Questions on modding motors.....???
01-11-2008, 08:12 PM
#1
Questions on modding motors.....???
Hey guys..
I was wondering if smoothing out the intake port on the crank would improve power or fuel mileage?
I was looking at the crank of my 427 motor and was wondering if cleaning up the machine work on the inside of the crank would make some improvments?
Please have a look at the picture below.
I am talking about the "lip" at the bottom of the intake. The "lip" is about half way down the inake.
I know with these cheaper motors the companys wil not take the time or spend the money to remove the extra material.
Are the lips there for a reason? timing, fuel mixture?
I would like some feed back before atempting to grind off the "lip"
Any help would be great...
What about knife edging the sides of the intake port?
I was wondering if smoothing out the intake port on the crank would improve power or fuel mileage?
I was looking at the crank of my 427 motor and was wondering if cleaning up the machine work on the inside of the crank would make some improvments?
Please have a look at the picture below.
I am talking about the "lip" at the bottom of the intake. The "lip" is about half way down the inake.
I know with these cheaper motors the companys wil not take the time or spend the money to remove the extra material.
Are the lips there for a reason? timing, fuel mixture?
I would like some feed back before atempting to grind off the "lip"
Any help would be great...
What about knife edging the sides of the intake port?
01-11-2008, 08:41 PM
#3
my opinion is dont mod engines at all .unless its done from the factory .thats why factories offer tuned versions.
01-11-2008, 08:42 PM
#4
I do not believe that lip serves any purpose. It will be difficult to grind out though, so be ready to spend some money on bits for your dremel. 
I've done lots of messing around with my motors over the years, but never on the expensive ones, only the engines I knew I could probably improve the performance of, and if I screwed up I wouldn't be out $400. I've got an Axial 28 spec 1s in my XT8 right now with the XRC head button mod, a couple little fang style cuts in the sleeve, some polishing, and minutely increased exhaust port height and width. Good enough to put me in 3rd at the Canadian nats this year. The only downside is the fuel consumption: 6 minutes max! Power is good though, down the straight absolutely nothing has ever pulled on me, but it does lack a little bit of torque, which does make the truck easier to drive.....anyway, that was kind of off topic....but, just thought I'd share...
I've done lots of messing around with my motors over the years, but never on the expensive ones, only the engines I knew I could probably improve the performance of, and if I screwed up I wouldn't be out $400. I've got an Axial 28 spec 1s in my XT8 right now with the XRC head button mod, a couple little fang style cuts in the sleeve, some polishing, and minutely increased exhaust port height and width. Good enough to put me in 3rd at the Canadian nats this year. The only downside is the fuel consumption: 6 minutes max! Power is good though, down the straight absolutely nothing has ever pulled on me, but it does lack a little bit of torque, which does make the truck easier to drive.....anyway, that was kind of off topic....but, just thought I'd share...
01-11-2008, 09:03 PM
#5
I do not believe that lip serves any purpose. It will be difficult to grind out though, so be ready to spend some money on bits for your dremel. I've done lots of messing around with my motors over the years, but never on the expensive ones, only the engines I knew I could probably improve the performance of, and if I screwed up I wouldn't be out $400. I've got an Axial 28 spec 1s in my XT8 right now with the XRC head button mod, a couple little fang style cuts in the sleeve, some polishing, and minutely increased exhaust port height and width. Good enough to put me in 3rd at the Canadian nats this year. The only downside is the fuel consumption: 6 minutes max! Power is good though, down the straight absolutely nothing has ever pulled on me, but it does lack a little bit of torque, which does make the truck easier to drive.....anyway, that was kind of off topic....but, just thought I'd share...
I've done lots of messing around with my motors over the years, but never on the expensive ones, only the engines I knew I could probably improve the performance of, and if I screwed up I wouldn't be out $400. I've got an Axial 28 spec 1s in my XT8 right now with the XRC head button mod, a couple little fang style cuts in the sleeve, some polishing, and minutely increased exhaust port height and width. Good enough to put me in 3rd at the Canadian nats this year. The only downside is the fuel consumption: 6 minutes max! Power is good though, down the straight absolutely nothing has ever pulled on me, but it does lack a little bit of torque, which does make the truck easier to drive.....anyway, that was kind of off topic....but, just thought I'd share...So are you saying that removing this materal will decresae the mileage?
Also what are "Fang style cuts?
What do you polish? Crank/ports(In/EX) ?
01-11-2008, 10:58 PM
#7
Its only a little bit you need to take out, so it will have minimal effect with milage, at worst the air speed will be slower thru the crank but not bad enough to affect performance.
My Traxxas crank looks very similar stock and i radiused the crank where you are on about an knife edged the side walls to help flow and it made the engine perform much better.
A small stone in a dremel will clean it up nice, i would do it if i was you, its cheap machine work by the factory to keep cost down and some hand modding is a good thing, just dont go overboard and take too much out, just shape it nice and leave it at that, and clean it very well before you re assemble.
As for a Fang Job, look at the picture of my old sleeve that i modified, thats a fang job.
The groves going into the main intake port, and i dont reccomend you try that unless you know what your doing.
Can sacrifice bottom end if done wrong but generaly increases mid to top end quite a bit.
http://www.users.on.net/~danzig/Meh.jpg
http://www.users.on.net/~danzig/Picture%20059.jpg
My Traxxas crank looks very similar stock and i radiused the crank where you are on about an knife edged the side walls to help flow and it made the engine perform much better.
A small stone in a dremel will clean it up nice, i would do it if i was you, its cheap machine work by the factory to keep cost down and some hand modding is a good thing, just dont go overboard and take too much out, just shape it nice and leave it at that, and clean it very well before you re assemble.
As for a Fang Job, look at the picture of my old sleeve that i modified, thats a fang job.
The groves going into the main intake port, and i dont reccomend you try that unless you know what your doing.
Can sacrifice bottom end if done wrong but generaly increases mid to top end quite a bit.
http://www.users.on.net/~danzig/Meh.jpg
http://www.users.on.net/~danzig/Picture%20059.jpg
Last edited by GenReaper; 01-11-2008 at 11:43 PM.
01-11-2008, 11:58 PM
#8
Guys thank for all the information.. I have a good understanding of modding a 4 stroke automotive engine.
I understand smooth edges are good for performance.
Recap: Removing the "lip" will increase flow in return improvment in power and reduction in mileage?
What about knife edging the sides of the intake? will that effect timing?
and what about polishing? what do you polish? what are the pros and cons?
Im still trying to understand what Fanging is? Thank you for the pictures GenReaper
I understand smooth edges are good for performance.
Recap: Removing the "lip" will increase flow in return improvment in power and reduction in mileage?
What about knife edging the sides of the intake? will that effect timing?
and what about polishing? what do you polish? what are the pros and cons?
Im still trying to understand what Fanging is? Thank you for the pictures GenReaper
01-12-2008, 12:33 AM
#9
You will get better power and milage, minimal but none the less more of both.
Knife edging the crank will increase flow and its recessed below the blocks intake port that is machined below the carbi, so it will pull air/fuel at the same timings regardless because of its design.
Polishing exhaust has gains but because of deposits from the burnt fuel it will defeat the purpose real smart and besides there is pretty well nothing on the exhaust side you can polish except the blocks exhaust outlet, and thats minimal. Polishing the intake side decreases performance as it does not allow the fuel to atomise propperly and droplets can form which reduce power, rough surfaces make the fuel " Mist " when it passes over it, smooth makes it stick and form droplets so there is no gain in polishing anything.
Anyone who polishes their crank and claims to be pro is pulling their dick IMO.
The only thing it will do is make it slightly stronger and less likely to form cracks or break if done correct.
If you look at my pictures you will see the grooves cut into my intake ports on the sleeve, they look like sharp teeth "Fangs" hence the name and they guide the fuel into the chamber, some people cut these slots on an angle "opposing each other" to create a "Swirl" effect which makes the air/fuel mixture swirl inside the combustion chamber which promotes a good even mix of air and fuel thru out the chamber resulting in a more efficient burn cycle. Makes the fuel go to areas inside the combustion chamber which normaly would have a poor sections of mixture inside the chamber where fuel is in certian spots more than it would be in others which creates pockets of fuel in some areas and not others and is less efficient. the Idea of swirl effect is to promote a good even intake charge of fuel and air thru out the whole chamber.
Hope i didnt confuse you too much but thems the facts, tho im sure some nub will tend to dissagree, coming from a racing background in Drags and porting building my own motors, you tend to learn these things pretty fast.
Knife edging the crank will increase flow and its recessed below the blocks intake port that is machined below the carbi, so it will pull air/fuel at the same timings regardless because of its design.
Polishing exhaust has gains but because of deposits from the burnt fuel it will defeat the purpose real smart and besides there is pretty well nothing on the exhaust side you can polish except the blocks exhaust outlet, and thats minimal. Polishing the intake side decreases performance as it does not allow the fuel to atomise propperly and droplets can form which reduce power, rough surfaces make the fuel " Mist " when it passes over it, smooth makes it stick and form droplets so there is no gain in polishing anything.
Anyone who polishes their crank and claims to be pro is pulling their dick IMO.
The only thing it will do is make it slightly stronger and less likely to form cracks or break if done correct.
If you look at my pictures you will see the grooves cut into my intake ports on the sleeve, they look like sharp teeth "Fangs" hence the name and they guide the fuel into the chamber, some people cut these slots on an angle "opposing each other" to create a "Swirl" effect which makes the air/fuel mixture swirl inside the combustion chamber which promotes a good even mix of air and fuel thru out the chamber resulting in a more efficient burn cycle. Makes the fuel go to areas inside the combustion chamber which normaly would have a poor sections of mixture inside the chamber where fuel is in certian spots more than it would be in others which creates pockets of fuel in some areas and not others and is less efficient. the Idea of swirl effect is to promote a good even intake charge of fuel and air thru out the whole chamber.
Hope i didnt confuse you too much but thems the facts, tho im sure some nub will tend to dissagree, coming from a racing background in Drags and porting building my own motors, you tend to learn these things pretty fast.
01-12-2008, 08:35 AM
#10
GenReaper thanks again...
I understand, It the same concept as a 4 stroke build.. The "fangs" are cut on the outside of the cyclinder?
Would you polish the exauste port to a shine pretty much?
I understand, It the same concept as a 4 stroke build.. The "fangs" are cut on the outside of the cyclinder?
Would you polish the exauste port to a shine pretty much?
01-13-2008, 10:12 AM
#11
Hey guys
Please hook me up with some information on exasute port polishing and the "Fang" porting.
01-13-2008, 03:00 PM
#12
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the best thing you can do is what i did to mine. port out the intake and exhaust ports on the sleeve. then tak out the crank and polish the inside. youll need a drimel tool this worrks the best high rpms. when you port the sleeve you must be sure that you are porting the the right way. on the intake side you want like smooth groove so the fuel flows faster. the exhaust port just make it alittle bigger. once i got all this done i noticed a significant increase in power range and throttle response.
01-13-2008, 04:19 PM
#13
the best thing you can do is what i did to mine. port out the intake and exhaust ports on the sleeve. then tak out the crank and polish the inside. youll need a drimel tool this worrks the best high rpms. when you port the sleeve you must be sure that you are porting the the right way. on the intake side you want like smooth groove so the fuel flows faster. the exhaust port just make it alittle bigger. once i got all this done i noticed a significant increase in power range and throttle response.
"take out the crank and polish the inside" Are you talking about the hollow part of the crank? I have heard from people that its good to keep it rough to atomise propperly .
dieseldog20 Quote "when you port the sleeve you must be sure that you are porting the the right way" "on the intake side you want like smooth groove so the fuel flows faster"
GenReaper Quote.."Anyone who polishes their crank and claims to be pro is pulling their dick IMO" Two different ideas... Please explain.....
dieseldog20 Thank you for all the information... Quick question dieseldog20 How did you fine your mileage after the mods? Increase/decrease of xx? mins?
Thank you every body for all your help so far.. Please subscribe to this thread..... We need all the infor we can gather...
01-13-2008, 05:34 PM
#14
making cuts on the sleeve and the crank face only gets u so far...the REAL Modded motor's had advanced crank timing #'s that 99% of moder's have NO clue how to do...and CANNOT do because all they do is stick it in the mill and make some straite line cuts....A real modded motor has been touched with Hand jewelery files...plain and simple.
01-13-2008, 10:58 PM
#15
Integra is right, there is more power to be made in advanced port timings which your average joe blow wouldnt understand, you need computers and lots of experience to achieve this properly.
Some slight porting with the sleeve with the fang job does help but if you take too much material out the air speed will drop and you will lose bottom end power if your not carefull, and polishing the inside of the crank is NOT a good idea IMO but each to there own. I just know from my vast experience it does more harm than good, its proper shaping thats important not a smooth surface for the reasons i have already stated.
Some slight porting with the sleeve with the fang job does help but if you take too much material out the air speed will drop and you will lose bottom end power if your not carefull, and polishing the inside of the crank is NOT a good idea IMO but each to there own. I just know from my vast experience it does more harm than good, its proper shaping thats important not a smooth surface for the reasons i have already stated.