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Old 06-20-2016, 08:58 AM
aham2003 aham2003 is offline
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Default Hemi or non-hemi

Ordering another 212. I have dealt with them before, but not sure which is better. Does the hemi offer more power? It appears that the performance parts are all the same for both motors. Same price too. Which should I buy?

---------- Post added at 10:58 AM ---------- Previous post was at 10:44 AM ----------

Thought I should note, my only plans for the motor are governor removal, header, intake and bigger jets.
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Old 06-20-2016, 09:17 AM
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The difference is imperceptible, based on what I have read. Being able to say "I've got a hemi" is apparently worth 2-3 hp to most folks. The headers will not be compatible with both engines, I don't believe.
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Old 06-20-2016, 09:36 AM
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Ok. So not enough difference to matter which?
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Old 06-20-2016, 09:46 AM
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In my opinion, no. But no doubt some feel very passionately that there is a "significant" difference. If you want more feedback, just sit tight for a few.
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Old 06-20-2016, 09:56 AM
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Sitting tight as we speak lol. Thanks.
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Old 06-20-2016, 10:18 PM
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There is a tiny bit of info here, but better yet 99 dollar coupons!
http://www.diygokarts.com/vb/showthr...highlight=Hemi
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Old 06-20-2016, 10:53 PM
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Predator 69730 that says 3800RPM on the Box with the RTC-6 or RTC-8 heads are good.
Hemi Predator 60363 that says 3600RPM on the box is good.

All of the above have bigger valves I think.

The Hemi has 5.5mm valve stems.
The RTC 6/8 have 5.0mm stems.

Hemi has flat top piston.
Others have dished piston.

The Hemi has 0.5HP more than the Old Style Pred.
I am researching all of this now for a future build.



ALL ARE PROBABLY GOOD ENOUGH AND UNLESS RACING MAYBE WON'T REALLY NOTICE???

The 3800 RPM one says 55mm is like 2.8" so somehow the engines are decent without being able to do math???
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Old 06-21-2016, 05:12 AM
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How GAB should I go with this response??

Do you want me to steal flow data from each head and post it??
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Old 06-21-2016, 07:37 AM
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First lets discuss the metallurgical chemistry involved in the development of the alloys used in each application.
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Old 06-21-2016, 09:09 AM
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I haven't touched a non-hemi before, so I can't give an honest comparison, but I do have a hemi predator on my Manco Rattler and the thing PULLS
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Old 06-21-2016, 11:50 AM
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A hemispherical or domed combustion chamber is basically intrinsic to the overhead valve design which is the reason why I call the 69730 a semi-hemi. The hemi version is just a real hemi in the truest sense of the word.

There's also a difference in the valve train vis--vis the different types as the older style has the pressed steel rockers and the hemi has roller rockers retained by 'E' clips:
Attached Thumbnails
Cylinder Head.JPG   Hemi Cylinder Head.jpg  

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Old 06-21-2016, 12:18 PM
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Quote:
Originally Posted by Hellion View Post
A hemispherical or domed combustion chamber is basically intrinsic to the overhead valve design which is the reason why I call the 69730 a semi-hemi. The hemi version is just a real hemi in the true sense of the word.

There's also a difference in the valve train vis--vis the different types as the older style has the pressed steel rockers and the hemi has roller rockers retained by 'E' clips:
Do you know if all the predators come with 27mm intake and 25mm exhaust valves?

Is it just the honda's that come with 25mm intake and 24 mm exhaust?
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Old 06-21-2016, 12:25 PM
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Hemi it is. Thanks guys.
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Old 06-21-2016, 05:02 PM
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Quote:
Originally Posted by bob58o View Post
Do you know if all the predators come with 27mm intake and 25mm exhaust valves?
I know that's what the hemis have in terms of valve sizes. Specifications are difficult to find on these engines...
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Old 06-21-2016, 09:47 PM
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Also Hemi blocks are same as gx200 and clone engines.

Non-hemi Predator blocks are different.
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Old 06-22-2016, 11:00 AM
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Quote:
Originally Posted by Hellion View Post
I know that's what the hemis have in terms of valve sizes. Specifications are difficult to find on these engines...
Even though the OP has decided. And It was a good choice!

A little more on the heads.

Some non-hemi predator do have the smaller 25/24 valves. You need the RTC-6 or RTC-8 head, compared to the RTC-4 or JTXXX (JT -173 is one of em, I think).

There are JT heads on Ebay with 27/25 valves, but not sure how they compare to the RTC-6 / RTC- 8 heads.
$30 free shipping.
http://www.ebay.com/itm/22cc-Clone-G...3D201602266906

Only the RTC - 6/8 and the hemi have the 27/25 besides the above ^
The below have 25/24

TG-1 heads flow good, but warp sometimes due to the casting
JT - 05 are good
JT - 109 are good
JT - 139 are good

There are lots of JT castings. Most are OK, I guess.

RTC 6/8 use automotive style retainers keepers and have thinner valve guides (5 vs 5.5mm).


And that's all I have to say about that. lol
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Old 06-22-2016, 08:34 PM
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Quote:
Originally Posted by bob58o View Post
And that's all I have to say about that. lol
I don't believe that!
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Old 06-24-2016, 01:34 AM
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Quote:
Originally Posted by Hellion View Post
A hemispherical or domed combustion chamber is basically intrinsic to the overhead valve design which is the reason why I call the 69730 a semi-hemi. The hemi version is just a real hemi in the truest sense of the word.

There's also a difference in the valve train vis--vis the different types as the older style has the pressed steel rockers and the hemi has roller rockers retained by 'E' clips:
The 69730 is in no way shape or form a semi- hemi. I don't see any canted valves there, nope I even looked again. It is however a wedge head.

Denny
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Old 06-25-2016, 10:18 AM
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RTC 4 vs RTC 6
JT 173
JT with 27mm intake 25 mm exhaust
18cc
Hemi
18cc
Sickness!!!
Attached Thumbnails
RTC-4 vs RTC - 6.jpg   JT 136.jpg  

jt 27.jpg   hemi.jpg  

BradH.jpg   18cc head.jpg  

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Old 06-25-2016, 10:31 AM
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standard 196 clone head vs 14cc head
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14cc.jpg  
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