I'm hoping for a full field. Here are the rest of the images. Now it's on to porting, boring, and honing.
Tim
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Here is a different cage that could be used in one of those builds that doesn't have to comply with any rules. Slightly larger and maybe easier to mount. Attachment 50290Attachment 50291
[QUOTE=David_L6;124858]Here is a different cage that could be used in one of those builds that doesn't have to comply with any rules. Slightly larger and maybe easier to mount.
Hi David,
The 4-port cages look interesting. Have you compared internals dimensionally? The fact it's a pyramid already will save some machine work. Do you mind sharing the application?
Tim
I haven't done much measuring. They look bigger to me though. Those are from a McCulloch.
Sorry to hear about that.... Pretty as the McCulloch cages are, it's not worth the chase knowing they are NLA and that custom reeds must be made. Boyesen offers several 8-port cages with two- and now three-stage reeds available.
For the 666 & 444, the OMC 6-port cage is compact, plentiful, cheap, offers 50% greater opening area compared to the Merc reed cage, and fiber reeds are available multiple sources.
All that said, thank you for offering an interesting alternative.
Tim
that reed bolt pattern looks very familiar?
Here are images from the Bridgeport showing rough port work - hand work to follow. Exhaust ports are not raised to maintain compression and mid-range punch. A 5/16" mill is used and bridges are not narrowed to maintain heat transfer and strength. Final cut is with a 3/4" ball end mill to improve gas escapement from the center exhaust port. Intake ports are opened with a 1/4" mill which allows slightly greater area increase as this side runs cool. Again, bridges are not narrowed to maintain strength. This is one of the easier, more pleasurable operations on the build. The 444/666 projects are not for beginners unless taken slowly. Through the many hours and mods I must remind myself the results are worth the effort!
Tim
Here you see the results of several hours work...... A beautiful new casting from another source proved improperly patterned at 1:1 - aluminum pattems must be built with a "shrink scale" allowing 1/8" shrink per 12". The filler block for the MK75-78-700 is 18" tall, so was 3/16" short overall. This error required sectioning, welding, and much addional fitting - bummer! It is salvageble however and will be mated to the divider plate and elbows this weekend.
Tim
Tim
You should have told me you needed a filler block. I have 3 left that I patterned up and made to complete one of my deflecters.A small trim job on each end and bottom slides thru exhaust drop outlet and swings down in. Fits like a glove. Shrinkage rate is 1/64 inch per inch.Attachment 50407Attachment 50408
[QUOTE=R Austin;124991]Tim
You should have told me you needed a filler block. I have 3 left that I patterned up and made to complete one of my deflecters.A small trim job on each end and bottom slides thru exhaust drop outlet and swings down in. Fits like a glove. Shrinkage rate is 1/64 inch per inch.
Hey Dick,
At the time, I didn't know there was a problem with the casting in hand. Sure wish I knew before, your casting would have saved hours and $25 Heliarc..... Thanks for the casting knowledge: 1/64" shrink/inch (.0156") makes more sense as the 18" filler block X .0156" = .281" shrink. Will make due with this for now, but would like one for a backup. Please bring to Suter's.
Tim
Here are images of filler block, divider plate, and elbow machining and fitting. There are numerous steps required because of the sandwich construction, and piles of chips: The pictures don't do the work justice. All told, there are over 12 hours work so far, and the rear water bypass has yet to be built. The good news is IF all goes well tomorrow, the powerhead will be ready for assembly Monday or Tuesday. Gotta take time for the turbo tomorrow afternoon. Enjoy!
Tim
With the water manifold done, we're cooking with gas - or maybe alcohol? Gotta go......... the turbo is calling.
Tim
Just post the sound clips when its running
The powerhead is comming along great. Have you started the tower for the unit or will you use the three cylinder unit?
Alan
PS: Time to start thinking of a 999!
The 666 will be fitted to one of my steel towers with a 45SS gearcase. Two reasons: 1) It's already built. 2) I can't bring myself to carve up that beautiful Speedmaster. It belongs on a vintage Merc in complete form.
I like the idea of Dick Austins 99 inch "Beast", and can't wait to see/hear it run. Not sure if 9 carbs would help, am pretty sure six would be plenty.
Look for major progress this weekend. Time is getting tight!
Tim
We'll all be looking!
This is an exciting build with great photos!
Jeff
OK everybody,
The 666 powerhead was mated to the tower for the first time today. The spacer shown is a simple casting pattern to be poured and machined late this week, following a driveshaft will be cut & squared. Meanwhile the distributor bracket and inter-carb linkage will be completed - tomorrow if all goes well. The flywheel and roping plate needs to be turned as well. Next weekend should see final assembly, barely in time for Mark Suter's.........
Tim
In a word, WOW!
Jeff
Hi Tim,
Engine looks great. Can't wait for the 6 cylinder fest next year. It sure will be a great event. If we can get 8 engines on the water it will be a great show!
Alan
You just can't imagine how much time it takes to engineer and build throttle linkage and a fuel system for six carbs. Factory OMC looper choke linkage pieces were scavenged from a "box-o-carbs", hammered into new shapes, and now serve as inter-carb linkage. As noted before, a trick to mounting carbs close together was to reverse the port side butterfly shafts. Careful planning and delicate rework was involved. Be aware you MUST grind the protruding, swaged portion of the screw from the back side of each butterfly screw or they simply break off upon removal! One butterfly shaft was ruined in the process. The throttle pulls were made from bicycle brake cable & housings. The cables will be terminated together at the dead-man cable attach point low on the port side of the engine.
Fueling six carbs with three pumps looked at first to be a plumbers nightmare. After several scenarios were sketched, it was decided to use one main fuel inlet to feed the three pumps (and the primer yet to be mounted; the pumps in turn feeding six carbs. But how to make sure all are fed evenly? Elementary: A vertical fuel rail was gun drilled, machined, and attached as shown. Pumps feed the common rail from the top, middle, and bottom. Carbs are then fed by individual equal length hoses spaced in between. Fittings are due in tomorrow, with hoses to follow. It's sure to look interesting, especially once the primer and its hoses are fitted!
Tim
BTW: It's been a wild race to build the 666 in time for Mark Suter's October 20 show. We will make it - but just barely! Many thanks to all of you watching, offering your engineering insight, and words of encouragement. You'll all see images of the finished rig late next week, or after the show if I'm late on the clock.
As winter is closing in quickly, you'll have to wait until next spring to see/hear the video. Also, the IOA has agreed to host at least one special event for Merc sixes (stock, mod, and alky) at Hillsdale next year - they race there late spring and late summer. You'll want to attend this event. Stay tuned!
Tim
I was looking forward to seeing how you were going to accomplish the throttle linkage. Very clever and professional looking.
Thanks, but it's not done quite yet. All my race engines use push-to throttle actuation for safety. That way closure is not totally dependent in springs: You can forcefully pull the throttle handle back to close the throttle should the Bowden wire bend. The 666 is obviously a pull-to, so a reversing arm must be designed and built. Hopefully in the next few days.
Tim
Here are images of the simple pattern ready for the casting foundry - it was sent today. The trick is to make it big enough to compensate for 1/64" shrink per inch including a 2-3 degree draft angle cut into vertical surfaces that allows removal from the green sand mold.
If all goes according to plan, the raw casting will arrive Fri-Sat for machining this weekend. Time is running out: The flywheel, roping plate, and distributor bracket need to be machined and fitted. Oh yeah, it might be nice to assemble the powerhead!
Tim
Looking good Tim
I'm in just total AWWWWWWWW amazing what man can build.
eLove the neat work and thought involved. My question is why is the adapter plate so thick? I don't know if I'm missing a good reason since in my mind lowering the heavy powerhead an inch or two would be a good thing. Or is that height necessary for clearance on the bottom carb to the swivel pin? Can't tell from pics.
Sam
Thanks for your kind thoughts, Sam. I've worked diligently to design and build elegant, functional mods - something that might have been designed in the empire room.
Otherwise, you guessed right. The adapter pattern is thick clear the bottom carb over the clamps & swivel because: 1) The tower is a drop-down design for the OMC loop triple with it's angle-up carb position. 2) The Mercury bottom cylinder to powerhead flange dimension is shorter than the OMC and the very low 666 bottom carb means you need to raise the powerhead even on a conventional Merc tower. 3) The pattern was made 3/8" taller than needed assure more than sufficient material for machining.
If the 66 Merc was legal in Mod, I'd build a custom tower. My hydro uses a transom sized for the 45SS For the once/twice each year it runs, height is no issue.
Is there any chance you'll make Suter's? You would absoultely love it!
Tim
With all components in hand, another 2+ hours were consumed in careful layout of the hose runs and primer. It's hard to believe, but you're looking at over 10' of hose: 5/16" for primary feed, 3/16" for carb feeds, and 3/32" for the primer injector system. This was needed to work around the vertical throttle linkage and assure kink-free fuel delivery.
Tim
What an elegant solution for feeding 6 carbs with 3 pumps!
Jeff
Tim;
What about setting it up to run Fuel and put it on an 1100cc Runabout ?????
Here is the completed reversing throttle system. Packaging was tricky, but the finished piece works nice.
Also, the spacer casting arrived yesterday. It will be machined and installed this weekend. Only six days to go, gotta slave this weekend!
Tim
Tim;
Can't wait to see/hear that thing run on a runabout ! Hope your "DeckRider" knows what he is getting into ! :-)
John Biagio (Mad Cat)
With the intricate throttle linkage out of the way, shop activity turned toward the spacer and steering bar. More complicated than it looks, the spacer was completed, and mockup assembled. Next the flywheel and roping plates will be turned and the shop cleaned for powerhead assembly.
TimAttachment 50677Attachment 50678Attachment 50679Attachment 50680Attachment 50676Attachment 50675