piston talk/Qs...

hardtimes

hardtimes

Well-known member
I'm thinking of 'gathering' stuff for another block build....hopefully TOD'S new 3 main ALUMINUM block :) !! I have an OHV Head for possible build, and some other necessary parts.

Now looking for set of pistons. I'm kind of set on Ross pistons, this time. My main question is, do any of you who have used Ross pistons have any regrets about buying/using same ? I know that they are pricey compared to other pistons, so my second question is, if I can locate a Fordbarn member who has a used set in good condition, do you have any reason/advice against my using them :confused:
 
Have you thought about the 283 piston that fits Model A length rods. Very good quality piston, the set of four is accurately balanced and they're $250.00 a set. Trade Name "Pete's Pistons". Can be purchased by contacting John Cosper, Pete's Auto Machine Co., 749 Old Coors Drive SW, Albuquerque, NM 87121......(505)836-3110.
 
It has been more than a decade since I used a Ross piston, but what I would do is start by asking each manufacturer for two weights, ...the piston itself and the pin weight. The 283 piston is actually heavier than the ones most vendors sell as replacement. The only advantage to the 283 piston is less ring drag. Rich Fallucia was bringing out a new piston that was lighter and had the thinner rings but I have not used one.
 
yeah the chevy slugs are way heavier than oem. never used ross in an A before but if they are like v8 ones ive used excellent quality and light .Sure you could order them with metric rings also. The metric ring package is the hot ticket for low ring drag in competition engines but you need to have the right cyl wall finish and I have my doubts about longevity in a daily driver.
 
I had Ross pistons, and they did not work for me. They are made from the type 2618 aluminum which expands more, needs more clearance, and I had piston slap when cold. Later switched to JE pistions with 4032 type aluminum and work fine with .003-,004 clearance. The 2618 is stronger, but I do not think an A this side of Bonneville needs it. Research the aluminum type, ask questions, and get opinions before spending your money. Lots of guys here have lots of experience on this stuff. And talk to the tech reps at Ross, JE or any others you might consider.
One other thing, get a verified measurement for the block height so you can accurately calculate the compression height and calculate popup if you want that. I took a guys word for it when I bought his block, and things did not fit quite right. He had taken off .025 he told me about, but someone before him took off more, which I only figured out later when I got an actual measurement.
One question I have for the experts, is in using the Chev pistons, they have a smaller pin size than the 1" Model A rod and pin. How is this compensated for? Thanks
 
There are new rods avail specifically for chev pistons. I think 394 olds pistons were what was used back in the day...
 
Hardtimes
I had my engine built with Ross Pistons. The only problem I had was they stick up further than the stock pistons. With the standard head there was enough clearance. With the crows foot Winfield head I used a sandwich of standard head gaskets and a solid copper spacer. All in all, they are great. I also have Ross Pistons in my race build Lotus twin cam engine.
 
Wow, lots of great information to consider ! Thanks to ALL !!
I do like the thin 'modern' rings and have just put them into my newly made B, on Egge custom comp ht alum pistons. I like the idea that the thin rings seat quickly, and it looks like mine have already done just that after 1/2 hour running. I guess from all this information , I have a lot to choose from, as far as pistons use goes. I may have to special order for 'popup', as I have plenty room in a Schofield head comb chamber.

There was a past great thread discussing piston stats. Can't remember how or who started it, but remember that Mike (engineer Mike:)) had a great contribution of piston comparisons. Can't locate the thread now .

Do any of you guys foresee any particular (piston use) problem with aluminum block ?
 
hardtimes said:
Wow, lots of great information to consider ! Thanks to ALL !!
I do like the thin 'modern' rings and have just put them into my newly made B, on Egge custom comp ht alum pistons. I like the idea that the thin rings seat quickly, and it looks like mine have already done just that after 1/2 hour running. I guess from all this information , I have a lot to choose from, as far as pistons use goes. I may have to special order for 'popup', as I have plenty room in a Schofield head comb chamber.

There was a past great thread discussing piston stats. Can't remember how or who started it, but remember that Mike (engineer Mike:)) had a great contribution of piston comparisons. Can't locate the thread now .

Do any of you guys foresee any particular (piston use) problem with aluminum block ?
Click to expand...

Rick,

Having pistons made give you the ability to specify exactly what you want. Generally, the issue that bites hardest are the pin diameters. The stk "A" is 1.000, most aftermarket rods are built for Chev .927 pins.
Ross, J&E, Venolia and others all make good parts, they would not be around if they made junk. They are the best source of recommendations for their product, especially for clearance.

As for Tod's alum block, no issue, he plans on putting in iron sleeves.

As of today I have Venolia and Ross in my motors.

John
 
John Cosper's 283 style pistons use a 1" pin like a stock A rod and it is in the correct location to use a stock A rod. Thus, they are a drop-in with no need to replace the rods. Have installed many sets and they are super
 
This thread had my piston comparisons: LINK.
Keep in mind things have changed since then. AER (Rich Falluca in Skokie) now has a new piston that I have not seen and Egge materials (alloy) and quality have changed- for the worse.

You may notice there are no forged pistons in my posts in the thread linked in the paragraph above. I'm no fan of forged pistons due to the extreme expansion coefficient requiring excessive cold clearance. Since internal undercuts are impossible during forging manufacture (unless machined after forging) they all have frighteningly short slipper skirts to keep the weight under control. That makes for a real rattle can motor until up to temp, and a lot of unnecessary ring and cylinder wear due to the piston rock from the high clearance and short skirts. Offset pin holes combat this by inducing side thrust, but there is a limit.
 
I use Ross in my Bonneville engine. They are set at .009" skirt clearance and use Chevy pins. I ordered them for A/B pin height but they were a bit high so took .015" off the top where they made contact with the Cook head, at high RPM only, no damage to anything. They are light and strong!
 
Hey MikeK,
Thanks for input, now and in past thread(s) :) !
And, thanks for + on the hyperutectic pistons in my new B. I'm glad to hear that they do not expand as much as some other pistons, because I used 'close' to minimal recommended clearance(piston/cyl). Makes me think positive about them not seizing ! Still using your shared analysis as guide.
I have gotten really great/helpful info from ALL responses !!
Many posters know more, regarding this subject, than most and we appreciate your sharing. No drama, just the facts mam :D
Can't get tooo much info on such subject, IMO. I know that learning from experience is , at times, very costly and hard way. Whereas, learning from others shared expertise ..is most like learning/ 'acting intelligently'
!!
 
Jim Brierley said:
I use Ross in my Bonneville engine. They are set at .009" skirt clearance and use Chevy pins. I ordered them for A/B pin height but they were a bit high so took .015" off the top where they made contact with the Cook head, at high RPM only, no damage to anything. They are light and strong!
Click to expand...

Hey Jim :) ,
'a bit off of the top'...
Hm, thought that this only happened to neophites like me , as I had to have a bit taken off of the tops of my new Egge pistons to make them flat with deck. No matter how it happened ...now. But, I am now wondering how this 'mistake' comes about? Someone above statement (PS) stated that he had similar problem...because of info (or lack of info) regarding PAST block decking. Jeeze, never even thot of that when ordering. Can now see where past decking info might be critical :confused:

So, just what is the original block height, and how to determine a blocks current height, if figuring out correct/wanted comp height ? What is the 'formula' for such.
 
Rick,

it is simple math, the block is 11.500 tall in stock form.
crank stroke, 4.25/2 =2.125
rod centers 7.500
11.500-2.125-7.500 = 1.875 CH of piston.

These are basic dims to work from, flatheads are generally not that tough to do, adding pop-ups to overheads can get interesting.

John
 
Rod length (7.500") + 1/2 stroke (4.250"/2 = 2.125") + original piston compression height (1.906") = 11.531". If the deck height is 11.500 the piston will protrude 0.031". Original blocks usually came off the line on the high side of the 11.500 - 11.505" range.

Every time the block gets a haircut the piston protrusion increases, but most of the replacement pistons the vendors sell are somewhat short of the original 1.906" compression height. Reground cranks are also notorious for having each throw 'off' from the original stroke spec. a different amount. Replacement rods do not necessarily measure 7.500", either. All I can say is measure everything twice, and keep a build sheet.
 
You must log in or register to reply here.
Back
Top