"Stage 5" Predator 212

[idkcool]

I want to build a predator 212 non hemi, "stage 5" that runs on e85 and I got a few questions to ask. Are there any dangers to running 356 cam with 1.35 ratio rockers, 55 lb dual valve springs? Such as coil binding? Can there be too much compression with a flat top piston, 0.010 head gasket, and a 22cc head milled 0.065? Will there be any risks involved after installing a 56mm stroker kit, or a 58mm stroker kit? I want to keep the stock block but it would be fine if I buy a new racing block with a 72mm bore. Also I'm not an experienced builder but I know someone who is very experienced with building engines.

 

[flattop1]

Yes coil bind is a Possible problem . Thats a lot of lift . Long valves may be needed .
not too much compresion , only a problem if theres detonation or valve piston contact .
in addition there may be plug too piston contact .
Additional stroke can bring interference problems .

 

[bpoirier]

You will run into coil bind for sure. I'm not sure if they make valves long enough to do the 356 cam with the 1.35 ratio rockers. You'd also have to find springs to control the valves. The 55's may not be tall enough at installed height. An off the shelf 308 or 310 cam with those rockers and springs would make a solid setup. I'd also reconsider the e85 fuel. I've experimented with and the alcohol level is never consistently the same. I chased the jetting all over the place. I just went to straight methanol and the engine runs great. As far as the stroker crank they are always a good choice. You'll have to do some clearance work to the stock block. The Tilly 72mm race block and stroker kit they sell is the way to go in my opinion. I've built several of these engines and they run great, are reliable and make very good horsepower. You didn't have any specified carb but I's look at a 28mm PWK or Mikuni jetted for alky.

 

[Hobbs]

I second the Tilly stroker kit from ec carbs and the methonal. Stay away from e85. I also second the 308/310 cam with 1.3 rockers. And just FYI you’re not going to be able to reliably pull start this engine. You will need an electric starter.

 

[Darreng]

Ducar/Predator 224 block comes with a 58mm stroke crank, they are also reinforced, the Tillotson block has even more reinforcing to prevent the neck and crank case separating. You'll need a billet rod, these are good for any abuse that's thrown at them. Any good Aluminium flywheel. Billet side cover for strength and double bearing support to the crank. Now you can add performance, the engine is basically an air pump, the quicker you can get air in and the quicker you can get it out the better it will perform, in other words gas flow the head, buy a gx160 head, they range from 16-18cc, this will up the compression without skimming. Install stainless valves something like 32/28. Warning you're now into dangerous grounds, 56lb springs will require molly rods, seats machined and you'll obviously install stainless followers with gage 1:1.3 rockers. The engine will breathe heavily so you'll need to install breathers from the block to rocker cover, then a vent to atmosphere, you can use a catch can or a simple filter, a one way valve is your choice. KEEP ANY PRESSURE OUT OF THE CRANK CASE Look at Pauls Karts or old MINIDRAGBIKE videos
Now you can start to get the engine to work, aim for 32-34BTDC ignition, PVL if possible for a stronger spark, clock the cool running spark plug if you want. Carburettors are a minefield, you need a good idle and main jet circuit with full adjustability, I don't run a carb, my engine uses fuel injection, some of the other guys will give you some good advice on carbs, although I'm more of a flat slide fan, Black66 has some videos on youtube for good carb setups. Next move onto exhaust, seems most use some sort of torque tube, Robertsons have good results, again I like a nice exhaust note, so I'm willing to sacrifice a little power for a sweet sound.
Enjoy the build, it's a great learning experience.