29 F-head Performance

paulrhd29nz
paulrhd29nz Member
edited November -1 in HUDSON
I am close to starting on building a late 20's indy car replica using all Hudson frame and drive line. I am inlove with the F-head, and I am wondering if any of you out there has herd of or knows any one that has modiffied a F-head motor. Things like cam grind, larger valves ect.
I read an article many years ago about Wally Parks before the war showed up to some race at a lake bed or beach in his 29 hudson coupe and blew the doors off the entire feild.

I know of the things that can be done to the early flat heads but never have heard or read of any mods, to the F-heads.

Paul

Comments

  • [Deleted User]
    [Deleted User]
    I would think if you could build your race car about half the weight of a stock 29, it would be pretty quick. May play with the gearing also. Would be very interesting.
  • bob ward
    bob ward Senior Contributor
    Geoff Clark from Nelson NZ, a regular on this forum, has a lot of experience with the F head motors, cam grinds etc, and will doubtless be along soonish.

    Geoff Price from Toowoomba Queensland has a 27 sedan that gets down the road quite sharply, twin SU carbies and extractors.

    The ultimate F head hot up is probably the 2 cars done by Wolfgang Rebien in Victoria a few years ago, one of which has ended up in Eldon Hostetler's Hudson museum in Shipshewana, Indiana

    http://www.conceptcarz.com/vehicle/z16845/Hudson-Speed-Six.aspx
  • Geoff
    Geoff Senior Contributor
    The only experience I have had is modifying the cam to give better utilisation of modern unleaded higher octane fuel, shaving the head .060", and fitting a down-draught carby. This is sufficient for ordinary running, giving around 20% h.p. boost, and 20% better economy. Geoff Price's modifications are much more radical, entailing re-working the combustion chamber, raising the compression ratio to something like 9:1, and using a huge side-draught S.U. However, this did not perform as expected, as detonation was very bad, and once this occurred, the timing had to be retarded which led to overheating, and very bad vapor-lock. With my mild mods I had only good things happen. The cam mods I do give 14 deg overlap(as against 1 deg original) ,1/32" higher lift, and slightly later opening of the exhaust valve. This results in a vastly quieter exhaust note, which indicates that the fuel is being burnt in the cylinder, instead of going out the exhaust as waste heat. The cam grind could be even more radical if the lobes were built up, but this is expensive. The biggest drawback in the F-head design is the huge expanse inside the cylinder head intake chamber. This allows extreme turbulence to take place. It would be vastly better if a new head could be designed allowing a smooth flow 6-branch intake pipe assembly. There is no way you can fit twin carbs on the later version heads as there is water jacket in the way. And the first design F-head with the plugs on the top of the piston are very bad for detonation ,as you have the blank area over the valve.
    Geoff
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