Cotter pin in oil pan
 

What purpose does this serve? Looks like a cotter pin installed in a hole in the bellhousing part of the oil pan on my 1940 v8
Attachment 78295

Re: Cotter pin in oil pan
 

It keeps the hole from stopping up. That would let oil from the rear main get on the clutch plate and make it slip. All '48 back engines had this feature.
Eddie

Re: Cotter pin in oil pan
 

Scott, it is indeed a cotter pin, and its presence was Fords acknowlegement that Fords leaked oil. The cotter rattled to prevent the hole from getting clogged.:)

Re: Cotter pin in oil pan
 

I think I'm confused. I have this same thing on my '35 (motor and trans I believe are out of a '46). What is the purpose of the hole?

Re: Cotter pin in oil pan
 

It's an auxilliary oil drain hole. How else would you do it? :rolleyes:

Re: Cotter pin in oil pan
 

all early flatheads have it, i got one on my 35 motor

Re: Cotter pin in oil pan
 

My first car, a $50 '32 coupe leaked so bad the oil ran out in a stream when you parked. :D

Re: Cotter pin in oil pan
 

Make sure that cotter pin stays a little loosey goosey so it can jiggle around in that oil pan hole, otherwise, it can't do it's job. Old Henry knew what he was doing. He would never have wasted a cotter pin.

Re: Cotter pin in oil pan
 

Model A's also have it.
paul in CT

Re: Cotter pin in oil pan
 

That was a consept used also in some early machinery oil passages before high detergent oils came along. It was called a "wiggle wire". It prevented sludge build up and blockage. That's why it's lose in the hole, it keeps wiggling while you driving, keeping the hole open.

Re: Cotter pin in oil pan
 

When I started rebuilding my first flathead I saw that cotter pin and thought to myself "what kind of ill boggered job is this?". Then later finding out what it was for.:)

Have to admire all simple mechanical additions. Today there would be an electric/computer sensor that when faulty would cost $200 for the part. Cotter pin/1 part .50cents. :p

Re: Cotter pin in oil pan
 

Don't you people use the search feature? I don't know why I have to repeat everything...sheesh:

Remember those old Murray Fahnestock manuals explaining Ford features in a Question and Answer format??
Here's my take:


Q. Why does the new Ford have a cotter key hanging out the bottom of the bell??

A. Its natural shaking as the car is driven ensures that the hole will not become blocked by dirt.

Q. Why is the hole there?

A. To allow oil leaking from the engine to drain out before it can get to the clutch frictions.

Q. Why does the oil leak so??

A. The leak is provided in order to prevent the formation of rust on the cotter pin.

So there. Skilled engineers design everything as a system.

Re: Cotter pin in oil pan
 

I am a big fan of and frequently use the 'search' function...but sometimes you aren't sure what search parameters to use and when the search returns 15 pages of threads that have nothing to do with what you're looking for it can be frustrating...

Re: Cotter pin in oil pan
 

Just needling you...that bit of history was over on the Model A board, anyway!

Re: Cotter pin in oil pan
 

But at least when you do a search here it includes the model T, model A, early and late flatheads, so there is little chance of missing something. Maybe that's why you get so many returns of threads?

Thanks all for ALL the replys, once again I've learned sumthin' new! :)

Re: Cotter pin in oil pan
 

Me too...new to flatheads..always wondered what that cotter pin was for..I can assure everyone that mine has no rust on it!

Lane

Re: Cotter pin in oil pan
 

Bruce's answer is the most logical :rolleyes:, but stay tuned, as the cotter key is making a comeback in modern cars.
It seems that while cars no longer "high center" on deeply rutted roads, modern cars must contend with speed bumps, which results in "bottoming out" as bad as in the old days. The oil drain hole in both cases befowls with dirt & crud, for which problem the cotter key is employed to prevent.
Welcome back, Cotter!

Re: Cotter pin in oil pan
 

Keep in mind that searches find every instance of every word in the search, not the combination of them. So, a search for cotter pin would not only show every post with cotter in it but also every post with pin in it, even if cotter wasn't in that post at all. The solution is to search with one key word only, no more.

Re: Cotter pin in oil pan
 

I like the Ebay search better, where you can specify a string of words or use an asterisk as a wildcard in part of a word, or even exclude certain words or phrases by using the (-) sign.

(old, vintage, antique) ford ...will give you any listing that has 'ford' and at least ONE of the other words.

(old, vintage, antique) ford -injectors...will eliminate any posts that have the word "injector" but still give you all the ford listings with at least ONE of the other words

In our example "cotter pin oil pan" would ONLY give us posts pertaining to all four words. But apparently our board doesn't work that way.

Re: Cotter pin in oil pan
 

Thanx Guys for answering the question, this Downunder 'Barner has frequently awoken in the middle of the night wondering what the hell that cotter pin's purpose was.

Re: Cotter pin in oil pan
 

A few week's ago while Walt Dupont was assembling the pan on a 39 flathead, I had asked him about the cotter pin. Good thing he told me, I almost snipped the one on my engine, wondering "what the hell is that doing there" :D

Re: Cotter pin in oil pan
 

The V-Bulletin Boards (used here and on The Hamb) have a poor search function when compared to engines like Ebay and Google et al. It comes down to who has pockets deep enough to pay some very bright people to write the logarithms needed to predictively search through billions of characters written as code.

Simple logarithms used here will not be able to pinpoint exactly what you are trying to find, and so will give you what it thinks is a reasonable search. My experience in searching here has been either one of luck (rare) or frustration. So many times we see someone starting a thread with "I've tried searching but..."

While I sometimes bemoan the poor soul starting his enquiry with 'I've tried...' I understand that the fastest and most reliable way to have a question answered is to ignore the search function and just ask the question. We keep repeating ourselves a lot, then again, none of us are getting any younger lol.

PS. I also have wondered about that little bent split pin, now I know something I didn't know before.

Re: Cotter pin in oil pan
 

I know I am really showing my ignorance here but please bear with me....why would you have an "auxillary oil drain hole" when the large "normal hole" seems to work just fine? Again, brand new flathead owner here so I hate to sound so ignorant. Prior to this the oldest motor I've worked on is a '74 (and it's a Chevy). Thanks all, really enjoying the new experiences and challenges of being a flathead owner!

Re: Cotter pin in oil pan
 

35Coup, sorry for the confusion, I was putting you on! The rear main is known to leak, and to prevent (leaked) oil from contraminating the clutch, a drain hole was provided for the escape of that oil. As the hole could get plugged by road debris, the cotter key fit loosely in the hole to vibrate and rattle, thereby keeping the hole clear for drainage.

You'll find that we kid around a lot here, but that goes with the territory as we're just a bunch of kids at heart, after all! ;)

Re: Cotter pin in oil pan
 

No problem, I figured as much but had to make sure. Thanks for all the input!

Re: Cotter pin in oil pan
 

Hey guys. Digging up this old thread.

I had my '40 flathead rebuilt last year. Ran it for a short period (like less than 30 minutes) and then set it in. Put the body on and got it home to the garage where it sat all winter.

About a month ago I come out and see a huge pool of oil on my floor. Roll it out, and it's coming from the cotter pin. What does this mean? Does this mean rear main seal is gone on my rebuilt engine?

Re: Cotter pin in oil pan
 

I just noticed I originally posted this thread 5 years ago!
It's been a great ride, met some really wonderful folks and have thoroughly enjoyed working on and learning about my old 36 Ford!

Notice the updated avatar pic compared to 5 yrs ago.

Re: Cotter pin in oil pan
 

I'm surprised that no one has so far mentioned the other sort-of benefit of the cotter pin in the oil pan, namely to create a focal point for that dripping oil so that drops form on the ends of the pin and don't spread all over the bottom of the pan.

Re: Cotter pin in oil pan
 

I have a Massive oil leak from this cotter pin. It just started? what can I do?

Re: Cotter pin in oil pan
 

Possibly the cork gasket at the rear main cap that helps seal the oil pan gone bad.Pull the oil pan and replace the gaskets.
https://i.ebayimg.com/images/g/HKwAA...l/s-l1600.webp

Re: Cotter pin in oil pan
 

Pretty cool to see this old post come to the top again. I recall working on my first early Ford V-8 at 14 or 15 years old and wondering why in hell would someone have put a cotter pin in an oil drain hole like that. It was also cool to see the names of some who originally posted on this thread like Bruce Lancaster, and what a wealth of knowledge he was.