4g64 2.1 Attempt with Questions.

[phizzalot]

Hello all,

I picked up a 6bolt 4g64 for a project Iam working on but am afraid it may not be any good.

I haven't measured deck height as of yet but the initial measurement I've taken of the cylinder diameter with piston's still in the block are 3.505in ( 89mm ). Where at oem specs should be closer to 3.404in ( 86.5mm ).

The cylinder walls have signs of scoring which I would think is a result of incorrect piston size.

So is this block toast? or can I get by with the options below given the cylinders are totally round?

K667M87AP Evo piston Asymmetric skirt 3.4252 ( 87mm) + .080 = 3.505in ( 89mm)
or
K626M87AP Dsm 1400hd pistons ( 87mm) + .080 =3.505in ( 89mm )

I would add these to a 6bolt 4g63 88mm crank and a set of strong 156mm rods, for a total of 2191cc 2.1 build. Other than requesting custom pin height of 1.375 is there anything iam missing?

 

[BogusSVO]

I would say check your Mic and measure the bores again.

How and what did you use to mic the bores?

If the block was taken that far over, you should see a 2.50mm stamped on top of the pistons

But I would not know where to start to look for 2.50mm /.100 over cast pistons.

If you just can not find another block, I would have all 4 cylinders dry sleeved and taken back to STD bore.

That would run $250-400 just for the sleeve work,

 

[phizzalot]

I was in a hurry and grabbed my dial vernier caliper and got a measurement before going to work. I probably should of use a bore gauge or mic'd a telescoping gauge or even mic'd the piston but haven't got a chance. Just picked it up from a junk yard over the weekend on a half off black friday sale

Thanks for the help bogusSvo, I will get some more measurement's after work.

 

[BogusSVO]

A dial caliper.... I bet a piece of grit is in the teeth and caused it to jump.

 

[phizzalot]

Little Update,

After taking my time and measuring again with telescope guage / dial caliper, I read the caliper wrong

The cylinders are within factory spec and appears to be able to be freshened up. BogusSVO, Ill be sending you a PM.