Hemi Predator Build #2

[bob58o]

I suppose I can check push rod length with only the intake.
I'll set the lash to 0.002" according to the cam info. Exhaust is 0.003".

The lash cap is black, so I'll see if I can use this prussian blue dye to see where the rocker tip contacts the lash cap.

Blueprinting is the best part.

 

[bob58o]

Here are some close up pictures of the rocker tip and the lash cap.
Shows the contact point at between 1/2 and 3/4 lift, and then at max lift.
Also shows max spring compression. The spring pockets have been cut to accomedate the larger diameter 37lb springs.

The contact point is above the mid point, so I suppose I need shorter pushrods. I can grind a stock rod shorter to the next available size and check again.

 

[bob58o]

So what I've found says 5.44" pushrods as a starting point (vs 5.54" stock) for heads with extensive milling. I milled 0.040" and decreased gasket thickness 0.018".

NR says 5.34" - 5.44" pushrods for use with the +0.070" valves. I'll try to take 0.100" off the length and test again. If

 

[Whitetrashrocker]

That seems like a lot there, .100"
Don't cut 3 times only to find it's still to short...

 

[bob58o]

So ordered some keepers, the head studs, the push rods (5.44") and a new side cover gasket.

The rest of my wish list includes...

Billet Flywheel
30*
https://eccarburetors.com/estore/sk100-sk-slipstream-predator-hemi-flywheel.html
32*
http://www.arcracing.com/6626-predator-212-hemi-kohler-ch270-billet-flywheel/
34*
http://www.trjkarting.com/ambush-racing-billet-predator-flywheel/

Exhaust Header
Robertson 3 Stage Minibike Pipe
https://www.smallenginecams.com/

Reinforced Rockers
http://www.ebay.com/itm/PREDATOR-21...ash=item3f8097e82a:g:M3UAAOSw-3FZBQfF&vxp=mtr

And then maybe some structural reinforcement.
Top Plate?
Billet Side Cover? (The TC backplate should provide some bracing, right?)
Some DIY Bracing?

---------- Post added at 03:17 PM ---------- Previous post was at 03:11 PM ----------

That seems like a lot there, .100"
Don't cut 3 times only to find it's still to short...

5.44" is the next shortest to stock. Besides that, it's cut to length.

If the 5.44" was too short I'd use the stock length. I also had another pushrod to paly with. 0.100" is basically the whole round tip at end of the rod.

But I put a fresh lash cap on checked the wear pattern. It's close enough for me with the 5.44".

 

[Scout]

Crap, you just made me think I should check my pushrods, after going from a stock gasket to a .010 gasket.

 

[Randy H]

http://www.vegascarts.com/product-p/champ200.htm

I don't know much about these. Just another option.

 

[bob58o]

http://www.vegascarts.com/product-p/champ200.htm

I don't know much about these. Just another option.

Don't think they'll work with the Hemi Head.

---------- Post added at 02:01 PM ---------- Previous post was at 02:00 PM ----------

Crap, you just made me think I should check my pushrods, after going from a stock gasket to a .010 gasket.

Can't hurt to check and see, but I think you'll be ok with the stock length.

 

[bob58o]

Going to attempt to make a valve spring tool.

Picked up a 6" C clamp from Harbor Freight.
https://www.harborfreight.com/6-inch-industrial-c-clamp-37850.html

And a 1/2" Threaded Rigid Conduit Coupler from home depot.
I don't know much about conduit... This coupler has a 0.75" ID and a 1"OD. I guess it is used for conduit with a 1/2" ID, 3/4" OD. Like 1.75" long or something.

http://www.homedepot.com/p/1-2-in-Rigid-Conduit-Coupling-64005/100353841

A few cuts and some grinding and now I have

finger sized keeper positioning access ports on my small engine over head valve valve spring compressor tool

 

[Whitetrashrocker]

Looks good.
Is there enough to hold the retainer ring? It kinda looks like the coulping could spread and then grab on the retainer making for a few cuss words to be emmited.

 

[bob58o]

I added a 1/2 washer.
The welding is garbage, but the design is ok.

The washer was to help grab the retainer and to give support so I could open up the keeper access ports bigger.

 

[Whitetrashrocker]

Beat me to it ...

 

[bob58o]

After attempting to weld today, I ordered the $55 (shipped) welded/reinforced stock hemi rocker arms. I don't think there are any other options for Hemi's with 1:1 ratio.
http://www.ebay.com/itm/272740378666

 

[bob58o]

After a short month, the 48mm air pod is here and it fits.
$4 shipped

 

[bob58o]

I'm not a fan of how it looks.
It looks ridiculous sticking out like that, or is it just me???
Not a fan of how the rubber hose/boot fits the adapter either.
The ID on the rubber hose is larger than the OD on the manifold.
The hose has what is like a built in O-Ring(a few mm thick) , but the O-Ring ID is about the same as the manifold OD. A hose clamp will help.

Also it just fits on the end of the manifold. I'm thinking about getting a rubber sleeve to fit around the base of the manifold (matching OD of the "boot") then using a thick T-Clamp to secure the sleeve and the boot.

 

[bob58o]

I was looking at these Reduces.
https://www.pegasusautoracing.com/group.asp?GroupID=COOL35MM
35mm for the carb. (1 3/8")
32mm for the Carb Adapter. (11/4")

I was worried about the flow where the two met inside the hose.
I assume there would be a gap between the adapter and the carb. Meaning it would go from 24mm (ID Carb) to 35mm (ID hose1) to 32mm (ID hose2) to 28mm (ID Adapter) then to the head.
I figured a thick O-ring (like 36mm OD, 28mm ID)
http://www.ebay.com/itm/Viton-FKM-O...4b847c9&pid=100033&rk=1&rkt=8&sd=162299191775
between the two would help if using a straight reducer. I imagine it is not stepped inside the hose, but IDK.

If I really hate how far out the carb sticks and can't live with it, I was thinking this 45 pointing it towards the back of the bike, but I think the gap between the carb and the adapter (at the bend) - not to mention the fact that it bends - would hurt flow. Because of the bend, a simple o-ring wouldn't work. Again, I don't really know.

I think my best bet is to use the hose that came with the carb.
There's a ridge in the middle that acts like a venturi between the carb and the adapter. Both pieces butt up to that venturi. It acts like the "O-Ring" I would use with the straight reducer.

So I got some 32mm ID Silicone hose.
http://www.ebay.com/itm/1-25-inch-3...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649
I'll cut a sleeve 5/8" long and put it on the base of adapter. It is probably 1.64" OD. The hose that came with the carb is 1.8" OD. I figure I could wrap the sleeve I make with some duct tape. Like 5 times around should make a 1.64" OD hose into a 1.80" OD hose.

Then I'm going to take this T-bolt clamp
http://www.ebay.com/itm/Mishimoto-M...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649
and put half on the 5/8" sleeve I make and half on the hose that came with the carb.

I feel this should secure the carb much better than just a hose clamp around the 1/2" of the hose that actually goes on the adapter. Turning the 0.5" deep boot inlet into a 1.125" deep boot inlet, giving me much more to clamp on to and secure the carb. This may not work at all????

I may try to boil the 32mm ID hose and see if I can get it to fit the 35mm OD of the Carb. Then use one of the O-rings.

If all fails, I'll buy the straight reducer, cut to length, use an O-ring between the two parts, and use two clamps.

 

[ezcome-ezgo]

So you're troubled by the aesthetics of the long intake, but not troubled by the use of duct tape?

 

[bob58o]

So you're troubled by the aesthetics of the long intake, but not troubled by the use of duct tape?

Not at all. It would just be one band and it would be covered by a shiny SS clamp. Nobody but us would even know it was there.

I googled how thick duct tape is. Like 11 thou for the cheap stuff and 17 thou for Gorilla stuff.

My duct tape usage is still very scientific.

 

[ezcome-ezgo]

GAB on the duct tape, I like it.

 

[Kentucky Boy]

I think it looks awesome.