02-16-2019, 06:11 PM | #1 |
Senior Member
Join Date: May 2010
Location: Dallas
Posts: 1,046
|
1940 221 rods
Crazy little thing, she had ..
1 - L1 rod 2 - L2 rods 2 - L3 rods And 3 with no numbers on them . Probably ran like a top … |
02-17-2019, 11:43 AM | #2 |
Senior Member
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 16,367
|
Re: 1940 221 rods
Some large overhaul shops didn't pay any attention to the numbers on the rods. They didn't keep track of matched sets.
|
Sponsored Links (Register now to hide all advertisements) |
|
02-17-2019, 02:54 PM | #3 |
Senior Member
Join Date: May 2010
Location: Dallas
Posts: 1,046
|
Re: 1940 221 rods
rotorwrench, that kinda sucks hu, Im kinda weird about putting things like they should be, don't think that's gonna happen here, I think Ill measure and weigh them all and if all is good, Ill just have everything balanced.
|
02-17-2019, 07:37 PM | #4 |
Senior Member
Join Date: Jul 2016
Location: Lake worth Florida
Posts: 1,073
|
Re: 1940 221 rods
|
02-17-2019, 08:53 PM | #5 |
Senior Member
Join Date: May 2010
Location: Dallas
Posts: 1,046
|
Re: 1940 221 rods
Why is that Ggmac ?
I bet it would run fine right there lol .. |
02-17-2019, 08:58 PM | #6 |
Member Emeritus
Join Date: Nov 2012
Location: Wichita KS
Posts: 16,132
|
Re: 1940 221 rods
Sponsored Links (Register now to hide all advertisements)
|
02-18-2019, 12:29 PM | #7 |
Senior Member
Join Date: Jan 2011
Location: Central Ohio
Posts: 5,009
|
Re: 1940 221 rods
You can pretty much look at the forgings and numbers/letters to determine if they are the same 'version'. Unless they threw in some earlier rods (really spindly), then they should all be either 91A or 21A rods (all 8 of them). If you are having the rods balanced, make sure the shop knows the specifics of how you balance flathead rods - it is NOT the same as modern rods that have 'balance pads' on them. Grinding on the bottom of the big-end caps is NOT the correct way to do it - should be done in a lathe with a special fixture.
Here is an example on my lathe - using 21A rods and my own fixture: 2015-02-02 21.34.42 copy.jpg 2015-02-10 13.16.06 copy.jpg 2015-02-07 19.33.56 copy.jpg Here is the 'wrong way' - that I see all too often (great way to weaken the cap): CapGrindingExample.jpg |
02-18-2019, 03:03 PM | #8 |
Senior Member
Join Date: May 2010
Location: Dallas
Posts: 1,046
|
Re: 1940 221 rods
Thanks Bored&Stroked, where should the weight come off ?
|
02-21-2019, 11:11 AM | #9 |
Senior Member
Join Date: Jan 2011
Location: Central Ohio
Posts: 5,009
|
Re: 1940 221 rods
You'll notice on the second picture where there is a fresh machined area around the perimeter of the cap. If you look at original rods, you'll see that Ford did it the same way. They also took material off the small end of the rod by turning the bushing area on both sides. Just take a bit of time checking out an original rod and you can see exactly what I'm talking about.
|
02-21-2019, 02:15 PM | #10 |
Senior Member
Join Date: Jul 2016
Location: Lake worth Florida
Posts: 1,073
|
Re: 1940 221 rods
What I meant is , if you're having it balanced , let them do it . I wouldn't add any info to the mix .
It's not just the overall weight . If you know this please forgive. Its measuring the big end and little . With the nuts your going to use . Not that a buggered nut would throw off the numbers too much . |
02-21-2019, 05:20 PM | #11 |
Senior Member
Join Date: May 2010
Location: Qld, Australia
Posts: 4,195
|
Re: 1940 221 rods
I use an assortment of ARP nuts to also help adjust the big end weight.
Lawrie |
02-21-2019, 08:11 PM | #12 | |
Senior Member
Join Date: Jan 2011
Location: Central Ohio
Posts: 5,009
|
Re: 1940 221 rods
Quote:
So put some die-chem on the rod caps and tighten down the cap (in a rod vise) with the new nuts. See where the contact pattern is. You may find that it is NOT in the machined area/base, but out on the machined radius toward the inside. If so, this is a problem. |
|
02-21-2019, 08:15 PM | #13 |
Senior Member
Join Date: Jan 2011
Location: Central Ohio
Posts: 5,009
|
Re: 1940 221 rods
You might be able to measure things like the bore diameters, but you will not be able to determine if they are balanced by overall weight. There are specific tools/methods used to weigh the big-end, versus small end --- and you can't just throw a rod on a gram scale. So, unless you have the tools and knowledge, don't think you can figure out your rod balance at home.
|
Thread Tools | |
Display Modes | |
|
|
Sponsored Links (Register now to hide all advertisements) |
|