Pistons

[Bill B]

I need to replace one piston in my Model "A" Can I use one split piston with the three non split pistons? Thanks for your help.

 

[2manycars]

You could, but I would not. I think it is bad practice to mix pistons. They will likely weigh differently, and that will effect balance.

 

[Kurt in NJ]

If the weight is close and the fit is proper it won't matter
The NOS Ford pistons I have weighed have been within 5 grams --even different sizes (standard weighing within 5 grams of .060)
GM mixed pistons in the same engines in the factory, I have seen different styles on left-right sides, and wouldn't have known from the way it ran.
many A engines I have taken apart have mixed pistons---center lock--end lock, different bore sizes
Some of the cars I drive the engines have been made of the used parts of 5 or more engines, I have reused pistons rings and bearings that had over 300,000 miles on them in some of the Mercedes engines I have put together for my own cars --

a light piston can be used with a heavy wrist pin----if you weigh the rods end for end a light small end of a rod can be matched to a heavy piston---I have no problems mixing engine parts if clearances and weights can be close ---

 

[pat in Santa Cruz]

as said above, match the weights. Even the same brand from different batches can vary enough to cause vibration.

 

[Scott Foldenauer]

What I have learned from the folks in my local club is that "balance" is a friend to the Model A engine. Anything that disturbs this balance should be avoided. Mixing pistons might not be the correct thing to do.

 

[Kevin in NJ]

Keep in mind Ford was putting together engines that had the piston, rod and pin combos within 4 grams of each other.

Each part was held to close weight tolerance and then sorted after assembly into bins. All the assemblies in one bin would be within 4 grams of each other.

Each end of the rod was made to +- 1 gram.

So while you have stuff apart you may want to check and see what you got. I have seen pistons in later non Ford sets be off by as much as 50 grams.

If you have the crank out you might want to check it for centers or even have it balanced with the flywheel.

Ya, might be more work then you were planning, but a well balanced engine has a big comfort and performance pay off. At the very least some more info to keep in mind.

 

[George Miller]

I need to replace one piston in my Model "A" Can I use one split piston with the three non split pistons? Thanks for your help.

That depends on why the piston broke. Re member they have all went the same distance.

 

[Jordan]

I would never mix match pistons. But maybe that's just me. If you're going to spend the time to do it, do it right.

 

[hardtimes]

I need to replace one piston in my Model "A" Can I use one split piston with the three non split pistons? Thanks for your help.

Bill,
You don't give much info to go on (other than used engine). For example,is car used for long hard use; is it just for putting to meetings; how many miles/years (wear) on engine; is it stock or hopped up..you get the idea?
With what you've given, I agree with Kurt. I'm thinking you have an old stock engine and not modified..otherwise you'd most likely not be asking such question.
As an example of what can be done, A six cyl '50 ford worn out engine froze solid on a sub zero winter night and burned the top out of ONE piston. Well not having two dimes to rub together...I got a used piston from a junk yard and attached my rod. This engine ran great and just as well as before damaged piston for years.

 

[James Rogers]

I would never mix match pistons. But maybe that's just me. If you're going to spend the time to do it, do it right.

Jordan, I always said, There's two ways to do anything, do it the right way or, do it over.