A/B engine Piston use Q

[hardtimes]

Are there any good mechanical reason(s) / benefits for using heavier pistons -vs- using lighter pistons in A/B engines. Assuming that all 4 pistons are matched in weight ?

[J Franklin]

How fast will you be reving it? I have a car (not the A) with Cast iron pistons and they work great. I think lighter puts less force on things.

[johnneilson]

simple answer, no, go as light as possible.

due to the asymmetrical acceleration between the bottom of the stroke and the top, the lighter piston will have less influence on vibration.

J

[Jim Brierley]

As John says!!!

[100IH]

Any part that is reciprocating piece should be as light as possible without jeopardizing strength. It takes energy to get the mass to stop and go back the other way made worse by more velocity and / or mass.

[hardtimes]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by Jim Brierley

As John says!!!

THANKS for all input !


Ok, these answers are kind of what my sense says.
However, I was speaking with an race engine builder/balancer(business) and he said that the A/B engines were/are crudely made/unbalanced machine, compared to todays engines. Therefor, the heavier piston can be of benefit in off setting those engines' basic design (i.e.- two up/two down pistons rotating masses). His answer was more complicated, of course, but this was the idea as I took it. Kind of like adding balancer and like keeping flywheel HUGE in this design idea. Maybe bad dream(popping eye face), but wanting comments to clarify thinking.

[hardtimes]

Originally Posted by J Franklin

How fast will you be reving it? I have a car (not the A) with Cast iron pistons and they work great. I think lighter puts less force on things.

Looks like '36 Chev, eh ?
I think that my chev had cast iron pistons also.
Well, I think that engine 'application' and 'revving' has a lot to do with things, but I was asking about an A/B engine that was stock, pretty much as ford built it. They weren't made to rev very high at all, I don't believe. For that matter, neither was the old chev.

[hardtimes]

Originally Posted by johnneilson

simple answer, no, go as light as possible.

due to the asymmetrical acceleration between the bottom of the stroke and the top, the lighter piston will have less influence on vibration.

J

Hey john,
Are there different ways to 'lighten' piston weight , without damaging the integrity of the piston ?

[ursus]

The original pistons Ford provided for the Model A are generally lighter in weight than any provided by the various aftermarket manufacturers. In some cases it can be over 200 grams difference per each piston + pin.

[johnneilson]

Originally Posted by hardtimes

Hey john,
Are there different ways to 'lighten' piston weight , without damaging the integrity of the piston ?

Yes, many ways.

The first order of business is to be realistic in the intended application.
If a stock motor build, you can use the stock ones though I think some modern ring technology would help.
If racing, pick your poison, you cannot beat a set made by one of the Premier piston manufacturers.

I have never met a piston with any integrity. I have had a few cams with attitudes, but then you would too if you looked all bumpy like that.

If you want to see what can be accomplished, look for the pictures of the Honda F1 motor parts online.

John

[hardtimes]

Originally Posted by ursus

The original pistons Ford provided for the Model A are generally lighter in weight than any provided by the various aftermarket manufacturers. In some cases it can be over 200 grams difference per each piston + pin.

Do you know what Ford original aluminum piston weight was , without pin and rings attached ?

[ursus]

Originals, per Ford, were 476.8 grams each and, with pins, 597.3 grams.

[ursus]

Originals, per Ford, were 476.8 grams each and, with pins, 597.3 grams.

[ursus]

Originally Posted by hardtimes

THANKS for all input !


Ok, these answers are kind of what my sense says.
However, I was speaking with an race engine builder/balancer(business) and he said that the A/B engines were/are crudely made/unbalanced machine, compared to todays engines. Therefor, the heavier piston can be of benefit in off setting those engines' basic design (i.e.- two up/two down pistons rotating masses). His answer was more complicated, of course, but this was the idea as I took it. Kind of like adding balancer and like keeping flywheel HUGE in this design idea. Maybe bad dream(popping eye face), but wanting comments to clarify thinking.

Ford would certainly not have agreed with the "race engine builder/balancer" that gave you such information. Here is Ford's take on it, from Vince Falter's excellent website:

http://www.fordgarage.com/pages/etbaebalancing.htm

[d.j. moordigian]

Originally Posted by hardtimes

THANKS for all input !


Ok, these answers are kind of what my sense says.
However, I was speaking with an race engine builder/balancer(business) and he said that the A/B engines were/are crudely made/unbalanced machine, compared to todays engines. Therefor, the heavier piston can be of benefit in off setting those engines' basic design (i.e.- two up/two down pistons rotating masses). His answer was more complicated, of course, but this was the idea as I took it. Kind of like adding balancer and like keeping flywheel HUGE in this design idea. Maybe bad dream(popping eye face), but wanting comments to clarify thinking.

That guy is blowing smoke,...it's all BS

[40 Deluxe]

Originally Posted by ursus

Ford would certainly not have agreed with the "race engine builder/balancer" that gave you such information. Here is Ford's take on it, from Vince Falter's excellent website:

http://www.fordgarage.com/pages/etbaebalancing.htm

Did you notice that this is an "ELEMENTARY" textbook?! I'd hate to see the "Advanced" textbook! It sure blows holes in that "race engine builder" guy's misconceptions!

[johnneilson]

Originally Posted by d.j. Moordigian

that guy is blowing smoke,...it's all bs

x2

j

[hardtimes]

Originally Posted by ursus

Ford would certainly not have agreed with the "race engine builder/balancer" that gave you such information. Here is Ford's take on it, from Vince Falter's excellent website:

http://www.fordgarage.com/pages/etbaebalancing.htm

Yeah, I also 'wondered' about the information. That's why I asked here !
Sometimes you hear an 'opinion' (like other things..everyone has one, eh) and wonder whether you missed something along the way. Most of what I got here is the usually accepted information/opinions.
Also, thanks for the piston data. It will be used for comparison with a number of old time used different make pistons. No makers mark on some.