Hemi predator build

SnakePliscan

SnakePliscan

New Member
#41
#41
How many horse per cube?

fastreddevil1 said:
What kind of power are you expecting from this
Click to expand...
I like to use the 1 Hp per cubic inch rule, for the average motor that is acheived with improved intake and exhaust, mild porting and a cam in the 220-230 degree range.
Wulfs motor has decent porting, raised compression and a big duration cam, (324* gross so 260ish net); With a proper sized slide carb and header (valve seat finish will factor a bit too) he'll be between 1.25 and 1.5 Hp per cube.
So 13 cubic inch x 1.25-1.5 = 16.25-19.5 HP

The higher # if he jets it right, Solid mid to top end power.
 
Last edited:
David wulf

David wulf

#42
#42
SnakePliscan said:
I like to use the 1 Hp per cubic inch rule, for the average motor that is acheived with improved intake and exhaust, mild porting and a cam in the 220-230 degree range.
Wulfs motor has decent porting, raised compression and a big duration cam, (324* gross so 260ish net); With a proper sized slide carb and header (valve seat finish will factor a bit too) he'll be between 1.25 and 1.5 Hp per cube.
So 13 cubic inch x 1.25-1.5 = 16.25-19.5 HP
The higher # if he jets it right, Solid mid to top end power.
Click to expand...
Snake that sound good , if I can get that or close I'll be a happy camper .
 
David wulf

David wulf

#43
#43
Well today I got my other head pulled off the other Honda 160 I have . I have always thought it was probably a 18cc head because it's a newer motor that the other one I have .
Well after pulling the head this 160 has a flat top piston which supposedly means a 18cc head . The 14cc head 160's had a dished piston . The number on this head is ZOT 5 which I've never heard of , but the chamber looks close to the 14cc just bigger .
I've read that these 18cc heads are supposed to have really good flowing ports , but just a bigger chamber.
 
David wulf

David wulf

#44
#44
And yes I pulled it from a perfectly good running aircompressor, will put the clone head back on it .
And one more thing I weighed my clone side cover with bearing installed and my Honda 160 cover with bearing to . The Honda cover weighs 5oz more than the clone cover . Now I was going with the Honda cover anyway, because they are stronger . 5 oz's of aluminum is a good start to maybe why .
 
David wulf

David wulf

#46
#46
Ok back to the build , I got parts today for the predator . A stud kit and side cover gasket , oil seal and 1.3 billet rockers from NR racing .
Got the studs installed and the cover on .
I'am kinda on the fence about using the the rockers with this cam . I have found out from my friend OLE 4 that this combo puts me at .400 lift , and gives me some valve train problems to deal with . I think my plan is to use my champion rockers this build with the 36 lb springs I have .
For a carb I'am gonna try the VM 26 mm 606 mikuni that is on my pit bike 140cc motor . This motor makes 12.5 HP they say and is right on the
edge of being to big for it . But ti runs and revs great with the 155 jet and I can get a 140-145 for it if I need to go smaller .
 
SnakePliscan

SnakePliscan

New Member
#48
#48
Valve guide seals with a big cam and big lift, do we need im?

If your worryed about the retainers hitting the valve guide seals with 0.400'' lift, the easy fix is remove the seals, with as big a cam as your running your not gona pull a lot of vacuum on the intake side or oil down the guide as a result. so really your probably better off with out them.
 
ole4

ole4

#49
#49
Coil bind will be the issue if he is using true 1.3 ratio rockers with a .308 lobe lift total lift will be .400 and the 36lb springs will coil bind at .450 inch compressed height. Average installed height with aluminum retainers and the regular key locks that I see are around .830 so if his spring pockets are not cut he will hit coil bind. I don't know what size valves you are using but with that much lift you would benefit most with a 32mm valve. If you are going to use 27 or 28mm intake I thing you would be better served with the champion stud mounted 1to1 rockers and use the billet 1.3 rockers on your engine with the black mamba which is a known killer combination.
 
David wulf

David wulf

#50
#50
Well today I made a decision to pull the dyno 308 out of this motor and go with the black mamba and the 1.3 billet rockers . After swapping out the cams I started working on the head , I had already taken off about 30 thou . I made a valve spring compressor from a C clamp and got the 36lb spring s in and the retainers on , the valves had already been lapped and I checked them by filling up the ports with water an no leaks . Then I got some play- douh and checked the clearance and decided to take the head to 65 thou . I got a little carried away and ended up with 78 thou off the head . So with 20 ITH and a .009 gasket the NR racing chart puts it at about 12.7 to 1 . Looks like a race gas motor .
I checked the clearance again and have about 60 thou from the piston to the open valves .
 
ole4

ole4

#54
#54
Black mamba w 1.3 rockers is a great combo mine has a wild idle and is really strong from 4k up till I get scared. And back off. Motor looks great!
 
SnakePliscan

SnakePliscan

New Member
#55
#55
Ok So your 36lbs springs are installed at 0.830 and they stack at 0.450, that leaves 0.380'' for travel.
The Mamba lifts 0.275 x 1.3 = 0.3575 - 0.003 (lash) = 0.3545'' lift.
And 0.380 - 0.3545 = 0.0255'' before coil stack.
So thats a little tight so the springs may run a little hot over time.
On the up side if you ever float the valves it will only be 0.0255 and you don't have to worry about piston to valve interference.
 
David wulf

David wulf

#56
#56
Well today I got the push rods cut down and the head on and torqued down . And the rest of motor together. I decided to put it on my rupp for testing , so I got her bolted on . For a carb the 22mm mikuni that was on my 160 was still hooked up on the rupp and it will bolt right up,to the predator along with the he
 
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