2G Just to confirm: I can use 6-bolt (forged - Not stock) Rods and pistons in a 7- block if I trim 2mm of the 6 bolt rods to fit the 7-bolt crank?

[miliman13]

I ask because i have an entire 7 bolt engine from valve cover to oil pan, with a fresh head stored from 12 yrs ago
And i have a 6 bolt Rods and Pistons 8.3:1 86mm Wiseco/Eagle H beam rods and i noticed from all advertised specs that theirs a 2mm difference

 

[bastarddsm]

Yes you can use the 6 bolt rods on a 7 bolt crank if you narrow them up. Use 6 bolt bearings. BUT, you may need to narrow the bearings and tune up the chamfer on the rods if your crank has a large fillet like the aftermarket cranks. The OE crank has a rolled radius and narrowed 6 bolt rods with unnarrowed 6 bolt bearings work just fine.

All that said, I would not go straight to 86mm bore if you didn't have to.

 

[pauleyman]

I think it would be less trouble to sell those and get a new set.

 

[miliman13]

yeah, I'm not crazy about 86 bore rather sleeve an engine and stick to 85 or 85.5 and yes i rather just buy a set of rods and pistons for the 7 bolts. but I figure I would ask to see if it's feasible.

 

[99dsmer4g63]

Here is a great read on what you are asking about. I’m thinking on doing the same thing when I get to rebuilding my original motor that came out of my car. Not because I’m scared of crank walk but more or less the 7 bolt rods being “weaker”. So I’ve heard.

DSM / EVO - CRANK WALK - Jacks Transmissions

When you have a crank walk issue, the engine crankshaft thrust bearing is wearing down and causing the crankshaft to 'walk' forward and back. This is a very common issue with the 2G DSM 7-bolt engines. I probably have more experience with crank walk than anyone. We have rebuilt 7-bolts for a...

www.jackstransmissions.com

-Daniel

 

[miliman13]

Here is a great read on what you are asking about. I’m thinking on doing the same thing when I get to rebuilding my original motor that came out of my car. Not because I’m scared of crank walk but more or less the 7 bolt rods being “weaker”. So I’ve heard.

DSM / EVO - CRANK WALK - Jacks Transmissions

When you have a crank walk issue, the engine crankshaft thrust bearing is wearing down and causing the crankshaft to 'walk' forward and back. This is a very common issue with the 2G DSM 7-bolt engines. I probably have more experience with crank walk than anyone. We have rebuilt 7-bolts for a...

www.jackstransmissions.com

-Daniel

Thank you for posting it, amazing read and a different perspective to the thread.
I have a 98-99 7bolt (non split) still, it all applies.

Might just use what I have , honestly I have plenty and wanted to see how far I could stretch my old parts. I’m working out a deal for a shell and was trying to keep things on the low end for the first time , using all the things I’ve learned along the way.