If it sounds like it is rattling then it'll be a bearing change. Whatever you do don't continue to run the engine! Take it apart and change the bearing.

How deep are the pits in the piston and head? You can try to polish these out with very very fine paper you won't get it all out but you may get it better. If the pits are deep then it'll be a piston and liner, rod and head button change as well and that will cost the same as a new engine!! So before you go much further I'd recommend stripping the engine and posting pictures of the piston, head and sleeve on here for us to advise.

For info pitting on the piston is usually caused by running the engine too lean or with too tight head clearance or a combo of both. Bad bearings don't usually present themselves like that unless you've been running it for a period with the bad bearing and it has started to break up.

Good luck and feel free to PM me if you want.

Live Range
 

Looks like there are 8 new members to the Novarossi line up.
http://www.novarossi.it/2012/index.p...e-engines.html

This ia more interesting http://www.novarossi.it/2012/index.p...virtus-12.html

+1

-1
The .21 Virtus has not shown any improvements promised in the advertisements. Again a special made bearing making the price of the engine and replacement bearings.

That's why we have your mill buddy!:D

guys I changed both bearings already, 50dollars. Fine. But theres bubbles on the piston sleeve. To make matters worse, to buy it Costs 200dollars. That's too high,it should be priced at best,half the price of the engine,and a new pair is not available in my local shop.what a pickle!

The issue you're having is caused by a too lean mixture.

The 'bubbles' are caused by pre-detonation, the mixture ignites too early causing too much heat at TDC. This melts the aluminium.
Also the metallic noise you hear is caused by this.

You can sand the top of the piston and the burnroom with 400 grit sandpaper and finish with 1000 grit.
Then richen both LSN and HSN needle and see if the issue disappears.

Not only lean mixture but too tight head clearance as well.

I wouldn't be surprised if the piston side is also damaged. After trying to blend out some of the damage you need to check the head clearance is ok but you need to be prepared that the engine will never perform at 100% now - a replacement piston/sleeve/head/rod will probably restore most of the performance.

Have a go at blending out the damage, run it in again for a couple tanks and see how you go.

I wander when the Virtus .12's will make it to the online shops? I wander if the offset carb design will fit in my 747. The .21 fits in my 977 ok but its quite a squeeze and I know others have had difficulty with the fit.... If it fits then it will be the engine I use at the WC this year.

I also wondered about that! I had to twist my carb to get it to fit my mtx5. and that is with a Max Motor. It's a tight fit like it is..... Was just curious about that situation.

All new virtus engines come with a new carb with a shorter carb wich will fit all cars .

Nice. I didn't notice the difference in the online pics but it makes sense. I haven't seen them available anywhere yet. I'm assuming a couple months before they arrive at amain etc.

The carb looks the same as the previous one that come on the Keep model but the barrel part is shorter,engines should be available mid Feb.

Thanks for the clarification. I think this will be the engine I take with me to the Worlds this year! I just hope its ok on runtime....