rz1a

I have a hyper .28 motor that won't turn over by roto or pullstart. The piston does move when you begin rotating around the clutchbell. Any ideas what I can do?

jmackani

iTrader: (14)

Pull the rotostart backplate off. Either the one way bearing is bad or you snapped a rod in the engine. Did you mean turn it over by the flywheel or the clutch bell. Normally the clutch shoes do not engage when turned over by hand and the clutch bell will not turn the crank over.

NitroXray80809

iTrader: (24)

If the engine isn't locked up by moving the flywheel like you said you can then you have a bad one way bearing on ur backplate starter(roto start/pull start). This is a very common thing, thats why most racer consider anything other then a starter box as garbage. Pull starts break quick and roto starts eat one way bearings. Putth then engine out of the car and take off the roto back plate and look at the bearing on the shaft. That i gurantee is ur issue. This happens because the bearings cant handle the force of a engine that has compression. To avoid this and get a little more lasting out of ur roto start or pull start pre heat engine with a blow drier or heat gun to around 175.

rz1a

Yes I meant flywheel

jmackani

iTrader: (14)

If it does not move with the flywheel, then you probably broke a rod.

rz1a

Sorry I'm a noob to this. It wil move with the flywheel and after moving it with the flywheel I'm able to move it again with the pullstart but then later can't move it again with the pullstart unless I repeat the process

What do I need to look at to fix this?

beidle99

iTrader: (9)

Finish breaking in the motor and always get the piston to the bottom of the stroke before it cools. Before the motor is broken in the mechanical pinch will be tight and the piston will stick at the top of the stroke when the motor is cold.

Zao18

Sounds like your piston is just getting stuck TDC (top dead center). Is it a brand new engine that you are breaking in? If so, are you using an engine heater (Comp Heat heater, heat gun, or even hair dryer). If not, you are in for a world of headache. You need to preheat the engine before starting, and always make sure to start the engine with the piston BDC (bottom dead center). You should also make sure the piston is BDC when the engine is turned off and cooling. You'll know the piston is BDC when you spin the flywheel and feel it push just past the tightest point of resistance, then move the flywheel just a fraction more. You can also know for sure by removing your exhaust manifold and actually watch the piston. Make a mark on your flywheel where the piston is at BDC.