Paul's Karts Head

#1
Hey guys, new to this forum and I have a question.

I'm currently doing my first full build and I ordered a head from Paul's Karts. It's a Predator 212 hemi head with a welded intake tube, 60lb valve springs, big titanium valves, etc. Basically his flagship product with all the options.

I'm waiting on it now and the excitement killing me. I've never had an upgraded head, just valve springs.

What can I expect out of this thing?
 
#2
his heads have a reputation of being overpriced and underperforming. if you go to po boys forum on Facebook some of his customers have complained about issues with his stuff and sent his pauls head to Barry young to fix. He flowed it stock and after fixing it and it was bad as received and performed well after Barry filled port with epoxy and reshaped it. I do not have any hands on experience with pauls stuff so I can’t say his reputation is deserved or not.
 
#3
What experiencence does any body have on a head that performed well? Where did you get it? Should I just go to my local machine shop and get them to tune it up?

have a built bottom end but man 600 bucks or more for a head. I can buy a 14 horse with electric start and Frankenstein this thing!
 
#4
What experiencence does any body have on a head that performed well? Where did you get it? Should I just go to my local machine shop and get them to tune it up?

have a built bottom end but man 600 bucks or more for a head. I can buy a 14 horse with electric start and Frankenstein this thing!


That's the video that sold me on his product.
 
#5
I have done quite a few heads and basically charge $185.00 setup with springs of your choosing. there is a slight extra charge for TI retainers. You have to match the head to the engine. The head determines the max power the motor can make but does not by itself do that, If you put a big valve high flow head on a low compression stock cammed engine with stock valve springs and a govenor (as an extreme example) you would have less power than the stock head. The camshaft is the heart of the engine. You can somewhat work around some head limitations by careful camshaft selection. Also max lift is determined by the intake valve size duration and lsa by the intended application. The following people are know for their heads and will be a lot cheaper than Paul's karts. Barry Young of Barry Young engines, Johnny Berry of laid back racing, Jason Anderson of Janderson racing heads. Jason is an amazing head porter but is busy with automotive heads a lot of the time as he is known for his NHRA stock and super stock work and certain times is too busy for the little heads.
 

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#8
I'm probably not the right guy to do it since I've never had a performance head before but I'll put up a video reviewing it as soon as I get it.

I mostly cruise on the streets and my bike has a predator 212 hemi with 18lb valve springs, jet, air filter and pipe.....the basics.

The new engine I'm building has a ARC billet flywheel, billet side cover, billet rod and piston (stock bore and stroke), Dyno cam .315 grind, mikuni 28mm flat slide and this head that I ordered from Paul's Karts.

As I stated, I'm pretty much riding stock and I have no idea what to expect out of this new engine and head. Will I be at 15-20hp? Is this thing going to scare me?
 
#9
It will probably run good until the 60 LB springs wipe out the cam. Actually I am sure he does not check seat pressure and in some of his other heads the valves were longer so the seat pressure was very low. You should get the correct springs to match the cam. Dyno specs follow.
Engine: 196cc OHV Clone, 212cc Hemi PredatorRecommended Class: ModifiedTarget (MAX) RPM: 9000Spring Pressure (In / Ex): 34-36 lbsValve Lash (In/Ex): .003"Ignition Timining: 34 Deg BTDC
Can I ask why you did not ask here first about your build? Your build is for a top end motor. Are you using a tc or a clutch? With a clutch you will need a lot of gear. In addition pay attention to your valve to piston clearance with a hemi. What are you using for rocker arms? Does paul supply you with flow data? That would have helped with cam selection. What was the thinking behind the .315 cam? Just curious, its a good cam for drag racing with the proper gearing but for the street the 308 would have better overall manners.
 
#10
It will probably run good until the 60 LB springs wipe out the cam. Actually I am sure he does not check seat pressure and in some of his other heads the valves were longer so the seat pressure was very low. You should get the correct springs to match the cam. Dyno specs follow.
Engine: 196cc OHV Clone, 212cc Hemi PredatorRecommended Class: ModifiedTarget (MAX) RPM: 9000Spring Pressure (In / Ex): 34-36 lbsValve Lash (In/Ex): .003"Ignition Timining: 34 Deg BTDC
Can I ask why you did not ask here first about your build? Your build is for a top end motor. Are you using a tc or a clutch? With a clutch you will need a lot of gear. In addition pay attention to your valve to piston clearance with a hemi. What are you using for rocker arms? Does paul supply you with flow data? That would have helped with cam selection. What was the thinking behind the .315 cam? Just curious, its a good cam for drag racing with the proper gearing but for the street the 308 would have better overall manners.

This is my first build and I just found this forum. I got the cam from a buddy, it's new. I plan on using a clutch and I have not purchased rocker arms yet.

I'm definitely open to suggestions and advice. I'm not looking for a 80mph cruiser like some of the kids. 60mph is good enough for me. I just want to be able to punch it at 30 and feel some good acceleration.
 
#11
This is what I have so far. The only things I've done are changer the case bearing to a better german made one and clearanced the crank.

20210409_141557.jpg
 
#14
you are off to a good start. When assembling the engine before installing the rod, install the sidecover then measure the crank and cam endplay. When you change the sidecover the original endplay goes out the window. If the cam has too much endplay you get variable valve timing due to the helical gear going in and out. you can reach thru the bore grab the cam and it should move back and forth just enough to feel and if you cant feel any movement but it is free that is OK.
 
#15
Let us know when you get the head. If it really has 60lbs of seat pressure you may have issues with the stock rockers. Hemi heads have an issue where the rocker or the pedestal itself can break. The other issue will be rocker arm geometry. You are going to need to understand fixed pivot rocker arm geometry. When you have a fixed fulcrum rocker you need to set geometry on both the valve side and pushrod side. With aftermarket non hemi roller rockers like gage or EC you have to set fulcrum height to set valve side geometry. After that you set pushrod side by the pushrod length. On a stock hemi rocker the adjuster sets the valve end geometry as the fulcrum is cast in the head and cant be shimmed or moved. Aftermarket hemi roller rockers this cannot be adjusted. You can only change the rocker geometry by pushrod length but its usually close enough. Gage motorsports has a great video that explains setting the non hemi roller rocker geometry and you should watch it to understand rocker geometry. You can also google Jim Miller rocker arm geometry to learn about the mid lift method of setting geometry.
 
#16
Let us know when you get the head. If it really has 60lbs of seat pressure you may have issues with the stock rockers. Hemi heads have an issue where the rocker or the pedestal itself can break. The other issue will be rocker arm geometry. You are going to need to understand fixed pivot rocker arm geometry. When you have a fixed fulcrum rocker you need to set geometry on both the valve side and pushrod side. With aftermarket non hemi roller rockers like gage or EC you have to set fulcrum height to set valve side geometry. After that you set pushrod side by the pushrod length. On a stock hemi rocker the adjuster sets the valve end geometry as the fulcrum is cast in the head and cant be shimmed or moved. Aftermarket hemi roller rockers this cannot be adjusted. You can only change the rocker geometry by pushrod length but its usually close enough. Gage motorsports has a great video that explains setting the non hemi roller rocker geometry and you should watch it to understand rocker geometry. You can also google Jim Miller rocker arm geometry to learn about the mid lift method of setting geometry.
I have not purchased rockers or push rods yet. Definitely not going to use the stock ones. Do you have any suggestions on which to use and ratio?
 
#18
I have not purchased rockers or push rods yet. Definitely not going to use the stock ones. Do you have any suggestions on which to use and ratio?
I do not I am currently using the stock ones with 37 lb springs and a custom isky grind with 330 lift. I have not run it enough to say if it will last or not.
 

65ShelbyClone

Well-Known Member
#19
This is the box that the German case bearing came in (no pun intended). I made sure to lube and pack it (also no pun intended). View attachment 277527
Trivia: If you've ever wondered what that stands for, it's "Fischer Aktiengesellschaft." It is a bearing company founded by Friedrich Fischer in the middle 1800s which of course predates the modern meaning if pronounced as an acronym. The brand is now owned by INA. They're good bearings IMO.
 
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