The Ford Barn

fordfixer · 05-15-2026, 02:44 PM

Just wondering what people are using for cotter pins inside the engine. I have another car in the shop for connecting rod failure, do to failed cotter pins.
Everything I can find is made in China.

stevests · 05-15-2026, 03:36 PM

There are several "Made in USA" cotter pin suppliers - use Google.

ModelA29 · 05-15-2026, 06:30 PM

Orig castellated nuts only use about 4 full threads. Get some ARP 300-8333 nuts and forget the cotter pins.

Big hammer · 05-15-2026, 06:32 PM

Aircraft supply companies should have stainless steel cotter pins .

Brad in Germany · 05-15-2026, 08:02 PM

Only use genuine Nettlefolds cotter pins for Ford cars:

Brad in Maryland

PS: Good luck finding them however.....

.

nkaminar · 05-16-2026, 05:13 AM

Sponsored Links (Register now to hide all advertisements)

The stainless pins that Big Hammer introduced are also available at McMasters-Carr. Those pins are twice as hard as the usual steel pins.

Y-Blockhead · 05-16-2026, 10:22 AM

Cotters are available at Bolt Depot also. https://boltdepot.com/Cotter_pins

J Franklin · 05-16-2026, 11:11 AM

Even where I would use cotter pins, I use blue LockTight as insurance.

katy · 05-16-2026, 11:46 AM

Why do cotter pins fail?

bobbader · 05-16-2026, 04:00 PM

Fordfixer, hard to imagine a cotter pin failing if properly sized and properly installed. Before we all start dropping our oil pans to investigate, can you relate the failure and ensuing issue you experienced. Thanks.

old31 · 05-16-2026, 04:43 PM

Oh, dont talk to me about broken cotter pins. I found this on the bottom of my oil pan one day.

mcgarrett · 05-16-2026, 06:57 PM

Quote:

Originally Posted by katy

Why do cotter pins fail?

A few things I can think of are: inferior metallurgy resulting in premature metal fatigue, incorrect size pin required for application, improper installation, loosening of nut causing a shearing effect on the pin, installing a used pin, and centrifugal force acting against all of the above. There are probably other factors also.

Synchro909 · 05-16-2026, 07:00 PM

This is a cotter pin!
https://en.wikipedia.org/wiki/Cotter_(pin)

nkaminar · 05-16-2026, 07:05 PM

Old 31, Those are not cotter pins (as Synchro would say, split pins) but pieces of round wire. They look like pieces of safety wire. They look like they were twisted together at some point.

old31 · 05-18-2026, 10:04 AM

NK, you are 100% correct. I never picked up on that; I just assumed that they were cotter pins.

OK, where in the hell did twisted wire come from? Geeeez.

David in San Antonio · 05-18-2026, 10:17 AM

The Wretched Roadster had the bottom few turns of the broken-off oil pump spring sitting in the bottom of the pan. Amazing how these engines will tolerate certain types of degradation without stopping.

Y-Blockhead · 05-18-2026, 10:42 AM

Quote:

Originally Posted by old31

NK, you are 100% correct. I never picked up on that; I just assumed that they were cotter pins.

OK, where in the hell did twisted wire come from? Geeeez.

If only we knew the secrets these Ol' Girls hold...

cadillac512 · 05-18-2026, 10:57 AM

Quote:

Originally Posted by old31

NK, you are 100% correct. I never picked up on that; I just assumed that they were cotter pins.

OK, where in the hell did twisted wire come from? Geeeez.

Well ya know...back on the farm when we didn't have cotter pins we used baling wire. That picture sure looks like it may be just that. On a rod nut it's less than ideal though!

nkaminar · 05-18-2026, 01:16 PM

100% original Model T's were found to have nails used instead of cotter pins in various places. There was a lot of pressure in the early days to get the cars out so an assembler would grab whatever worked.

john charlton · 05-18-2026, 01:31 PM

The GKN advert the " Birmingham" is big English city not the one in AL .In UK cotter pin is also known as "split pin" .

John in rain showers Suffolk County England

05-15-2026, 02:44 PM	#1
fordfixer Senior Member Join Date: May 2010 Location: Crete, Illinois Posts: 307	Cotter pins Just wondering what people are using for cotter pins inside the engine. I have another car in the shop for connecting rod failure, do to failed cotter pins. Everything I can find is made in China.

05-15-2026, 03:36 PM	#2
stevests Senior Member Join Date: May 2010 Location: Longbranch, Washington Posts: 684	Re: Cotter pins There are several "Made in USA" cotter pin suppliers - use Google.

05-15-2026, 06:30 PM	#3
ModelA29 Senior Member Join Date: Sep 2022 Location: SoCal Posts: 1,596	Re: Cotter pins Orig castellated nuts only use about 4 full threads. Get some ARP 300-8333 nuts and forget the cotter pins.

05-15-2026, 06:32 PM	#4
Big hammer Senior Member Join Date: Jun 2014 Location: Land of Lincoln Posts: 3,638	Re: Cotter pins Aircraft supply companies should have stainless steel cotter pins . __________________ Don't force it with a little hammer tap, tap, tap get a bigger hammer tap done

05-16-2026, 05:13 AM	#6
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 6,855	Re: Cotter pins Sponsored Links (Register now to hide all advertisements) The stainless pins that Big Hammer introduced are also available at McMasters-Carr. Those pins are twice as hard as the usual steel pins. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

05-16-2026, 10:22 AM	#7
Y-Blockhead Senior Member Join Date: Jul 2011 Location: Redondo Beach, CA Posts: 7,293	Re: Cotter pins Cotters are available at Bolt Depot also. https://boltdepot.com/Cotter_pins

05-16-2026, 11:11 AM	#8
J Franklin Senior Member Join Date: May 2010 Location: Oregon Posts: 6,586	Re: Cotter pins Even where I would use cotter pins, I use blue LockTight as insurance.

05-16-2026, 11:46 AM	#9
katy Senior Member Join Date: Jun 2015 Location: Red Deer, Alberta Posts: 6,076	Re: Cotter pins Why do cotter pins fail? __________________ If you don't hear a rumor by 10 AM, start one!. Got my education out behind the barn!

05-16-2026, 04:00 PM	#10
bobbader Senior Member Join Date: May 2010 Location: Huntington, NY Posts: 387	Re: Cotter pins Fordfixer, hard to imagine a cotter pin failing if properly sized and properly installed. Before we all start dropping our oil pans to investigate, can you relate the failure and ensuing issue you experienced. Thanks.

05-16-2026, 07:00 PM	#13
Synchro909 Senior Member Join Date: Jun 2014 Location: Melbourne, Australia Posts: 8,434	Re: Cotter pins This is a cotter pin! https://en.wikipedia.org/wiki/Cotter_(pin) __________________ When all is said and done, more is said than done. That's why we judge people on what they do, not what they say. I sometimes wonder what happened to the people who asked me for directions. If I am not in trouble, I've done something wrong.

05-16-2026, 07:05 PM	#14
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 6,855	Re: Cotter pins Old 31, Those are not cotter pins (as Synchro would say, split pins) but pieces of round wire. They look like pieces of safety wire. They look like they were twisted together at some point. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

05-18-2026, 10:04 AM	#15
old31 Senior Member Join Date: Jan 2016 Posts: 2,688	Re: Cotter pins NK, you are 100% correct. I never picked up on that; I just assumed that they were cotter pins. OK, where in the hell did twisted wire come from? Geeeez.

05-18-2026, 10:17 AM	#16
David in San Antonio Senior Member Join Date: Sep 2022 Location: San Antonio Texas Posts: 713	Re: Cotter pins The Wretched Roadster had the bottom few turns of the broken-off oil pump spring sitting in the bottom of the pan. Amazing how these engines will tolerate certain types of degradation without stopping. __________________ David in San Antonio Late ‘30 Deluxe "Wretched Roadster" 1931 Slant Windshield Fordor “Earl Gray” Alamo A’s Club

05-18-2026, 01:16 PM	#19
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 6,855	Re: Cotter pins 100% original Model T's were found to have nails used instead of cotter pins in various places. There was a lot of pressure in the early days to get the cars out so an assembler would grab whatever worked. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

05-18-2026, 01:31 PM	#20
john charlton Senior Member Join Date: May 2010 Posts: 1,372	Re: Cotter pins The GKN advert the " Birmingham" is big English city not the one in AL .In UK cotter pin is also known as "split pin" . John in rain showers Suffolk County England