new to the board ...

[847]

well my motor serial number is ..

130253 0598-01

it's a 1978 ( i think ) snow blower motor, 5 horse flat head.

i was just curious because i went ahead and got some parts for my go-kart but don't have a dyno to tell me what i have h/p and tq wise.

i have the head milled .30 i have a comp cam gp .. something with .289 lift, i also have the dual springs that come with it. i swapped the old heavy cast iron flywheel with a modern one, and replaced the ignition system, and filled the little hole for the old timing spot on the crank shaft. and my idea of an exhaust goes from 3/8th's to 2 inches .... also my carb is stock, and still has the little metal swirly thing in it. i don't have a go-kart per se, just yet, because i just want the motor to be built up, and go from there. i wanted to put it on a bicycle, special chain, special gearing. ( bikes aren't made for thousands of rpm's ... atleast ratio wise ).

so in short, what small improvements need i make? and what top rpm do you think i'm hitting? sounds like 8k to me, and a harley too.

 

[ironman]

where did you take your head to get milled what it cost you.

 

[847]

ateco, sons of *****es charged me 30 bux. also, i hear alot of tapping, maybe i've milled too much, and valves are hitting the head a tinch...

 

[847]

also - this is the cam..

http://www.compperformancegroupstor...Screen=PROD&Store_Code=GP&Product_Code=GP9530

 

[ironman]

got mine done for 15.00 and my shop guy said you can go .40 and be fine as long as your cam isnt to wild.

 

[847]

yea, if you don't plan on using a .289 ... you sticking to .233? if so then i'd opt for the compression @ .30 milled, it's even with the surface where the piston opposes... do you know what i'm talking about?

 

[oscaryu1]

"Modern" cast iron flywheel? Lol

 

[Russ2251]

i hear alot of tapping, maybe i've milled too much, and valves are hitting the head a tinch...

Unlikely.

 

[ironman]

yea, if you don't plan on using a .289 ... you sticking to .233? if so then i'd opt for the compression @ .30 milled, it's even with the surface where the piston opposes... do you know what I'm talking about?

i kept my stock cam and just went ahead and filed down on the intake lope. to get a little more power out of it.

 

[847]

making it smaller helps? or does it just make it have longer duration at the cost of peak height?

how much are you expecting hp wise?

see this thread, without buying stuff you can get decent power you know ? free upgrades

http://www.diygokarts.com/vb/showthread.php?p=8455

Unlikely.

i dunno, seen marks on the head toward the bolt side. maybe the guy who did the milling job did not know what the hell he was doing ....

"Modern" cast iron flywheel? Lol

i meant it to say that i replaced the iron cast flywheel with a modern ( more recent to say, not as far as technoligy wise ) aluminum one

 

[ironman]

yea i know i added a headder in the very beginning and gain 1 mph. im not for sure what i will gain out of doing this to the cam but i figure why not i mean sooner or later i going to need to rebuild it so i figure it be good to see what really works. the guys at the local race kart shop says this is what they use to do to gain a good amount of power before the techs found out and said no more.
but he told me i will notice a big differences

 

[847]

hmm, hopefully if you really wanna tinker, retard the cam by 1 tooth, or advance, i've never tried it, but it's non interferience, worst that could happen is it will run poor. it's up to you ... also, i'm 80% sure the crank will not hit any lobes, but spin it around a few times and keep an eye on the rod and cam area where they almost touch.

 

[Russ2251]

Will run worse.

 

[ironman]

yeap thats what i just did to night i used a number 66 timing tooth so now id say instead of pointing at 12 noon it now sit at about 1 o'clock

 

[ironman]

Will run worse.

why that russ explain. :toetap05:

 

[Russ2251]

My question first. What do you expect to gain?

 

[ironman]

hum not for sure i was told i would notice a major difference in take off power.you know im just a nub when it comes to alot of this but i dont mind trying.{lets not forget how adding a headder i did gain 1mph i know you are still scratching you head on that one.
---what do think i will get out of this if any thing.---

 

[847]

prolly gave it more topend and actually reached a higher rpm, in this case it was atleast 200 rpm gain to get 1 mph depending on your ratio.

 

[Russ2251]

Opening intake valve sooner will push exhaust gasses out of carb because piston has not finished its upward motion in its attempt to complete exhaust cycle.
Also, valve will close sooner while downward motion of piston is still creating a vacuum which results in a shortened intake stroke. Less fuel intake = less power.

lets not forget how adding a headder i did gain 1mph i know you are still scratching you head on that one.

Not scratching head. I could not duplicate this (nor my friends) and stand by what I posted. For it to be true, it must be repeatable and is not. This is assuming governor is intact and operating. Something else is going on there.
Sidebar 1: Grinding down intake lobe means valve will not open fully. Check tappet clearance.
Sidebar 2: Milled head requires a re-check of torque on head bolts after a few cycles. Possible blown gasket is the downside if not monitored.

 

[newrider3]

i meant it to say that i replaced the iron cast flywheel with a modern ( more recent to say, not as far as technoligy wise ) aluminum one

BAD idea, unless it is a billet flywheel. Cast aluminum flywheels will explode not far above governed RPM.