Crash's HPI F4.6 engine mod

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Cutting nice scoops is not as easy as it looks, I don't think it's worth it to attempt one of these cuts on your only mill. It is very easy for the scallop to head in the wrong direction and by the time you have compensated for it, the crank is hacked. If your serious you should get some old cranks and practice on them, once you know how to cut the scallop with precision, take that ability and apply it to a running engine and see what happens.
 
Ok I finally got a good run on the mill today...

After getting it back from Crash I had to lean out the HSN 1/2 turn and the same on the LSN to get it to start, dead ignitor could be to blame also but oh well. Once I got it started I then ran about 1 tank getting it warmed up good (mugen 125cc) and it suckes it up pretty fast when getting it warmed up. Anyways after I got it warmed up I then richened the LSN back 1/2turn and leaned the HSN another 1/4 and WOW! With a cen/mugen mid tank mod and the FLM ext. TVP's it still wants to live the front wheels up....and the buku is setup for top end at the moment. It comes out of the corners like a missile and the top end is amazing! I should have some footage of it this week sometime......

THANKS CRASH!!!!!
 
Your welcome bud,
It was my pleasure. I knew you would like it
:FarleyParty:​
 
Hi crash. I was looking at the pics on your crank mod. did you change the timing of the crank? I'm not so sure if the shaded red part of your picture was only on top or it was also shaded on the side of the crank to change the timing. A bug bit me and found my self holding a dremel and the crank :dunno: :hardlaugh:. I have already removed the sharp edges on the crank, its a matter of how many mm should i take from the side to increase the duration? I have read at some topic to remove about 2.5mm to get a total of 220deg I'm not sure if thats too much for a F4.6 or should i just knife edge it and leave it as is?
hammer time information over load. now I'm lost.:duh: thanks...
 
Awesome Crash, you do some great flow work and all. That thing screams and seems to run great.

Yes, Alvin looks like he changed the timing on the crank. However, I would steer an inexperienced moder away from this in tell he knows a bit of what he is doing. 2-2.5mm may be alright on the F4.6 but not sure on different brands.
 
Alvin said:
Hi crash. I was looking at the pics on your crank mod. did you change the timing of the crank? I'm not so sure if the shaded red part of your picture was only on top or it was also shaded on the side of the crank to change the timing. A bug bit me and found my self holding a dremel and the crank :dunno: :hardlaugh:. I have already removed the sharp edges on the crank, its a matter of how many mm should i take from the side to increase the duration? I have read at some topic to remove about 2.5mm to get a total of 220deg I'm not sure if thats too much for a F4.6 or should i just knife edge it and leave it as is?
hammer time information over load. now I'm lost.:duh: thanks...
Click to expand...

yes, crank timing is changed.

don't use 2.5mm as your measuring tool. most sport class mills
have different timing numbers from the factory

what I am saying is not all F4.6 's have the same timing.

check it and then start removing from the closing side

I onced measured 10 times to remove 10 degrees

don't go past 215
 
Ok. thanks for the quick reply. I think i would use your 10 deg. as a baseline and see how long my crank open up its duration before cutting. i don't want to mess up my cam degree wheel so I think i'll just PRINT a new one and compare the two for accuracy. it does not show the whole 360 deg. timing, but a simple math should do it.:bigsmilie:

http://www.toymods.net/forums/showthread.php?t=1635

I'm sure a lot of you guys will benefit from this... it will make reading and setting crank timing dimensions easy.

ps. do you have a pics of a modded crank from the right side? and having numbers dimensions as a guide in making this mod will surely make it easier. do you have more numbers to share which you think is proven and tested? thanks again crash
 
I would be very careful with the crank timing, just about all the engines are different. 10 degrees on the F will hurt performance for sure, it will be hard to tune as well.
 
Alvin said:
Ok. thanks for the quick reply. I think i would use your 10 deg. as a baseline and see how long my crank open up its duration before cutting. i don't want to mess up my cam degree wheel so I think i'll just PRINT a new one and compare the two for accuracy. it does not show the whole 360 deg. timing, but a simple math should do it.:bigsmilie:

http://www.toymods.net/forums/showthread.php?t=1635

I'm sure a lot of you guys will benefit from this... it will make reading and setting crank timing dimensions easy.

ps. do you have a pics of a modded crank from the right side? and having numbers dimensions as a guide in making this mod will surely make it easier. do you have more numbers to share which you think is proven and tested? thanks again crash
Click to expand...

I didnt mean to imply that you should remove 10 degrees
from any engine without measureing it first.
 
That thing is screamin Parker. What gearing are you runnin, out of curiousity? Judging from watching you vid, my truck accelerates the same as yours. Once I find the leak and get everything back together along with a new clutch, it should run alot better.

P.S. 2sp or 3sp?
 
I am running 18/49 right now. I did pull a wheelie today and it almost flipped over, it's not easy though right now. Running a 2 speed.
 
oh ok. Once I get a new/better clutch, I should be pullin the wheels off the ground. It wants to now, but the stock shoes just aren't good enough. Also think I've got a leak where the shaft goes through the backplate and not the bearings like I originally thought. Still gotta look into it.
 
Yeah my clutches are slipping to I believe so I'm gonna tear it apart and see what's up. I had to run blue thunder today to...it almost killed me!
 
awsome vid parker!!! looks like its almost to fast as i saw your savage "brush" that car parked on the street lol that thing flies...........
 
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