connecting rod, angle cut cap
Moderator: Team
connecting rod, angle cut cap
Why do some connecting rods have the cap placed asymmetrically? Looks to be around 45 degrees.
I suppose that it transfers some of the bolt tensile load to shear, and probably allows for a little more camshaft clearance.
But, there has to be more to it than the above. Assuming "the above" is correct. lol
Thanks, Danny
I suppose that it transfers some of the bolt tensile load to shear, and probably allows for a little more camshaft clearance.
But, there has to be more to it than the above. Assuming "the above" is correct. lol
Thanks, Danny
A friend of mine could have used such rods a number of years ago. He came into a great deal on a bunch of stock block Buick Indy parts and started building up a class-killer engine for a 170 c.i. boat racing class. When everything had been machined and he started bolting it together, he found that the bore he'd had to sleeve it down to was too small to get the rods through...
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
-
- Guru
- Posts: 2151
- Joined: Fri Apr 07, 2006 8:23 pm
- Location:
-
- Guru
- Posts: 2404
- Joined: Tue Dec 06, 2005 10:16 pm
- Location: N L Michigan
Truly a "DOH!" moment.MadBill wrote:A friend of mine could have used such rods a number of years ago. He came into a great deal on a bunch of stock block Buick Indy parts and started building up a class-killer engine for a 170 c.i. boat racing class. When everything had been machined and he started bolting it together, he found that the bore he'd had to sleeve it down to was too small to get the rods through...
tom
Pray for a secular future.
We used to speak to tell things , now they tell things to speak.
Si Vis Pacem, Para Bellum
We used to speak to tell things , now they tell things to speak.
Si Vis Pacem, Para Bellum
-
- Expert
- Posts: 546
- Joined: Sun Mar 18, 2012 11:37 pm
- Location:
Re: connecting rod, angle cut cap
Many diesel engines, including the millions of Cummins 6-cyls, are this way.
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering
Studebaker-Packard V8 Limited
Obsolete Engineering
-
- Guru
- Posts: 4604
- Joined: Sun Sep 18, 2011 11:31 am
- Location: Heading for a bang up with Andromeda as we all are.
Re: connecting rod, angle cut cap
They also did that to make changing out bearings easier while keeping the motor in place.
Boy I wish some big ass stationary Diesel generator’s that I have rebuilt where that way!
Boy I wish some big ass stationary Diesel generator’s that I have rebuilt where that way!
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
- davidbraley
- HotPass
- Posts: 22
- Joined: Sat Jul 31, 2010 2:29 pm
- Location: Fort Collins, Colorado
Re: connecting rod, angle cut cap
Sorry if this is a really dumb question...
How does clocking the parting line for the rod cap like what is shown above effect the bearing clearances? It's my understanding there is more oil clearance at the parting line.
How does clocking the parting line for the rod cap like what is shown above effect the bearing clearances? It's my understanding there is more oil clearance at the parting line.
I'm a machinist... because engineers need heroes too.
Re: connecting rod, angle cut cap
Good question.
Achieving tightest clearance in the loaded direction is one reason, but not the ONLY reason for bearing wall eccentricity.
The other reason is to counteract housing distortion from the bearing interference fit or "crush", so that's unchanged.
And another reason is to make up for flex in the housing, but a rod mainly flexes in a bad way when under tension.
Yeah having the tightest point at 45 degrees is not perfectly ideal, but it's not that bad either. No different than a 90 degree v8.
Many of these are LOW rpm, or diesel engines where the rod only sees high loads of compression, so they do not need a lot of wall eccentricity in the bearing.
Achieving tightest clearance in the loaded direction is one reason, but not the ONLY reason for bearing wall eccentricity.
The other reason is to counteract housing distortion from the bearing interference fit or "crush", so that's unchanged.
And another reason is to make up for flex in the housing, but a rod mainly flexes in a bad way when under tension.
Yeah having the tightest point at 45 degrees is not perfectly ideal, but it's not that bad either. No different than a 90 degree v8.
Many of these are LOW rpm, or diesel engines where the rod only sees high loads of compression, so they do not need a lot of wall eccentricity in the bearing.