in the top cause they were hitting before, the only modifications are extractors.

 

carved...do you mean eyebrowed?

 

yes

 

many many engines have eyebrowed pistons, so i wouldnt call that a clean indication that there had been prior issues. i would check to ensure that your camshaft timing is correct.

if it ran fine, then the next day was fine, i would have to think that somehow it jumped timing as you shut it off.