Harley CVK carbs on 230 Dodge Flathead

[maineSS]

Here's some info that might help Hudsonator with resin head casting- http://www.enginebuildermag.com/Arti...low_boxes.aspx . It's for OHV engines, but it lists how NOT to make your mold. I have some polyester fiberglass resin leftover from another project, and this "Mass Casting Resin" sounds like the same stuff. Haven't made a big mess in awhile, maybe this would be a fun way to use up leftovers...

[moparsled]

There is also "mass clear resin" which I looked into for casting chambers for visible wet flow. I spoke with a rep at the local supply, and he told me that there is more than one grade. He pointed me to a grade that had a lower curing temp and a higher clarity for thicker applications. I wonder how clear it would be after texturing it to accurately reflect a combustion chamber?

[maineSS]

In the Engine Builder article, the author had to wet sand and buff the casting to get see-thru clarity. He also mentioned it seems to shrink on curing, and pull away from the mold, which makes me wonder if the head chamber might end up a bit large. I was thinking of casting a metal insert in for the sparkplug hole, as threads in this stuff might not stand up too well to repeated use. It looks like a little Internet study might come in handy- there's an interesting writeup at http://users.lmi.net/~drewid/resin_faq.html .

It would be quite valuable to see how the flow around the valve changes in relation to lift, and which direction it wants to go as the valve opens and closes. I'm thinking a little work here could payoff handsomely. Joe Mondello once took a preproduction Harley head, and in three days increased flow by 52 cfm, of which 25 cfm were due to valve seat angle changes.

[maineSS]

Did some more checking, and found that boat/auto resin isn't suitable for thick sections- generates too much heat during cure. I ordered a quart of Silmar 41 Clear Casting Resin from U.S. Composites (www.uscomposites.com/polyesters.html) for $13.25. I'll try making the mold out of plywood, with a cast silicone head chamber.

Some more interesting info on valve shapes & seat angles- http://www.ret-monitor.com/articles/...to-performance - this is from Formula 1 world, but the discussion of tulip vs nailhead flow seems relevant to Flathead world. Another Engine Builder article on seat angles- http://www.enginebuildermag.com/Arti...lve_seats.aspx - good info on valve to seat throat ratios for port velocity, (which you need on the street). Finally, a Ford 427 SOHC head test which found that the nailhead likes a 45 deg seat angle- http://www.hotrod.com/techarticles/e.../photo_24.html - info, (thumbnail graph for nailhead vs tulip with 30 deg seat). Hit "Ford 427 Cammer Build " on photo header to acess page 7 flow info.

[maineSS]

I've gotten the prototype manifold back from the machinist, and am posting some pics to show how it's made. Pic #1 is the manifold tube- it's 4" long and was made from hydraulic cylinder tube with a 1/2" wall to allow for carb dia (40mm) vs block dia (1 5/16") differences. Pic #2 and #3 are the carb and block ends, the manifold tapers at 2 deg from carb to block. Pic #4 shows the manifold and base, pic #5 is the complete unit before Tig welding. It's taken awhile, but we're still moving on this project- who knows, maybe one day I'll even have a CVK40 pic!

[maineSS]

Here's some pics of the transparent resin head castings for the 230. This was my first experience with casting and patternmaking- believe it when they say "it's an art"! Polyester resin shrinks by 1% on cure- fortunately it shrank onto the head insert instead of away from it. I made 5 attempts before starting to get a decent result. Pic #1 shows the fresh casting, Pic #2 shows flycutting the top and bottom surfaces level, and Pic#3 shows buffing for "see thru" clarity. The heads will be bolted onto cyl 5 & 6 (after we drill some holes), and used to evaluate tulip vs nailhead valve shapes during flow testing, along with seat angles.

[moparsled]

awesome to see you making progress!

I've made absolutely NONE!, well, except for designing parts I can't afford to have made!!!

[Dead]

Just out of curiousity, with all this Talk of the Austin A series, what about the bigger B-series? Are the problems mentioned any similar?

Most Austin Mini Owners, etc, are getting rid of the A Series and sticking in Suzuki Swift, Vauhall 16 Valve, Rover K-series and Honda mills. Even People are replacing the B-series with Ford Essex, Cologne and Chevy V6's.Also things like the Rover O and K-series, Cosworths and Zetecs are popping up in MGBs too.

[maineSS]

I'm not familiar with the B Series- Vizard's work covered the A Series, after that it seems he came to the U.S. and took up SBC's. I'm not surprised people are transplanting more modern engines into the classic Brit cars- parts for really old iron are getting scarce and expensive, and the same amount of time and money spent on a decently designed modern engine will yield more power, mileage, and reliability. The reason I'm sticking with the 230 is that parts are still fairly available, and I think there's reasonable amount of Hp/Tq still left on the table. I can lug this engine WAY below any modern one without stalling, so maybe I'll end up with the gas equivalent of a DIesel engine.

[Flathead_6]

Hey fellas, long time no post but i followed this thread over from the p-15d-24 boys.

Thought i might chime in with my build.

1955 plymought 230 day shift block.
Line bored and decked 0.010
0.010 under polished crank.
Balanced and shot-peened rods, arp studs.
rebuilt oilpump, check valve tweeked to keep pressure up.
Federal Mougal mains and rod bearings.
Egge .030 pistons, cast rings. Flattops.
Ported with stainless steel chevy raceflow valves.
Custom ground cam. 107 lobe center, 236 duration, .485 lift.
217 head milled .020
Offy 2 pot intake with holly singles
langdons cast headers.

I have a turned down electronic ignition distributor from a 4.3 chevy that i think might be good for a little more power as well. Have yet to set it up.

Video is it running with only one carb hooked up. Ran out of fuel at the end. Should have a bit more when i get to tuning it up right proper.

http://www.youtube.com/watch?v=QfDw94-f_04