6 bolt internals in a 7 bolt block

[v8s_are_slow]

my buddy needs new internals in his 7 bolt (drove it around too long with a bad headgasket and burned up the bearings). anyway, i have a spare 6 bolt block layin around and was gonna give him the internals so he can get his motor rebuilt again for cheap. i'm using the 6 bolt block for my own built motor and won't need those internals so i don't need that stuff.

anyone know 1st hand if it'd work? dunno why it wouldn't since they're essentially the same motor. but wanna be sure. giving him my crank and rods but suggested he get some new 2g pistons instead of using the old 1g pistons in this motor thus lowering his compression. thanks for any info.

scott

 

[project_tsi]

Putting in 2G pistons wil raise the compression, not lower it. W/ 6 bolt rods on 7 bolt pisons, you need to have the rods machined out 1mm in order to fit the pistons.

 

[v8s_are_slow]

yeah, i know about that. but think ya misunderstand. he has a 2g car with bad internals. i'm giving him my 1g internals (6 bolt) to throw into his 2g (7 bolt). if he used the 1g pistons, he'd be lowering the compression so i'm advising him to keep the 2g pistons in it. would the 6 bolt crank swap over okay to a 7 bolt motor though?

 

[timloomis]

no,the crank main journals are smaller.you could have it machined,but that would cost more than just getting a 6 bolt swap.

 

[99gst_racer]

So, would 2G 7-bolt rods fit a 6-bolt crank? (i would never use such a set-up - i am just curious)

 

[blue1]

The journals are narrower in width, so you would have to much side float with the 7 bolt rods

 

[v8s_are_slow]

wonder how people get away with throwing on 6 bolt rods then. just curious....thanks for the info though.

 

[blue1]

The question was fitting a 7 bolt rod on a 6 bolt crank. by memory the 6 bolt rod is something like 1.117 wide on the big end and the 7 bolt is 1.038. i think?

 

[v8s_are_slow]

oh okay.

 

[99gst_racer]

The question was fitting a 7 bolt rod on a 6 bolt crank. by memory the 6 bolt rod is something like 1.117 wide on the big end and the 7 bolt is 1.038. i think?

Damn good memory. Yeah I did some checking and found that the big end's thickness is 1.115 on a 6-bolt and it is 1.038 on a 7-bolt. The bore is the same on each though.....

Being that they have the same bore size, will the small difference in thickness really make it so they will not work?