Powerland 420cc GAB 2.0

[bob58o]

And these
320 grit finishing buffs

 

[bob58o]

And that (PLUS SOME WET SANDPAPER OF FINE GRIT) is REALLY all you need...

"FOR ALL INTENSIVE PURCHASES!"
or is it Intended Porpoises?

 

[chancer]

380 seems rough? isn't it called P an "Polish"

 

[bob58o]

OK, OK, OK...

For the intake on a carb'd engine, I think I'm going to do 120 grit on the runner floor and 180 grit on the roof and walls.
120 grit is not so smooth. We need atomization of the fuel.
The floor is also the short radius side. This is my rough side.
The ceiling and walls will be smoother and faster.
This may create a tumbling? Maybe good maybe bad?
Maybe I should do 80 on the floor and 120 on the other three to start?


For the chamber, last time I decided I like 320 grit for a combination of detonation prevention and to help keep fuel from falling out of suspension and forming droplets.

For the exhaust will bling as much as possible.
I have wet sandpaper much finer and then I have black and white rouge.

320 grit is "PROBABLY" fine! For all "Individual Services".
But WHY GAB HALF WAY? is what my grandpappy always used to say.

---------- Post added at 10:08 PM ---------- Previous post was at 10:04 PM ----------

Please send me a Dyno and Flow Bench. My birthday is in like 5 months!

 

[Flyinhillbilly]

They sell what's called a rubber abrasive that goes in a dremel, and without doubt you can use them to make the exhaust port plenty "blingy". They leave a real nice (for head porting anyway) polished finish.

 

[bob58o]

They sell what's called a rubber abrasive that goes in a dremel, and without doubt you can use them to make the exhaust port plenty "blingy". They leave a real nice (for head porting anyway) polished finish.

Like this?
https://www.cratex.com/Products/Rubber-Abrasives/Cones/Cones

 

[bob58o]

He said Rubber. Ha ha
https://www.youtube.com/watch?v=7RlBUEHQ7bY

 

[bob58o]

Yep sure is. I'm gonna call and confirm tomorrow and order it. But it sure looks to be just cutoff to me. Which would be perfect. I let you know.

I was tryng to find it earlier but couldn't find it. Thanks !

Do you have some private line to get Russel? LOL

 

[bob58o]

So this is the Cam I want now.
Dynocams 308

12:1 CR
Leaded 110 Octane http://www.sunocoracefuels.com/fuel/standard Speedway #1418
32 degrees ignition timing
Dual HD Springs

http://www.dynocams.com/item/308-gx390/cams-clone13/
DESCRIPTION
The lobes are welded to increase durability, extending the life of this cam.

SPECS
Engine: 390cc OHV Clone 13HP
Recommended Class: Modified
Target (MAX) RPM: 7200
Spring Pressure (In / Ex): 48-50 lbs Dual Spring
Valve Lash (In/Ex): .003"
Ignition Timining: Pump Gas Not Recommended
110 Octane 32 Deg BTDC
Methanol 36 Deg BTDC
Compression Ratio: 12 to 1

PROFILE
Intake Exhaust
Open: 53.5 BTDC 91.0 BBDC
Close: 91.0 ABDC 55.1 ATDC
Lift: .308" .308"
C/L: 108.0 ATDC 108.0 BTDC
DUR @ 50: 244.2 Deg 244.6 Deg

 

[Joe-405]

Do you have some private line to get Russel? LOL

Haha. Well maybe. Cause he already got back to me. Lol

The piston has the same compression height as stock. So I will stick with my one off special one.

 

[bob58o]

Haha. Well maybe. Cause he already got back to me. Lol

The piston has the same compression height as stock. So I will stick with my one off special one.

If you keep planning and not doing, like me, maybe this one will be ready from VC?

Starting in October, we will be increasing rod length to 4.51" from 4.45" and replacing the 9cc dish pistons with lighter flat tops. The extra rod length will reduce piston speed and the flat top pistons will provide better flame propogation in the combustion chamber.
Also, our new "Drop-In" 4.51" billet connecting rods are ready to run right out of the box and there is ZERO clearancing required to the cam, balance shaft, and crankcase. They will be affordably priced at $99.99 (90mm or 92mm flat top piston INCLUDED) for those who want to add power and reliability to their existing 420cc or 440cc clone and keep the costs in check!





Do you happen to know the depth of the dish on the stock piston.
I'm trying see what kind of P2V clearance I might have with a flattop and short rod.

My piston and block are at a friend's house, I don't want to drive 10 miles to measure

---------- Post added at 09:31 AM ---------- Previous post was at 09:26 AM ----------

Timmy from Dyno Cams recommends Advancing the 308 grind 6 degrees to give me a more torquey version of this cam. 6000 RPM max!!!

 

[bob58o]

0.0825" +/- 0.0025"

That is the depth of the dish in the piston.
This dish also works as valve reliefs, right?

So I have to account for the 0.0825" in my Piston to valve measurements/calculations.

 

[KartFab]

So this is the Cam I want now.

Leaded 110 Octane

I'd hate to be the guy driving behind you. Do you have a formula for determining the loss of IQ per time spent breathing the exhaust?

 

[bob58o]

Well no 80 mm long by 10mm 1.25 pitch.
So no head studs, but I'm sure one of these is right for side cover?

 

[bob58o]

8mm 1.25 x31mm
38mm
40mm
46mm
50mm
62mm

Then 10mm 1.5 48mm

And 10mm 1.25 42mm
48mm
50mm

And some reducing studs.

All 1.95 each.
Ace hardware

---------- Post added at 11:26 AM ---------- Previous post was at 11:21 AM ----------

I'd hate to be the guy driving behind you. Do you have a formula for determining the loss of IQ per time spent breathing the exhaust?

Nope. lol.

Maybe I can do less than 12:1?
I'm going to change the center lines so maybe 12:1 is not the optimized CR anymore anyway?
And maybe less than 32 degrees will be ok?


Maybe 11:1 with unleaded 100 octane.

Or 12:1 with the same gas and some octane booster?

 

[Flyinhillbilly]

Like this?
https://www.cratex.com/Products/Rubber-Abrasives/Cones/Cones

That's the stuff

 

[bob58o]

Intake 60 grit.
Phase 1.

 

[bob58o]

And

 

[bob58o]

I may have opened up the throat a bit.
Looks good to me!

---------- Post added at 02:09 PM ---------- Previous post was at 01:22 PM ----------

Hhhmmm????

The guy at Eastwood told me at 6000 RPM
The fuel is moving fast enough where it should stay atomized and I should smooth the intake as much as possible.

But what about coming off idle at 2000 RPM???

I think I will research this a bit more.
60 is too rough.

I think 120 will be ok.
Then I'll think about 240, but don't think I'm smooth enough to pull that off.

 

[bob58o]

Lets do 80 grit and see.
Most say 80.