The Kart Engine Thread

[cpr]

The FrankenMess is mine to own. Seller and feebay broke it off in me so I'm walkin' funny...

Gathering info for what it's going to become. Not a full on kart-saw, but it will incorporate kart principles during the build for a factory hot-rod saw: I christen it the FX-125.

JJ made an absolutely brilliant post here:http://http://www.arboristsite.com/chainsaw/135464-3.htm#post2213056

Since the FrankenMess seems to have a CP-125 block, JJ mentions the concept of intake timing. I thoroughly understand the idea of intake timing on a piston ported engine, but on a reed ported engine my understanding is lacking (we'll exclude from our discussion transfer timing).

How is intake timing determined on a reed ported engine?


Lot's going on here in my personal and professional life, but as time permits, look for a brand new thread on the FX-125 build. It's going to be a blast, but have patience with me, please :handshake:.

 

[Eccentric]

The FrankenMess is mine to own. Seller and feebay broke it off in me so I'm walkin' funny...

Gathering info for what it's going to become. Not a full on kart-saw, but it will incorporate kart principles during the build for a factory hot-rod saw: I christen it the FX-125.

JJ made an absolutely brilliant post here:http://http://www.arboristsite.com/chainsaw/135464-3.htm#post2213056

Since the FrankenMess seems to have a CP-125 block, JJ mentions the concept of intake timing. I thoroughly understand the idea of intake timing on a piston ported engine, but on a reed ported engine my understanding is lacking (we'll exclude from our discussion transfer timing).

How is intake timing determined on a reed ported engine?


Lot's going on here in my personal and professional life, but as time permits, look for a brand new thread on the FX-125 build. It's going to be a blast, but have patience with me, please :handshake:.

Glad to see you finding the silver lining in the whole "working Chris 'til he can't take it no more" fiasco. At least you still have the "Franken-Kart Saw" thingee. You could have ended up out of pocket and without the saw at the end of the deal.

We'll be patient with you........................................now go get busy with this build dammit!!!

 

[cpr]

Right on, friend!!! Gotta get the high side flowin' on the Super 250, the low side flowin' on the Super 44, the ignition goin' on the D44... In the meantime, I'll start teardown of the Mess and get a list going... Have no fear.

The deal hurts, but... Well, see my sig for the words of guidance.

 

[GASoline71]

Great thread!

I've learned that the Super 250 and the Mc49 are round about the same. Prolly port timing differences. Kewl...

Gary

 

[PLMCRZY]

My Dad use to race one in the late 60s early 70s. He told me it had a MAC engine, it would get his sisters gto off the line then around 60mph she would fly right past him. He stopped racing after his buddy wrecked and broke his neck one race. I was always curious to what it looked like, he said you practically laid down in it. Engine was right by your head.

 

[nmurph]

Hey, that reminds me: Anyone know the maximum RPM of the hundred and first kartsaw points electronic racing MAC????

:angry2::angry2::angry2:

hey, you trying to hid from someone??? maybe someone in a farun country????

 

[cpr]

Watching the Super Bowl and contemplating saw surgery...

Anyone care to enlighten me on stuffer plates?

I'd like a better understanding of:

1. How do they work?

2. Why are the long-tail GEM ones better?

3. If you drill the oiler hole in a GEM stuffer, will it work in a CP/SP 125?

 

[leeha]

The purpose of the stuffer is the eliminate crankcase air volume.
This is so when the piston is on it's down stroke there is less air
to compress so the whole charge will pass into the ports and cylinder.
Aftermarket stuffers fill more of the case over a stock stuffer.
This help to get the most of the fuel charge to the top of the piston.



Lee

 

[thomas72]

I have seen larger stuffers to reduce crank case volume along with epoxying all the threaded holes, and putting in a full circle crank. Every little bit helps.

 

[cpr]

Interesting. I'd always taken the full-circle cranks as being important for torque (flywheel effect) and vibration damping, less for volume filling.

 

[heimannm]

Don't drill a hole in it, you'll lose the benefit of the volume filling characteristics.

Mark

 

[cpr]

Don't drill a hole in it, you'll lose the benefit of the volume filling characteristics.

Mark

HAHA! Yeah, but if it runs like I hope it will when I'm done, the power trade-off won't be worth the nuked vintage bar!

 

[thomas72]

I have also seen on dirt bike cranks where little ridges are ground like small fan fins around the circle part of the crank in an effort to get the air and fuel mixture into the ports faster. I do not know if this actually worked, but people pay a good bit of money to have it done. Also, if you cut down Boyesen reed valves and put them in a saw would probably help. They seal better than stock reed valves and will also let more fuel/air travel past them. Another little trick on bridge ported engines is to drill small holes in the piston skirt that line up with the bridge port. This helps keep the piston from galling there and beating out the port.

 

[Brian13]

Been watching this video cpr posted awhile ago, and it has me thinking. With my S44A being based off the MC10 I was researching the stroker kit. Not a whole lot of info, and havnt seen any for sale. If I am understanding this video right, instead of using a stroker kit, he just went to the next size crank, and got a thicker head gasket as well as a spacer for the stuffer. Am I understanding this right? Is it feasible to take a MC20 crank and use that with a thick head gasket on the S44A with the stock rod and piston? About 6min into the video is where he starts to talk about it.

<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/R2ZGg0LYSRI" frameborder="0" allowfullscreen></iframe>

 

[heimannm]

Interesting stuff indeed.

I found a more or less complete Mc40 last week, and have a good line on a couple of Mc10's. No 101's yet but it is a start.

I added the carburetor and engine mount from my big box (officially crazy thread) just to dress it up a bit and make it possible to hold it in my mounting device.

Now I need to find a new set of rings (47767), or maybe more than one set to be ready for the future.

Mark

 

[Brian13]

What are you going to do with that Mc40? I have given up on the 101s for now, too expensive. Wouldnt mind a decently priced Mc10 though to go into the S44A.

 

[cpr]

Looks promising Mark. Randy says go 6ci and fear no evil. To paraphrase, go kart or go home.

 

[heimannm]

Seems to me the Mc40 or Mc10 could easily slip in to a Super 44 or 1-70 frame and make a very interesting under 5 In³ vintage saw.

Hey, I may have one or two of those old saws up on a shelf, something to think about...

Mark

 

[cpr]

Me, too. With JJ's encouragement, I mean to try putting an MC-10 head on a saw block. Torque and HP combo. I reckon a Super 44A will cross paths with the heads I scored soon enough.

 

[cpr]

Actually, I would rather have hamburger b...

Plenty to keep me busy and there's another arriving soon...