What would I need for around a 10 or 11 horsepower clone, e.g. compression, lift and duration, timing, etc? This will be on gas up to 93 octane. I want to put this together myself without any high dollar parts. So far what I have to work with is a cam (origin unknown) with .275 lift, billet rod and flywheel, 14cc head, Holy Moses carb, 3 stage header, (1) 1.3 ratio rocker arm, and some assorted springs up to 18lb. I'm thinking this should be easy and maybe with the stuff I have now. Some of you may want to know that this will be used on a 1/2 mile, very tight sprint track, and I really don't want to buzz it past 6200 rpm.
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Clone recipe
- Thread starter jamiespop
- Start date
clone king
New member
With ratio rockers on a 275 cam its gonna want to buzz more than 6200. i promise.
youngengines
Member
^^Good advice above^^
With 1.3 rockers and 18lbs springs you may have coil bind, go with 26's,and use good valves (SS or stock Honda?) I'm pretty sure the 1.3 rockers add 30% lift to your cam
Wouldn't the 26 pound springs be even more prone to coil bind? I would assume they would be made of larger diameter steel. Also what about pushrod length and guidance? Thanks.
You need to know what 275 cam you have to know where peak power is, go to dyno cams web site there is two different ones with different rpm peaks. Isky has a 275 also, not familiar with any of them except dyno f275 and you wouldn't find peak rpm on that cam with 1.3's till around 8000 + or so if I can remember correctly.
How do you know this without putting it on a dyno? Not trying to be difficult, just trying to see who actually knows what they're talking about. You get alot of contrary input on these forums, and you have to sift.Peak will not be at 6200 it is falling off then.
Wouldn't the 26 pound springs be even more prone to coil bind? I would assume they would be made of larger diameter steel. Also what about pushrod length and guidance? Thanks.
No the 26 springs are stronger will let it rev out to higher RPM's , coil bind is when the spring is compressed to much, weaker spring easier to compress, valve float make sense? pushrods standard length will work ok.
I would try the cam you got and stock rocker length and the 18lb springs and see what you got. Wont cost you a cent you already have the parts.
We may be talking about three different things here, Dyno states a target RPM of 7000, you stated you wanted maximum power at 6200 there is a difference. Now are you looking for maximum torque, maximum horsepower or maximum RPM. At high RPM torque is falling fast, horsepower is climbing because hp is a factor of t * rpm/5252 --- hp levels off at high RPM.
clone king
New member
26 Lb springs are shorter, and stiffer than tall 18 lb honda springs
The capable rpms or target range of a 275 & 1.3:1 rockers will be 8200-8400
The 26 lb springs won't like that rpm range very long
The capable rpms or target range of a 275 & 1.3:1 rockers will be 8200-8400
The 26 lb springs won't like that rpm range very long
A clone engine, billet flywheel for safety, billet rod for longevity, Ign timing advanced to at least 32* your choice of adaptor and filter, GX140 Etube, main jet .036", pilot jet .021" 26lb springs, 1.3:1 rockers, cam of your choice(within reason (clearance important)), big pipe, RLVB91 silencer, .010 head gasket, you will be at or over 10hp and safely rev to 64-6500 or more.
A clone engine, billet flywheel for safety, billet rod for longevity, Ign timing advanced to at least 32* your choice of adaptor and filter, GX140 Etube, main jet .036", pilot jet .021" 26lb springs, 1.3:1 rockers, cam of your choice(within reason (clearance important)), big pipe, RLVB91 silencer, .010 head gasket, you will be at or over 10hp and safely rev to 64-6500 or more.
OK thats what I'm looking for. 1.3 rockers on both valves?
youngengines
Member
My turn. If allowed..a Predator. Mod2 cam with a 1.3 rocker on the intake. At least stock style SS valves from Dover (S/A SS valves with aluminum retainers would be better), 26 lb springs. Port the head and mill it at least .050. Billet rod and flywheel. Bored carb (at least .650 venture) and meth if no rules against it. Then hold on.
This is good except the head porting stuff which I am not competent to do. Also, why a Predator?My turn. If allowed..a Predator. Mod2 cam with a 1.3 rocker on the intake. At least stock style SS valves from Dover (S/A SS valves with aluminum retainers would be better), 26 lb springs. Port the head and mill it at least .050. Billet rod and flywheel. Bored carb (at least .650 venture) and meth if no rules against it. Then hold on.