Building a Hemi....for Dummies

gumpit

gumpit

#161
#161
Good point. What would be a good cam for
1)drag racing
2) fat bastard torque
3)good overall improvement over stock
Maybe if we start with each of those cams and work outwards we will have our “kits” so to speak.
 
M

moetrout

Active Member
#162
#162
I like my CS cam for drag racing. It's one of the cams Gray Goat suggested. I'd consider it a mild build cam that maybe an advanced beginner could handle if they educate themselves. It can spin to 7k rpms for good top end, but also still has plenty of low end torque to get you off the line. Drop in cam with no clearance issues. I am not much on doing videos, but I could try to get a good sequence of pics when I put my engine back together. First race is April 21st so it needs to get done soon.
 
gumpit

gumpit

#163
#163

I’m a dummy when it comes to cams but which category do you think this will fall into. We can use it as one of the three. Then someone can post another from another category.etc
 
gumpit

gumpit

#164
#164
moetrout said:
I like my CS cam for drag racing. It's one of the cams Gray Goat suggested. I'd consider it a mild build cam that maybe an advanced beginner could handle if they educate themselves. It can spin to 7k rpms for good top end, but also still has plenty of low end torque to get you off the line. Drop in cam with no clearance issues. I am not much on doing videos, but I could try to get a good sequence of pics when I put my engine back together. First race is April 21st so it needs to get done soon.
Click to expand...
Excellent. The more pics the better:thumbsup:
 
gumpit

gumpit

#168
#168
Well. Got the cam and the rod in. All holes are filled. Flywheel on.... waiting on the head(no hurry)Then carb,air filter,put the tank back on. Hook up the throttle linkage. Run the vent line. Exhaust.Test
 
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SmallEngine H.P

SmallEngine H.P

New Member
#169
#169
So I have a clone-of-a-clone engine it's from a Rural King water transfer pump called Country Way, when I have time I'll get the manufacturer name on the emission sticker below the KS but it had a hemi head on it and some kind of carburetor. 208cc. Meanwhile I have a genuine predator engine that I take parts off of and it has the non hemi higher compression head I put that on and ported the intake out pretty good and just rounded corners on the exhaust. Swapped the Rui Xing carb over, direct governor throttle / bypass and got some pretty good bottom end torque. But not as good top end as I remember with the hemi head. Wondering if I should open the exhaust up or what. Retard the cam CCW one of two teeth.
 
SAS289

SAS289

Well-Known Member
#170
#170
gumpit said:
Good point. What would be a good cam for
1)drag racing
2) fat bastard torque
3)good overall improvement over stock
Maybe if we start with each of those cams and work outwards we will have our “kits” so to speak.
Click to expand...
I'm interested in what the fat bastard cam would be? And I'm wondering if that fat bastard cam would work for a 180lb bastard? :laugh:

Also interested in the number 3 choice.
 
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gumpit

gumpit

#172
#172
SmallEngine H.P said:
So I have a clone-of-a-clone engine it's from a Rural King water transfer pump called Country Way, when I have time I'll get the manufacturer name on the emission sticker below the KS but it had a hemi head on it and some kind of carburetor. 208cc. Meanwhile I have a genuine predator engine that I take parts off of and it has the non hemi higher compression head I put that on and ported the intake out pretty good and just rounded corners on the exhaust. Swapped the Rui Xing carb over, direct governor throttle / bypass and got some pretty good bottom end torque. But not as good top end as I remember with the hemi head. Wondering if I should open the exhaust up or what. Retard the cam CCW one of two teeth.
Click to expand...
Id start with exhaust.....
 
M

moetrout

Active Member
#173
#173
If you ported the intake and if you put on a free flowing exhaust then you really should rejet the carb otherwise you will likely be running very lean. Those three things (intake, exhaust, carb rejet) should make some difference in power.
 
gumpit

gumpit

#174
#174
Head is out now getting done,I have a new stock carb and jets... header will be done when I decide which frame its going on. I am leaning on putting it on a baja warrior I picked up. I like the ride they give and have regretted getting rid of my last one... The other ones I have don’t need a motor built up.
 
gumpit

gumpit

#175
#175
I have not given up. Waiting on the head to come back.
Question on the header for a build like this. What ID should be used for the pipe? Or is it more important to have a smaller pipe with either a non restrictive muffler or no muffler or a bigger ID pipe with or without a muffler if that makes sense? Personally I would like to run some sort of a muffler even if it is just for looks and not so restrictive.
Also I am leaning towards one that goes under the seat and back so a kit type may be the best since I haven’t decided on the bike it’s going on yet.
 
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gumpit

gumpit

#177
#177
Fired mine up today. Now I need to figure out which bike to put it on. Came across this when I was reassembling. Push rods are pointing to the alignment dowels. Block allows for dowels in any spot. Head allows dowels in two lower holes. Gasket allows dowels in two of the diagonal holes. Needed to dremel just enough for the use of the two lower dowel spots.
 
Dr. Shop Teacher

Dr. Shop Teacher

#178
#178
gumpit said:
I have not given up. Waiting on the head to come back.
Question on the header for a build like this. What ID should be used for the pipe? Or is it more important to have a smaller pipe with either a non restrictive muffler or no muffler or a bigger ID pipe with or without a muffler if that makes sense? Personally I would like to run some sort of a muffler even if it is just for looks and not so restrictive.
Also I am leaning towards one that goes under the seat and back so a kit type may be the best since I haven’t decided on the bike it’s going on yet.
Click to expand...
So, here's a question the kart guys might be able to answer: The box stock (212 cc) RLV muffler is a 1/2" NPT muffler not the larger clamp on RLV. This means the exhaust pipe is pretty restrictive and I surmise adds back pressure. This for purposes of torque and not hp? This tall bastard needs the torque rather than the hp...:shrug:
 
gumpit

gumpit

#179
#179
O.k. Head is on. Linkage is hooked up like this.
https://youtu.be/4MtzJ0EriDc
Fired it up today with a header I forgot I had. I will probably add a muffler for more torque and to not be too loud. I did get it going 7550 rpms. Which isnt bad c9nsideringnI totally have no idea what I’m doing when it comes to valve lash adjustment.. But I seemed to get it close enough.
 
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