7-bolt crank conversion in 6-bolt block

[JackM]

Yeah, really stupid idea, right? I got it to work though, lol! I found a way to safely machine a 7-bolt 2.3L (4G64) crank to fit your old 1G 6-bolt block. Why would you do this? Well, the 2.3L 6-bolt cranks are known to break at the #4 rod bearing journal. Shoot, I have even heard of quite a few people breaking the 2.0L 6-bolt cranks now too. It just appears that the 6-bolt crank is not as strong as we once thought. I have yet to see a 7-bolt crank break though. I have built so many 7-bolt strokers by now that I should have seen one break, but they all take a beating without any issues. I figured if we could get the best of both engines- 7-bolt has the best crank and the 6-bolt has a nice block/won't walk as easy. Plus, it would be a good solution to the 1G guys that keep breaking old junkyard stroker 6-bolt cranks. Would anyone be interested in this?? I am trying the 'prototype' here soon, but I believe this will work perfectly. I'm just wondering if it's worth my trouble. If nobody likes the idea, I may just drop it... So far, what I have found with this prototype unit is you need a 7-bolt flywheel (duh). You will also need 2G rods and pistons, but I can machine your 1G rods to fit the narrower 2G crank if you already spent the money on the 1G rod and piston setup. It seems like many 6-bolt owners are a little afraid of the 2.3L strokers anymore because of the crank failures. I'm hoping my 7-bolt conversion will fix that. Let me know if you 6-bolt owners are interested. Thanks!

Jack

[Mirage]

Try it.

I think another reason people go to the 6-bolt is because of the stronger rods (in stock form at least) along with teh crankwalk "resistance".

It does sound like you're just dropping a 7-bolt engine into a 6 bolt block, but anything that will keep the best of both worlds. I do know of at least one local 7-bolt crank (2.0L) that snapped, but that's nowhere near the number of 6-bolt cases there are locally.

You may want to get 3 blocks built and put them into cars with different performance levels. One near stock, one with like a 20g size turbo and one that's balls out. See how eash one holds up with the abuse and punishment.

Marcus

[JackM]

Yeah, the car it's going into now is a 2.3L EVOIII16G car. Nothing spectacular at all, but I figured it would be a good start for now. If that works well, I might convince my brother to convert his 4G64 engine to a 6-bolt block with the 7-bolt crank. Right now he is building a 7-bolt 4g64 for his GVR4, which will be a pain to fit into the 1G. It will be easier for him to use a 6-bolt 4G64 block with the 7-bolt crank. I think I should be able to get him to go for it. His car is pretty close to balls out already, so his would be a good high HP car to test it in for sure.

Jack

[v413nc3]

Jack, explain to me some time exactly what machining is required and I'll test it for you in a 6 bolt. I have a 7 bolt 2.4 setup with Ti rods and Ross pistons.

[rlarsen]

Both of you, knock it off. Now. If you want to flame the crap out of each other, I'm sure you both have suitable email addresses. And wow, guess what? We feature a PM system, too.

[BlueVelocity]

Please stay on topic fellas. We do not allow for bashing of other members, regardless of here-say, past experiences, the like. You know the deal, keep it civil fellas.

Erron S.

[rlarsen]

I'm not sure that no less than THREE moderation posts were necessary, but okay. :D

[BlueVelocity]

I'm not sure that no less than THREE moderation posts were necessary, but okay. :D

LOL, now that's funny!

Erron S.

[Sparetire]

Yep, its doable. I have a 6/7 in my garage right now. Whoever had my car before me must have blown it up or something. The block uses a 6 bolt water pump, a 6 bolt tensioner etc. Yet 7 flywheel bolts and a locating dowell on that crank.

I had 160K+ miles on that motor before I put in my G4CS based motor. It still had good compression when I took it out, no CW or anything of that nature at all.

[v413nc3]

What differences are in the mains? The rod issue is cake, just use 7 bolt rods but I don't think I've ever checked to see if the main caps were close at all.

[Outlaw]

What did i miss? who was flaming who?

[rlarsen]

I would if one read who posted the deleted posts, one could figure this out.

And don't make pointless posts, they get deleted.

[Outlaw]

I would if one read who posted the deleted posts, one could figure this out.


huh':confused:

[rlarsen]

Actually, I apologize since I don't think you can see who the deleted posts were posted by unless you're a moderator. Quinn and Jake were wrangling, if it's really that important to you.

[Outlaw]

Actually, I apologize since I don't think you can see who the deleted posts were posted by unless you're a moderator. Quinn and Jake were wrangling, if it's really that important to you.
yeah, i had no idea posts were even deleted, and i am not a mod, so i had no idea. i was just curious.

[JackM]

Well, the first one here we did by machining the mains in the 7-bolt crank to fit the 6-bolt block. I fear though that this is taking strength away from the crank. We are now modding a 6-bolt block to accept a virgin untouched 7-bolt crank instead. My brother was going to do this for his car, but since he just lunched a rod and wants to make it to the 'trick or treat' drags at PMI with me, he may not have enough time now for this either on his new engine.

Sparetire, you probably have an early 7-bolt block in a late 1G. That block is still a 7-bolt, it is not a true 6.

Damn! I thought the bashing in my threads was only in RM, but it appears to go anywhere I guess, lol! Too bad I missed it...

Jack