ABN or ABC

I'm just getting back into UC and have been reading many different things that people are doing to engines to improve performance.
I saw they used the Tower Hobbies 40 ABC piston and sleeve in the OS 40 engines, to make it a true ABC. My question is, Is there that much of a difference in performance between these 2 parts when used in the O.S. engines?

LAST EDITED ON Nov-15-04 AT 06:49 AM (CST)
 
I don't know about performance difference but it might be more of a durability issue. I think the chrome plating on the Tower parts is considered a notch higher in quality than the nickel plating on the OS parts. I believe there were some problems with the nickel plating on some of the earlier OS ABN parts also.

This is precisely correct. There is nothing wrong with nickel plating when it is done correctly. There were some OS engines that were very thinly plated and these, especially caused problems. I returned a number of them to OS saying they were simply unacceptable to me. They were unhappy, but replaced the engines with equally thin plating and we did it again. In later runs they did change their plating process again and the later ones were much improved.

That said, some of these need to be replaced. Why even a good engine will eventually wear out. I was one who suggested early on to use the Tower piston/cylinder as a replacement. The new OS engines use a cast piston. The Tower used one machined out of bar stock. It is thus harder and should wear longer. It also uses true chrome plating adding to durability with the harder piston. The real kicker, however, is cost. It appears to be a much better made unit at a much cheaper price. And Tower will even ship it to you for free. (I wonder if Tower really knows why they sell so many piston/cylinders, crankshafts, and back plates for this engine?)

While on the subject, the crankshaft used on the LA 40 and 46 is cast with only a couple of machining operations. The Tower 40 shaft is a perfect replacement, machined out of bar stock (stronger), fully balanced (lighter), and much cheaper. It also fits the 35/40 FP. The same recommendation applies here if you need a new shaft.

Thanks for all the info, I guess in another sense why buy O.S. just buy the Tower engine?

LAST EDITED ON Nov-15-04 AT 12:43 PM (CST)
 
I don't think Tower Hobbies clone of the OS40FP is still being made.

>Thanks for all the info, I guess in another sense why buy
>O.S. just buy the Tower engine?

Those of us with suspicious minds figure that the Tower engine competed too directly with the OS line, a major seller for Tower. You can still get the BB Tower engines in 46 size and up. BTW, the Tower engines were made by a Korean(IIRC) company that will make any kind of machine part you need. The Tower 40 appeared on their home page for a while.

>Those of us with suspicious minds figure that the Tower
>engine competed too directly with the OS line, a major
>seller for Tower. You can still get the BB Tower engines in
>46 size and up. BTW, the Tower engines were made by a
>Korean(IIRC) company that will make any kind of machine part
>you need. The Tower 40 appeared on their home page for a
>while.

The Tower 40 was made by a company making sewing machines in Taiwan.

>This is precisely correct. There were some
>OS engines that were very thinly plated and these,
>especially caused problems. I returned a number of them to
>OS saying they were simply unacceptable to me. They were
>unhappy, but replaced the engines with equally thin plating
>and we did it again. In later runs they did change their
>plating process again and the later ones were much improved.
>
>That said, some of these need to be replaced. Why even a
>good engine will eventually wear out. I was one who
>suggested early on to use the Tower piston/cylinder as a
>replacement. The real
>kicker, however, is cost. It appears to be a much better
>made unit at a much cheaper price. And Tower will even ship
>it to you for free. (I wonder if Tower really knows why
>they sell so many piston/cylinders, crankshafts, and back
>plates for this engine?)
>
>While on the subject, the crankshaft used on the LA 40 and
>46 is cast with only a couple of machining operations. The
>Tower 40 shaft is a perfect replacement, machined out of bar
>stock (stronger), fully balanced (lighter), and much
>cheaper. It also fits the 35/40 FP. The same
>recommendation applies here if you need a new shaft.

Ron B.
F4Fguy

Leonard:

Some true, some partially true.

True:
"There is nothing wrong with nickel plating when it is done correctly."

Electroplated nickel,post heat treated,is almost as hard ,and has lower friction than chrome.It wets better with oil and retains an oil film better than chrome.It's adhesion, generally, is better than chrome( one reason it's used under chrome plate).

Not necessarily true:
"The new OS engines use a cast piston. The Tower used one machined out of bar stock. It is thus harder and should wear longer. It also uses true chrome plating adding to durability with the harder piston."

Hypereutectic Si Al cast alloys are considerably harder than any bar stock at the same heat treat condition.They cannot(without GREAT difficulty-read cost) be made as "bar stock".The SI content determines the low expansion characteristic of the Al piston,and this is what makes ABC/ABN work.The Si is also the alloying component in the piston which provides the low wear in an ABC/ABN engine. Actually, the hardness, as such, has little to do with wear of a single component. Generally the best wear and compatibility is found when the two rubbing components (espescially with boundary lubrication)have distinctly different hardnesses.

Give it another few years and modern tribology(fancy word for friction and wear) developments may trickle down to us. Currently with some fancy material selection and platings shafts are being made that simply do not wear under normal use. They have the potential to last literally forever. The materials are selected and made so that the material that usually transfers from one bearing surface to the other(as part of wear) simply moves right back. And these shafts are running with no lubrication to boot in hard disk drives and similar stuff. Would be nice to have a good piped 60 that needed no oil in the fuel. Might still be able to compete with the electric motors and LiPoly batteries.