Is it ok to use the O.s p3 turbo plugs after using a nova turbo plugs? I've seen someone posted that you can't use O.s plus after using the nova plugs because the thread of both plugs are different.

The threads are the same.
The angle of the taper has also been proven, beyond any doubt, through measurement and photographic evidence on here, to be the same.

What's different is how much of the end of the plug that is tapered.

The reason you wouldn't want to use Nova plugs after using OS plugs, is that the OS plug has a smaller section that is tapered.
Hence the smaller area pressuring onto the button, which MAY (yes, may, it does not have to) slightly deform the head button so that you no longer get a good seal if you go back to Nova plugs.

However if you've only ever used Nova plugs in your Nova, you have no such problem, and may freely use OS plugs.

The key here is THIS ONLY HAPPENS IF YOU OVERTIGHTEN AN OS PLUG.
If you tighten it normally, and do not torque it white-knuckle-Gorilla-death-grip-style, then nothing happens.

Personally I prefer the OS plugs, but you want to run the P4 as the P3 is a lot hotter than the Nova C6.. P4 in a Nova is like an inbetween C6 and C7, well, that's the impression I get from using it anyway.

I agree with everything...except a P4 is much hotter then a Nova C6

The major differences are the length of the taper and the diameter of the tip of the plug. The OS plug ( being the larger diameter tip) does not seat as far in the combustion chamber and will deform the very edge of the taper on the combustion chamber side. There will be some buttons that will deform more than others because of different tolerances. The nova plug don't care what the tolerances are because it fully seats onto and through the buttons taper. Not sure where you got your info from but you CAN switch from nova to OS. But if you switch back to nova plugs is the only time you may run into a leaky button.

If you go to a hotter plug you will need to add a shim or shims.

Rex

Thanks guys for the fast respond. Im Just making sure because I have a few O.s p3 plugs and wanted to make sure if I can or can't use them if I run out of my nova plugs at the track til I get more nova plugs. I guess i won't be using the O.s plugs.

http://i1294.photobucket.com/albums/...ps2d71f743.jpg

The new carburator and a bended mounting post on the pipe. Robert Batlles car at Padova

Nova tuning issues
 

I have a 4BTTS which is about 7L old. I have never been able to get the tune right. Other Nova's at my track scream down the straight and sound crisp and snappy.

My engine is very rich and not producing power down the straight. If I try to lean it an hour on top or bottom then it lean bogs after a few laps and has that pinging sound when coming into the pits when the bottom is too lean (though not too bad of a pinging).

Ive tried plenty of times going back to factory i.e. 3.5 turns out for HS and 5 turns out on LS, when I do this, again its very rich and any attempt at even the smallest amount of leaning makes the engine lean and doesnt sound or make no where near the same power as the other Nova's (or any other motor) at my track. I would expect a 4BTTS should make the same power.

I noticed in the last race, the engine was rich down the first half of the straight then all of a sudden it would run really really lean and had to back off as it was revving its you know what off! This was consistent throughout the race. Even after changing plugs, it kept of flaming out throughout the day.

Im going to check clutch and swap everything out, but is there any tuning tips or possible known issue?

What glow plug are ya using? Have you tried different heat ranges? Could be as simple as installing a cooler plug....

What fuel are you running (Nitro and oil and Brand)?

Sounds like some sort of fuel delivery issue. I would start with removing the high-speed needle housing. Remove carb, remove needle, then remove the brass needle housing. Clean high speed needle housing and nipple with some type of aerosol motor cleaner. Then spray it into carb opening where the housing goes. Blow dry with compressed air. Other possibilities could be tank, fuel line, fuel filer, carb boot, or maybe even your throttle servo is not opening carb up fully.

It was around 35C so weather was pretty warm, I used Nova C6TGC plug.

Brand is AT Racing, Platinum Series. Its a fuel that my LHS sells here in Sydney - http://www.atracing.com.au/products.html. Its 25% nitro, not sure of oil content.

Actually, I didnt check the fuel line/clunk in the tank, could be pinched. Found this out the hard way once when the engine wouldnt start.

Carb was opening up fully as I checked it.

From what Ive read, unstable and lean tune is not always, but most of the time an air leak so will check your suggestions probably one at a time to pinpoint issue.

Perfect. One thing I did not mention was some sort of debris or blockage in exhaust pipe, but that is more rare...

Something else worth checking is the rubber seals on the exhaust between the engine and the header, as well as between the header and the pipe. I've also found these the hard way ;)