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Predator 212cc HEMI Ultimate Performance Package

Predator 212cc HEMI Ultimate Performance Package

Mar 22nd 2021

I recently purchased the above package and I have quite a few questions. I am a novice builder and wanted input on best methods.

1. Based on what I'm reading from manufacturer specs on all billet parts and flat top piston I will have to grind down my crankshaft, is this correct? If so what is the best method?

2. Are chromoly push rods recommended? If not what length is recommended and how does that effect other internals?

3. Are the stock rockers ok? If not what ratio rockers are recommended?

4. What are crucial clearances I should be looking for, for the piston, flywheel etc.?


Here we go 1) We sometimes have to grind the top of the crank journal to clear the cam lobes. The Hemi has squared off shoulders that can hit the cam.. I tape the journal off so I don't nick it, then I bust out the angle grinder with a flap wheel and remove the material. I will hit the square edge and round the whole thing out. You can do this on a bench grinder as well Once you have that done, install the crank and cam with the dots aligned and loosely put the sidecover on. Look down through the cylinder while rotating the crank and check for clearance. I like to keep .040" clearance between the lobes and crank

2) Chromoly pushrods are great insurance, but not always required. This is dependent on your cam choice and spring rate. I am OK with using stock pushrods with springs up to 26#. Pushrod lengthy is dependent upon what rockers you are using and if you have milled the head. Pushrods do not have any effect on anything other than the rockers and valvetrain geometry

3) The stock rockers are quite strong. The Hemi head has a shallow spring pocket that only allows for cams up to .300" of lift and the head can only accommodate a 26# spring unless you have machine work done. All of the aftermarket rockers are "ratio rockers" and will increase the lift. Chances are you can use the stock rockers. The cam in that kit has .265" of lift and the lowest ratio rocker is a 1.2 and that would net .318" of lift which will lead to coil bind

4) Here what I look for when building a Hemi: a) make sure the crank clears the cam b) Make sure the billet rod is not hitting the cam between lobes c) This should not be an issue, but check that the rod clears the bottom of the cylinder d) The Wiseco piston may put you at zero deck. We need .030" clearance between the piston and cylinder head to allow for crank flex. If you wind up at zero deck, we can get a thicker head gasket. Every Chinese engine is a little different and each needs to be checked! Once you have the rod and piston installed on the crank, get the piston to TDC and let me know that measurement and I can help you e) The rod and flywheel have literature indicating how to install and the clearances. We set the billet flywheel coil gap at .050". The instructions list a .030" as a minimum figure. f) When lashing the valves, set both sides between .002" and .003". This will make the engine easier to pull start and perform better g) If you have a dial indicator, it is a good idea to check crank endplay. I like to keep mine at .008" to .010". We have crank shims here.

Other than that, be careful when assembling, keep things clean, and check all clearances.