3.0L, 84mm bore, 89.6mm crank?

[nando]

eta combustion chambers are "bathtub" shaped, not hemispherical. And many aftermarket pistons aren't very good..

I'm pretty sure the 89.6mm crank clears no problem. you may have to shave the intermediate shaft, but there aren't normally block issues. the M52 crank counterweights being larger is why there are more clearance issues in general (even if you don't use the 130mm rod/i piston combo).

also pretty sure the OP said it already fits and clears no problem.

[RobertK]

eta combustion chambers are "bathtub" shaped, not hemispherical. And many aftermarket pistons aren't very good..

I'm pretty sure the 89.6mm crank clears no problem. you may have to shave the intermediate shaft, but there aren't normally block issues. the M52 crank counterweights being larger is why there are more clearance issues in general (even if you don't use the 130mm rod/i piston combo).

also pretty sure the OP said it already fits and clears no problem.

Just because the crank by itself clears the block doesn't mean it will once the rods are installed. See the note from IE's website for installation of the 89.6mm crank. Its the rod angle that creates the clearance issue.

Note: This kit requires modification of the block at the bottom of the bore for connecting rod clearance. We can supply kits with any combination of bore diameter and compression ratio by special order - call us.

[nando]

Dunno. I haven't ever heard of people needing to clearance the block for the 89.6mm crank. Maybe it's because IE uses M20 rods.

[Raxe]

The 89.6mm crank drops right in and spins freely, no modification needed.

M20 135mm rods hit; they can probably be shaved down if needed but M54 135mm rods clear without issue as they're leaner and lighter right from the start.

[RobertK]

The 89.6mm crank drops right in and spins freely, no modification needed.

M20 135mm rods hit; they can probably be shaved down if needed but M54 135mm rods clear without issue as they're leaner and lighter right from the start.

Didn't think about the M54 rod being lighter / thinner and from what I've been told its a pretty strong rod. If you pull it off I would love to see some pictures of the build.

[Raxe]

I'll be going all the way with it, but I ended up going with new 85mm 9:1 JE pistons through IE. Unfortunately I just don't have the skill or equipment to machine these pistons to what I need, and there's no sense in paying someone else to do it for me when I can just outright buy what I really want.

If someone already worked with a lathe/CNC machine it would be a pretty sweet project though.

[nando]

Why 9:1? Going turbo?

[Raxe]

Our gas sucks, weak 91 octane is about as good as it gets here. My set goal is something very usable and simple, I don't want be hunting for higher octane if I don't have to.

I also haven't ruled out a turbo someday down the road when there's nothing left to do. ;P

[Wh33lhop]

Hm. Plenty of places are stuck with 91 octane, 9:1 is still a little on the low side. What are you doing to the top end?

[supernaughtIX]

I picked up an M54 bottom end today. Looks like I'm going to follow you on this.

I do have access to CNCs and a lathe so I'm going to try to work with the M54 pistons.

Chris, I haven't made it all the way through that 34 page e30tech link, but does it discuss machining M54 pistons somewhere?

[SpecM]

what c/r comes from an m54 rotating assembly and an 885 head?

[Wh33lhop]

what c/r comes from an m54 rotating assembly and an 885 head?

You don't want to do that. Read the thread.

[SpecM]

Yes, I know the pistons must be machined... and I know the the exact c/r will depend on how and how much they are machined...

Stock m54b30 is 10.5:1, iirc. But that is with an entirely different head

And I read the thread just fine the first time

Sent from my Vortex using Tapatalk

[Raxe]

Hm. Plenty of places are stuck with 91 octane, 9:1 is still a little on the low side. What are you doing to the top end?

Top end is mostly done at the moment, just standard mods: oversized valves, 272 cam, heavy duty rockers and adjustable cam gear. When I put it on that block (in a few months) it should have M30B35 injectors and throttle body as well.

[nando]

With the 272 i would shoot for 9.5 or even 10:1. 9:1 is really too low to be used with an aftermarket cam.