See full version: How to identify crossflow or looper
ok thanks fellas. So i am assuming that cutting heads on loopers with reeds and possibly bigger carbs will net a stouter engine than doing the same on a crossflow. and then again I am talking about same hp motors. Both motors being sam hp and rated at propshaft and not one at the crank and the other rated at propshaft.
You're comparing apples to oranges. They never made a crossflow rated over 115hp at the prop to the best of my knowledge.
Theres more to overall performance than top speed. The looper will pull harder from holeshot and will go faster propped right.
I see there are two models listed for my year and HP:
120TLCU & 120TXCU more
I have been searching for ways to figure out if my motor is the looper or the crossflow version and all I have been able to find is other users who can tell by the serial number but unable to find how they know that.
Also does anyone know what the last letters are for? the model run or suffix..all I see is it's not important to consumers, but I am just curious. Is it like the batch number in case of recalls? [links]
Is it the L (for looper) and the X (for X-Flow) in the model numbers that let them know which one is which?
Since there is no "L" or "X" listed in the design feature cross reference charts I am guessing it may be the case.
Not all 90 degree engines are crossflows, some are loopers.<br />As to the original question. The names refer to which induction design the engine utilizes. Crossflow engines have pistons that have a deflector which directs the intake charge towards the combustion chamber and prevents the air/fuel charge from going directly accross to the exhaust ports. A Loop-charged engine, as mentioned earlier has flat or slightly domed pistons. Carefull location and design of the intake ports ensure the air/fuel charge is directed into the combustion chamber and not towards the exhaust ports. Generally crossflow engines are smooth running, especially at low speeds while loopers are a little rougher but tend to make more power while being a little more frugal with the fuel. more
Actually 60 or 90 degrees has nothing to do with it. There are some big bore 120's, 130's and 140 90 degree loopers and single bank loopers. <br />Loopers and crossflows have different fuel mixture paths from the carbs to the cylinders. Crossflows simply full the crankcase with fuel mixture and the mixture enters the cylinder through ports above the piston when it is on the down stroke. Loopers pass mixture through corresponding holes (ports) in the lower skirts of the pistons and the cylinder walls. These ports lead to chambers that go around the outside of the cylinder wall and to intake ports higher in the cylinder walls back into the combustion chamber. The mixture "loops" around the piston. Thus the name Looper. That's about as simple as I can put it. I have some diagrams of the flow paths of each type but my scanner is down right now.
All V4 and V6 crossflows have bolt on covers over the intake passages called by-pass covers. They also have bolt on exhaust plates on the block and water jacket covers on the heads. In short, a bunch of bolts and covers.<br /><br />V4, V6 and V8 loopers do not have any of these bolt on covers. [links]
The difference between a 60 degree and a 90 degree is the angle of the vee form by the connedting rods as the point toward the heads.<br />A 90 degree motor is much wider across the back of the motor. A 60 degree would appear much narrower if it were setting next to a 90 degree motor.<br />90 degree are cross flow motors (they have domed top pistons which direct the flow of the fuel and air entering and exhusting the combustion chamber.<br />The 60 degree motor is a loop charged motor and has flat top pistons. <br />--------------------------------------------------------------------------------
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