1HD-T Piston Protrusion (1 Viewer)

[Harry Nelson]

Hi everyone, im rebuilding a 1HDt 12 Valve engine that got hydrolocked, it bent two conrods and required a full rebuild. I bought new pistons and rings for it, got the block rebored, got the crank checked and ground, put all new bearings in and got two replacement con rods. I got the my machinist to standardize all the rods and check them for straightness and so on, he also put on new small end bearings and fitted the pistons to the rods for me. Now with that explained i have the pistons in the block and my piston protrusions and quite varied. The protrusions are ,
Piston 1 - 0.61mm
Piston 2 - 0.77
Piston 3 - 0.37
Piston 4 - 0.72
piston 5 - 0.16
piston 6 - 0.65

I phoned the machinist and he says he did check all the rods but i am dough full and havent been able to find what the allowable protrusion difference is. (I would take the rods back to the machinist to check but the closest engineering shop is 800km away in another country and with covid i can get there. Will this engine be alright with these numbers?

 

[Harry Nelson]

(I am a self taught engine builder so bear with me) . Had an idea to swap rod and piston no2 and no5 to check if it was the crank but no2 then became the lowest and no5 the tallest. So either the rods are slightly different lengths or the aftermarket pistons could be slightly varied maybe ? The pistons are ARCO brand. Just a bit worried about very different compression in the cylinders or will it okay to run as is?

 

[McDowra]

More than likely rods are different. Bet the rods were resized and that is where your problem comes from