Crash's HPI K4.6 engine mod

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ntenc1 said:
No problem man. I found a good mod on this engine is to put fangs on the bottom bypass port. One fang in the middle of each transfer port. Also bringing the exhuast port up about .012. This mill will allow you to go this far with out having to modify your crank case. Will def wake this engine up.
Click to expand...


thanks again

do you have any pics of what you did to th 4.6k sleeve?

this is only my second mod.

the first was a axial 28 that was isane when I finished it.

although, I got it too thin near edge of ports and the sleeve started to
deteroirate and I lost my pinch.

I'm down to one mill (4.6k) and two trucks. If I can make this k
a bad a$$ I may but anotherone to mod, they are soo cheap.
 
alright, just finished stage 1 of port & polish

I'm chargeing the glo rite now for test run

cant wait.

I took pics before & after ( WILL POST LATER)

BIG THANKS TO BLAZER, I got the stripped head screw/bolt out with his help
 
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results from stage 1

The mill got a little more aggressive but, not a huge change.

I intend to go further with this mod, I wanted to start out slow removing the material.

Thanks to shift point for the rubber bits. removes material very nice with very little abrasions to polish off.
 
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OK,

went back in....

I did not change what I did yet, I just increased the angle on the ports

and polished it back up for one more test.

I don't want to over mod this one

I can remove the sleeve

and do my mod work in about 40 min. without removing the engine from truck.

its still too early here to run it (wife is sleeping) I'll test run it in a couple of hours.

I started it all ready in the garage and it fired rite up and sounds tuff.
 
I got it that time.

I got the power out of it, without taking the structural integrity away from
the sleeve and did not touch anything else in the mill.

to do a little more I will be taken the mill out of truck and breaking it down
so I can polish the crank. at this point it doesn't need it.

comparing it to my axial isn't a fare comparison the axial was made to be badder already but, this k is just as fun to drive. I had to gear up a Little
the k doesn't like to rev as high as the axial did.

I have 17CB 47 spur, and it pulls the front wheels and never lets them back down unless you let the gas off. JUST WHAT I WANTED

I'm going back out to run a couple more tanks through it, its 51 degrees today

I hope this thread will give someone who has been considering doing a port & polish , to give it a try.

Peace,

Dan
 
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Glad this turned out like you intended. I'm starting to get brave, so I may try this my ownself. I mean worse comes to worse just get a LRP if I kill the F4.6 lol.

I pulled my sleeve out of curiosity (basically wanted to see how hard it was to pull) and it has the fangs on the ports already, so basically all i would need to do is just polish away, and maybe polish the crank. :dunno:
 
XXX said:
Glad this turned out like you intended. I'm starting to get brave, so I may try this my ownself. I mean worse comes to worse just get a LRP if I kill the F4.6 lol.

I pulled my sleeve out of curiosity (basically wanted to see how hard it was to pull) and it has the fangs on the ports already, so basically all i would need to do is just polish away, and maybe polish the crank. :dunno:
Click to expand...

I would say take off any sharp edges on ports and polish
 
put five tanks through it, the clutch shoes are toasted. lol

Its too fast already on the street,( I'm useing my off road truck , my street savy has never been repaired from the video contest damage)
 
I went and purchased a 20 piece polishing kit for my dremel today. With some polishing compound. Wish I had my camera working, I would love to show before and after of my first try. Ill let you know how it turns out later. I wont be able ot see if I helped or did any damage till Monday afternoon because my One Way Bearing is due in the mail then.

I removed little bit of material around the ports (not alot just cut down the edge some), and polished the heck out of the boost and transfer ports. Then gave the outside of the sleeve itself a good polishing. Hopefully I didnt botch it, but hey first timer. If I messed something up Il just get a new sleeve and try again. I just hope this one is beginners luck lol! :hardlaugh:

If it works out fine and shows a good increase, ill polish my crankshaft.
 
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Hey Crash, I polished my crank also. Started it up it idled good, then died (thinking to much fuel) Went to start it again and my one way bearing went poof :cussing: If it werent for bad luck i wouldnt have any luck at all. I'm 99% positive its the one way, because it now spins both ways. I thought for sure I did something wrong when I noticed the rotostarter spinning freely with no cranking noise, but I'm not out of the water yet lol still got to see if she will run. :dunno:
 
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hang in there bud,

how many gallons do you have through the engine?

I ordered another hpi k today to mod and put in my other truck

for the price it is a very good mill (104.00)
 
1 Gallon through. I started it and ran idle for about 1 to 2 minutes. Took off stand and ran about 20 feet. It just sputtered out like it was flooding (like a cold start) and died.

I placed it back on the stand and placed the rotostart in it it cranked for a few seconds then spun freely. So i stripped it down to make sure everything was ok, sleeve looked good, no scratches on piston or sleeve.Piston rod was still on the con rod, and everything looked ok. No scratches on the piston etc.

Thats when I checked the one way .I spinned it on the shaft and it went both ways without stoppage. Also noticed a screw was missing from the backplate for the rotostart. I ordered a new OWB from Tower and be here in a few days. Will see then. :Xfingers: Bad thing is I just sealed the engine 24 hours ago. Waste of RTV lol.
 
I'd check the shaft isn't worn as well. If the shaft is worn the owb won't be able to grip it. A bit of tamiya ceramic grease seems to work well on the owb if it's not an internal one way (never owned a 4.6).
 
XXX said:
1 Gallon through. I started it and ran idle for about 1 to 2 minutes. Took off stand and ran about 20 feet. It just sputtered out like it was flooding (like a cold start) and died.

I placed it back on the stand and placed the rotostart in it it cranked for a few seconds then spun freely. So i stripped it down to make sure everything was ok, sleeve looked good, no scratches on piston or sleeve.Piston rod was still on the con rod, and everything looked ok. No scratches on the piston etc.

Thats when I checked the one way .I spinned it on the shaft and it went both ways without stoppage. Also noticed a screw was missing from the backplate for the rotostart. I ordered a new OWB from Tower and be here in a few days. Will see then. :Xfingers: Bad thing is I just sealed the engine 24 hours ago. Waste of RTV lol.
Click to expand...

How is the mod job going?
 
I finished my first gallon of fuel in the ported hpi 4.6k

This mill rips, alot more topend then it had and the lowend is more
aggressive. It spins the tires on most surfaces.

I ordered another hpi 4.6k brand new from Nitronutzz

I'm going to break it in and then go inside and massage the sleeve into
a power house like tis one. this 100 dollar mill will out perform most
mills in its class now IMO
 
Crash said:
I finished my first gallon of fuel in the ported hpi 4.6k

This mill rips, alot more topend then it had and the lowend is more
aggressive. It spins the tires on most surfaces.

I ordered another hpi 4.6k brand new from Nitronutzz

I'm going to break it in and then go inside and massage the sleeve into
a power house like tis one. this 100 dollar mill will out perform most
mills in its class now IMO
Click to expand...

you should start selling these modded engines once you get your method "fine tuned" i bet alot of folks here at the forum would buy modded engines from you, i know i would just to try it!!
 
Crash,

Unfortunately I don't. This was when I really got into truggy racing, and I sold my savage with this motor in it. It had tons of mods, it was ported and polished, the exhaust port was modded, and the crank was polished. If you ever get that far (which I'm sure you will be like tomorrow, lol) you will see what I mean!

:jamout::resp:
 
Thanks anyway Sd

I ran the engine today, its a rip saw.

230 degrees all session.
 
Can anybody tell me if I'm going in the rite direction with this?

Round off the bottom of the piston sleeve

Don't touch the exhaust port

Smooth out the boost ports with out touching the inside's at all

transfer/schnuerle- Smooth out like i did the boost ports but not as much. And for the little fang looking thing does that go wall the way to the bottom of the sleeve? Do this on both side of the sleeve

clean it up and put it back in.

This is my first time doing this, i am pretty good with a dremel i just wanna make sure I'm not gonna mess up my motor so all help will be appreciated. Thanks! TELL ME IF I'm DOING ANYTHING WRONG!!!

If any body has pictures of the k4.6 already done can you please post them they will help alot
 
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Crash do you still have the K 4.6? If so I want to go over a few things with you.
 
SavageSSBEAST said:
Can anybody tell me if I'm going in the rite direction with this?

Round off the bottom of the piston sleeve

Don't touch the exhaust port

Smooth out the boost ports with out touching the inside's at all

transfer/schnuerle- Smooth out like i did the boost ports but not as much. And for the little fang looking thing does that go wall the way to the bottom of the sleeve? Do this on both side of the sleeve

clean it up and put it back in.

This is my first time doing this, i am pretty good with a dremel i just wanna make sure I'm not gonna mess up my motor so all help will be appreciated. Thanks! TELL ME IF I'm DOING ANYTHING WRONG!!!

If any body has pictures of the k4.6 already done can you please post them they will help alot
Click to expand...

the fang doesnt have to go to the botton of sleeve.
 
Cool, when you find time...
1. Pull the piston and sleeve
2. Put the sleeve back in the block w/out the piston.
3. Look thru the exhaust port at the intake port.
At the top of the intake port look to see if the block obstructs the top 1/16 to 1/8th of a inch of the port. I ported my H.O last night to fix this flaw. Not sure if the other K has the same issue. 20%gains with no timing work are being reported. Ill post up findings after I run it myself. Again the block not the sleeve.
 
BANKRUPTER said:
Cool, when you find time...
1. Pull the piston and sleeve
2. Put the sleeve back in the block w/out the piston.
3. Look thru the exhaust port at the intake port.
At the top of the intake port look to see if the block obstructs the top 1/16 to 1/8th of a inch of the port. I ported my H.O last night to fix this flaw. Not sure if the other K has the same issue. 20%gains with no timing work are being reported. Ill post up findings after I run it myself. Again the block not the sleeve.
Click to expand...

interesting

thanks, I will look into that.

20 % gain would be alot
 
I have the K4.6 H.O engine. If I was going to Port and Polish mine could I just copy what you did or would it be a little different. If I'm not mistaken the main difference is the crank and piston / cylinder. I have been told that the cylinder has more ports. as for the crank I just know it has a different part number.
 
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