.12 rigger engine

[TimD]

OK Clay - lets approach this a little differently.

What % nitro in the fuel are you going to run and are you planning on running a conventional plug or turbo plug? Most of the car head inserts I've seen could have done with less volume. I guess the manufacturers play it safe and undercompress them.

 

[ClayGlover]

Tim, since I already run 65% and 55%, it'll be convenient to run one of these two mixtures. I can always shim up as a band-aid if i get detonation. Standard plugs for sure.

If I increase timings, then maybe the stock button's oversized volume might actually work fine? that sure would be convenient...hehe

 

[TimD]

You said the S word! h34r:

You want to retain the tight squish band so forget shimming it up - that can make it worse anyway. I'd say more than likely the bowl will be too big. Have you c.c'd it?

Tim.

 

[ClayGlover]

not yet Tim, I've got to get a new syringe. Maybe tomorrow.

lol on the S word. I see what you mean, even a couple of thousandths could adversely affect it? I know that optimally, I'd have a button with the perfect squish clearance and volume without using shims. but they can be usefull for testing and tuning.

 

[ClayGlover]

after taking a closer look at the head button, I see the squishband is angled slightly a few degrees.

if I go with a flat squishband, I'm wondering that if additional bottom-end torque is actually gained, it will be at the expense of top end rpm?

A squish clearance of .006" to .008" may be a good place to start based on the current .21's. Maybe a little tighter since the piston has a lower mass and theoretically less likely to make contact with the head when you cut throttle at high rpm? I dunno, lots of factors involved. Bowl volume is the question. I'll get the stock volume specs. It does look relatively biggish.

Being air cooled as well as the ultra small displacement is new to me. I don't know how big of a factor this is regarding plug temps. I think launchability may be a challenge with radically increased port timings too. Reliability and needle setting may be more of an issue with smaller displacement, and stable heat retention as well. Hmmmmmmm.... well Theres only one way to find out right?

Maybe Mr. Preston Hall could offer some experience? All hail King Hall!

I can't drive worth a h00t, so a little more power sure helps

 

[Watercadet]

In my short experience with air cooled small displacement car engines in boats, they run hot! I think that is is because they run at a sustained high rpm where in cars we drive them with short bursts from corner to corner. I added 1/8 copper tubing through my head for water cooling and voila down to 200 or lower depending on needle settings.

 

[ClayGlover]

hey, whatever works right? poorman's watercooling, i like it

What fuel are you guys running?

 

[Watercadet]

Poor man indeed! That is why we are all doing .12 and the like, for the budget right? h34r: I run trinity platinum blend 30% or 20 % depending what I have arround. I don't see a big difference in the slightly higher nitro and is costs more, so it usually is 20%.

 

[Andris Golts]

Hello i have been reading this thread and taking note on the fly wheel issue talking about light and heavy flywheels with no weights mentioned first im running my own design of outrigger an upsized outrigger which i won the the Candian electric nationals in 2000. The hull and hardware weights in at 18.4 oz at present the hull is rigged with a Trinty Picco .15 #TP122 running a Maacs 2.5ccc pipe Prather 220 prop a Octura alum flywheel which weights 1.1 oz using XP20 % fuel only gives me speed readings in the 49 mph on my A.D.S speedo. A friend gave me a Nova .12 sx with pilot shaft and slide carb and reg glow plug i email Trinity who now sell Nova on specs no one there had a clue . Do s any one know what kind of hp this motor puts out what about rpm what size thread dos the pilot shaft have ? What about flywheels the Octura is 1.1oz then i have .12 brass one i dont know what make is 2.3 oz im just wondering which flywheel to use and if its going to be to much hassle to do all the conversions any advice would be good.

 

[Preston_Hall]

Clay,

I told you we ran 66mph. That was the first day out and we had some minor problems. Went out the second time and ran 70mph with the stock 5 port. Still don't know what all this fuss is about.

 

[ClayGlover]

LOL! thanks Preston for clearing that up..heh

btw, your avatar makes me think "mahmah" :lol:

 

[ClayGlover]

Hello i have been reading this thread and taking note on the fly wheel issue talking about light and heavy flywheels with no weights mentioned first im running my own design of outrigger  an upsized outrigger which i won the the Candian electric nationals in 2000. The hull and hardware weights in at 18.4 oz at present the hull is rigged with a Trinty Picco .15 #TP122 running a Maacs 2.5ccc pipe  Prather 220 prop  a Octura alum flywheel which weights 1.1 oz using XP20 % fuel only gives me speed readings in the 49 mph on my A.D.S  speedo. A friend gave me a Nova .12 sx with pilot shaft and slide carb and reg  glow plug i email Trinity who now sell Nova on specs no one there had a clue  .  Do s any one know  what kind of hp this motor puts out what about rpm  what size thread dos the pilot shaft have ? What about flywheels the Octura is 1.1oz  then i have .12 brass one i dont know what make  is 2.3 oz im just wondering which flywheel to use and if its going to be to much hassle to do all the conversions any advice would be good.

Andris, if you can, try them both. The jury is out on flywheel weight.... heavier may not be better

 

[TimD]

Make sure you try different props with each flywheel to give it a fair test.

 

[Preston_Hall]

No to say a heavy flywheel is wrong, but they got rid of brass and steel decades ago.