small block is up to .18 /over that is a big block?

[Big-Mike]

I answered a guy the other day about .26 ofna/picco big block. He answered back he should have said that it was a small block. The question is what size makes an engine a big block----is it the .20 as or club has the Revo 3.3 race with all the other big block trucks. Not all of the tracks around us split the monster trucks into small block and big block. We do to get the most fun for those driving!!!!
How do your tracks run your monster trucks?
We may change?
Thanks for all your Help!
Big-Mike

 

[CharliesTheMan]

no you are correct, the .26 is considered a big block as far as I know. I was taught that anything over .20 inches is a big block. Now the .26 picco is a drop in for a small block engine, but it's a big block as far as displacement. It wouldn't be right to let the guys with .26 drop ins run with the small blocks and the guys with true .21 big blocks have to run in the big block. As far as I'm concerned the only fair way to do it is to have an engine displacement limit. I've always used .20 and that's they way our club track will be.

 

[joneser4u]

i have the sirio .23 and its a midblock, neither big or small. i think the os .21tm is a midblock also and maybe the picco .26max engine. so not all engines are big or small.

 

[CharliesTheMan]

no but when you are setting race classes there has to be a line drawn somewhere, or there will be 12 different classes with only 8 people racing.

 

[Rolex]

There's a lot of confusing information out there about this. Kind of like the early confusion on how and when to charge NiCad batts. Everyone had heard something different.

Correct me if I'm wrong here, but I was led to believe that a big block vs. a small block is determined by the length of it's piston stroke, not it's displacement.

ie: The Traxxas .15 and the 2.5 are the same displacement, .15 being ci and 2.5 being cc, yet the 2.5 is referred to as a big block.

 

[CharliesTheMan]

I'm out of it then, I was pretty sure that the trx 2.5 was a small block.

 

[joneser4u]

I'm out of it then, I was pretty sure that the trx 2.5 was a small block.

+1 to that?

 

[Big-Mike]

To Rolex
The Traxxas 2.5R engine is only a .15 engine/ the 3.3 is a .20 engine
as I understand? Sounds like still a lot of people not sure of how to make up their classes---- maybe just do it the way each club wants the racing to be best!!!!
thanks for the imput you guys
just remember to enjoy the tracks and racing you do!!
Big-Mike

 

[HeartBreak]

It's all up to interpretation. I personally think of a smallblock as any engine that fits a traditional .12-sized mounting pattern, and a big block as something that fits a .21 sized engine pattern, such as a .28 or larger.

This can be a bit confusing, as you have the Traxxas 3.3, which can be considered a "Mid block" (since it fits a smallblock mounting pattern, yet has a .20 sized piston/sleeve).

 

[Rolex]

I said to correct me if I'm wrong, so I'm just as eager for hard facts and new info as the rest of you.
With all this talk of small block, mid block and big block, I'm still a block head.

EDIT: Question for you 1:1 engine guys...
Isn't a small block a short stroke high revving engine and a big block a long stroke low rev high torquer?

 

[CharliesTheMan]

+1 for being a block head, thats for Rolex being a blockhead

 

[Rolex]

I added an edit above.

Hey, I admit it. I have a 4.6, and I'm a BIG block head.

 

[Mattyfats420]

Question for you 1:1 engine guys...
Isn't a small block a short stroke high revving engine and a big block a long stroke low rev high torquer?

A big-block engine is "generally" a V8 engine which usually has greater than 5.9 L (360 cubic inches) of displacement from what i was tought

but some people say that they differ in respect to the distance between cylinder bores, but not always in engine displacement since it is defined by bore and stroke.

For example, engines ranging from the 4.8 L chevy to the 7.0 L LS7 are all GM small block V8s, and share the same general external dimensions. The LS7 achieves huge displacement by having a very large bore and stroke in the same compact block as previous small-blocks, but has very little space between cylinders.

this may seem just as confusing as Nitro big and small blocks, therefore we have many conflicts with this issue. its been a debate from motor heads ever since i knew what a big block was

 

[CharliesTheMan]

typically like in a GM motor, the block is cast in one of two sizes. The actual displacement can vary greatly, inside these engines, and I've drivin a car with a 454 small block. But in general certain engine sizes are cast in small block, like 305, 350, and 400 from the factory, and certain engines are cast in big block, like 396, 454, and 502. So basically, if the block is small it's a small block and if it's big its a big block. In racing, there are usually limits on displacements, stroke, and bore, instead of just big or small block.

 

[Rolex]

Excellent info, Mattyfats420. It's good to know that motor heads of all sizes can be confused about the same thing.

So, if I'm correct, my 4.6 in the Savage is a Big block, and the 5.0 H.O. in my Thunder Bee is a small block?

 

[CharliesTheMan]

you're exactly right rolex. There's no confusion about your 4.6 being a big block (or in my opinion my 2.5 being a small block lol)

 

[Mattyfats420]

In racing, there are usually limits on displacements, stroke, and bore, instead of just big or small block.

I'm sure its the same for nitro racing too. "big block" and "small block" is a general term. theres alot more going on in an engine than just displacement. bore and stroke plays a big part

the 5.0 H.O. in my Thunder Bee is a small block?

Small block it is!

 

[bnrpat09]

well tecxhnically yes the size is refered to by the size generaly small block is up to an .18 ci but then traxxas came out with the 3.3 cc which is a .20 ci which is small block... it really depends on the size of the motor mounts...

a small blocks motor mount holes would be very close together, and a big block farther apart to prevent a break in the block...

an ofna picco .21 and .26 max are considered by them a small block, but in reality they are big blocks...

but the motor mounts on the picco "small blocks" are a tiny incy bit smaller than a general big block, which puts them in a "medium block" category

like team losi's lst motor mounts have "big block" mounting holes, and then they also have holes for a "medium block" but that truck is meant for a big block

in general though this is how it is ranged

.12 or lower to a .18 or possibly engines a bit larger like the traxxas 3.3 would be a small block engine
and anything from a .21 and up to whatever is out in largeness would be big block...

and for the record i have seen so many arguements about this but when i campared my TRX .15 piston and my TRX 2.5 piston the 2.5 piston was rounder and i called traxxas to clarify the sizes and the guy said the 2.5 is just a hair over a .16

 

[Captain Chaos]

Our track races unlimited monster truck.I'm not sure there are any rules although the small block OS .18 TZ I think it was was the hot motor.Almost everone races a Revo.Season starts 4/13/08.It will be my first race.