jac32224

Glad to hear the piston is fine... Maybe the reflection of the con-rod? By the pic, I'd swear it is cracked!!! Good to hear its ok!!!

Red7fifty

My Feedback: (73)

I Really enjoy this boat....I have 4 (so far)...2 white, 2 yellow.....
Here is #2 midway through new graphics......working on some custom checkers for the fins.
ebay seller "cyb3rp1mp_69" cut the Ferrari scripts, and Genuine Ferrari badge stickers come from "ferrariadvocates"

More pics to come later

Tip: To quite down this boat, install a 45 degree turndown into the exhaust.

Red7fifty

My Feedback: (73)

#1

sheerider1026

i have a question to you guys that are familiar with port timings on these motors.. here is my idea.. most people take the head shim out of the motor raising the compression (i understand the concept) ok raising the port timings on 2 strokes adds more top end power.. so what if you take the head shim that you removed, then remove the sleeve from the block, when reinstalling the sleeve put the shim between the sleeve and block(you will have to notch the shim to clear the pin that aligns the cylinder to the block).. this will raise the port timing just a hair , thus giving it more topend power, and will also put your compression back to the stock specs.. just take a moment and think about this mod and tell me what you think?? i have also ported the transfers ports in the block to gain more flow (there is quite a bit of metal to cut, but will optimize the flow of the engine).. someone please tel me what they think.. has anyone tried doing this??

Dan S

yes,

raising of the sleeve, not only it as been done but its something that is still being done.

but the 2 are two different things, (I'm not trying to tell you how to suck eggs) raising the sleeve like you said changes your port timings.
adding or removing shims at the head changes your compression ratio and this one goes hand in hand with the Nitro %.

The Norm is ( I did say the Norm, right?) the lower the Nitro % is, the more compression is needed to ignites (glow plugs also come into play) therefor we remove shims.
The higher the Nitro % is, lesser compression is needed to ignite (glow plug involvement again) therefor we add shims.

like I said this is the norm but you can also play with the bowl (lathe is required) to change its volume.

I'm barely scratching the surface.

Dan.

sheerider1026

would raising the sleeve shorten the piston/sleeve life?? by doing this mod your compression would end up back to stock.. i will be running 30% nitro.. i know that the sleeve has a pinch point with the piston.. doing the sleeve shim would lower the piston in the sleeve at TDC. therefore the piston would not be reaching to the top of its design pinch point.. i wanna do the sleeve shim but don't wanna shorten the engine life.

Dan S

I would like to be able to give you an answer but I am not an engine guru ( yet ) still an apprentice.

I do know some people here and on another site that would have the answer.

Dan.

Dan S

Here is something I just found on another site reference raising the sleeve:

if you raise the sleeve,and it loses too much torque to reliably launch the boat, you can drop the sleeve back down. if you cut the exhaust higher and it loses to much torque, then you buy a new piston and liner. i'd probably try the shim first. sometimes the only way to know for sure is to try something. also, if you put too many shims under the liner, you can lose the fit,and torque. you can sometimes get the fit back by squeezing the liner or by re grooving the piston. another thing to remember is to maintain the head clearance at about .006. also check your head volume and compression ratio. the little motors need 10 to 1 or a little higher to make good torque. if your volume is too high, cut the head down to raise the compression ratio,then raise the sleeve, and i would grind the top of the case ports, if there showing up in the port windows. use a hot plug, like a 1L, and don't over cool. sometimes running water will put the fire out. sometimes these things are as hard to set up as a cup car.


just a point, they are talking about a .12 engine

Dan.

sheerider1026

i did port the transfer ports in the ccrank case.. they are definately restrictive from having extra casting metal in the way.. i opened and cleaned it up.. from what i hear you can expect 2-3 mph from doing it.. would like to raise the port timing a little with the shim.. but if its gonna shorten engine life its not worth it to me.. i wanna keep my engine durable and happy.. not sure what the life expectance is from them anyway.. i put a thicker cylinder gasket on a homelite weedeater(used gasket material and made my own gasket) and man does it scream!! lol.. it really loves the high rpm.. it definately revs a lot higher with lots more power.. lol.. one bad weedwacker!! haha

Dan S

Check post #3251

Dan.

sheerider1026

yes, but if i use the shim that i took out of the head, then the compression ratio will be put right back where it was when it was stock. so thats not a concern.. only concern really is the reliablility... not sure how thick the head shim is anyway.. say that it is .05.. okay, when it is removed the head is .05 closer to the piston (raising compression higher than stock form) when the same shim is used to raise the sleeve, the head is moved .05 away from the piston, putting the compression right back where it was when it was stock, but ou will have the port timings .05 higher than stock.. thats just my thinking on it.. hope that makes sense.

mike walker

both my MV are running great, 30% fuel,one is running a mccoy 9 plug the other an odonnell red.Both bosts are right at 4 turns or alittle better on the carbs You all talk about 2 to 2 1/2 turns do I have a problem. I am running aircraft fuel tanks.They have had about a gal. of fuel each. they are running nice and cool. I also have had all the other problems inclueding the busted radio box fixed it , last night I had a blow over, fished it out all was dry pumped water out the motor and ran it some more

The MVs are just to much fun when are running right

Larcor69

as far a needle setting's every engine is it's own, if its running great at 4+ out, thats where it's at!! no problem, and Blew over huh?.. check your turn fin, it might be causing lift on the right front sponson, I have been running and racing my vegas for over 3 season's never ever had it blow over even in stiff head wind's, I race mine in IMPBA District 2 in sport 20 class, got to more Throphy's with it in the last two race's, a 3rd, and a tie for 2nd, which ended up a 3rd, because I didnt have the run off..Corey

mike walker

Hey Corey thanks for the info, I dont know where to set the turn fin but I will play with it. I think I want to race next year I am going to go to whatch a race this week end in madison In. If you want to run a stock vegas what can you change can you make mods to hull

Larcor69

you can do what ever to the hull, engine, pipe in sport 20 class, even put in a .21 engine!!, just wont be legal in like a rtr class but if your running in a namba event you will need the strut under the hull, but the way it is ,is fine for impba but there in madison, there's IMPBA club's so no problem

Dan S

Like Larcor said but if you want to run the Vegas in the stock class (RTR) that's exactly that.

Stock engine (Aqub 18), stock hull (no mods).

The only mods allowed are prop and turn fin, correct me if I'm wrong.

Dan.

Larcor69

your right Dan, if there where more vegas's here, there's a small club, non-sanctioned here there's a few vegas's with that group, but there a free for all play club, so no rule's, just make em' fast..lol, I would love to run a stock class, but if I wanna race, it need's all the help to run with the big boy's!!, mine hold's it's own, took 3 rd's the last 2 race's!! in sport 20!! and incase someone here aint been there here's the real web site forum's for nitro boat's..http://www.intlwaters.com

mike walker

Thanks you guys thats pretty much what I got out of the rules for both I think Ill Leave my girlfriends alone an play with mine, I cant just leave it alone I simply must do some to screw it

Larcor69

what all do you have done to it so far??

mike walker

I forgot to ask about turn fin what is the theory where dose it lift or pull it down

mike walker

I havnt really done anything, just been reading things here on this thread and I cant keep my hands off things

Larcor69

AHH, cool a fresh hull..lol, well hopefully you epoxyed the interior, if not, brush on a thin coat of 30 min. epoxy coat the entire inside of the hull, get a Grim Racer turn fin, then take your strut off, drill a hole the same size as the strut's slot, and make the slot about 3/8th longer so you can raise the strut up more so the center of the shaft hole is about 3/4" to 7/8th " from the bottom of the hull, get a m-535 3 blade metal prop, ballance it and sharpen it, I think grim racer make's one all ready finished for it, remove your tuned pipe from hull and cut off about 3/4" off where it meet's the header to shorten it, this will bring you higher RPM's, remove the engines head and take out the brass shim's, reinstall the head, take her back down to the lake and just play with the strut's height and angle till you find your boat's sweet spot!! also for right now, play with different angle's on your turn fin till the boat run's flat, not wanting to pull up on the right side..Corey and for a cool build up thread something to ponder over this winter go to..http://www.intlwaters.com , under rtr thread, there's a bad azz vegas build up there!!

mike walker

Corey I have coated the inside of both boats cleaned up rudder and turn fin, head shim is next all the rest is yet to come thank you very much

Larcor69

Oh yea, forgot to mention the rudder, cut off about 1/2" off the bottom, I cut mine off leaving a slight angle to help lift the rear of the hull, also take your rudder and file or grind that flat on the bottom also

Larcor69

all this stuff is also done to my wife's boat, it's only been ran like 2 time's, also both of the boats have os cvr-m non-pull start engine's with mac header's and mac 3.5 pipe's and custom built wood radio box's with tape down lid's..Corey, I never cut out the little vent hol's not big enough to worry about, I should post a pic of mine got an e-mail addy?