Hemi Build #3 -Boogie Woogie Woogie

[Nosandwich]

He graduated from Screw U.

 

[bob58o]

Do I immediately regret not getting the Ram Air version of the top plate?
Yes I do. It looks so much COOLER!!!
Who doesn’t want a scoop on their Minibike engine?

Not sure if I mentioned that people had issues with top plates and the manifold I picked. The economy plate might have more room for the carb than the full plate would. Still not sure it will fit without modification.

 

[firemanjim]

I like that ram air top plate! Pretty nifty.... But it really doesn't do anything, does it ? The cooling air is forced out from the flywheel fan. So where does the air from the ram air go or do ?

 

[bob58o]

I guess the design is suppose to capture some of the head wind and direct it across cooling fins on the jug and head. The top plate may block THAT air flow (which the stock gas tank might allow) from the head wind.

But are you saying that space under the plate will be filled with the air from the fan?

Not sure if you are considering this utility engine will be traveling (hence the head wind) or if you are saying that the air from the fan and the air from the head wind will be "competing" to fill the same space?

Either way, I just like the way it looks. Like a Hood Scoop. On a MiniBike with no hood!
I'm not too worried about temperatures. My riding style usually means I am at pretty cool cylinder head temperatures. On my current bike, I am considering taping up the fan shroud/blower housing to INCREASE head temperature. And in all reality, the Ram Air "lip" might just hurt the aerodynamics and slow me down.

I didn't get it though. No scoop for me.

 

[bob58o]

I guess I’ll show how I remove the governors on these engines.
I unscrew the screw holding the governor arm on. Then I use a flat head screw driver and tap with a hammer to loosen the arm from the post/lever that extends into the block.
I leave the clip on and have at it with an angle grinder/dremel/die grinder.
Once I snip the tip, then I’ll remove the clip.

 

[bob58o]

Step Two:
Spend 90 minutes looking for gear puller.

 

[bob58o]

Remove flywheel.
Remove side cover.

Rotate crank and pull hockey stick thing down into the block.
Collect bits, parts, washers,...
Punch governor gear shaft out from the flywheel side and into block.
Collect parts, bits, washers,....

And that's as easy as it gets.
I am not a fan of removing the clip on the governor gear shaft. This is much easier IMHO.
Just got to plug the holes, or make vents, or make birds.

Yep let's make them birds now.

 

[bob58o]

I guess this needs investigating...
I don't think I remember doing that.

 

[bob58o]

I used 1/4-20 x 3/4 long in the top.
I used 5/16-18 x 3/4 long in the side.
I tapped the top hole.
I drilled a 5/16” through hole and used a lock nut for the side.
I don’t really like having a nut inside the block like that, but last time I don’t think I was happy with how the threads came out after tapping.

 

[ezcome-ezgo]

Couple things:
"the Ram Air "lip" might just hurt the aerodynamics" You aren't serious of course. A human on a minibike worried about aerodynamics?

"I guess this needs investigating..." Nasty gouge there, did you check for cracks?

 

[bob58o]

Couple things:
"the Ram Air "lip" might just hurt the aerodynamics" You aren't serious of course. A human on a minibike worried about aerodynamics?

"I guess this needs investigating..." Nasty gouge there, did you check for cracks?

Nope not serious.

I’ll will continue to investigate.
Difficult to see in the pic, but this shows where the flywheel was rubbing.
Rubbing is Racing?

 

[bob58o]

I wish I could weld aluminum and fill in that area where the governor gear used to be.
Then I could grind away the spot where the flywheel was rubbing.

Ignoring the fact the flywheel might not really fit the HEMI Predator Block,
I'll move on (for the moment).

My plan was for 10.35 :1 Static Compression Ratio.
I've read that 8.5 :1 and under Dynamic Compression Ratio is where you want to be for pump gas. I've also read that 185 psi cranking pressure is max for 93 octane with Iron Heads and with Aluminum heads you can go to 195 psi cranking pressure.

The simulator gave me DCR of 8.21 :1.
And a THEORETICAL Cranking Pressure of 212 psi.

Guessing Blowby reduces the theoretical 212 psi to 195 psi????
I should probably add venting (block, valve cover).

The simulator says the engine likes 25 BTDC timing at 4500 RPM and 26 BTDC at 5500 RPM with 93 octane.

The 102 Intake Centerline cam says 11 :1 SCR or Lower.
The 106 Intake Centerline cam says 10.5 :1 or Higher.
I got a 104 ICL cam, so I think 10.35 :1 static compression ratio will be ok??

 

[bob58o]

Exhaust is here.
Mikey Likes It!!!

One of these days I'm going to have a 2 foot true straight pipe that sticks out the side of whatever.
No bends, just the most unrestrictive exhaust possible. The last bend on this pipe looks restrictive. I really have no way to tell. I should probably rig up some type of flow bench.

I do have a new(ish) 5HP shop vac. It is my apartment vacuum. When you are a guy looking to buy a vacuum for the apartment where you do shop work, you don't pick out your mother's vacuum.

 

[bob58o]

Fixed?

 

[65ShelbyClone]

One of these days I'm going to have a 2 foot true straight pipe that sticks out the side of whatever.
No bends, just the most unrestrictive exhaust possible. The last bend on this pipe looks restrictive. I really have no way to tell. I should probably rig up some type of flow bench.

It's probably not as restrictive as it looks. Ever see the Hot Rod TV show where they dented the heck out of the headers on a smallblock Chevy and it actually began making more power? It suggests that the headers were too big to start with, but interesting nonetheless.

More important than the bends IMO would be getting it long enough to take advantage of the resonant length for better scavenging. Usually exhaust length is a compromise because the "right" length for strong pulse tuning is too long to fit practically in a vehicle. Same with intake ports.

 

[bob58o]

It's probably not as restrictive as it looks. Ever see the Hot Rod TV show where they dented the heck out of the headers on a smallblock Chevy and it actually began making more power? It suggests that the headers were too big to start with, but interesting nonetheless.

More important than the bends IMO would be getting it long enough to take advantage of the resonant length for better scavenging. Usually exhaust length is a compromise because the "right" length for strong pulse tuning is too long to fit practically in a vehicle. Same with intake ports.

I considered how the short header wouldn't be long enough to help with pulse tuning, but then again the cam has a short duration and relatively wide LSA, so there is not much overlap (where I think pulse tuning would show the most gains).

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

 

[bob58o]

I guess I will grind the tall "lips" around the Hemi crank journal today.
Nobody likes loose lips.
Loose Lips sink Ships.

Just a lil bit more should be fine.
I’ll just flatten the top of the lips and smooth/round everything out.

 

[bob58o]

Calling this good ‘nuff.
I tend too take things too far.
Sometimes I just need to put the grinder down.

 

[bob58o]

What's next?
I can do the Connecting Rod while I'm waiting on other stuff.


I'll see if I can find the plasti-guage, or I will stop at O'Reillys and pick up some more.

Plastiguage
Calipers
1/4" 12 pt socket for 1/4" drive
1/4" drive Inch pound Torque Wrench
Bench Vise
Cloth
Motor Oil

I think that is all you need to install a connecting rod the way I do it (per ARC instructions).
https://www.youtube.com/watch?v=owahpOeLYaw

---------- Post added at 02:55 PM ---------- Previous post was at 02:41 PM ----------

Started off by measuring the crank journal with my digital calipers.

I measured across in 4 different spots and got maximum 1.1870" and minimum of 1.1865".

The ARC instructions say it should be round within 0.0005".
Also ARC instructions say the journal should be 1.1880" shouldn't be any smaller than 1.1865".

The Crankshaft appears to be within specs for the rod.

We will use the plastigauge to check oil clearance with the rod installed on the crankshaft. The last build, I think I was right at 0.002" oil clearance - which is the minimum.

 

[bob58o]

Have to install the connecting rod while running errands and doing laundry and cleaning.

A hot Austrian girl is coming over to hang out tomorrow and my place is a mess.
Austrian girl with a Southern accent. Some of her family lives in Georgia now, IIRC.
Never thought the German language was attractive till I heard her sing 99 Red Balloons. LOL

I'm going to have to dust off the old Hasselhoff albums.

https://www.youtube.com/watch?v=Lur-SGl3uw8