Hi, guys I need some help here. I just got myself a 2nd hand serpent 966. Is there any cheep 21 size engine that I can fit in? I not going to race it just to have fun running it. I was looking at the Novarossi ISON.21 to fit in the car cause the price is not too expensive. Can the ISON.21 fit in the 966? Hope you guys here can help me out

ISON.21 is a perfect choice and will fit the 966 perfectly. Couple it to the 2052 and short manifold and you'll be good to go!

Thanks again.... And thanks for the great info I will take note about it

Is this the manifold ( Novarossi 41015 Short Conical On Road Manifold )?

I would not sugest the short manifold, the middle or the long does give a noticeable more power without loosing much top RPM. I do run all my Nova engines with the long manifold on all kind of tracks.

Oh.... Different manifold for different kind of track?

A long exhaust system wil give more torque but less top RPM
A short exhaust system will give more top RPM but less bottom torque (=poor acceleration)
And then there is a middle manifold to get a bit of both.

I use only the long manifold because most tracks are made to accelerate from corner to corner, that tiny bit less speed on the straight is pinuts compared with the gain on all corners. With changing gears you can correct the top speed.

Now I understand what's the long, middle and short manifold are made for.... Thanks a lot for the great information.

I need to learn more about on road engine. How about the shim for the block head, what is it for? And what it can do engine?

Headshims do set the compression.

To get the right timing on the ignition (self combustion) the compression has a huge impact, with the compression there is the nitro content but also outside temperature and the plug number to have the same impact

All factors shifting the ignition to an early point:
- higher compression
- higher nitro content
- lower plug number
- higher outside temperature

To shift the ignition to a later moment:
- lower compression
- lower nitro content
- higher plugnumber
- lower outside temperature

In basic:
The nitro content is corrected by the headshims
The outside temperature is corrected by the plugnumber

But making the step fron 25% to 16% nitro content I just changed the plug 8 to a 6 and it works very good.

And shifting the ignition does:
- give more torque but lower top RPM when shifted sooner
- give more RPM but less bottom torque when shifted to a later moment.

Oh i see now I know what it for..... Than the glow plug why do they have cold, mid and hot plug? Dose the weather temp play a part for which plug I use?

And I see many size for Carburetor Restrictor Insert for dose it do? How do I know which went is the correct one to use?

Thank you so much for your time to helping me...

A hot glowplug is a plug with a lower number. Due a lower cooling it will become hotter. Heat is one of the things needing for the self combustion and the ignition timing.

The carb inserts do determ the amount of air going into the engine. For the optimized combustion with the amount of air there is a need of fuel in the same proportion. Less air less means fuel so it will determ the milage but it also determs the maximum power. This is usefull for trying to make a qualification without a fuelstop.

All explained are nice things to know but for a hobbydriver and even a starting racer less important, Running the engine on the fuel where it is made for with the advised glowplug will run the engine in all kind of circumstances. In very hot or cold weather you probably only need to change the plug.....

Thank you again for your time.... Now I have batter understanding for on road nitro engine

Thanks for sharing. useful!