MTFCA Forum

I’m currently using H840CP pistons and was looking for something with a longer skirt. What other options are there?

EGGE Machine makes the correct pistons for using an A Crank and Rods in a T block. https://egge.com/

I purchased my engine with it already converted to an Model A crank and it came with Ford 292 V8 pistons. I have no idea what the skirt size is. Don’t know if this helps you any.

Thanks all for the input. The Egge link helped and got me on the right track.

Ok, the Egge phone call didn’t go well. They don’t make the cast “A” Crank pistons anymore. They said they were having mold issues and had to throw away 1/2 of the last batch. They do make forged pistons but at this time they’re cost prohibitive ($1000). I’ll look at the specs for the 292 pistons...

Seems to me Ross pistons was charging bout $500-$600 for a set last time I bought some... 10-15 years ago. I hear that they now have some designs on the books for T’s and A’s too. They will make you bout anything you want... but piston skirts are usually as short as possible these days. Good luck

Just looked up the H840CP pistons... look like an incredible piston to me!! Only drawback is the flat top... but I’m sure you could call any aftermarket piston company (Ross, Aries, Silvolite, etc.), give em that number and tell em what dome shape you want.

Kevin, they aren’t bad pistons. I wanted to see what else was out there and available. Here’s a picture of a comparison with a cast iron original piston. The A rods have to be bushed to the new wrist pin size of .870 and other than that is stock .010 under main bearing A rod.

Those look like a interesting piston choice.
To compensate for the flat top I would consider offsetting the wrist pin bushings. Obviously need to be careful that the rings stay in the cylinder bore.

What is the “compression height” of these pistons?
I have a 2 up 2 down crank with A size journals but T stroke and I don’t have any pistons yet

Just received my set from Ross, very happy with their work. Took about 4 weeks. Egge not doing anymore.

Sam, can you post a picture and part number? Thanks.

Les, with this set up the pistons are even with the top of the block. The loss of the protrusion was unnoticeable performance wise. I ran this engine in my touring car and it made the Ruxtell unnecessary. When I put the engine in my speedster it ran up the Newport hill climb hill in high gear with 2 of us in the car. I had an aluminum head on the engine but it had a ignition knock that couldn’t be timed out. I put the iron head back on. A lot of people run distributors on these but my goal was a strong touring motor with the original T ignition system. L

On a side note, I would like to hear about the experiences that people have had running the cast aluminum connecting rods that used to be available for running stock T pistons with A crank?
I have a unmachined set.
I could see using them in a pressure oiled engine without babbit (aluminum straight on the crank with filtered oil)

Kenny
I can understand the potential for spark knock.
My understanding is that the mag only has 3 effective timing positions.
Fully retarded is about TDC
1/2 advanced is about 15 crank degrees
Fully advanced is about 30 degrees.
Optimal is 20-25 degrees. Unfortunately the design of the Ford mag doesn’t provide any power there (being AC it is at the neutral phase then).
I know people have relocated the flywheel to deal with this

Les:
I think we have spoken of this before … regarding aluminum connecting rods … Lycoming used aluminum connecting rods that were Babbitted ( with pressure oil) … I have re-babbitted 2 sets of these rods without any difficulty … you should be able to bore the rods to allow for .030 to .050 Babbitt thickness and Babbitt and finish bore as needed … on the Lycoming ( Auburn 8 cyl. ) rods I did bead blast with a course iron carbide media …always an optimist ...Gene French

Gene
Thank you for the information. Something for me to consider doing