Spiro

Having only ever run the stock engine in the single nitro car I had years ago, I never had to worry about such things. Now I am thinking about changing to a different engine type and I notice there are all sorts of crankshaft options for engines. Short shafts, "standard" crank, pilot shaft, SG, etc. Sometimes it seems like they can be used as is and sometimes it seems like the threads need to be cut in order to put whatever particular clutch nut on.

Can someone offer a brief explanation of these different shafts, or point me in the right direction to read more about them?
I am wondering:
- what each one looks like
- what the different types are for
- how I can correctly match a crank type, flywheel, collete, clutch nut, clutch, and clutch bell

These questions are mostly for my education. However if you are interested in the particular application, I have a Kyosho DBX and am considering putting in an OS TZ18 to replace the now worn out stock engine. The crankshaft/clutch choices are bewildering! I just need something that works and wont break the bank. But mostly I need to know what the heck all these options are about.

Thanks in advance,
Sprio

SAVAGEJIM

This is an example of an SG shaft crank shaft:
http://store.savagess.com/product_in...roducts_id=873
What it looks like on the engine:
http://www.hobbywarehouse.com/Produc...cvsfp=PTH2502B

Here is the older standard shaft engine: (These are rather obsolete since SG shaft is the newer industry standard:
http://www3.towerhobbies.com/cgi-bin...&I=LXGEG5&P=FR
and an engine with standard shaft:
http://hobby-shack.amazonwebstore.co...B000BLM330.htm
(You cant see it too well unfortunately, but it is very clear it is not an SG shaft)

Sugafree

I'll let one of the Engine Guys Explain it better than me

But these are the Basic's for Car Engines.....

SG Crankshaft (without PS) No Pin on the Crank for Pull/Roto Start ( found on Bump start Only engines)



SG Crankshaft (with Pull Start) has the Pin on the Crank for Pull/Roto Starter



and the Standard Crankshaft's are shorter and have the threaded portion,

Spiro

Awesome. Thanks a bunch for the pics and links. At least now I have some idea of what I am looking at I have been out of the hobby for over 15 years and I am just used to the old "standard" shaft i guess.

Questions:
So what does SG stand for?
If the SG shaft is indeed the current standard, why is it superior?
Is the clutch nut now just part of the SG shaft?
What do you need for a clutch on such a shaft.

Thanks again for your help,
Spiro

Sugafree

The "SG" refers to the shaft end where the Clutch goes.

SG type Engines, the end of the shaft IS the pilot shaft for the Clutch Bearings, the Flywheel nut slides down the shaft to the threads on the lower prtion of the shaft, and a threaded hole in the end retains the Clutch.

Best Pic I could find, (No CB on.... Obviously)

46u

My Feedback: (3)

Correct me if I am wrong but the SG and pilot shaft is the same thing. I have a OS 18 TZ in my HPI MT and it is a POWER HOUSE. All most to much for a 1/10 scale but a lot of fun.

Spiro

46u,

I was wondering the same thing about the SG shaft and the pilot shaft

Can you describe your HPI MT clutch settup? What engine shaft, flywheel, nut, clutch shoes, clutch bell, clutch bearings, etc.

What engine did the MT come with stock? I was wondering what you had before and how the OS 18TZ compared to that

Thanks much!

bikeracer

The pilot shaft is integral with the SG shaft.
If you have a normal threaded shaft it needs cutting and a pilot shaft fitted.
http://www3.towerhobbies.com/cgi-bin...haft&search=Go

.

46u

My Feedback: (3)

My HPI MT was the Racer kit and did not come with a engine. I have up graded it to a MT 1 3/4 or what I call it. I have up grade to the MT2 SS specifications other then the upper deck, chassis and radio box and is why I call it a MT 1 3/4.

The OS 18 TZ is the most power full small block I know of and has as much HP as some big blocks. I had to modify parts on my MT 1 3/4 just to handle the power.

I race 1/8 buggies and a fully modified race Savage and my MT 1 3/4 is just as fast if not faster. I had to gear my MT 1 3/4 WAY up just to keep the front wheels on the ground most of the time and still way to much low end. [X(] When I nail the throttle my tires balloon in about 4 or 5 feet even geared so high.

My OS 18 TZ came with a standard shaft crank and had to use the HPI extension. I am running the stock flywheel with the HPI race clutch that came in the kit. The clutch that has the spring that goes around the outside of the shoes. I am running a Savage Race CB which is much better then what came stock on it like the newer MT2.

I just went to some engine sites and they have them listed as SG (pilot) shaft.

Spiro

Thanks very much to eveyone with all your help here. It is very educational!

So it looks like I should probably get an engine with the SG shaft since that is the standard these days and will have the most parts available for it. Now I just need to get a clutch figured out It looks like just about all the major manufacturers have flywheels and clutches intended for SG shafts, as you guys implied, and I suppose I could choose any one. Or I guess I could go with an aftermarket one, but I am trying to keep things on the cheep.

If anybody thinks one particular clutch is a good design and worth considering over the others (AE GT2, HPI MT2, etc.) Feel free to make suggestions. Or if you know of one that I should be sure to avoid, that information is just as valuable!

Thanks again,
Spiro

46u

My Feedback: (3)

Are you going to race or just bash? If you are going to race only 2 wheel drive trucks are race legal. I hope this changes as 4 wheel drive like the HPI MT 2 handles SO much better and will go places a 2 wheel drive only dreams of going so it makes a better basher. Now to put a engine with the power of the OS 18 TZ you better beef it up all you can not matter what truck you put it in.

In the stadium truck form the LONGEST thread on all of RCU is the MT2 thread. Check it out.

Spiro

You said it. Just bashing and informal racing with my friends. No 1/10th 4wd class, so no racing. Not a huge deal as I am more interested in working on and modifying the cars than competing in class X.

Why do you ask?

Spiro

46u

My Feedback: (3)

If all you are going to do is bash then I recommend a 4 wheel drive stadium truck as they will go places and handle better then a 2 wheel drive truck. I all so recommend a engine with less power then the OS 18 TZ to keep from having to modify the drive train to keep it from tearing up. Something like the OS .18 CV-R series which is more then enough or the stock engine is fine.