High Mileage Engine Rebuild In Truck

Im very deep into my 3rz. ive got the pistons out through the top and im planning on replacing them. everywhere i see is telling i need a new block or need it bored. each piston had some slap marks on it but the crosshatching on the cylinders is perfect. ideally i would like to throw some new pistons in and get back on the road but i would like some advice.

 

If the bore checks out why not just new rings and call it good why new pistons?
You did measure the bore??

 

I dont have the correct tools to check the bore accurately. is there any cheap methods or could i call it good with crosshatching?

 

My 3.5 in my mr2 I tossed new factory pistons in and rings.

my 2.7 I’m rebuilding right now (1ar, not 3rd) is getting new rings. Old pistons…


If the crosshatching marks are still good, you can measure the bore. But a new set of rings and cleaning the pistons should be perfectly fine assuming you put them back where they came from

I measured neither. The 3.5 has lived it’s best life at 300 wheel horsepower and 5,000 miles with no issues

 

that gives me more confidence.i would like to do the pistons aswell but with the mileage im unsure, i have 310k.

 

Big thing is get them really clean and make sure the ring lands are cleaned out well.

 

what is your opinion on using a cylinder hone tool? and recommendations for cleaning the cylinders.

 

Not sure what style rings the rz uses. But you’re likely fine to use a ball hone and lightly hone the cylinders. I use throttle body cleaner to clean out anything (brake clean leaves things too dry) follow by some oil to prevent rust and make things move nicely.
Before honing I’d do a little research. Modern Toyotas use low tension rings. So the hone requirements are different since those rings don’t really seat like traditional ones