Has anyone that's driver a Max California also driven a standard/modified version of this? Whats the differences if any?

I think it's pretty much an RP9 with a low profile heatsink. That's about it.
Unless you race on a very high grip track, don't bother with the extra cost.
Maybe you are super critical about C of G. In that case, enjoy the benefit of a Low Profile Head.

What is the manifold that comes with the O.S. SPEED R2104 WORLD CHAMPION COMBO?

MR03

I just bought this motor from Rody. I will be running it in using the tuning bible method from here. I also will use an engine heater.
Its my first nitro ever... Does anyone have anything to add?

You can also bring it over and do an oilbath break in.

But you you want to do it on the track. adjust the clutch to a low engage. It makes the car easy to run forward at a good rich setting and it will save the cluch shoe and aluminum clutchbell from a lot of slip and wear.

thanks

Has anyone tried the max power pipe and manifolds on the OSR2104 or OSR2102 or any other OS based engine?
if you have how does it compare to the OS pipes and manifolds .

I too am interested in this info.

The MAX engines and the OS do share almost the same timings, there is only a slight difference in bore/stroke. I expect simular performances but can not tell which one is better. I know some who say the Novarossi 2015 also works good on OS engines.

The OS guys usually use the Novarossi 2015 pipe for improved fuel economy if needed as far as I understand.

Hey fellas,

Looking to move on from Nova Rossi. Was looking at the GSR.21 9R. Any feedback? It's based off the OS 2104 correct?

Thanks!

It's the same as the OS 2104. I have one and it works great.
Match it with MR02 manifold and TR02 pipe

hey guys,
please see attached pics.

This 2104 was ran in on the hudy stand for approx 1.25 Litres.

I then installed the engine in the car and slowly started running it in, even by the 4th litre of fuel it was still very right and I had it set still quite rich, I was Aiming for around 90-95°c during run in, while not to excessive load up or rev the engine.

​​The engine had a new glow plug, rod and fresh air cleaner before being installed in the car. I noticed this scratch at approx 4.5L and decided to remove engine and replace with another for racing following day.

What would cause this, and had this been seen before on the 2104?

Would you remove this piston and liner or just keep using it until it breaks now?

Thanks for any help
Hamish

Looks like something has gone through the engine.
If you have not broken a glowplug then it could be wise to check the main-bearing.
To be honest, it does not look very bad either, if the engine has a good compression and has a good idle then I would not worry too much and use it as is.