Offset crankshaft grinding

[TH Performance]

I ordered custom JE pistons, I don't use CP.

I use only Wiseco and JE. JE had faster custom service, that is why I used JE.

Both are great quality pistons.

5S can be overbored without worries, since the walls are 4-6 times stronger than 3s block.

[TH Performance]

stock 3s rods? or shortened? what stroke do you have now?

I have 95mm on my engine now.

I am just telling you that for destroked version you use 3s crank and rods, just with custom pistons of 88mm.

[Roundy]

For destroke version, just use 3s crank, rods and custom 88mm pistons. You will gain shorter stroke (86mm) and bigger bore (88mm) which will give you oversquare engine ggod for higher revs.

You will have an engine that can rev as well as a standard 3S with 2mm OS bore.

Just cause an engine is oversquare doesn't mean it will rev well.

[jonathan yee]

i was under the impression that the 3s rods could only be used with the 5s crank if you didnt offset the grind just made the big ends the 3s size. as the 3s and 5s rods are the same length from little end to big end centre's just the 5s rods have bigger dia big ends.

if you increase the stroke more then you need to get shorter rods.

yes i understand what your saying about destroked but it's not a shorter stroke than the standard 3s which is what i was referring to.

[TH Performance]

Yes you will, but oversquare will always rev better, if you leave all other parameters as they were.

All racing 3sgte engines are made like this, to 2.1L and oversquare.

I didn't invent this, I just learned from the professionals.

Also, there are some other added benefits, as larger area of the piston etc etc...

[Sam_Q]

I thought a larger area of the piston was a bad thing? anyway please continue I am finding this thread quite interesting.

I wonder what it costs to get a custom grind. So TH-man hows it work with the rod lengths? sorry for the ignorant questions

[TH Performance]

I did a custom grind and ION current nitriding in USA for 240+175$

[Sam_Q]

that sounds reasonable, now about the rod length thing? if the 5S block is the same height does it have shorter rods? or how does it work?

[TH Performance]

5s and 3s are same lenght 138mm from center to center. the only difference is in big end.

[Sam_Q]

ok I am confused, if the stroke is longer and the block is the same height how does the piston not come out the top of the block? or is the gudgen pin height higher?

[TH Performance]

it is the custom piston

please read what i type carefully

I have CUSTOM JE pistons inside

[Sam_Q]

nah not your build I read that, I mean what did Toyota do from the factory to make up for the difference in height from the stroke between the 3 and 5S?

[TH Performance]

it is a different compression height for 5sfe and 3sgte

the difference is:

3sgte 35mm ch
5sfe 32,5mm ch
5s stroker with 3sgte conrods 32,5mm ch and 3sgte piston
5s 95mm stroker 30.5mm ch

is that clear now

[jonathan yee]

the pin height is higher in the 5sfe pistons by 2.54mm. so you can use the 5s pistons with 3s rods if you grind the big end journals down to 3s size.

but if you offset this grind then you'd have to change the rods length to suit. which is my "bone to pick" with stroke'd strokers. you end up with a not so favorable stroke/rods ratio and the piston is pushed into the bore side wall more causing wear.

[jonathan yee]

CP sell pistons off the shelf to suit 5s crank and 3s/5s rods lengths.

pin to crown height as mentioned is approx 2.54mm different