i goes to CP every saturday and only seem you once. nah, KZ brings me bad luck, trying to stay away from that place at all cost.

tg
its not that your ideas are good bad or otherwise,some off them are quite good, it your general smugness that I find offensive, your attitude appears that your opinion is the only one that counts, period. I have no doubt that your an intelligent man, but the rest of us ain't stupid either. It appears you feel the rest of the world doesn't experiment therefore you figure we are ignorant. And don't blame it on you english, your attitude comes across loud and clear. I refuse to stoop to your tit for tat level, I just wont do it. The gentleman at the beginning of this thread asked a question and I gave him accurate information to put him in a position to have the opportunity to have some reliable fun. I didn't drag him off on some distant tangent that was designed to confuse him even more. But obviously your not happy unless you invade every discussion with the intent of making everyone else who might discuss anything about an engine look stupid. Its pitiful you feel the need to do that. you certainly have the right as this is america but I don't think your doing anyone any favors.

PS I'm not even going to reply to your 7mm shorter rod response as its just unrealistic and you know it.

Don't call TG underage,shame on you Jedi !!!

:eek: :spidey: :ha:

Motorman.
if you read my posts in this particular thread, you will understand that you are just playing the words. my first post say what I use on my P/S sets , my second post began "I sugest.." So where did you find, that where I sad my ideas is the best? You sad you can pull more power then I can, but even make this statment without seeing my work is nonsence and you know this very well. You are acting here as the "Man" and the rest are just backyarders.
The racer who start this thread didn't ask particularly you, he ask everybody. You felt it is your responsobility to give him some accurate advice and I felt I can add some other opinion. But because my opinion isn't the same as yours, I am already enemy. every time when someone sas something which is not what you think is enemy for everybody. Do you think you can blame people for having their own opinion and sharing it with everybody? I didn't push anybody , I just sad what I am doing and what I am sugesting-and it is already wrong and I am melting somebody's hardware.

About 7mm-it is not 7 , it is 8 mm shorter.:D

call it what you want. I could have posted it differently.
I did not edit my post for being aggressive you did. I stick by what I type. or I wouldn't say it.
I certainly am not the man, it appears you are.
Enemies I have my share but I don't think I ever said you were one of them, you are making that statement.

I await your next dig at me, however you wont get a response.

Forget him Dennis...

We all know who the "man" is.

You have been on here and the older HPI forums helping us all out with correct and usefull information for years. Your engine mod skill and knowlege speaks for its self.

And whilst it may be true that no question about engines is directed at anyone in particulay, most of us hope to see a reply from Dennis. Accurate and informed responses!

TG777 your posts while interesting do not constitute an answer to the persons question. You have special pistons and sleeves, rods etc etc that none of us have so using any of your tuning teqniques or advice is pointless to 99.99999% of the forum users, and as Dennis quite rightly pointed out using your advice may actually damage peoples equipment.

I am happy to read your posts but please remember that most of us will never buy your engines or equipment so keep your "experimental" posts in the "experimental" engine war thread.

Is this the engine shim thread?
 

I think my question is getting lost in this soap opra.

Can anybody please answer my question about boost bottles being the same concept as expanding the chamber by adding shimms?

Why don't we just take the "experts" to the sideline and let us mortals state our experiences with what works and what not:D

As I stated earlier, I run my Nova Rossi based engines (Mugen, RB, Nova Mega and Top, most modified and ugly fast) in very hot weather.

I use 30% O'Donnell fuel with 0.3mm shims under the head.

For plugs I use either MC 59 or CT5F which are the hottest plugs of their kind.

I have never had a problem with pre-detonation, neither has any of my engines developed a hunger for plugs (I actually ran a CT5F turbo plugs for over 3 month, racing every Sunday)

Usually I run them between 240 and 265 F.

So, all theoretical knowledge aside, these are real world experiences that are prooven to work.

Next opinion please!

Slammed,
A boost bottle has nothing to do with the combustion chamber. A boost bottle theoretically evens out the pressure pulses in the crank case and improves low end response and smoothness.

So, to answer your question, a boost bottle is not the same concept as expanding the chamber with shims.

Stefan I heard that somewhere before?http://www.activistsandiego.org/wwwb...smiles/mur.gif

Rapid Roy
:nod:

Maybe an echo?

Maybe just a way to keep you two lovers from cutting each others throat.

Better real information twice than y'alls catfights :spidey:

Motorman - all respect to your knowledge. I missed it when you took your sabbatical from this forum.

Can you give a General principle for shimming and a starting point for, say, an MT12.

What I mean to say is - at a given % Nitro- increasing the gap generally does X (and you need to do Y to your plug). . .

Also - I've heard that you can use a piece of Solder to measure the gap. . .is that an okay method?

I used the solder method. It worked OK. just bend a piece at a small right angle and insert into the head and tun over the engine then mic the flat piece.

It came out the same as measuring the depth of piston and thickness of head button so but it did confirm the measurement

boomer have PM

break-in + adding shim
 

Hai Motorman...
I need your input, do you always add xtra shim, let says .5mm in total when you break in a new engine ?
Im talking about high end one.

For your reference.. im a newbie but im done a lot of engine break in the hudy bench.

no not usually, I usually run it like I expect it to be. Usually I rarely change the head shimming to start with unless its off from the recommendations I have posted.

Help! I am running a Rossi Pixi 5pt. on 40% Byrons. I want the most out of my engine. I have 2 shims under the cooling head now. Should i take both of them out. I really don't know the thickness, but they are stock. Please help ASAP

yess loose them and install one of the thinnest ones you can find or see if it will seal without any. Use an odonnel 77 plug in that setup. you need the extra heat This is only a recommendation for the PIXY.

This is a great topic! :D I'd like to thank everyone for shedding light on this for me.

Although I do have some more questions if someone can help...


Do all 0.12 engine manufacturers use the same size ball mill for the button?

If they do, do all chambers have the same milling depth?

Considering different bore/stroke ratios between manufacturers, would "compression testing" be a more accurate way to determine the number for head shims?

My thanks for any help, :)

Hi again

I got the pixy running great. now its the NS3's turn

I measured the head and its stock with 0.008" no shims and 0.010 shim added.

I use a C6 TGF plug with 16% nitro. I was thinking it might be better to reduce the shim by 0.004 for this nitro content and plug

What do you think?

Cheers

Ziggy yes on 16% you can drop to .014 Change to a number 5 plug

Vaportrail: there not all the same but very very close. unfortunatly static compression means very little , or should I say it is only a good indicator of what will happen when the engine is operation at slower speeds and off the pipe. Lots of CR is good at low speed however detonation can occur as it comes on the pipe. The pipe and the boost it makes has more to do with what CR you want to run than not.

Generally on a 12 engine .004 thousanths will change the Compression ratio about 3/4 to 1 point. I said generally.

Somone asked about plug fatigue the other day, plug fatigue can occur under high sustained RPM's this is where the plug stays shiney and the wire just fractures for no reason. This is why I have always run Mccoy MC9 or the new Odonnell plugs as they dont do this. When this happens it is usually not a tuning or head clerance problem. If you see the wire start to pull out of the hole this means that the engine is scavenging really hard and when this occurs the engine is making serious power.

Hi Motorman,

In the land down under, I haven't seen either the McCoy or O'Donnell plugs.

I'd be very interested in hearing your thoughts on about them compared to the usual Nova/RB plugs.
And maybe a recommendation for say, a Nova .12 engine . . . Turbo plug.

Cheers.

Hi Motorman

If shiming theory applies for all .12 engines can you shed me some light on the following???
S12 Sirio Evo 2 head shiming: I measured cylinder recess with piston at top and got 2.45mm, measured head recess and got 2.00mm, so we have a difference of .45mm.
To use the engine with 20 - 25% nitro, what is the ideal total chamber one should have? I've read that it should be around .55mm, is this correct?. The engine comes stock with two copper shims, one is .10mm and the other is .15mm, so i could just use the .10mm, am i right?
Glow plugs: What is the equivalent of O'Donnells 77 and 99 on Novarossi??, because that is the only plug available down here.
AFM

0.45 mm is 0.018" which is perfect for 20-25% nitro as I read it.

Measure the actual squish clearance using a piece of solder. Take out the plug and insert a piece into the head and turn over the motor by hand untill the solder flatens between the piston and head. Then measure the thickness of the solder.

Dont stick the solder in too far and through one of the ports and loose a piece inside the engine! (as I did!)

My Pixy had 2 shims which i removed completly to have 0.020" head clearance.

I just reduced my NS3 down to 0.014" and a C5TGF Turbo plug as Motorman suggested and it has a lot more low end power with no loss of top end and slightly cooler running.

Cheers

I'm a bit confused as to what constitutes a "Hot" Turbo plug.
The Novarossi site says they have a Hot range and a Cold range of plugs. Then, each of these "ranges" have various hot and cold filaments available.

The C.5TF is a cold body with a hot filament.
The C.5TC is a hot body with a hot filament.

I mean, wouldn't that make the C.5TC the hottest plugs of their kind?
Or did you mean the hottest of the Cold range? :confused:

Here in Oz at the end of January the ambient is likely to be about 30ºC and we'll be using 16% nitro in a Nova 3-port .12.

So, the question is . . . . which plug?

Placing stefans sarcasm to the side here is how to tell visually.

look at the plug from the bottom. the hot plug of the same range (ie5) will have a bigger hole or more clearence around the filament than the cold one.The smaller hole draws the heat away faster from the element on the sold one.
If its the long/short turbo variety the hole may be the same but the short one will be hotter than the long cold one. The extra plug depth draws the heat away faster on the cold plug.

Jus the facts man

I don't have the two types to be able to compare, but yeah, understand the physics.

Since you suggested that the hot plugs are barely hot enough, I'm trying to figure out why you would recommend the C5TGF to ziggy12345. :confused:

The C5TGF will be a long body/ hot filiment, yeah?
Whereas the C.5TC would be a short body/hot filament?

I'm presuming the C.5TC would be hotter than your recommendation.
What am I missing here? :confused:

I dunno why but when I lowered the head to 0.014" and used a C5TGF plug it goes like snot off of a stick!!

OK.
The question I'm trying to get an answer to is:

Would it go like snot off a greasy stick if you used a C.5TC?

[QUOTE]Originally posted by Taylor-Racing
OK.
The question I'm trying to get an answer to is:

Would it go like snot off a greasy stick if you used a C.5TC? [/QUOTE

That would depend on the consistancy of the snot. If its one of those sticky little bastards that you just cant flick of and end up wiping it on the underside of a chair.......


:D

:ha: :ha: :ha:
Now this is the problem, see . . most analogies really don't stand up to close scrutiny.

I did not recommend a TGF someone else did. If I made a recommendation it was just to use a 5
however a 5 cold is what I use. I believe stefan was referring to the number 5's as the hottest plugs of their kind. (generally an accurate statement) and yes the TGF is a cold 5, yes the TC is a hotter 5.
Personally I agree with Stefan and use the TGF. Heres why but it is my personal reason. The TC for me suffers harmonic failure in engines I build, so therefore I cant use them successfully unless its below 50 degrees on 30% max fuel.

Where can you get extra head shims?

Thanks Motorman,

That's exactly what I was trying to get to.
. . I'll see if I can get this hair back into my head, now. ;)

No hitter
call either Robert at ashford hobby
www.ashfordhobby.com
or Lee Muse at Winner Circle
www.gasrccar.com

They both stock engine parts and are great people to deal with

Motorman, whats your opinion of the OS.#8 plug? I been using these exclusibly over the MC59s for the last few months and the tune of the engine seems to stay the same longer. I want to try the O'donnels but I cant find them localy.,

Thanks,

Steven Muller
MPP Team Palmaris Racing

I personally have only used them a few times, and they worked well. I would say they tend to be touger than the mccoys. They're just hard to locate most of the time and relatively expensive. If you like the OS8 get you some odonnel 77's you will really like those.

question for motorman......
 

Motorman...

what is your recommendation for my motor....

-powerplant: Novarossi NS12T1 3 port
-fuel: odonnel 30%
-shimming: ???????

based on what I have been teading in this thread, you know your "s h _ t ":ha: