dubs1946

Is it possible to hot up a TT46 Pro? I have not seen anything on this anywhere so i am guessing not.
I know you can take the head gasket out and run no nitro but can the liner be cleaned up or the crankshaft induction hole.?

the Wasp

My Feedback: (1)

of course you can, or simply use a Tuned Pipe, see my link

http://mecoa.com/acc/index.htm

or you could just use a different engine, like a 50 or 55, even a 61,,,,, or a 50 size Heli engine, see my link,

http://www.rcuniverse.com/forum/glow...ne-engine.html

Jim

dubs1946

Yes but thats not what i want, i want to modify the TT46.

aspeed

You can do the usual stuff. Higher compression with higher nitro until it detonates or blows plugs , then back it off a bit. Radius the crank window to a near knife edge, and smooth the back of the window. Stuff the front of the crank hole with epoxy to make a radius with epoxy.(I use solder) Shim the liner up for a higher rpm band if you like smaller props. The exit hole in the crank can be widened where it exits so the fuel/air goes around the rod easier. File and polish the rod to a radius or point. Uncommon sense applies to the amount removed. Lightening the piston... Less moving weight makes a big difference especially at higher revs. The crank closing timing can be altered if you know what to do. I would say 60 degrees max. Exh timing 155 degrees, or 180 degrees max with a pipe.Of course that is the point of no return unless shimmed.

the Wasp

My Feedback: (1)

yeeaa, that cool !! there is a lot of things you can do to an engine,

(see my link) I suggest strongly that you go to the RCU page in my link and ask "if any one can post a link for a Site about modifying a glow engine for more performance"

Extreme Speed Prop Planes - RCU Forums

Jim

Mr Cox

Since you are asking here I would recommend to stay away from changing the timing etc, unless you are willing to sacrifice a few engines while learning.

The simplest thing is a different muffler, there are "tuned" mufflers that can give you a boost in rpm (compared to stock muffler) without changing anything else. These are good for instance: https://www.dubjett.com/mufflers2015.html

dubs1946

I am not after extreme speed, at a guess changing the timing is out of my league but this looks interesting, perhaps you could enlighten me on these changes. Some pics would help if there are any out there?. I bought a TT46 for $20 and changed the bearings and cleaned it up so i will not lose much if i stuff it all up but its all knowledge and good to know and learn and others might like to have a go as well.
"Stuff the front of the crankcase hole with epoxy". Why do this? i am a novice when it comes to hotting up small nitro motors so explanations would help as well. Thanks.


"Stuff the front of the crank hole with epoxy to make a radius with epoxy.(I use solder) Shim the liner up for a higher rpm band if you like smaller props. The exit hole in the crank can be widened where it exits so the fuel/air goes around the rod easier. File and polish the rod to a radius or point. Uncommon sense applies to the amount removed".

Mr Cox

That mod improves the flow through the crank and also gives you a better pumping action as it also reduces dead volume in the crankcase. This mod will also increase the effective compression ratio, through better scavaging, and some engines will also need an extra head shim or two after this mod is made.

Below is an image shoving the principle, together with the other mods on the crank exit, as mention earlier, plus it is better balanced. This is from a Rossi engine (not mine);

dubs1946

Thanks that is interesting the red is a filling for the hole in front of the crank shaft perhaps JB weld.
Where the gasses come out of the crankshaft, what determines the shape i see in the pic.? as i cannot properly see the shape and why it is that shape?
The filling of the 3 holes in the counter weight, have all crankshafts counterweights holes ? i cannot remember seeing them in a TT46.
Thanks

1QwkSport2.5r

The silicone ramp in the crank will really doesn't do much for top end power but rather smooth out the power delivery in the low to midrange and increase idle quality. Common "mod" on racing buggy engines. Not going to be of much benefit on an aircraft engine.

Your best modifications for using standard or tuned mufflers would be bore the crank out, radius the ID of the crank bore at the crankweb, and increase the induction timing. If using the stock TT carb, bore it out about .030". Next would be to cut a shim and install it under the liner. The latter would be geared more for a tuned muffler or pipe as the shim under the liner would increase timing. A .001" shim would make a substantial change, so start small if you do this. If the liner gets shimmed up, the head needs to be shimmed lower the same amount to keep the head clearance the same.

Boring the carb and changing the induction timing requires baseline measurements so you know where it is to start with and you must be very diligent in doing so.

blw

My Feedback: (3)

Mr. Cox is right about maybe sacrificing a couple of engine parts or whole engines to learn these basic improvements, but it would be worth it to me.

Come to think of it, I'm in an unusually good position right now for such projects. I have 3 NIB Evo 46NTs in my shop. I was going to sell them but maybe I should take the plunge on a few of these mods......

aspeed

I finally found a $20 Evo .40, and it already outperforms all my other .40 and .46s. I was kind of surprised, as there was a lot of bad reviews. I noticed the crank was filled at the front, much like the epoxy fillet. I bet it would be great with just a pipe and a few tweaks. The liner shim might have to be .030" easily to get it up to 180 degrees total exh timing. That will not change the motor or ruin it, unless you turn the top of the liner too much to get the compression back.

earlwb

Another thing is that you need several engines to modify. You will basically modify a engine by performing each mod one at a time. Then test the engine. Document everything too. Then make the next change and test run the engine again. Then keep making the changes until the engine gets worse. Then pull out another engine and make all the mods up until you stop before the last change that screwed it up. Then you make different changes to that engine until it gets worse too. Then pull out the next engine and repeat the process. The model airplane racing people are the ones to contact about changes they make. But they don't use Thunder Tiger engines in racing like that.

Now then as you get more and more power out of the engine(s), the engines become less and less tractable (easy to run and use). The highest performance is achieved with engines that have no throttle and run wide open using a pressurized fuel system, so that the intake can be as large as is possible. These engines reach a point where they may not even idle below a fast RPM setting. You see the same or similar thing with motorcycle and car racing engines too. For example, you can't drive a dragster on the streets in rush hour traffic. Nor will a Formula One car work on a busy street at rush hour either with a traffic jam.

It can be a lot of fun modifying your own engine to get more power out of it. It is a hobby unto itself actually. There are quite a few people that do it too.

the Wasp

My Feedback: (1)

no matter what mods you do you will need a much better exhaust system, rather a tuned pipe, or a tuned muffler, or a muffled tuned pipe, you do need one or the other !!

in my opinion the easiest and quickest way would be to buy a Muffled Tuned Pipe (see my links) and maybe find a slightly larger Carb, and run 30% Nitro, or even 40% (note you may need to shim the Head Button), in the end your engine will most likely run more consistent and stay together longer, and at the end of the year if you don't fly it that much all you will have in it is the price of the Pipe and Header and fuel, yet you will have seen a good increase in speed

HP Muffled Tuned Pipes are rather well priced
http://mecoa.com/acc/pipes/hppipe.htm

Mack Pipes, cost more
Untitled Document

http://mecoa.com/acc/index.htm

Jim

airraptor

My Feedback: (66)

If you grind on the liner you need to make 150% sure that there are no burrs in the liner or you will scratch the piston. Tuned pipes or Jett style muffler are not needed as an engine with a good set up runs well on a Tower style muffler.
On the crank some say to make the diameter bigger which can help but has to have other engine mods to see a gain. just by making the crank hole/tunnel larger may see a decrease in RPM. If your carb measures .320 and you bore the crank out to .400 the engine will still only pump .320's worth of air. Quick is correct on filling of the front of the crank as it helps some engine pipe up easier if running a pipe or 1/4 wave muffler (jett style).

Every thing in these engines has to work together to see gains. If you want to do some grinding just widen the exhaust port some and put a small angle on the exhaust port maybe around 5-10 degrees max. Open up the carb barrel with dremel tool dont drill it. Have to work slowly here if you go to much you cant get a low idle. Do these two things and put a Tower style muffler on there will like the gain.

dubs1946

"if you want to do some grinding just widen the exhaust port some and put a small angle on the exhaust port maybe around 5-10 degrees max"
Could you show how this is done.?
Thanks.

1QwkSport2.5r

Modifying a glow engine is a very calculated task. In the last year, I've done three engines - made for RC buggies and trucks. My list of changes includes boring the crank, smoothing crucial areas of the crankweb, increasing induction timing, boring the carb out, changing port timing of all induction ports in the liner, altering exhaust port size and timing, relieving the bottom of the liner and piston on Boost port side to unshroud the Boost port, adjusting head spacing to .4mm, and changing the exhaust system. The liner port changes have to be well calculated - change them too much and you could ruin it. Also know that nickel plated liners can peel if you interrupt the plating. As airraptor said - you must de-burr the ports carefully to not damage the piston. I use diamond files to modify the liner - often all it takes to get the desired result is simply removing the plating in the port. I probably put 8-10 hours into each of my modified engines - much time is spend measuring and remeasuring rather than grinding.

airraptor

My Feedback: (66)

Dubs I will see if I can get some good pictures of a few engines from the exhaust port. It will be a while before I grind on another engine though. One thing about all of this work is you're trying to make gains on an engine for a certain prop. Most engines in planes will unload some. When doing mods you need to find a target rpm you want and work for that. So if the engine spins at 16,000 in the air at full power then need to prop it for that on the ground. If not you can have a engine that makes awesome power on the ground but falls on its face in the air. It is a system and one bad link can slow the system down. Trial and error with a lot of engines will help you learn a great deal. I race Q40 and our engines dont see a big gain from 1-3 degrees of timing but see the biggest gains in flight with head clearance. We typically run .016-.027 depending on the air that day. A lower head clearance will great numbers on the ground and may not unload much in the air but our Nelson unload a large amount. I have launched at 22,500 or so and seen 29,400 on the race course.

Anyway do one thing at a time run the engine and record your results. have fun and keep playing with them.

dubs1946

G'day this is turning into a hidden trove of knowledge.
In Australia our Q500 must run stock so no fiddleing but i am sure it go's on. I am not racing Q500 but just trying to gain some knowledge My Cheapo $20 fiddle engine will not be on a 10X6 prop but a 11X6 APC with 10% nitro and standard muffler so its bogged down to start with, and i want to keep the prop and muffler as is.
The exotic tuning stuff that is coming out in this blog is beyond me and requires previous conversions and i am sure blow ups, so what i am after is the first steps with a bogged down engine running a 11X6 it runs about 12000 on the ground at the moment on a good day, turned back to 11500 for flying. so the "widen the exhaust port some and put a small angle on the exhaust port maybe around 5-10 degrees max" looks within my relm of ability, with the blocking of the front of the crankshaft.
Good fun to show my mates.
Dubs

the Wasp

My Feedback: (1)

I tried to buy one, that muffler is discontinued

Jim

the Wasp

My Feedback: (1)

it sound like to me that for that combo you need to get more Air/Fuel mix in your engine, note that if you raise your Exhaust Port you will lose some Low End Torque (that's not good for turning a large prop), and if you raise the exhaust port you should need to modify the Intake anyway. also note that your engine is not filling it's Combustion Chamber completely with air, so for starters just start with getting more fuel/air in to improve what you have, so find a slightly larger Carb and enlarge the center of your crank shaft some, if wanted open up the Timing on the Crank a bit,,so with that you will not have to mess with the Liner

Jim

the Wasp

My Feedback: (1)

also,, you said "you want to use the stock Muffler", well a restricted muffler is a bad, bad thing, with a restricted muffler you can only go so far with modifying your engine before your efforts become worthless, with that you should find another brand's muffler that will fit but is larger, this will look stock yet help increase power a bit, you can also take the muffler apart and remove the Cone.

Jim

Mr Cox

The muffler is the first thing to change, it is easy to do and it is reversible
Changing the exhaust port in the liner is wasted on a restrictive muffler...

airraptor

My Feedback: (66)

Making the exhaust port wider isnt wasted if you know what you're doing......

Tower style mufflers are still around look at MECOA.
These mufflers were on Tower 46, GMS 47 and also made by aqua craft.

https://www.mecoa.biz/shopdisplaypro...asp?search=yes
Has them in stock good price too, at 17 dollars. Will see 300-500 over stock muffler on a bone stock engine. These mufflers are very close to open exhaust numbers.

dubs1946

Yes the stock muffler is very restrictive, how do you modify the exhust port?