Can anyone school me on engine sizes? I have a Losi 8t coming in the mail. It says it has a 427 big block. What does that mean, How are engines actually sized? Does it mean it is a .27? What is considered small, and what is a large engine? I'm new so just trying to figure it all out. It is the rtr version and I will need to buy a few more things, so if anyone can tell me what is a must have right off to get going that would be great too. Thanks
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Engine sizes
- Thread starter zworld
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Big block vs small block typically is in direct relation to the size of the crank case. Big blocks are typically for 1/8 scale vehicles while small blocks are for 1/10 scale and smaller.
The 427 is actually 4.27cc which is the volume of the combustion chamber at bottom dead center. That is also 0.2606 cubic inch, so a .26ci.
This is a photo of a .21 compared to a .18:
The top pink headed engine is the .21. Notice how the crank case is longer and taller. It's also fatter and requires a larger engine mount.
Now, with the advent of the t-maxx, there were a few new engines made that were described as mid-blocks. These are higher displacement engines (larger than .18) that fit into an area the same size as a small block. Big torque, little package.
A .21-.32 (or larger) is typically the range for big blocks. .10-.18 is typically the range for small blocks. .12 and .21 are usually used for racing but they are also typically tuned for more power which makes them more pricey than their larger cousins.
The larger displacement engines (larger than .21) were generally made to get more bang for your buck. You can get a .21 that will rival a .32 for power, but it will cost you 3 times more and generally no matter what you do, the .21 will have higher peak RPM's.
I know there are a few engines out there that are technically big blocks like the TRX2.5 (same bore/stroke diameter/length), but what I described above is the general differences between hobby "big block" and "small block".
The 427 is actually 4.27cc which is the volume of the combustion chamber at bottom dead center. That is also 0.2606 cubic inch, so a .26ci.
This is a photo of a .21 compared to a .18:
The top pink headed engine is the .21. Notice how the crank case is longer and taller. It's also fatter and requires a larger engine mount.
Now, with the advent of the t-maxx, there were a few new engines made that were described as mid-blocks. These are higher displacement engines (larger than .18) that fit into an area the same size as a small block. Big torque, little package.
A .21-.32 (or larger) is typically the range for big blocks. .10-.18 is typically the range for small blocks. .12 and .21 are usually used for racing but they are also typically tuned for more power which makes them more pricey than their larger cousins.
The larger displacement engines (larger than .21) were generally made to get more bang for your buck. You can get a .21 that will rival a .32 for power, but it will cost you 3 times more and generally no matter what you do, the .21 will have higher peak RPM's.
I know there are a few engines out there that are technically big blocks like the TRX2.5 (same bore/stroke diameter/length), but what I described above is the general differences between hobby "big block" and "small block".
Last edited:
MrClean
Hardcore RCTalk User
IMO, 'must have's':
1) Temp gun, it is a great tuning aid and will help prevent overheating the engine.
2) Fail-safe, it's an electronic device that goes between your RX and throttle servo. In case of interference or battery failure (on the transmitter), it will return your throttle to the idle position. Some models have the ability to engage the brakes. This can prevent a run away rig, which can end in an expensive crash
3) Throttle return spring, it's a mechanical fail-safe, when you let off the trigger, it pulls the throttle back to the idle position.
I'd buy #1 before I even buy fuel. I ran without a fail-safe for awhile, but after sinking even more money into my truck, I realized it was just not a good idea to continue without one.
There is more stuff and I'm sure I've forgotten some things, someone will be along to give more advice.
Welcome to the site and the addiction.
1) Temp gun, it is a great tuning aid and will help prevent overheating the engine.
2) Fail-safe, it's an electronic device that goes between your RX and throttle servo. In case of interference or battery failure (on the transmitter), it will return your throttle to the idle position. Some models have the ability to engage the brakes. This can prevent a run away rig, which can end in an expensive crash
3) Throttle return spring, it's a mechanical fail-safe, when you let off the trigger, it pulls the throttle back to the idle position.
I'd buy #1 before I even buy fuel. I ran without a fail-safe for awhile, but after sinking even more money into my truck, I realized it was just not a good idea to continue without one.
There is more stuff and I'm sure I've forgotten some things, someone will be along to give more advice.
Welcome to the site and the addiction.