otto69":1u7ww7i7 said:
No one else is playing around with these ??
Clayton
No, not here. The SOHC engine was extensively worked over by Tickford/Prodrive in its early years, (specilist production engineering for Aston Martin and Ford and also Subarus race preparation team). Your better off getting English help fine tuning the combo. Your engine is effectively a Lemans style Aston Martin Zagoto or Jaguar C or D type pre injection engine. See
http://www.astonenhancements.com/sub-db ... at-26.html
They state that with fast road camshafts and with the triple Weber DCOE 9 carburettors, the resulting increase in engine torque is of the order of 35 to 40% and a reliable power output to better than 340 to 350 bhp. Up from the 314 to 325 hp gross of the last DBS. I'm a sceptic, because I've found the 40 mm choke in the DCOE 45 is too big, and cfm suffers a great deal verses the DCOE 48 or DHLA 48 with 42 mm choke.
You can seriously undercarb a SOHC engine, and loose a lot of mid range and high end power. A set of E49/DB6/DBS Vantage 4 litre six size DCOE 45 carbs with 40 mm chokes won't give the power a combo like what you have . They ran out at the 295 to 325 hp mark, tops. You'll be looking at much more power, and your better off studying the twin cam British websites for Jaguar XK6's and Aston Martin DB stroker sixes.
I'm adamant that the best info
does come from Ford Six, because of the Grecio Roman conquest of knowledge that is best spearheaded in a good old USA forum. Aussie7mains and some others on the Aussie Six sub forum are great ambasadores for the soak and doak (sohc and dohc), though. Although we've got the best Aussies here, the engine is best supported in detail by the following
FordMods (The Ford Modifications Website,)
http://www.fordmods.com/ucp.php?mode=register&coppa
and the Australian Ford Performance Forums.
The support from these guys is
really good, though its lacking in the depth of the American websites, for Americans ask some pretty tough value of modification verses value of improvement questions that wouldn't be tollerated on sites with Aussie and Kiwi dominance. Because of a sort of backyarder Jessie James thing going on, we antipodeans are rip in and DO IT people, where reaction speed to the application is the key, not discussing all the issues first.
With Aussie forums, its not exactly intollerance or knocking, but in America, its everyones right to be clearly heard without the Merv Hughes Sledge (See
http://en.wikipedia.org/wiki/Sledging, and click the cricket explaination for 'mental disintegration' or a kind of Hazing
http://en.wikipedia.org/wiki/Hazing. After making allowance for that, we all get along just fine!
The Inliners international and HAMB also are options, as the triple carb I and L6 is a real fascination to every red blooded American. There are a lot of very smart SOHC Firebird guys there, who have really worked on the special cam needs of a SOHC engine. Your peak lift curve is stable at any speed with SOHC, and valve train flex is a fraction of the OHV engines, so the loss of peak lift and the gain in 50 thou lift durations with a flatting of the peak at lash, 20, 30 duration requires extra knowledge of the compresssion, igntion and air flow requirements. David Vizard explianed that Fords Pinto SOHC cam geometry is really complicated, and nothing has changed with the Aussie Ford SOHC or its CVHH Escort style valve gear.
I'd be looking at a low load stress cam, with less 50 thou duration, and the full amount of total duration. I'd try and pump up the C/R to a maximum amount with V-power 98. The sohc doesn't like as much duration as the ohv Ford six, as the rocker ratio is very high, and the port angles very good. Any Hemi combustion event is rough, harsh, and that SOHC won't be tame with that cam unless some serious sorting is done on the needs of the cam. I'd certainly work with your custom cam, and fill out the jetting and venturi requirements, but I'd be starting with rare DCOE 48/50's or more common Dell Orto DHLA 48's and 42 mm chokes, and spend time figuring out the cold cranking compression. I'd add a David Vizard style fuel standoff stub stack or special air cleaners and look at increasing intake runner length as much as possible.
I've seen work with SOHC engines, and they typically take 20 years to show any performance gains on Detriot Canted valve and wedge OHV engines. The x-flow 4.1 is a much easier engine to calibrated and got power from, because you can wack a Ivan Tigue roller cam in it, and run huge duration and lift, and the a) valve train lost motion and dampening from the pushrods and b) lower rocker ratio (1.73 vs 1.8 or 2.0) protects the engine from too much low lift duration.
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