sleeve & piston

[steve palgreene]

Have a question on novarossi motor 21 outboard marine can you change sleeve & piston from one motor to the other or are the ports different .

 

[Andy Brown]

I'm not 100% sure but the case ports on most of the Nova 21's has been the same for last 12 years that I know of.

They just put sleeves in the block with different numbers of ports.

 

[steve palgreene]

So if you put in a sleeve with more ports what does that do to the motor would it still run . Do you have to change anything In the rest of the motor.

 

[brad nichols]

I would say no as the cases would be different I think? Contact Ron Shaw.

Brad

 

[Andy Brown]

So if you put in a sleeve with more ports what does that do to the motor would it still run . Do you have to change anything In the rest of the motor.

Yes, It will still run. Nova purposely makes sleeves with more ports and sells them for more money, because under certain conditions they make more power.

 

[Andy Brown]

I would say no as the cases would be different I think? Contact Ron Shaw.

Brad

Last I checked ( worked on a new Nova 21 OB last week) the case had the same 3 ports as Novas I have from 12 years ago.

But the sleeve, I believe, had 7 transfer/boost ports and 3 exhaust ports.

However I think Nova may have made a rod length change in recent years. Therefore the case /port height in the newer engines may be different than the older Novas. You'll have to wait for a Nova guru to chime in.

 

[Marty Davis]

I would say no as the cases would be different I think? Contact Ron Shaw.

Brad

Last I checked ( worked on a new Nova 21 OB last week) the case had the same 3 ports as Novas I have from 12 years ago.

But the sleeve, I believe, had 7 transfer/boost ports and 3 exhaust ports.

However I think Nova may have made a rod length change in recent years. Therefore the case /port height in the newer engines may be different than the older Novas. You'll have to wait for a Nova guru to chime in.

Not a Nova Guru for sure BUT, Over the years there have also been various crank strokes so that will also affect it. Some liners are larger in diameter also so they might not fit the case.

 

[John Knight]

With the older RX21 engines there is a difference I the sleeve diameter. Those made before the year 2000, the sleeve diameter is .756. Those made after 2000 are .767. The newer Keeps are different. But generally the 7 port engines can use the standard sleeve of .767. Other than the newest engines the P/S works in an IB or OB.

 

[RonShaw]

So if you put in a sleeve with more ports what does that do to the motor would it still run . Do you have to change anything In the rest of the motor.

Steve,

There are two different current engines categories to consider, long stroke, and extra long stroke. There are also some different families of engines within these two categories to consider such as T21 Sport Competition, KEEP, MITO, Flash, Bonito, TX, and 35 PLUS. There have been different variations of the different families of engines over the years, but as long as you keep the switching "within the family", you are good. Outside of that, different types of problems can arise. For example, sport competition engine sleeves, no matter which port, 3/5/or 7 port, as well as the Hybrid, are all interchangeable. The KEEPS are interchangeable, etc. I hope this helps answer your questions. Thanks.

 

[brad nichols]

There you go the parts supply man himself!! He will know and set you right.

Thanks for what you do for our hobby Ron!!

Brad

 

[Brian Sorgente]

And i've always said... "Im pretty sure they do this on purpose to confuse everyone" ...

 

[RonShaw]

There you go the parts supply man himself!! He will know and set you right.

Thanks for what you do for our hobby Ron!!

Brad

Thanks Brad. Glad to help anytime I can.