67 tunnel.

[jeff baham]

where can i buy a 67 size tunnel hull or what length would be the right sze for a K-B 67 outboard motor stock.

 

[Bob Kensill]

The HTB360 from Mark Hopper is the boat to get.

 

[jeff baham]

do mark have a web-site.

 

[Russell Bear]

Hey Jeff, Try this one....

http://www.precisionboatsracing.com/

 

[Jerry Dunlap]

I would also recommend the HTB 360 for a 67 outboard. I just installed a 67 K&B on my 360 and it runs really well. However, the stock 67 isn't as fast as my K&B 7.5 Pro.

JD

 

[[email protected]]

Jeff,

The Bandit 35 inch hull works great.

http://www.banditboats.com/tunnel.htm

 

[DaddySundown]

The HTB 360 I like. Mine has a tuned pipe and really lights up the water!

 

[Guest_bzubee]

try www.HTBBoats.com

 

[Rules]

I also messed with the early 67 with only fair performance. I bought 4 for spares, and ran twins with custom built opposite facing Equi (Equalizer) 65 pipes on an Aeromarine Cat boat. I built the thing as a toy and a test bed for the new engines and entered the '88 IMPBA Top Gun twin event in Huntsville. My driver wanted one of the "Top Gun" hats they were giving if he made it to the finals. We stumbled into the finals, (using our emergency plan with stock 45's) so he was happy . I found that the engine had lots of problems. The compression was incredibly low for good performance, and even re-machining the chamber would not work, since the water jacket hit the block. I ended up re-machining Rossi 65 chambers which seemed best at .005 clr. The engine ran way too cold,so water restrictors were added. Next thing was the lousy carb, way too big, again Rossi 65 was used with adapters I machined. The engine balance was way off, and even with a lightened piston and "I" beaming the rod, it was still rough. :angry: I slugged the early style crank with 2 tungstons before the balance was even close. Then I squared the ports to see if the thing was air starved, no change. Finally I Packed the case with RTV to raise the primary compression and saw good promise. I scrapped the pipes and made new ones with longer midbands to lower the "kick-in" RPM which worked great. With the engines running correctly the boat was way too light since the CG was un-correctable for a race boat. If the engines staggered, as the pipes kicked in, the hull would vioently spin and roll, no way to put points on the board!!!(which prompted the use of 45's). It was a good thing I could buy wholesale since I owned a hobbyshop, I broke skegs on 9 sets of lower units which were machined for O-ring attachment to the engine. I later saw that K&B added a fillet at the factory to reduce skeg harmonics, which was far better than my Epoxy fillet.

So my personal advise for piped 67 O/B twins on a Cat boat, GOOD LUCK, YOU'LL NEED IT! :unsure: :unsure:

John in Huntsville

 

[DaddySundown]

I freind of mine is going to attempt putting a pair of stock 67's on a 41" Stryker Cat. Hope he does not run into those kind of problems.

There is nothing like the sound of a twin engine boat!

 

[Rules]

Daddy, that hull sounds like it might work out better, longer to keep the C/G further forward, where the tanks are located. Also by keeping the motors stock, he won't have the lurch and flip like we had. It won't be fast, but most likely a lot of fun. He will gather points by sheer endurance since there are very few twins finish "running" at the races I have seen. If he sleeves the original carbs or re-carbs he will have good performance. I think there is an inherant problem with the stock carbs, that really messes things up. A pointer, I ran 2 each 134 ($25.00) servos & short 4-40 rods to an external 1/8-3/16 inch thick, wide as practical (3-4") Alumimum T6 bellcrank with sealed ballbearings. The bellcrank was mounted on a beefy structure attached to the radio box. Then massive 1/4 inch rods/arrowshaft rods were run to small ballbearing Heim joints on home made tiller arms, on the outmost points of the foot flange, not the engine rails. Then I mounted a tie rod with more Heim joints connecting the engines, similar to Latham Marine designs. I drilled/tapped the rear corner of the foot top flange and had the bar below the engine/foot mounting surface. The bellcrank gives a mechanical torque increase which I needed, servos on the outside, and dumps all of the loads into the bellcrank pivot 3/16 Allen bolt. The other advantage is a closed loop for zero steering slop with the Heims, and complete control even if a link breaks somewhere in the loop. With the boat held on it's side, the servos will easily, easily lift the engines to any position with a 6 volt, 1800ma pack. All my outboards used this system, no whimpy cables which kicks you to a DNF if something breaks. Rods guarantee points, so I can't see why anyone would ever, ever, think of using cables. The bellcrank is work, but allows straight runs for the steering. Have fun!!

 

[DaddySundown]

Thank for the tips Rules, this ought be be interesting.

 

[Tommy Lee]

I had really good luck with the K&B 67, of course I had it on a really good boat that I built for the engine. The powerhead was STOCK with a GERAGHTY carb and a custom made pipe from JOHN EQUI. I set the IMPBA oval record at 22 secs. and change. If you don't think that is fast, try going around the course in 11 secs. I never had any problems with the engine until I broke a flex shaft. over revved the engine and scattered it into little pieces but hey the performance was great. I am not bragging. the point is that as bad a reputation as this engine has when set up properly on a good boat it is awesome. You will always have flex shaft problems with this much power on a 3/16 cable but with proper maintenance it will give good service.

 

[lohring]

I helped the flex shaft life on my K&B 67 by running a "pressure" lube system. I used pipe pressure to a tank filled with automatic transmission fluid through a fitting into the lower unit. Two oz. lasted for several heats. Castor oil probably would work as well and is better for the pond. I haven't broken a shaft since I started using the system, but I don't run as fast as Tommy. By the way, the Leecraft XT-460 can be very fast with an 11cc engine. It requires careful driving in the corners. My thoughts on props and setup are found at www.BandMLeecraft.com

Lohring Miller

 

[XtremeRcBoats]

I use the same pressure system. My oil mix is 25% STP teflon oil and 75% just normal car oil. Works pretty wel.

 

[Tommy Lee]

Lohring-I agree with you completly on the XT-460. I have seen some drivers who have that midas touch, go really quick with that boat. We all know it wasn't designed for that engine but it is still a great boat. Another idea on the shaft oiler, I used a small shock body from an offroad car mounted on the side of the engine as a reservoir and it just gravity fed into the lower unit. Fill it before each heat and you are good to go. The pressure system seems like a good idea but I was always nervous about robbing the pressure from the engine when there is not that much to begin with. But hey, whatever works is all that matters.