What to do with this 6 bolt short block and head. Help.

[Drift_SM]

Alright lets start with the block.

91 6bolt. Decent condition.

I want to do a bearing and ring job. But from what I have heard....you cant just hone the cylinders and then put new rings in. Because the posibility of the walls being tapperd.

it would have to be bored over...but then what piston would I use?

*side question* are 2g pistons bigger (larger diameter) then 1g pistons?
If so...could I have the cylinders bored to fit them along with the 91 rods . (1g big rod, 2g piston combo)

or, Is It safe to just get new rings and hone the cylinder and put the old pistons back....will the compression be lost?

Next For the 1g head. I rebuilt a 2g head about 18k ago...and im wondering how many INTERNAL parts are interchangable from a 1g and 2g head...minus the cams.

Thanks.

 

[steel_3d]

All standard bore 4g63 pistons are 85mm. If you bore the block, you need overbore pistons.

I would do just what you said. Hone the cylinders a bit and replace the bearings and rings. It will work fine. IE it likely won't work any worse than other engines with 100k miles on them, and it will likely work better and last longer.

If you're gonna do any more than that, I would go all out on a forged engine build and the works for machine work.

 

[Burnett03]

Alright lets start with the block.

91 6bolt. Decent condition.

I want to do a bearing and ring job. But from what I have heard....you cant just hone the cylinders and then put new rings in. Because the posibility of the walls being tapperd.

it would have to be bored over...but then what piston would I use?

*side question* are 2g pistons bigger (larger diameter) then 1g pistons?
If so...could I have the cylinders bored to fit them along with the 91 rods . (1g big rod, 2g piston combo)

or, Is It safe to just get new rings and hone the cylinder and put the old pistons back....will the compression be lost?

Next For the 1g head. I rebuilt a 2g head about 18k ago...and im wondering how many INTERNAL parts are interchangable from a 1g and 2g head...minus the cams.

Thanks.

Who told you that you cant just hone and re-ring? I've done it many times on 4g63's and Motorcross bikes.

 

[TimG]

I've done the micropolish crank / bearings / hone / re-ring many many times on the 4G63 with great results.

 

[Defiant]

Cylinder bore taper was a circumstance you ran into in the sixties, when ring and block metallurgy was much, much less-developed than what we're dealing with. It is likely your block will be within tolerance for a hone and ring job, but your machinist will make that determination.
It used to be routine to have to use a ridge reamer before removing the pistons from an engine, a cutter that cut the unworn portion of the bore from the top of the cylinder before you could get the pistons out. I've never had to use one.

 

[dsm-onster]

Alright lets start with the block.

91 6bolt. Decent condition.

I want to do a bearing and ring job. But from what I have heard....you cant just hone the cylinders and then put new rings in. Because the posibility of the walls being tapperd.

it would have to be bored over...but then what piston would I use?

*side question* are 2g pistons bigger (larger diameter) then 1g pistons?
If so...could I have the cylinders bored to fit them along with the 91 rods . (1g big rod, 2g piston combo)

or, Is It safe to just get new rings and hone the cylinder and put the old pistons back....will the compression be lost?

Next For the 1g head. I rebuilt a 2g head about 18k ago...and im wondering how many INTERNAL parts are interchangable from a 1g and 2g head...minus the cams.

Thanks.

He!! I've even dropped in new IRON rings and did no rehone and read 160 psi across the board on a 1G. . . Anyway,

The, springs, shims, retainers, valves, valve keepers are the same. That is the limit of my experience w/ swapping 2g parts into a 1g head. . . I don't know about guides, cams, cam towers, followers, seats.

 

[Drift_SM]

Awesome guys! Thank you so much.

As of Now I am going to do new rings and bearings with a rehone.

As far as the head goes. Im going to swap all the newish parts from my 2g head i rebuilt into the 1g head + new valve seals. Anyone know if the rocker arms, also the lifters will fit in the 1g head?

Thanks! DSMtuners has never let me down!