Page 1 of 1
Mopar RB Crank Journal Spacing
Posted: Sun Nov 10, 2019 5:09 pm
by Rick!
Does anyone know if distance between main journals 4 and 5 is the same as between journals 1 and 2?
I've got a two piece crank and a vernier and it's not quite the right equipment to make the measurements so I can complete the CAD model of it.
Thanks.
Re: Mopar RB Crank Journal Spacing
Posted: Sun Nov 10, 2019 8:53 pm
by BillK
Rick,
I have several cranks at the shop. I will try to remember to measure a couple of them in the morning.
Re: Mopar RB Crank Journal Spacing
Posted: Sun Nov 10, 2019 10:21 pm
by SchmidtMotorWorks
Most Race cranks are.
The OEM stuff was all over the place.
Re: Mopar RB Crank Journal Spacing
Posted: Mon Nov 11, 2019 10:58 am
by Diodedog
What is a two piece crank and why not just check the mains in the block, if the spacing is different on the crank the block will be spaced accordingly.
Re: Mopar RB Crank Journal Spacing
Posted: Sat Nov 16, 2019 4:39 pm
by Rick!
BillK wrote: ↑Sun Nov 10, 2019 8:53 pm
Rick,
I have several cranks at the shop. I will try to remember to measure a couple of them in the morning.
Thanks for the measurements, Bill, much obliged.
Diodedog, "two-piece" is another way of saying broken crank. The block, along with a new Bryant billet crank, is in Immokalee this weekend.
Re: Mopar RB Crank Journal Spacing
Posted: Tue Nov 19, 2019 1:43 am
by SchmidtMotorWorks
Rick! wrote: ↑Sat Nov 16, 2019 4:39 pm
BillK wrote: ↑Sun Nov 10, 2019 8:53 pm
Rick,
I have several cranks at the shop. I will try to remember to measure a couple of them in the morning.
Thanks for the measurements, Bill, much obliged.
Diodedog, "two-piece" is another way of saying broken crank. The block, along with a new Bryant billet crank, is in Immokalee this weekend.
What is your goal?
To make one?
Re: Mopar RB Crank Journal Spacing
Posted: Tue Nov 19, 2019 7:41 am
by Rick!
My goal is to have a reasonably accurate CAD model so I can do a bunch of modals on it to understand what rpm the crank shouldn't be run. By reasonably accurate, I mean it will have the right physics but not be perfect enough to to send to CAM and make a crank. (It could be but there is minimal data I can find on the interwebs to place mains 1 and 5 perfectly and to mimic the angles of the cuts on the pork chops.)
Free-free modals are already done. Now I need to CAD up an ATI balancer and create a physically correct TC (inertia-wise) and simulate the mains and finish the analysis stuff. That will drop the torsional mode shown by a bit, I just need to know by how much as it's right at a shift point currently.
Re: Mopar RB Crank Journal Spacing
Posted: Wed Nov 20, 2019 10:07 pm
by SchmidtMotorWorks
Rick! wrote: ↑Tue Nov 19, 2019 7:41 am
My goal is to have a reasonably accurate CAD model so I can do a bunch of modals on it to understand what rpm the crank shouldn't be run. By reasonably accurate, I mean it will have the right physics but not be perfect enough to to send to CAM and make a crank. (It could be but there is minimal data I can find on the interwebs to place mains 1 and 5 perfectly and to mimic the angles of the cuts on the pork chops.)
Free-free modals are already done. Now I need to CAD up an ATI balancer and create a physically correct TC (inertia-wise) and simulate the mains and finish the analysis stuff. That will drop the torsional mode shown by a bit, I just need to know by how much as it's right at a shift point currently.
Are you also including the attached objects?
Are you hoping to optimize angles of the CWs through modal analysis?
Re: Mopar RB Crank Journal Spacing
Posted: Wed Nov 20, 2019 10:42 pm
by Jeff Lee
I always just go kinda high on the RPM then fix the broken parts and back off a few hundred RPM’s...LOL