Con rod cotter pin

[VFRhugh]

What is the proper way to bend the connecting rod cotter pins? I've searched the WWW and haven't found anything. A photo would be most helpful.
Hugh

[dave in australia]

So they don't come out. Some will spread the legs slightly, some will just bend one leg out at 90 degrees. In aviation, there's two preferred ways, one, the US way is to bend one leg over the end of the bolt and bend the second down the flat of the nut. The second way is the English way, and the pin goes in sideways, and the legs are spread and wrapped around the nut in opposite directions, and then the ends are bent in to the next castellation slot. The English way is excellent for cabin doors etc, where your hand is operating something. There are no ends to scratch your hand on as they are tucked into the castellation.

[George Miller]

They really need to be tight, so they do not move every time the rod reverses or they will end up in the oil pan. I have found many in the pan.

[Bob Bidonde]

The use of cotter pins and castellated nuts on the connecting rod caps needs an improvement because the cotter pins will fatigue and break apart from splashing through the oil troughs. I have found bits of cotter pins at the bottom of the oil pan in several Model A and Model B engines.

Use modern self locking nuts instead.

[John Stone]

Originally Posted by George Miller

They really need to be tight, so they do not move every time the rod reverses or they will end up in the oil pan. I have found many in the pan.

I totally agree. I use 1/8 X 3/4 pins. Work just fine, tighten up nicely and I have never seen one of those in the pan. The list I have seen calls out 3/32 X 5/8 are way too loose on installation and cause the aforementioned problem.

[VFRhugh]

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Any recommendations on brand or material?

[tbirdtbird]

ARP for sure
they have a good website, too

PM sent

[Kurt in NJ]

The pieces of cotter pin in the pan is because they weren't cinched to be tight, if they wiggle they will wear through

[Kohnke Rebabbitting]

Agree

[Dollar Bill]

As others have mentioned, proper size is critical. Ensure head of cotter pin is snug against nut and is tight in hole - No floppage allowed. Trim legs as shown.

[John Stone]

I bend them the US style.

[Kahuna]

Do not use cotter pins

[SSsssteamer]

Originally Posted by John Stone

I bend them the US style.

Ditto

[PC/SR]

Cotter pins are not necessary. Just tighten the nuts to torque. I use 35 lbs.

[31forder]

My dad gave me his 1931 coupe two years ago.. It was only driven a few times in 20 years.. I dropped the oil pan today to clean the sludge out and change the gaskets.. I found a cotter pin in the #2 drip pan.. I also found the #3 connecting rod was missing a rod cap cotter pin.. The #1 and #4 connecting rod's each had one cotter pin about 1/3 of the way out as well.. Whats odd is that all these cotter pin problems were on the passenger side.. The drivers side cotter pins were all good.. Engine was running good with no knocks.. Should I just install new cotter pins and replace the ones on the drivers side too?

[Pete]

Originally Posted by 31forder

My dad gave me his 1931 coupe two years ago.. It was only driven a few times in 20 years.. I dropped the oil pan today to clean the sludge out and change the gaskets.. I found a cotter pin in the #2 drip pan.. I also found the #3 connecting rod was missing a rod cap cotter pin.. The #1 and #4 connecting rod's each had one cotter pin about 1/3 of the way out as well.. Whats odd is that all these cotter pin problems were on the passenger side.. The drivers side cotter pins were all good.. Engine was running good with no knocks.. Should I just install new cotter pins and replace the ones on the drivers side too?

Replace ALL of the rod nuts with modern MARSDEN nuts.

[700rpm]

It's foolish not to use cotter pins. A friend forgot pins on one rod in his engine and less than 300 miles later that cap worked loose and caused all kinds of havoc.

[700rpm]

Originally Posted by 31forder

My dad gave me his 1931 coupe two years ago.. It was only driven a few times in 20 years.. I dropped the oil pan today to clean the sludge out and change the gaskets.. I found a cotter pin in the #2 drip pan.. I also found the #3 connecting rod was missing a rod cap cotter pin.. The #1 and #4 connecting rod's each had one cotter pin about 1/3 of the way out as well.. Whats odd is that all these cotter pin problems were on the passenger side.. The drivers side cotter pins were all good.. Engine was running good with no knocks.. Should I just install new cotter pins and replace the ones on the drivers side too?

If it were my engine, while I had it open at that point I would remove the rod caps and check the babbitt condition, and if good, set the clearances, then put it back together with nuts torqued to 35 lbs and new cotter keys installed as George describes.

[Mike V. Florida]

I use the US method, and using a small ball peen hammer gently tap the head to be sure it is seated in the slot before bending.

[BILL WILLIAMSON]

Originally Posted by Pete

Replace ALL of the rod nuts with modern MARSDEN nuts.

PETE JUST TOLD YOU THE BEST WAY, LISTEN TO THE MAN!
This is WAY better than OLD TIME cotter key CRAP!
I worked on Jaguars for years & "somehow" they would blow a cotter key end, it would find its' way through the COARSE oil screen, then through the oil pump & end up stuck under the flat oil pressure relief valve, resulting in a LOW oil pressure gauge reading
I'm sure many won't BELIEVE this could happen without wrecking the oil pump, but I've seen it happen, MANY TIMES!
I would DUMP the castellated nuts & use Chrysler nuts & NEVER a problem again.
Bill W.