Re: THe NAC Lots-O-Post Thread
Just get some cool motor mounts. When you break another bell housing you can tell everyone to stfu.
That's $320 I really don't have to spare right now. At all. The jeep ate every spare cent and then some when I got the beat up old AW4 out of it and put new rod bearings in it, and I had to buy a whole transmission to get this bellhousing, which put me further behind.
Also, it's 50/50 whether this one will even have the same issue. The new one in the MJ is fine and I changed nothing about my behavior or the way it's set up. Still the same junkyard OEM motor mounts (not kidding, I couldn't find the new ones I bought for it when I did that motor swap so I chose the best out of the pile of random used ones sitting around the yard) and if anything I've driven that thing ten times harder since swapping the trans than I did before swapping it. Zero problems since then.
So if it doesn't fail, it doesn't really prove anything either way. If it does fail, it does prove something. Maybe.
Check out the motor mounts on my 440 next time you see my MJ. They're basically at the #1 and #2 cylinders and this motor weighs close to 700 lbs with cast iron accessories on it.
TF727s had aluminum bellhousings and the motor mounts these things used were completely retarded/useless and the motors made close to 400 HP from the factory.
Tell me why I've never even seen a broken bellhousing behind one.
Hell, my NP241 is basically a giant lever as well since the "trans mount" for my doubler setup is right behind it. With your logic, why hasn't it cracked yet since the motor mounts are basically at the front of the engine and it has that weight PLUS over 200 lbs of NV4500 between them?
I honestly think you're overthinking this Ken.
I honestly don't know for sure, but I'd guess that it's because it is a few feet further from the engine, and has more leverage on it, so it doesn't need to be as strong to deal with it. And it's mostly cylindrical and securely bolted all the way around at both ends - you know how they're held on with 6 studs? Take the lowest 3 out, now it's a closer comparison to a bellhousing, and see how it does that way. Probably not so well. Unless you put the lower 3 studs back in... or brace the bottom of the bellhousing to the engine block. Which is what I want to do here.
I'd rather overthink it and follow a method used by Chrysler on the 4 engines I listed, with the transmission I have (AX15) and the transmission you have (NV4500), that costs me like 10 bucks in metal and some time, than blow a few hundred on Brown Dog motor mounts right now, especially when front motor mounts simply aren't designed to prevent movement on the axis that I think is causing this breakage. Rear trans/motor mounts DO, but mine's fine and the rear mount keeps the ass end of the engine up using the bellhousing, which is what I think the problem is.
I wish I had a better answer. I just don't think the motor mounts are going to help that much. If they were designed to keep the motor from moving up and down at the back, there'd be front and rear block mounts instead of left and right, eh? I just don't understand how anyone can look at two mounts side by side and seriously suggest that making them stiffer is the absolute best way to keep the engine from rotating around them.
Now, if you think the block thrashing back and forth/rotating around the crankshaft is causing the problem, I'll stop arguing at all. My gut says it isn't, but I could easily be wrong about that.
atriot:
