2.4l 6bolt Vs. 7 Bolt

[CDeutsch]

I have a built 7 bolt 2.4 as well. All new stock parts were used except eagle rods and ross pistons. I'm pushing 7000 miles and at least 8 trips down the quarter mile. I would NOT recommend building a 7 bolt. I started building mine over 2 years ago when people were still hoping the 2.4 was less prone to crankwalk. It's since been proved that it's probably just as bad as the 2.0 as far as your chances of crankwalk go. I wanted to do the 7 bolt because it's less work to install in a 2G, but the paranoia of having a 7-bolt at this point was/is not worth it. Why risk it?

If you do build a 7-bolt consider doing what this guy did:
http://www.dsmtuners.com/forums/showthread.php?t=8817

Creating dowel pins sounds like a really good idea.

When you're done I'd go with a twin-plate clutch to be safe. I'm running the HKS and the pedal pressure is like stock but it's really chattery.

[Goat Blower]

Originally posted by CDeutsch@Oct 1 2004, 10:15 AM
Creating dowel pins sounds like a really good idea.


That's been done, it's the CRCO kit mentioned above. That didn't seem to fix the problem. Personally I'll take the 6-bolt anyday. The one I built last year still runs great with no endplay whatsoever, now if the rest of the car performed as well as the engine does. :headache:

[CDeutsch]

Originally posted by Goat Blower@Oct 1 2004, 12:53 PM
hThat's been done, it's the CRCO kit mentioned above. That didn't seem to fix the problem. Personally I'll take the 6-bolt anyday. The one I built last year still runs great with no endplay whatsoever, now if the rest of the car performed as well as the engine does. :headache:
The CRCO kit is not the same as what that guy is talking about. Hey's talking about creating alignment dowels for the whole girdle not just the bolts (kind of like the dowels on the caps for the cams).

[sleepydsm]

Ok, so I'll stay away from anything 7 bolt and just build the 6 bolt 4g63 thats sitting on my garage floor.

[SlowWhite]

On the same lines is it recommended that anyone going 2.4L go with a Twin Disc Clutch?

or what's best for the Crank Walk senario?

[Enes]

Scenario fyi

[SlowWhite]

Well - in general.

550-650whp range.

[Pimpin Dsmstyle]

depends on what kind of power, what type of driving, and how long you plan to make it last.

[Shane@DBPerformance]

I wouldn't recommend people building any 7-bolts. But I am a cheap ass who didn't want to buy a bunch of new parts for a 6-bolt. I also think that any 7-bolt that crankwalks very soon after being built didn't crankwalk from the traditional 7-bolt reasons. It took most 7-bolts 2.0ls 60,000-100,000miles to crankwalk. When a newly built 6-bolt crankwalks, and it does happen, nobody trys to instantly blame it on it just being a 6-bolt. But if a newly built 7-bolt crankwalks, everybody just assumes it's because its a 7-bolt.

[Raptor]

In Carey's motor, the dowel pins are the traditional CRCO bushings. The thrust surfaces were aligned very carefully. As far as assembly, this year we have done 16 fully built engines, almost half 2.4's, all 6 bolts except Chris's. One walked, you do the math. 7bolt + heavy clutch = bad idea. Personally, before this year, I have built well over a hundred various motors from bikes to stroked v8's with not one bearing spun, or assembly issue in any of them. Can anyone else here say that? We are looking into the use of hardened pins as well, the machine shop we use is the best around and if it can be done correctly, they can do it. It could help, but I wouldn't bother without using higher load bearings and a pressure plate that causes less pressure on the thrust surfaces.

Personally, I don't think Shanes motor is in any more danger of walking just due to the twin plate clutch. How many of the fast 7 bolt motors out there are on 2900 6pucks as opposed to twin disk? One of the engines we pulled out of a 2G that was walked and showed up on a trailer was built by a reputable shop with Crowers, JE's and ARPs as well as a 2900 pucked clutch . Go figure I am not sure it made it more than a couple thousand miles either with a lot less demands on it. Question is, how many times does a person have to be hit before they figure out they should duck?