I want to bore out my XTM .18 engine but I don't know all the equipment needed to do this. What equipment do I need to bore out my engine? My XTM has a displacement of 18ci, what would be the next size of displacement? Any info will be appreciated, a step by step procedure would be nice too.

Also, where can I find a nice orange replacement engine head??

This isn't an American V8, what do you propose to bore, the already thin sleeve?

When a Nitro engine's time is up, replace the piston and sleeve and, if neccessary the bearings...

yup, if your engine need rebuilding, theres no point in "boring" it.

you cant really bore it, the next size would be .21 cu and even if somehow you could resize a sleeve to that exact size it would be super thin and you would have to re-chrome the inside of the sleeve.

Frost,
I didn't ask for your smart ***** remark. I if wanted a smart ***** remark I would asked for it. I asked for help, IF YOU CAN'T HELP DON'T REPLY!!! There's some many smart ***** people on this website it's pathetic. You people think you know everything. I was told by a professional at my hobby shop that I can bore out my engine. He even showed me one of his bored out engines. My engine's time is not up it's running fine.

adr_ian64,
My engine doesn't need rebuilding yet.

N-Rusty17,
If I can't bore my .18 can I bore a .12 to hold a .18 displacement?

I'd rather be called a smart ***** than look like a dumb *****; how about that? If you have any concept of the piston/sleeve setup you would realize that this is rediculous. It was helping to tell you that it was impossible; it may not be what you want to hear, but it was the answer.

Another tip, don't ask that "professional" any more questions about anything....

Oh yeah, NO you CAN'T "bore" out a .12 to .18....you would grind away the ENTIRE sleeve before you got there.... MAYBE you could stuff a sleeve and piston from an .18 into a .12 casing, but given the cost of piston and sleeve with the time&work it would take, this is economically un-sound. .18 size motors can be had NEW from 90-135 depending on what you want... you could easily pay 60 bucks for a piston/sleeve alone....

Understand you do not BORE these SLEEVED motors out, I thought I was clear.... Let's go the route of PURE fantasy here though: You bore your sleeve (ha) .005" and all of the scars are gone; where on EARTH will you find an over-sized piston? Again, this isn't a chev. 350, you can't go buy .030"-over (thirty-over) pistons for it......

If you dont know enough about rc engines to modify them, then dont even bother taking the poor engine apart. If you are looking for more power, get a $400 novarossi engine.


stupid questions get stupid answers


I sure do wish I could wedge a 350 in a rc car

i read some article about one guy in the coubtry who "resizes" piston sleevs crushes them or something.
if you really had to do it i think researching the O.D. of your current piston sleeve and try to match it to another piston and sleeve from a larger displacement engine. i might look into this just out of curiousity i think you would probably end up boring the engine casing to fit and you would definetley have to take into consideration connecting rod travel as wel as stroke.

But if you replace it with one you matched (same size) where does the increase come from? The answer is the higher displacement engine had a longer stroke, but since you aren't moving the crank shaft that volume doesn't move either.

People, why waste your time on this fantasy, BUY A MOTOR THEY ARE CHEAP.... You can get a Wasp 18 shipped to ya for 1 bill....

but there could be a benifit to a larger bore shorter stroke. faster filling of larger volumne = faster revving. and yes the fantasy theory is extremely hypothetical but interesting bench racing none the less

yes it is cheaper to buy a motor. just givin youngspeed a thought

First of all, what kind of car did the guy at the hobby shop have? I know I used to have a Duratrax Max BX which had a TORQ .12 in it. I found out that the TORQ .16 piston/sleeve will fit it the .12 block, so I had a motor that was an illegal "ROAR" spec motor. Maybe that's what he meant by boring over. As far as getting it bored and honed to a bigger size and fitted with a matching piston, it's not yet available in R/C and would require a special tool to bore and hone the cylinder (sleeve) and another device to cast a new piston, which is unheard of right now in a motor that small.

Another thing you've GOT to realize...engine boring is meant to renew engine performance. When a cylinder wall is worn, egg-shaped, and scratched, it is meant to be be bored and honed along with a new piston and rings to restore engine performance. It IS NOT intended as a "hop-up".... boring the engine without the need to just wastes valuable cylinder life.

To give you an idea of how much cc's you gain...I had my Honda 110 three-wheeler recently bored .030 over because it is 22 years old and the cylinder wall was scratched and worn as well as a grooved piston and bad rings. The engine is only 105cc even though they call it a 110 and when I was done with the motor work (the new bore) I had a 108cc, still not even a true 110, gaining only 3 cc's. Now consider a .15 r/c engine. A .15 is the equivalent to 2.5 cc's. If I bored a 105cc engine 30 over and gained only 3cc's, how many do you think you would gain boring a 2.5cc motor 30 over. Nothing. Any noticable difference would make the cylinder wall so thin, it would crack before you could think about it...thus destoring a perfectly good sleeve.

One of my worst pet peeves is the way people think about the method of bore size. Lets say you have a 400cc engine (like on an ATV or something) Ok, ALOT of people think when you bore it .050 over... it means it makes it a 450cc. That is absolutely NOT true. Think about this incase you didn't know... .050 over is 50 THOUSANDTHS of an INCH over a standard bore size. There has been a lot of good cylinders screwed up and wasted misunderstanding this.

Sorry for the long post...I just HAD to explain this.

Maybe I was mislead on this concept but I will do some research just to check it out.

I have also heard about places that 're-pinch' the sleeve. I don't have any links or documentation, just 2nd hand info. The way I understood the guy, they take your worn piston and sleeve, measure the piston and then re-pinch the sleeve accordingly. I don't understand how or with what, just that somebody does it.
This is not a performance upgrade though, on the contrary it would seem. If the piston is worn(being aluminum, I would think it would wear before the crome plated sleeve), and you re-pinch the sleeve, then you would be losing displacement. Sounds like a cheap rebuild, in my opinion. If I remember right, he said it was only about $15 plus shipping.
avg_joe

yeah i seen that also, its like a little band tool. rc car action.

I have to put in my 2$ (can't find a cents key). Okay, I agree with Mr.Nitro that boring a single cylender engine won't give much in the way of performance and thats absolutely true. Also, boring an R/C is pointless. (Switching the sleeve and piston is not however.) If you intend to build a full size and very competitive car for formular racing or something like that a boring job will almost be required. Why? Because everyone else is doing it. In proffesional racing money is not much of an issue and if you go through an engine every race it is not too uncommon. But again, with a single cylender it will not give a noticable performance gain.

well high dolor motors arent always the best considering i smoke a p2 and a p3 with a os cv .12

Just a thought, but maybe he meant porting instead of boreing? maybe the guy at the hobby shop had ported his sleeve, and there was a little communication error? this woul make more sence to me considering porting a sleeve is a common performance upgrade the the RC hobby..

1. Nobody uses boring to find performance, they do it to get the scratches out of the walls... The improvements are MINISCULE. A 350 at .030" only yields an extra 5 ci, just over a 1% increase in displacement.
2. Again, it isn't "because everyone else is doing it"
3. Your sleeve has a chrome or nickle coating, the sleeve itself is only made of brass... This coating gives the sleeve it's life; brass is entirely too soft... How do you guys intend to do this and leave the sleeve's layer of protection intact??

Maby he meant he wants to bore out his engine block, not sleeve, block. Then after hes done boring out the block drop in a .21 piston and sleeve. You'll probably have to enlarge the exhaust port as well but it is probably possible with the right equipment and experience.

Look Frost, in number 1 and 2, your wrong. In formula racing everything counts.

As far as porting and engine goes yes, go ahead. I have done it to all my RC engines and it can make a noticable difference. This is when you match the size of all the openings to all thier counterparts. Notice I said match. You want to be as exact as possible. Use calipers! Even if the exhaust manifold opening is bigger than that of the block there will be losses.

I doubt he confused the two but porting is a great and simple performance job. You can use a dremel for roughing and then use a small, fine file to finish is up.

Boring the engine block for a larger sleeve and piston is a good idea too - if you have some machining experience. You can't just do it with a twist bit and hand drill. You need access to a machine shop and some understanding of machining. Be very careful to let the block cool before measuring. It will expand slightly during the machining. Take frequent and presice measurements.

Good luck!

Wow I'm sorry, was this thread, "Engine porting question ?" NO IT WASN'T.

In "formular" racing, why the hell would they bore their engines? Why not cast the cylinder to the RIGHT SIZE?? I can't speak for what's done over-the-pond, but here in the US if you are running a bored block it was to clean up scratches...
PROFESSIONAL racers don't recycle blocks and as such, they buy their stuff the right spec... WHY ON EARTH WOULD YOU BORE A $20,000 BLOCK that can be made WHATEVER SIZE YOU ASK FOR???? WHY would you ask for a precision piece to be made too small so you can bore it yourself??? ...especially considering the precision of your equipment VS. the OEMs...

I'm sorry to get you upset. I am not trying to start anything but I am saying formula racing. Where you have a set of guidelines to stay within. It covers a broad spectrum of racing. Say you have a maximum of 355 cu.in. but you have a 350. Boring it .030" over will get you to the limit. I understad it is uncommon but it does happen.

About the porting thing I just wanted to share my experience with others.

Again I'm sorry. Have a nice day everyone.

Hey no need to be sorry; I'm not upset, I relish debate.... NASCAR here run 355ci's also, only NOT A SINGLE TEAM ON THE TRACK is running a bored block, seeing as how they can get one NEW that fits their displacement agenda... My argument is that it seems natural that ANY pro-team would-do the same....

I'm not arguing against "guidelines" either, they don't care if the liner is bored or made that size to begin with, size is the rule, not how you obtain it...

It's new VS. recycled... and with winning on the line Pros are not recycling...

I bracket raced for a few years and ALL of our blocks were bored, but with no sponsor-ship, that's all you can afford... NOBODY I have EVER heard of "bores" for performance... if you wanted the extra displacement you either added a stroker crank of some sort or you went up a size... I had a 434ci stroked small-block based on a 400ci block and the .030 overbore is figured in the size but look at like this... The .030 even on the LONGER stroked motor still only yields an approximate 1% increase in displacement... Let's assume that 1% can apply to the .15 (and it can't, in the V8 we bore all 8 cylinders, not one) you go from a 0.15 to a 0.1515 so even if you could, why would you?