Hi everyone, spent yesterday and today just workin on the new sammy. I got everything  that I know of to insurable satisfaction. and i did just that insured it and went for my first ride. well it is all factory so it seems fairly stable and rides pretty good, considering looking underneath looks like rust city. cant get the speedo cable out of the transfer case and i would like to since the outer housing is broken right there. any ways back to the topic..... my motor starts good and seems to get the truck up to speed ok but at about 3500 rpm it gets a tinny knockin noise that makes me wanna shift gears bad. any ideas ? could it be a timing adjuster or belt ? valves? I am not used to these small aluminum motors but I know when something dont sound right. this is a 1987 samurai lwb. 1300 stock. new plugs cap and rotor , fresh oil change and new exaughst, even when I first start it it makes that same knockin noise for a bit then goes away. help!

mine does the same thing, and i JUST rebuild it, its got less than 20 k on it lol .... maybe its just what they sound like, i duno   ... buggs me too though

i was thinking last night that the lash on the valves might need setting. i would imagine that was just done on yours? i think i will check them for some peace of mind.

piston slap.... not much you can do about it unless you get new rods and pistons

what is piston slap exactly and what can be the extreme consequences? can the motor last a long time with it?

thats what I think it is too... and yes I just set all my valves... I did use the pistons that were in it only because the previous owner had also just rebuilt it and did it wrong, but bought new pistons and prety much everything else, but it spun a rod bearing and the crank was pooched.    and just to clearify, what exactly is piston slap?  

i am not sure what the slap is but it is probably due to connecting rod bearings being worn and the piston is topping out or else worn cylinders. but my sometimes knock has turned into a full blown all the time knock, spun a rod bearing now maybe? I am po. engine swap or rebuild that will be my next post i guess.

Piston slap is when the piston is able to rock back and forth in the cylinder and the skirts are hitting the cylinder basically.  Lots of vehicle do it cold and once warmed up they fit the cylinder better and don't do it.  Many times it is dependent on the material the pistons are made of.  I can't think what would be causing it at specific rpms though.

Andrew

thanks andrew could you have a look at my rebuild post? thanks dave

Piston slap is when the piston is able to rock back and forth in the cylinder and the skirts are hitting the cylinder basically.  Lots of vehicle do it cold and once warmed up they fit the cylinder better and don't do it.  Many times it is dependent on the material the pistons are made of.  I can't think what would be causing it at specific rpms though.

Andrew