Powerland 420cc GAB 2.0

[bob58o]

My linkage needs work.
I want to try replacing the spring with some 20lb galvanized wire I picked up.

 

[bob58o]

http://mudmotorkit.com/forum/stats/index.php
This gives some jetting info for different engines and different mods.

For example this 420cc engine that spins 4100 RPM and has a Stage 1 kit (Robertson torque tube, K&N intake, NGK plug)
uses...
110 jet with adjustable needle

This 420cc engine spins 3250 RPM
has...
NR Racing air intake, NR mud motor exhaust
uses....
111 Main Jet



These engines are on boats.

 

[bob58o]

Going to try a different plug and maybe some different jets today.

Going to BPR7ES. This plug came installed even though specs call for the hotter BPR6ES.

I also have some jets laying around. I'm using 0.046" now and have 0.042" and 0.049" here. Going to try 0.049" and see what happens.

First lets see what this plug looks like.

 

[Flyinhillbilly]

Have you made a full throttle pull on a new plug and checked the heat mark on your ground strap? I don't give a crap what the specs call for, I just give the engine what the plug tells me it wants. Spark plugs never lie.

 

[bob58o]

Well still no load on it so trying jet may be dumb, but every time I gave it more than a tiny blip of throttle all I got was popping.
The cylinder head never got hot. A bit warm, but I could hold my hand on it for ever. So less than it should be I think. How hot should it get idling for 40 minutes in a cold garage on a 35-40 degree day?

I took the AR3923 out. Don't even remember how I picked that one.
It was pretty black. Like carbon fouled. Like it never got hot enough to self clean. I mostly had the engine below 2000 RPM. So not sure what I can tell from the plug.

It seems to be running better now with the BPR7ES and a 0.042" main jet.

Here's the last plug AR3923 with a 0.046 main jet.

 

[bob58o]

Camera sucks. I wiped off the carbon and didn't really see any lines on the strap. Maybe something very near the threads but maybe that was just carbon I didn't get to.

I plan on letting this run for a while.


How bad is it to let my TC Driver Unit spin wide open with nothing attached for an hour???

 

[bob58o]

Holy Tracheotomy Batman!!!

From Vegascarts...
32mm ID for the 32mm carb which is on the way.

https://www.ebay.com/itm/32mm-Bille...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

https://www.ebay.com/itm/32mm-PWK-C...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

https://www.ebay.com/itm/1-5-8-40mm...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

 

[bob58o]

Origin of GAB

I had to go back and re-read this thread to find out what I've done so far.

Milled 0.085"
0.032" Copper Head Gasket
3 Angle Valve Job
Some Port work (needs more)
35lb Valve Springs
I purchased a timing key, but not sure if I ever installed it. Hmmm?

People always want to now what GAB means...
This might be my favorite quote.

Go All Bob, a term I coined for making a simple thing complicated...Bob, is [...] learning from scratch. So he's like a Terminator, trying to understand humans.

 

[Joe-405]

Those ar supposed racing plugs suck FYI. Never ever could get mine to run right. Put a regular ngk in and it ran perfect every time ! I think I ran a bpr5 or 6es. Can’t remember exactly. And I used that exact intake and a koso 34mm carb and it definitely picked up some power.

 

[bob58o]

Those ar supposed racing plugs suck FYI. Never ever could get mine to run right. Put a regular ngk in and it ran perfect every time ! I think I ran a bpr5 or 6es. Can’t remember exactly. And I used that exact intake and a koso 34mm carb and it definitely picked up some power.

I was going back and reading about the Flattop Piston and Rod Combos. I wonder if Vegascarts ever released the drop in 90mm flattop piston and rod combo?

Otherwise I think it was the ARC 4.45" Rod with the -0.020" flattop piston?

 

[Joe-405]

Ummm I just shaved the lip off my stock piston with a angle grinder and used the long rod. So not sure. And yes I rechecked the valve clearance. Lol

 

[bob58o]

NR has nicked/scratched (says damaged in shipping) 90mm flat top pistons for $5. The non-damaged ones are $30.


Anywhoooo.

New carb on the way, so I ordered a new throttle cable.
80" should be plenty long (I hope).

https://www.ebay.com/itm/301231915730

 

[bob58o]

Used my piston stop and degree wheel to find TDC. Then I moved the flywheel to the position where I think the spark happens.

When the trailing (left) edge of the magnet passes the right edge of the coil's left leg.

This (no-timing light) method shows ~25 degrees BTDC.

I’ll try the light later.

ADDED:
Checked with the timing light and got about 24.5 degrees.

 

[bob58o]

Carb showed up today. Pretty fast coming from China.
No boot or extra jets with this one.

I ordered this 40mm ID Silicone Hose.
https://www.ebay.com/itm/1-5-8-40mm...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649


I ordered a few air filter options.

Number 1.
Red and Black Air Pod
https://www.ebay.com/itm/Black-Red-...m=172444283595&_trksid=p2047675.c100005.m1851

Number 2
Velocity stack with screen filter
https://www.ebay.com/itm/191981355574

 

[ezcome-ezgo]

Used my piston stop and degree wheel to find TDC. Then I moved the flywheel to the position where I think the spark happens.

When the trailing (left) edge of the magnet passes the right edge of the coil's left leg.

This (no-timing light) method shows ~25 degrees BTDC.

I’ll try the light later.

ADDED:
Checked with the timing light and got about 24.5 degrees.

More like 24.56 degrees, I think.

 

[bob58o]

More like 24.56 degrees, I think.

I thought it was 28 for the win?

Step 1. Take possession of brand new carb.
Step 2. Take apart brand new carb.
Step 3. Stare at disassembled non-working carb.

This one says PWK on it so you know it is good.
It has the Hex style main jets (6mm hex vs the round slotted jets all the smaller ones have had).
Stock main jet said 122 which should be 1.22mm, (0.048").
Idle jet was 32.
Mixture screw was 1 turn out.

 

[bob58o]

Glad I started playing around with my carb.

There’s your problem.

Do not try and bend the screw. That’s impossible.
Instead only try to realize the truth.
There is no screw.

Since I don't believe in luck, due to systematic preparedness I have an extra 30mm carb of the same style that I can steal the screw from. I purchased that carb for the blown 212 project, but this project takes precedence.

 

[bob58o]

Had a #6 offset timing key.
A #6 key is shaved 0.060".
On a 212 or 196cc engine, every 0.010" shaved = ~ 1.3 degrees of advance.
So on a 212 this key would be around 7.8 degrees advance.

The shaft is bigger on a 420cc. The same #6 key should provide less advance on a larger shaft.

The arc length stays the same, but the circumference changes. So I would expect less advance when using a key on a 420 compared to that same key on a 212.

However the NR site seems to say the opposite?
GX200, 6.5 Chinese OHVs, and 212 Predators
2 Degrees - Recommended for Dyno PVL flywheels
4 Degrees - Recommended for use in GX160s on Gas and GX200s using GX160 Flywheels
8 Degrees - Recommended for use in GX200s on Gas and 160s on Alky with stock flywheels
12 Degrees - Recommended for use in GX200s on Alky with stock flywheels

GX270 & GX390s (will provides approx 2 to 3 more degrees than shown)
6 Degrees - Gas Applications with ARC or Stock Flywheels
8 Degrees - Alky Applications

The #6 key advanced the ignition timing about 6 degrees on the 420cc.
It was about 24.5 BTDC now it is about 30.5 BTDC.

 

[bob58o]

Took some measurements before I fell asleep.
Crankshaft end play measured about 0.025". Not sure what it should be. That seems like a lot. Even for a big block, but I'm not sure.

The stock cam measured about 0.235 -0.240" lift on the exhaust and about 0.255 -0.260" lift on the intake.

On page 1 of this thread I had copy and pasted 0.259" lift for the intake and 0.235" lift for the exhaust. I guess the info was decent. I didn't measure duration and the duration specs from the 1st page seem odd.

---------- Post added at 07:49 AM ---------- Previous post was at 07:22 AM ----------

I've played this video once or twice before but never paid any attention. I guess I was hoping to learn through osmosis. I call it background learning. LOL

https://www.youtube.com/watch?v=PoPZ4XbQ85E

 

[bob58o]

ARC replied to my comment on a Youtube video. They say 0.010" to 0.020" crankshaft end play is what I want. 0.010" being the minimum. I like getting and using stuff I never used before.

Crankshaft shims! One at 0.2mm and one at 0.1mm. 0.3mm total = 0.012"

I was at 0.025" end play. The 0.3mm shims will put my end play around 0.013".
https://www.arcracing.com/6059s-gx390-crankshaft-shim-kit/