Tuning 1776, 9:1, FK-44, Semi-Hemi, 44 IDF's, 022 Dist?

[milo]

Hello,
I just finished building a new 1776 for my fiances car. I am in the process of fine tuning it now but have some questions. The engine has some old stock valve heads ported by Clyde Berg with the typical Berg Semi-Hemi. My friend flycut them down from 60cc's to 47cc's so I could get closer to 9:1 with the FK-44. I am using a set of 44 IDF's that I currently have 50 idles in (Needs 52's pops a little and has a flat spot off idle with accelerator pumps, float level (11mm top 22 drop), etc all set. One of the problems I am running into is because of the semi-hemi I have the timing currently at 36 total using a old 019 that is close to 18-20 degrees at idles. I don't know if there are any long term downsides to doing that but I find that it's hard to get the idle down with that much initial advance. I am going to mess around later today and try 38-40 total (I have heard depending on the motor the semi-hemi's can respond well to that much advance). I know if I do that though the idles is going to be near impossible to get down to a 900 rpm idle. I was toying with the idea of trying a 022 Porsche distributor (Happen to have a few) as I have heard they have more advance. Ideally to get closer to 8-10 degrees at idle and 36-38 fully advanced. I am also not sure I am going the right direction at all. As the heads have been fly cut and have 47cc's and .017 deck + .040 copper gasket = .057 total deck height. I am also trying to get a idea of how to jet this thing. I tried 145 mains to start with and have worked my way up to 155's now. It doesn't seem to be rich at all (No black smoke out the exhaust tip) and with the 50 idles the idle is smooth and the mixture screws are about 1 turn out (The old Italian hex mixture screws with the abrupt adjustment). I notice it pops a little while cruising at low rpms so I am going to try some 52's. I guess where I am going with this is does anybody have any experience working with semi-hemi's. I was reading in the Berg books they typically want a leaner jet size but I am finding it like a bigger main so far. I am wondering if this is because even though it's hemi cut it has high compression. Any input / suggestions are appreciated I know it's really a trial and error thing but I was just hoping to get a better starting point.

Thanks you,
Nate

Also, here are some pictures of the heads on my facebook page
http://www.facebook.com/photo.php?pid=636461&l=a2cf60f495&id=1681133316

Below is a fairly detailed spec sheet:
Displacment: 1776
Compression: 8.9:1 (.017 Deck Height + .040 Copper Head Gasket = .057 Total Deck Height).
Crank Play: .005, Press Fit (Between Crank/Flywheel).
Cam Thrust: .003
Bearings. .020/.020 Kobinschmit Main Bearings, .020 Clevett Rod Bearings, Mahle Double Thrust Cam Bearings.
Cooling: Stock Dog House with Flaps Installed but no Thermostat.
Oil Cooler: New Stock Dog House Style.
Generator: Porsche 50 AMP 200 Watt 6 Volt, Dog House Fan
Distributor: 019 from Old Empi Screamer Kit (Blue), Rebuilt.
Coil: Bosch 6 Volt Blue Coil.
Spark Plugs: NGK B6HS, Gapped at .030.
Breather: CB Generator Stand Breather (Modified for
6V Generator Stand).
Oil Pump: Shade k 30MM, Blue Printed, Plugged for full Flow.
Oil Pump Cover: gene Berg non-relief Style (Lapped Flat).
Pulley: 5.5 LBS Equalizer Pulley, Balanced, gene Berg Degree Rung.Head Studs: German 8MM (Torqued to 20FT LBS).
Rods: Berg 311B's Balanced End to End, Torqued to 30 LBS with Loctite
Case: Berg Mexican AS21 Case, Step Cut for Thick Wall 90.5's, Full Flowed, Cut for Cam Plug, Silicon Bronze Lifter.Bores by Brothers Machine, Line Bored .020 by Tims ACVW.
Pistons and Cylinders: Berg Cima/Mahle 90.5 A's, CB Light Weight Wrist Pins, Berg Tru Arc Retainers, Grant Cast Iron Rings .014 Top, .012 2ND, Polished Piston Tops, Balanced to 1 Gram.
Crank: Berg 69MM Welded Counter Weight Crank, Additional Chamfer Added to Oiling Holes, .020 Mains, .020 Rods, Micro Polished.
Heads: Clyde Berg Ported Stock Valve Heads, Berg Chromoly Retainers, Berg Dual Valve Springs Shimmed, 3 Angle Valve Job by Tims ACVW, Semi-Hemi Cut with 47CC Chambers.
Rockers: CB 1.4 Ratio Rockers, CB Lash Caps, CB Tool Steel Adjusters, CB Long Rocker Studs.
Push rods: Gene Berg 3/8 Chromoly.
Push rod Tubes: Windage Style.med for .550 Lift, Back Cut Valve and 3
Cam: Engle FK-44 on 108 LC Ground on a SC1 Billet, Clearanced for Stroker, Taper Added to Cam Lobes.
Lifters: Eaton 2-Piece Lifters with SLR Treatment.
Cam Gears: CB Straight Cuts with Filed Teeth.
Flywheel: 200MM O-Ring Type Flywheel Lightened to 12LBS, 6V Ring Gear Installed by Rimco.
Clutch: Diakin Super Disc
Pressure Plate: Sachs Stock Diagraph Style with Collar.
Header: Bug Pack 1 3/8 with Flanged Heater Box Connections.
Muffler: Modified Bug Pack Hide-Away with Thrush Muffler.
Carburetors: 44 IDF Webers with 36 Ventures, CB Manifolds (Match Ported) and Hex Bar Linkage, 50 Idles. 155 Mains, 190 Airs.

[Ian Godfrey]

Milo, I can't help you with the carbs, I have IDA's, but I do have semi hemi heads flycut to 9.4:1 that work quite well with a lot of initial advance 15 deg, and 36 total. I think it needs even a bit more total, 38 maybe. It idles at 900 easily (86B cam) and is crisp off idle. When I had the idle at 8 deg and a long advance curve there were lots of stumbles that jetting couldn't fix. The limitation on initial advance is getting it started. Some ignition modules have a start retard function while cranking for this problem, though mine starts fine with 15 deg. You will probably need a wide band to sort the jets. (I did)
good luck

[milo]

Thanks for the help.  I seem to be getting differnt responses on the hemi cuts with high compression.  Some say since the heads have been flycut and the compression is high the need for advanced timing is no longer necessary. So far I have found at 36 degrees total it runs awesome.  It would pull a little harder at 38 but would run a little warmer.  Yesterday made a deck lid prop out of a tennis ball and that dropped the temp dramatically.  Today I pulled off one of the springs on the 019 after reading that it makes them advance more like a 010. It loves that and has a lot more bottom end drivability as well as low end pull.  I figured the faster advance would be more like a Porsche distributor but without the extreme advance.  So far it runs great still waiting for smaller vents but even with the 36's it pulls strong and smooth had to jet the idle circuit a little rich to get the last of the stumble out (Think that's due to the lack of proper vac with the 36 vents and 35 intakes.  The timing thing has been the oddest part of this combo.  It really runs good where it is and hasn't ever felt close to being heat soaked or pinging.  I mean the pad across from the plug is scooped out.  It seems like no matter what due to the odd combustion shape it would require more advance regardless of the compression ratio.  But if I am wrong there could be damage going on I don't even know about.  Aside from pinging, and running hot how else can you tell if your over advanced.

Thanks,
Nate

[martin]

Berg said that if you advance it more and there is no more power, then that is too far. You need just enough to burn what fuel is there. I have a set of SH heads too and wondering if a piston domed up to fit into the chamber would work better to raise compression.

[Darth Weber]

The company that came up with the hemi cut for VW heads back around 1970 had a domed piston that was sold with their modified heads. Berg found that the piston dome cut off half the combustion chamber from the flame front thus producing an incomplete burn and detonation. Berg replaced the domed piston with a stock flat top piston and found more power and no detonation. That was the start of him experimenting with the hemi chamber shape and volume.

Gene found that better performance with the hemi head was gained with increased timing, to a point. He experimented with timing advanced from 12 to 15 degrees BTDC. He also found that if the timing was up around 15 degrees, and the motor still ran good, he could drop down a size on the main jets and go back to 10 degrees BTDC on the timing then work back up to optimum timing a couple of degrees at a time.