Potje

Hi D,

Mega/Picco plug are indeed different from Nova based plugs.

Don't know if I can explain it properly but I'll give it a try.
The thread of the Mega/Picco plug stops about a millimeter before the conical part of the bottom of the plug. The thread of the Nova plugs runs al the way down therefore the Picco plug will fit the Nova combustion chamber. This is because the thread in the Nova combustion chamber also goes all the way down so it doesn't matter if the thread on the Picco plug stops earlier or not. However, in the Picco combustion chamber, the thread stop about 1 millimeter before the conical part. And as the Nova plug needs thread all the way down to the conical part to seal the combustion chamber properly, it wont fit correctly.

I've attached a picture. The left plug is Picco, the right one is Nova. As you can see, the thread of the picco stops about a millimeter before the conical part.

Hope I'll explained it so you have an idea how it fits in the combustion chamber.

Regards,
Maarten

Potje

True indeed. Can't solve that as we have to buy them from Picco.

Potje

LOL, good idea! Do you have anything to do during the day, D?

I have a bucket of paint and about a thousand plugs, can we sort something out

1FastSerpent

iTrader: (1)

Hey Ron,

Yep. I'll be setting up on Sat. I hope to see you in the mix of it all. Good to hear from ya.

speedy100

Do we need to add shim in ZX21 ?

Potje

Hi Speedy,

Do you mean a head shim? And for the purpose of....?
When you buy an engine, you don't need to add anything, it runs fine as it is supplied.


Regards,
Maarten

click, dublin

Hi Maarten,

Thanks for the reply.

I'm aware of changing the conrod after break in; not an unusual practice.

My enquiry was about the general running cost of the new Mega/Picco engines. If one has to change the conrod every 1 hour of run time after break in, this adds to the overall cost of these engines.

I've always run Novarossi engines & have found them to be robust & reliable which is what a club racer needs. The top racers can chase endlessly power at high cost.

I think the 'old' Picco engines were known for having, lets say, not the strongest conrods, what has changed with these new engines?

I think the pricing is very good BUT I'm trying to see if I can get an angle on the upkeep costs.

I saw these engines first hand at the Euro's in Luxemburg before they were officially released & they, at the very least, held their own against the MAX, JP's etc.

My questions are for the .21 & .12 race engines.

Many Thanks

Kevin

speedy100

Maarten,

yes,i meant the head shim. How do we judge which air venturie should be used in the new mega ? thxs

ttso

iTrader: (1)

Hmm... I guess MegaPicco is using a different plug thread design with Picco. I'm using Picco .12 XP 5 ports quite a while, fit with Nova plug from the begining of engine breakin. So far everything is good, or did I just get lucky?

I can already image what feature will be on MegaPicco based modified engine:
Modified head compatiable with Nova plug.

cdelong

iTrader: (12)

Instead of worrying about where I can get Mega plugs, I'll just put a Nova head button on it.

Solara

iTrader: (17)

Well, I think I will stick with what Maarten said, using the MEGA plugs for the performance, but those of course, I am sure I will give those leftover NovaMega plug to try and see I will be able to start the engine or running the engine...

About the conrod issue....changing conrod after breakin is standard (already mentioned) but changing conrod after 1 hour of racing.....I am sure that is some individual case.....but if that is a standard practice, then MEGA engine does have a big problem.

About adding head shim.....that is depends on what % of fuel that you are using....20% or less, nothing you need to add, 25%, may be another 1mm shim, 30% fuel, 1mm shim is a must....and I think that is the only reason why ppl add or remove shims.

P.S....now I really forgot, is that 1mm or 0.1mm more shim?

Solara

iTrader: (17)

But I know even NOVA base button have plenty to choose from, I have at least 3 different button (MT12, X12 and RS12) with 3 different thickness at the button plate, which they required its own engine heatsink head in order to get a perfect fit setting....

ttso

iTrader: (1)

For .12, stock Nova already has 0.2mm shim. usually add another 0.1mm for 25% nitro fuel. MegaPicco? I don't know.

1mm shim... maybe 60% nitro.. if it doesn't explode...

cdelong

iTrader: (12)

I have a 321P with a Palmaris (WC based) BRB liner set. I used a 3/1 head from a WC for it. I was running it for a while with the stock 2/1 head and a 0.050" custom machined shim. All you need to do is have the correct piston to head clearance ~ 0.028". It's not rocket science.

If you can use a set of calipers you can figure it out......

Solara

iTrader: (17)

Thanks TTSO....I know that doesn't sounds right....but just can't seems to remember is 0.1mm or 1mm.....LOL

I thought typical engines 12 or 21 are standard 0.3mm? Or is 0.2mm like you mentioned....thanks.