I am getting ready to make my R5 crank adapter.

My question is does it need to be 4340 steel? OR can it be 1045 steel? It will be .375 thick.

This engine will be around 850 hp 560 tq. Just want to make sure this will be strong enough.

Thanks

This is a true engineering question. I am to guess that bolts will thread into this adapter from one side, and bolts from the flywheel or flex plate will thread into it from the other side? If this is just a "spacer" and the bolts go all the way thru then any mild steel would even do. But assuming as stated above I will also assume 6 bolts will go each way, 7/16 bolts, grade 8 from each side. Even with this scenario, the 1045 will be good providing there is at least a minimum of , say. 0.250 between the holes from one side to the other. Now if there is like 8 bolts then that separation difference can be far less and once again even mild steel would probably be acceptable. Also, unless you can power tap this with some serious machine, and machining knowledge out of a professional manufacturer with experience with this steel, you probably can't do it. Hand taping those holes in the 4340 is going to be very difficult (if you can do it without breakage). Once again even the 1045 ain't going to be fun. So, from me, I would go with the 1045, but I don't have all your info. Also, if this is for an automatic, you have far less shock loads that with a stick, and that should factor in as well.

If you have the choice between the two then by all mean's go 4340 as it is a much higher quality steel and will machine just as easy and will give a higher quality finish, plus it's tougher and your thread's will hold up better.

i agree if you have the option go with 4340. although the 1045 should work as well.

It is just a spacer. No threads in it at all. There will be 6 holes in it for the R5 crank. The 6 holes are almost evenly spaced. We will be using grade 8 bolts and the adpater will be .375 thick. From what I read above the 1045 will be more than good?

It is just a spacer? I don't know what the part is doing but it sounds like maybe it is changing the crank flange diameter for the torque converter or something? If it is just a spacer then aluminum would probably work just fine.

It's just a spacer to make up the difference for the adapter plate to go from R5 bellhousing to LA bellhousing. The flywheel is being redrilled for the crank bolt pattern.

So aluminum can be used? This is just a spacer. No threads will be in this piece. It is being used to make up the difference from the crank to flywheel because of the mid plate. We are drilling the flywheel to match the bolt pattern on the crank.

I have a 2024 billet available.

Maybe, depends on how thick it is. I'd have to see the design before I knew which material would work. The bolts are going to transmit the torque, not the spacer so aluminum should be fine. Only problem is if the spacer is fairly thick since then the flywheel could start to whip around. If the spacer is less than 1/2 inch thick then I think aluminum would be fine.

Hey, if you let me know what you want I will cut it for you, just give us a call in the AM.


Rick

Ok. What number?

The shop,
570-561-1746



Rick