NWDave

Okay, I have an old fiberglass deep vee hull boat my Dad and I raced NAMBA B class Deep Vee and Mono in the late 70's to early 80's, and I'd like to get it up and running again. It's a 40" long Frank Ward built hull, which held the speed record for both deep vee and mono classes back in the day. We custom fabbed most of the hardware, and ran a rudder with the water pickup built in for less drag.

My main problem is the engine. We ran a carbureted rear rotor K&B 7.5 inboard, with the engine case turned around 180 deg., and the exhaust ran down the left side of the hull's interior. This boat has been stored outside in the garage for the last 20+ years. The original engine was all corroded inside, the piston was frozen to the sleeve. The crank case had some of its bolt holes repaired with heli-coils, and most of the remaining threads gave way when I went to take it apart. Not being able to find a source for a complete new K&B 7.5 engine, or parts for that matter, I sold it on eBay last year for parts. This boat ran on 40% nitro, and went 54 mph, but was pretty prone to barrel rolling from prop torque when it came out of the water. One major pain of running it at this power level was that it needed a new glow plug nearly every tank, to keep the performance up.

Though I haven't been into R/C boats for the last 20 years, I have a lot of recent experience with building, running, and tuning nitro R/C cars and trucks. Rather than start from total scratch with R/C boats, I'd really like to get this boat going again. The hull is still in good useable shape, as is the running hardware. The radio gear is also long gone, but I planned to put new modern equipment in it anyway.

This brings me to repowering it with a new engine. I've researched the OPS .45, the Picco .45, and the O.S. .46 engines. I really think the hotter CMB and MAC .45's would overpower the hull design, and are out of my price range. Of them all, I'm leaning towards the O.S. .46 since it's fairly modern, and readily available. I like to go with easily attainable parts, no custom order, custom built stuff that takes weeks or months to get when something breaks.

Sorry for the lengthy discription here, but I wanted to lay it all out and offer it up for opinions.

Thanks!

Square Nozzle

My Feedback: (1)

So what's the question? You seem to have it all lined up with good reasoning. I agree with your thoughts on an engine. The CMB or MAC would certainly be adaptable to the hull but would take some care in driving the boat to keep the bottom side down. I'm personally not an OS fan but the engine certainly is readily available. Price wise, is it really that much less than a CMB or MAC? Seems to me it was pretty pricey also. As I said, I'm not an OS fan so I don't pay attention to them. OPS has always been a good engine and the engine and parts are readily available from Aeromarine. Your money, your choice.

NWDave

Are you basing your opinion of O.S. marine engines from personal use? I don't have any experience with any O.S. marine engines, and don't know anyone running one either. I know they make top notch R/C car and R/C heli engines, I know this from first hand use. We ran the K&B engines back then because they were about half the cost of an OPS or a Picco engine, as were the replacement parts. I saw the OPS engines on Aeromarine's site, and they seem to be priced well considering they come with a pipe. The O.S. .46 needs a header, a flywheel, and a pipe, which does throw it up into the $300 price range. Now I'm rethinking my game plan.

Ron Olson

My Feedback: (1)

The OS .46's have a little problem with the cases cracking diagonally from one one of the intake side bolts to the flywheel side. I had one that didn't last long at all.
The OPS's I didn't care much for the carb as the barrel never fully closes because of the size of the hole as conpared to the barrel. I bought one but never used it because of that reason, I wanted a carb that would fully close.
Barrel rolling at speed was a problem with a few boats back then. A friend of mine had some 3-D hulls which would roll just about every time that he turned. It was kind of funny because it always landed upright and kept on going.

piper_chuck

My Feedback: (12)

I still see people saying good things about the OPS .45s.

NWDave

We had a lot of trouble with the K&B engines stripping screws, and cracking exhaust flanges from vibration. We ran a solid Octura engine mount, it was before the nice rubber isolated mounts came out.

Square Nozzle

My Feedback: (1)

Dave? You hit apon one of the issues with the OS marine engine. It comes with nothing while the OPS at least supplies the header and I believe the pipe. Besides, it's Italian and not japanese. I still carry this thing about japanese stuff. I was around on December 7, 1941. Rather young but somewhat aware. If I can avoid them I do not buy japanese products. Others may think I'm foolish but that's me. Another thing that bothers me about os is Tower Hobbies. The local hobby shop killer. Another place I choose to avoid, in favor of the local shop or in the case of R/C Boat items, the little guys that serve us on the web. Without them R/C boating would be dead.

NWDave-RCU

Wow, sorry I rekindled some bad memories from your childhood there. Hey, weren't the Italians against the U.S. in WWII as well? Strange how a fairly simple request for information to further my knowledge on a seemingly inocent topic has turned into a political venue for someone else to vent on..... Regardless of their country of origin, O.S. engines are some of the best, bar none. Maybe not the best for this particular application, but they rule several other forms of R/C competiton, hands down.

Tower Hobbies doesn't kill small local hobby shops either. With local small shops, it's usually their outlandishly high prices, lack of any useable inventory, and poor customer service that kills business. When a guy at a shop says he can order it for me, well so can I. Why place someone else, who could really care less, in the middle of your business? There's many other cheaper sources on the web for parts than Tower, which I use. I enjoy this hobby, and have no choice but to shop online because the local shops set things up the way they like them, and it's based on what sells the best, flavor of the month.

tazmaniaboats

hello dave
who are the other shops that you buy online from as i,m interested in buying some items
i think the problem with small hobby shops is the idea that evrey person that steps in the shop must be charged or let,s say must pay even
for a question ,idea .
that,s why this forum is fantastic because here we help each other for free .
in malta we have few shops but on 1 is abit human as he is a plane crazy guy.
martin[8D]