Rebuilt questions/answers for 7 Bolt DSM

bouncer07 · 02-27-2008

I have a late 2G (1998) dsm and with 150,000 miles on this car and still running. No sign of crankwalk and did a leak down test which my motor is still in great shape. I know the theory in crankwalk works but mine has just been good to me. Instead of moving to a 91-94 6 bolt motor, i want to rebuilt my engine so what is your best bet to insure a long lasting 7 bolt w/o bearings or crank issues? Have anyone is this forum done a 7 bolt crank nitrided and added new bearings? In my opinion, cryo treating the crank is good too but i think nitriding is my best bet. Throw me some Q's+A's, before i start my engine rebuilt this spring!

side notes (have supporting mods)
past turbo's installed
I had run on 16G for (50,000 miles) on 15 pounds
20G turbo (3,000 miles) 18 pounds

I'm currently running the SBR G50 turbo in my car for 10 miles now and not much abuse was pushed on my 150,000 mile motor on all the turbos.

This post is for the rebuilt, suggestions, and past experiences. Thanks.

**Shane@DBPerformance** · 02-27-2008

Don't rebuild it, if it's in good shape.

MustGoFaster · 02-27-2008

I'm with Shane.

**JET** · 02-27-2008

Yep, I am with them. If you rebuild it you will likely have more problems than just leaving it alone. Run her until she blows!

Pushit2.0 · 02-27-2008

Your motor has the revised thrust bearing setup that uses thrust washers, 2 half's just in the block, nothing in the main girdle. Keep up on your oil changes and use a Wicks or similar filter and the car should last a while longer yet, no need to "build" a motor unless you plan to make tons of power.

~John

bouncer07 · 02-27-2008

yeah, good points.

iceminion · 02-27-2008

Quote:

Originally Posted by bouncer07

Instead of moving to a 91-94 6 bolt motor, i want to

Not trying to be a dick.....but the 6-bolt was only available from 89-92.5.

Just trying to keep the correct facts circulating.

As for your car, I would find a cheap 6-bolt and start building it up. Currently, it sounds like you should just leave your engine alone, eventually you will want more.

It can't hurt to have a built shortblock built and ready to install ready in your garage.

Its better to be ready to before hand. 4g63's can last a long time, but seals, and rings do wear out eventually.

**Kracka** · 02-27-2008

If it runs well and still shows good compression #'s there is no reason to rebuild it unless you suspect other problems or are going for a ton of power.

bouncer07 · 02-27-2008

7 bolt motors can hold just as much boost as a 6 bolt. I like the 7 bolt for many reasons for a FWD.If it was AWD, yeah.. i'd swap into a 1G no problem. But being a FWD, 400hp is where i will stop at.

RichardBBY · 02-27-2008

sorry for my ignorance, i'm not vary familar with early DSMs, but why would a 6 bolt be better for AWD then a 7 bolt?

**Kracka** · 02-27-2008

Quote:

Originally Posted by RichardBBY

sorry for my ignorance, i'm not vary familar with early DSMs, but why would a 6 bolt be better for AWD then a 7 bolt?

The 7-bolt has no advantages over the 6; the 6 is a better choice when building an engine for any DSM. Search for "crankwalk" and you'll find plenty of info!

**JET** · 02-27-2008

Yes, the 6 bolt is a stronger engine. The 1g 7 bolt seems decent, but the 2g 7 bolts have a tendency to crankwalk.

**scheides** · 02-27-2008

6-bolts have bigger rods, so theoretically they can hold more power than a 7-bolt.

They both seem to be able to take 350-400whp pretty easily, I don't think you'll be getting there on that 50-trim unless you switch to E85 or alky injection.