MTFCA Forum

I don't suppose cast iron pistons in oversizes are an option if some benighted soul wished to use them in a rebuild ? - asking for a friend

I had a set of (iirc) 25 over CI pistons I found in a barn once... kept them until I realized I'd never ever use them, they went out with a box of various and sundry T parts. I had figured that they would pair with my oversized 2 piece valve collection, genuine historic electrodeless spark plugs, and my collection of multi-piece babbit thrust washers. (Seriously, tho, unless you had a matched set, I would think balancing them would be difficult at best...) )

Another consideration is if you can find some good (NOS) cast iron pistons is to sleeve the block. Just a thought

An honest question - Why, if you have the pistons out, would you not go the Aluminum route?

someone will want those pistons if they are new and available for purchase (no, I am not that person)

John Codman wrote: ↑

Mon Jul 10, 2023 2:42 pm

An honest question - Why, if you have the pistons out, would you not go the Aluminum route?

Because I'm perverse John. Truth is, I'm sure I'll use aluminum pistons for lack of an available set of cast iron, unless some appear miraculously.

More than 60 million cast iron pistons left the factory in Model T cars and trucks and replacement engines.
Apparently they can be used with some success.

Some folks think a backfire and running with a cough and a snort is how they ran "back in the day"
Some folks can't tell when their car is running on 4 cylinders or 3 (or 2)
Some folks will never, ever experience what a good running T can accomplish, or how it goes about doing it because their car is so lame and they've never driven another T (which I believe is the vast majority of folks in the hobby - the Forum members notwithstanding).

A T with cast iron pistons will drive and sound like a T. All others drive and sound like T's with aluminum pistons. Most people won't or can't tell the difference and that's a shame.

Few years ago I had a bunch of NOS cast iron pistons in some stuff I got. The largest I remember was .005 os. Some most of them. May still have a set or two.
Just saying they are out there. But not seen any big size.

Hi Rich,
I sold a set of iron pistons on the classifieds 3 years ago marked Ford .031 OS to someone. My rememberer is not helping me with who it was.
I put .030 high compression pistons in the engine because I'm too cheap to buy a high compression head They may still be out there.
Craig.

Most people won't or can't tell the difference and that's a shame.

I don't know if it's most, but a lot of folks don't notice details. They mix different sizes of fasteners in the same bin because they can't tell the difference. They use a crappy camera because they can't see how bad their pictures are. Their dog has big ticks all over. It used to drive me nuts when the teacher showed a film slightly out of focus. The oblivious have always been with us.

Scott_Conger wrote: ↑

Mon Jul 10, 2023 4:06 pm

Some folks will never, ever experience what a good running T can accomplish, or how it goes about doing it because their car is so lame and they've never driven another T.

Sadly, I am in that category. Have never driven another T. No idea how a "running well" T compares to my bag of hammers...

Steven

get thyself to a tour!

I run and use cast iron pistons. My TT truck uses 30 thousands over and I just put new rings on them . I'm also looking for over sized pistons to buy too. I have several sets in storage.

I have listed a set of cast iron piston rings cheap on classifieds. I don’t need them. Dan

Over the years, I have seen or seen references to oversizes for model T pistons in the following odd sizes; .0005, .001, .0015, .0025, .005, .010, .015, .020, .031 (WHY the one thousandths over common .030???), .040, .050, and .060.
I believe that .010 and below were all used to rigid hone individual cylinders to get a better fit when the engines were nearly new, and had suffered a miss-fit or minor damage.

The .031 oversize cast iron pistons always seem to be the most common oversize for the model T, and .030 oversize rings do show up for the cast iron pistons fairly often.

I am fairly certain that I have a good full set of .031 pistons. I have NOT checked them for balancing! On my tight budget, I always figured I would use them someday. However, so far I have not used them. Mostly, I have been fortunate enough to come up with low mileage blocks that I could rework with standard size original cast iron pistons! And so far, that has worked out well for me.

Wayne Sheldon wrote: ↑

Tue Jul 11, 2023 12:36 am

Over the years, I have seen or seen references to oversizes for model T pistons in the following odd sizes; .0005, .001, .0015, .0025, .005, .010, .015, .020, .031, .040, .050, and .060.

My Runabout has .025"-over cast iron pistons. You can add that to your "references" list, Wayne.

Thank you Mark N! I thought I remembered a .025 from years ago, but just wasn't sure about it.
Most of the other numbers I have had myself (except for the .050 and .060, seen but never had those myself). I thought I had seen .025s, just wasn't sure. Several of the little numbers (.0025 and below) I have had and used in engines I reworked with cast iron pistons. I sure like a rigid hone for cleaning up slightly worn bores, and the couple thousandths oversize pistons reduce piston rattle.
Ford factory used those small numbers to clean up misfits on the assembly line. Again a final hone to fit.

I think the reason why Ford had so many different and odd sizes of pistons, is that you could hone your cylinder to a piston size instead of boring it. That would easier to do especially if you didn't have a boring machine. I did that with one motor I had. Also that would make sense for motors found with different sized pistons.