Small Block & Big Block Question

[NitroRC4Life]

What is the cut-off mark of an engine going from small block to big block?? Is small block up to .20 sized and big block is .21 and up???

 

[JettaManDan]

it depends on who you ask....i say anything that is .21 and up is usually considered a big block...a .26 and up is for sure...

 

[revo_rob_1984]

from what i have been told up to .21 is small block, .21-.26 is a midblock and .26 and up is a big block. . .i don't know how true that is. . .but my honest opinion is .21 and under is small block and anything over .21 is a big block. . .just my opinion. . .this small, mid, big block stuff is confusing to me.

 

[NitroRC4Life]

ok so is the o.s 21 tm a drop in motor without mounts or what??? thats the motor i want to race my revo with next year!!!

 

[alpinehyperlite]

What you need to do, is post a new topic with each question....... It will help the other newbs who come up with the same problem find the solution easier using the search function.

 

[robmob]

Alpine is right.

I would also suggest you put the subject of the question in the thread titles.

 

[NCNitro]

Alpine is 100% correct.

Plus you are going to expect people to keep checking this thread to see what new question may or may not be posted. Also, many of the questions you will have have already been answered, sometimes over and over again, so use the search function before asking, you may just find the answer you are looking for.

 

[robmob]

I have edited your title to reflect the subject of the thread.

I have also removed everything in your fist post except the question.

Here is the original post:

I'm really into this hobby but I'm still new and i have a bunch of questions so what i was thinking was to make this thread for any questions that I have and just update it so you guys know i have a new question!!! what do you guys think??? But my first question is: What is the cut-off mark of an engine going from small block to big block?? Is small block up to .20 sized and big block is .21 and up???

Thread has also been moved to the Engines Forum.

 

[NitroRC4Life]

ok thanx.. but is the os 21tm a direct drop in for the revo 3.3???

 

[basketcase45]

ok thanx.. but is the os 21tm a direct drop in for the revo 3.3???

NO. It can be put in the REVO, though. you will need a big block engine mount for the REVO, and maybe linkages, exhaust, etc.,

 

[NitroRC4Life]

could someone like tell me what i need if they did this so that i can do it to???? or is there like a kit with everything!!!!

 

[frickenjoey]

Actually the OS .21TM WILL fit with no real modifications or special mounts. Go to Tower Hobbies web site and check the mounting dimensions. It will be a direct drop in unlike the .26 Picco Maxx or RB 523.

 

[NitroRC4Life]

oh wow/..so just some little mods like for the linkage??? i want this cause its a popular motor and its on easy pay!!!! yayayay

 

[frickenjoey]

Ok lets break this down…..there is not truly a magical dividing line between “Small Block” and “Big block”. It is not truly the displacement of the engine that makes it one or the other. You have to look at the size of the case. A Small Block is going to be physically smaller than a big block. The small block is going to be shorter when measured from back plate to the front of the case. Also if you measure the width of the case you will notice the small block is narrower. Now with this in mind you will find most Big Block engines start at the .21 size. Don’t let that be a benchmark though….because there are exceptions to the rule. What are these exceptions you ask? No problem! There are variants to the small/big block equation. The OS TM series, the Picco Maxx series, RB 523, Sirio .27 are all considered colloquially to be a “Mid Block”. A mid block is not really a true term but is what we give the name to since it is not a true small block since many have the displacement of a Big Block and the width of a big block but are shortened to fit in a Small Block application. There are other exceptions to the rule as well such as CEN at one time made a Big Block .15. It was a big block sized engine with a wide piston with a very short stroke. It did not catch on very well. So in short the true determination of a big block or small block is the external dimensions of the engine not necessarily the displacement.

oh wow/..so just some little mods like for the linkage??? i want this cause its a popular motor and its on easy pay!!!! yayayay

Should be very easy...I am not even sure if you have to mess with the linkages even.