Detonation and piston slap

[strokedcj8]

I have an 82' scrambler with a 4.7 stroker. I built the motor 2 years ago and has never been quite right. I just had to put new pistons and rings in it because of a tick noise. Piston closest to the firewall had shrunk do to some overheating and was slapping the cylinder wall. I put on about 50 miles and now having the same sound. Pulled the oil pan to inspect and looks as though I have detonation in 3 of the cylinders so far. The piston closest to firewall is slapping the cylinder wall again. I need some help, advice, anything! I have dumped so much money into this motor and feel like giving up. Thanks in advance.

[Cheromaniac]

The no.6 cylinder is furthest away from the water pump and will run hotter than the others if there's a blockage in the cooling passages of the block preventing proper circulation of coolant. There could be some ovality in that cylinder since the piston was slapping around inside it.

[SilverXJ]

You just put now pistons and rings in w/o a bore or hone?

[strokedcj8]

No, I did have the block honed. I run an aluminum radiator with electric fan. The temp never went over 190. The thought of a blockage makes sense. Thanks I will look into that.

[SilverXJ]

Did you go with over sized pistons, or stock with just a hone?

[strokedcj8]

I am running .060 over icon pistons. I did find some info today on my injectors. TOO BIG! 30lb viper injectors. I am going to pick up a set of #24, replace the pistons, rings and bearings. Also change my fan temp switch to be more accurate.

[SilverXJ]

TOO BIG! 30lb viper injectors. I am going to pick up a set of #24, replace the pistons, rings and bearings.

Holy crap those are huge! Who's idea was it to use those? I wouldn't doubt it if your oil is diluted with fuel.