I wouldn't swap out a 7 bolt for a 6 bolt, unless the 7 bolt had catastrophic failure.

I hate it when tools swap out their mint sub-100 thousand mile 7 bolts for 200 thousand mile 6 bolts in fear of crankwalk.........

 

That's what I imagined. I mean my engine just hit 98,000 miles today and its going great. It is a 7 Bolt but all I hear from everyone is "OH MY GOD, CRANKWALK!!!".

I don't know very much about crankwalk and have never experienced it based on symptoms, but it can probably be fixed before any damage occurs right? Or no?

I'd love to hear more opinions just for the hell of it. Thank you for the first 3 answers guys, I love DSMtalk, you can get great information, and people are awesome here!

 

Theoretically, the 7-bolt is a superior engine when modded (according to AMS).

However, it gets a bad rap from the crankwalk possibility and weaker stock rods.

IMO, not worth swapping unless there is a problem with your 7-bolt.

 

If it's not broke don't fix it. The availability of 6 bolt motors makes it an easy swap for 2gs when they need be.

 

Well there are some preventive things you can do, but as far as "fixing" it, that's a whole different debate.

 

I wondering about the same exact thing. Looks like I got my answer though, thanks for asking this.

 

Theres a few guys here with built 7bolts, heck macgsx even used his stock crank and ran 11s. IMO its alot cheaper to just replace the stock crank for a topline ($300) when your rebuilding and bam you have the same chances of crankwalk as a 6bolt.
Ams is right, they built there 1000hp evo on a 7bolt.
Crankwalk is real but it can happen to anyone and any motor. Im building mine

 

Replacing the crank doesn't fix the issue.

 

It MIGHT also be a question of money, to rebuild a 7 bolt it requires a lot of $$$ when you could buy a well built 6 bolt from a TRUSTED member here for $800 or so, patience is the key.

 

Are you making a comparison and saying one costs more than the other? You can buy a 7 bolt engine from a trusted member for similar costs as a 6 bolt. No performance gains either way. If there were...why would anyone build a 7 bolt?

 

I only replaced my 7bolt because I broke it. If I wasn't an idiot It would still be in my car today and probably have stupid mileage on it.

 

I love the main girdle on the 7 bolt blocks. Also I am debating getting a Kiggly for my 6 bolt as extra strength. Probably an overkill, better safe then sorry lol.

 

7 BOLT FOR LIFE!!!

7 bolt's have a larger wrist pin, OE gridle. Either motor can walk. The 95-96 motor are a little more prone though.

I have a 99 block in my car, been great thus far...

 

Now that all these cars are 11 to 12 years old now anyway, on the newest of them. Its safe to assume that most that will crankwalk have by now. 7 bolts are easy to get, there are an abundance of them and are just as strong. No reason to swap a 6 bolt other than you just want a 6 bolt. Its a car, its ganna have problems either way.

So really, "everyone wants nothing to do with them" is a unknowing, uninformed and likely a honda or nissan owners advice. LOL, I kid. Listen to the guys who have been doing this for years, your safe with your 7 bolts.

And if AMS says they like 7 bolts, than DANG IT im using a frikken 7 bolt! I want to be like them

 

Haha. I wasn't saying "Everyone wants nothing to do with them" as if it is true. I meant it "seems to me" like people try to steer clear of them when building, mostly for the fear of crankwalk. This is based on what i've read and what people say sometimes. I know that crankwalk is possible on any engine in this world, I just wanted to see what the big deal was. I personally love my 7 Bolt. I've had two in my life and never had crankwalk problems.

Thanks for the info!

 

i have had both a 6bolt and 7 bolt walk if u have the 7 run it tell it fails and put ur money into other things if u are worried about crank walk find a 98 or 99 block and build it

 

Please do not post like this again.

 

After swapping my 6bolt into my car..I don't regret it because its built and at the time no one was wasting their time to build a 7bolt but now a days I'd rebuild a 7bolt. Theres so many revised parts available to avoid crankwalk or atleast make your motor least prone to it that it would be worth it. 6bolt swap is easy but has little things that will get under your skin and become nags if you don't do it properly the first time.

 

My 7 bolt stock bottom end has 150 thousand on it and is still going strong. Most of the miles were stock albeit, but the last 3000 or so were boosted to 20psi on a 50 trim. The topend is getting worked on right now with new valvetrain, cams, and headgasket for my big H1C. When the bottomend gives way (which it will sooner or later with as much HP it will be getting) I will also build the 7 bolt. Correct me if I am wrong but isnt more prone to walk with a heavier clutch like say the 2900? Also removing the clutch switch to prevent "unnesissary use of the clutch" helps also.

 

My take:

-Swap it when you have had a problem. To worry about it or swap out a perfectly fine 7 bolt is silly.

-If I had a 2G and was building a motor in preparation for big power then I would not risk building a 7 bolt. Cost associated with either build is the same and it is a very easy job to swap a 6 bolt into a 2G these days. If you are spending the same money either way why even take the increased risk of crankwalk in a 7 over a 6 if you don't need too.

 

I completely agree with Erik ^^^. I still have my 7-bolt in my car. I've got 52K on it and have no problems with it whatsoever. So, for now, it stays in.

But, when I do have a problem, and when that time comes I have a bare 6-bolt block on a stand in my basement and I already have a fully machined head ready to go.

 

Oh and I never had any problems out of my 7 bolt till now.. But I still like em. The 420a is ok but not the best thats for sure.

 

You dont have a 7 bolt...

Personally I refuse to build a 7 bolt but I have my reasons and wont fault anyone for building a 7 bolt as that is their choice.

As for the 6 bolts being out of spec at 150k miles I disagree, i've taken apart many 6 bolts and only had 2 that were out of spec, one was WAY out (.03") the other was only .001-.002 out.

 

I have a 7 bolt and it has never given me any problems at all. I was sketchy at first but, if it does happen to give me an issue down the road then i would build it again.

 

What if...you got a 6 bolt motor, machined up (stock bore/honed/allign honed/decked), 1g rods machined to accept 2g pistons, brand new 2g pistons (8:5:1), new OEM oil pump, new lightweight flywheel, motor mount already cut for 2g, 1g CAS sensor wired correctly - for 250$?????

Even though my 99 7 bolt is doing great, crank end play still well within check - I plan on 'building' this 6 bolt over the next several months and dropping it in with a Holset turbo. By all means I'm keeping the 7 bolt, and will be a nice piece of mind if the 6 bolt ever gives way.

 

I can say that I probably would not have built my 7 bolt if it was not a 99 block... The only reason I was willing to throw the money at it like I did was because they say the 99's are less likely to walk, and I had 140k on her with no problems

Jordan