Looper & X-flow in same production years?

[Boilermaker]

Why did OMC produce Crossflow & Looper engines in the same years??? If the loop-charge engines are so much stronger then the x-flows, why not just produce the loop-charge engines??? <br />Is there a down side to loopers??? <br />And why all the differant "Vee" angle blocks>>>60* 90* ect????

 

[Dhadley]

Re: Looper & X-flow in same production years?

Yes, they were produced in the same years sometimes. And then theres the question about why did they bring out the V4 and V8 loopers in 1985 but not the V6 looper?<br /><br />To be honest I'd bet it had something to do with contracts with vendors. OMC (and most every other engine builder) has contracts to purchase a certian amount of product each year from certian vendors. If they didnt, the vendor charged OMC for it anyway. And sometimes that "left over" product found its way into aftermarket companies.<br /><br />The other thing was tooling. OMC had the looper technology for quite some time but didnt bring it out until Yamaha forced them to. In the begining the V4 looper blocks werent cast here in the states. They were cast in England.<br /><br />The downside of the original loopers was the weight. Definately a concern in some cases. But man do they make torque!<br /><br />The 60 degree blocks make for a quicker revving motor and lighter block. All engineering theorys that obviously have merit. Theres all kinds of configurations -- 90*, 72*, 60* etc.<br /><br />It all makes it interesting to follow along, doesnt it?

 

[Boilermaker]

Re: Looper & X-flow in same production years?

Thanks Dhadley,<br />Must be fun keeping inventory on all the different configurations!<br />How much difference in V4 engine weights>>>say a 115/120Hp???<br /> Also, are the current production Johnny-Rudes Loop Charged, Crossflow, or both???

 

[Mercathode]

Re: Looper & X-flow in same production years?

OMC made their 1st looper in '68. It was 55 horse. In the early 70;s they came out with a 2 cyl looper at about 50 horse. Often times a company will not introduce a new style because of the cost of development. OMC went as far as they could with the cross-charged engines and when ready they introduced their loopers. <br /><br />OMC used a 90 degree blocked becase their early V-6's shared the same block geometry as did the V-4 so they used existing technology. Example: A 1976 135 Johnson had the same bore/stroke as the 200 V-6. OMC just stacked 2 more cyl on their V-4's. Merc started their V-6 program from scratch and they used the narrow V for higher RPM operation and quicker rev. If you ever wonder why just think $$$$$$