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Engine porting


locky

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I have a hpi k4.6 engine which I'm thinking about doing my own porting on the sleeve. I have an old sleeve to practice on first.

 

I dont know whether it will make a big difference but will give it a go.

 

I will follow some images I've found on the web and also the fuel marks on the sleeve.

 

The only question I have is on the transfer/boost ports, as some have modified below and some above the lower of the 3 ports.

 

Anyone got any tips and whether it will make much difference?

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back in the day it used to make a huge difference to performance. i did it to one of my engines many moons ago however if you don't know what you are doing to run the risk of ruining the engine.

 

my job of it turned it into the rc equivalent of a F1 engine, stupidly powerful and quick but only really good for afew hours.

 

these days however if you want more power you tend to be better off just buying a better engine.

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I have a hpi k4.6 engine which I'm thinking about doing my own porting on the sleeve. I have an old sleeve to practice on first.

 

I dont know whether it will make a big difference but will give it a go.

 

I will follow some images I've found on the web and also the fuel marks on the sleeve.

 

The only question I have is on the transfer/boost ports, as some have modified below and some above the lower of the 3 ports.

 

Anyone got any tips and whether it will make much difference?

You can cut grooves and smooth the outside of the sleeve to potentially improve flow volume/direction..but remember that any material removed increases crankcase volume and reduces flow speed.

The lines left on the outside of the sleeve can show the general direction of flow and even display temperature variations...you can never add material back on... trust me... :)

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These are the images I'll be working from.

 

Just going to do it for fun

What one side a smiley and the other a shout>?  :xd:

I have never seen anything like that before. :)

 

You would make more potential power from just altering the crank window than what that would achieve....the crank timing is very easy to alter...

I made a thread about how to measure timing somewhere here...altering the timing will do far more than cosmetics...

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What one side a smiley and the other a shout>?  :xd:

I have never seen anything like that before. :)

 

You would make more potential power from just altering the crank window than what that would achieve....the crank timing is very easy to alter...

I made a thread about how to measure timing somewhere here...altering the timing will do far more than cosmetics...

 

What one side a smiley and the other a shout>?  :xd:

I have never seen anything like that before. :)

 

You would make more potential power from just altering the crank window than what that would achieve....the crank timing is very easy to alter...

I made a thread about how to measure timing somewhere here...altering the timing will do far more than cosmetics...

 

I would like to adjust the crank timing but scared as dont know where to start or have anything to work from,

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I would like to adjust the crank timing but scared as dont know where to start or have anything to work from,

Ok...at what point does the crank open pertaining to the piston position...and what is the closing point?

Measuring what you have is the easy part. :)

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Modifying the ports is a great idea and can, if done correctly, greatly increase engine performance but there are other things you can do to th engine to boost performance that are a lot easier.

 

Firstly the amount of nitro in the fuel. 25% is about average and you can increase this to 40%. You will have to raise the head by adding shims and use a very cool plug.

 

Secondly use a decent tuned pipe with adjustable tuned length.

 

If you then still want to try port mods than you first need to measure the existing ports. I use an old CD with a 360 degree print out stuck over the top bolted to the crank. You can then align the 0 to TDC and rotate the crank to measure the port timing. Shine a laser pointer in the plug socket and observe when you see an indication of the port opening through the exhaust. I have all the measurements somewhere. I'll dig them out and post them here. Basically raising the ehaust port timing increases revs. Off the top of my head I think 134 degrees was about optimum for my Novarossi 35PLUS21 but dont quote me.

 

From my experiance it is much easier to mess up the engine and make it so it doesnt run than it is to get it to perform better...lol

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Thanks, I've read up on measuring timing and think I can do that to get base line figures. But dont know where to go from there really. 

Have a read of this...plenty of reading in the links.

http://www.msuk-forum.co.uk/topic/177885-how-to-measure-crank-and-port-timing/?hl=%2Bhow+%2Bmeasure+%2Btiming

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