Replacing A connecting rod in place

[truesdaleg]

Can a Model A connecting rod be replaced without removing the head or the engine from the car, like Tom Joad did on the 1926 Hudson in The Grapes of Wrath?

[Kurt in NJ]

Yes, but it does require some wiggling ---I changed out a #3 on my car using right angle snap ring pliers----most likely original centerlocks pins won't be able to be removed,
pulled the piston as far down as possible, rotate 45 degrees, by grabbing the end of the pin with snap ring pliers and wiggling in unison with the rod the pin can be moved over enough

[truesdaleg]

Sounds interesting. Maybe I’ll try it.

I’ve got a bad rod knock, and I have been too lazy to fix it. I’ve got another engine to rebuild and put in 29 Roadster, but no telling when I will get around to doing that. I’ve just been running it around town on three cylinders for a couple of years.

[truesdaleg]

Has anyone else had any experience trying to do this?

[Step-down]

If the rod isn’t bent , hoping the small end of the rod is Acceptable
Remove shim from rod cap

[emf]

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You may find it easier to remove the entire piston/rod assembly through the bottom. I had a Studebaker that had a bad rod and I removed the piston with the rod through the bottom. I had to rotate the crank a little at a time to get the piston around and out. Once the rod was re-poured, I merely reinstalled the piston and rod and all was well.


Frank

[Kurt in NJ]

Originally Posted by emf

You may find it easier to remove the entire piston/rod assembly through the bottom. I had a Studebaker that had a bad rod and I removed the piston with the rod through the bottom. I had to rotate the crank a little at a time to get the piston around and out. Once the rod was re-poured, I merely reinstalled the piston and rod and all was well.


Frank

the crankshaft is in the way, the piston can't even be pulled down enough to pop out the oil ring ---and the main webs are in the way with the crankshaft out

[emf]

I never tried my technique with an A. I know it worked with the Stude, but that's quite a different engine. In light of this news, I'd be tempted to take the head off and be done with it. With a rod being bad, better make sure it's not the crank journal.



Frank

[George Miller]

Originally Posted by emf

You may find it easier to remove the entire piston/rod assembly through the bottom. I had a Studebaker that had a bad rod and I removed the piston with the rod through the bottom. I had to rotate the crank a little at a time to get the piston around and out. Once the rod was re-poured, I merely reinstalled the piston and rod and all was well.


Frank

How did you get the rings to go back in the cylinder.

[George Miller]

Originally Posted by truesdaleg

Can a Model A connecting rod be replaced without removing the head or the engine from the car, like Tom Joad did on the 1926 Hudson in The Grapes of Wrath?

Yes but how are you going to get the wrist pin out.
You will have to use the right under size rod.
How do you know if it fits the wrist pin right.

In the end it is always better to do things right the first time. I would pull the head and do it right. I have changed rods in a old chev 216 that way, but I would not do it now. In the end it will take as long and will not be as good.

[Corley]

All that manovering sure makes pulling the head sound easy... Just sayin'.

[gustafson]

how hard is it to pull a head?
Ran on 3 cylinders for a couple years? No chance that all the gasoline mist the fourth inhaled would wash the oil off the cylinder walls and kill the rings/bore

[George Miller]

Originally Posted by gustafson

how hard is it to pull a head?
Ran on 3 cylinders for a couple years? No chance that all the gasoline mist the fourth inhaled would wash the oil off the cylinder walls and kill the rings/bore

Most likely the engine needs a complete rebuild. All the rods rings pistons valves had traveled the same distance. So unless some thing happened to just that rod the rest are not far behind. Like I said it is always best to do it right.

[emf]

Originally Posted by George Miller

How did you get the rings to go back in the cylinder.

I compressed the rings the same was as on top. There was enough room to get a spring compressor in above the crank. This was a LONG stroke engine...


Frank

[jhowes]

I had a Willys Knight engine and that is the only way to remove a piston. (through the bottom). I agree that with an A do it right and remove the head then you can also check then rest of the engine. Jack

[John Stone]

I have done it. Used battery terminal pliers to pull the wrist pin out far enough to remove the rod. Engine went another 3,000 miles and was rebuilt for reasons other than rods.

It is not impossible but a lot of being horizontal under the car with oil dripping on you. I did it for a good friend. Old enough now I wouldn’t do it again.

[Kurt in NJ]

I did it because there was no crank damage---- and I didn't want to drain the coolant -- didn't even replace the pan gasket, I had figured it "temporary", the replacement rod is 10 grams heavier, dropped 3 mph off top speed---- and I know it was just that, it was the only thing changed, and timing, carburetor not touched

That temporary repair was over 25 years ago

[gustafson]

"I had a Willys Knight engine and that is the only way to remove a piston. (through the bottom). I agree that with an A do it right and remove the head then you can also check then rest of the engine"
Any Knight engine is a very different beast than all the rest, no comparison

[asapguy]

Do what my grandfather & his brother did. They were driving across Montana in a Model T & a rod bearing went bad. They dropped the pan & cut the leather heal out of a boot, wrapped it around the crank & replaced the rod cap. He said it ran that way for 3 yrs.

[truesdaleg]

Thanks for all of the good advice. I knew it would be better to do it right. I was was just curios. It’s not like I’m in the middle of the desert at night with 50 cents in my pocket, like Tom.

Maybe this will get me started on my new rebuild engine project, or maybe I will just keep putting it off, and let my grandkids worry about it.