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1985 F1 cylinder head modification question
http://www.ducatittandf1.com/viewtopic.php?f=24&t=1677
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Author:  duck-stew [ Thu Jan 05, 2012 5:16 pm ]
Post subject:  1985 F1 cylinder head modification question

I'm in the process of fitting some 900i.e. cams (2x horizontal) into some 1985 F1 heads.

All 4 valve seats are fairly well beat-up so replacement is in order (likely guides too), so with that and the performance in mind...

How large can the valve diameters get w/o risking the castings? (These were originally the small-valve and 14mm spark plug heads BTW).

The remainder of the engine is being built to similar specs. Kind of a 'hot-street' set-up here @ 5000 ft elevation.

ANY help would be appreciated (especially some FHE in this area...)

Thanks much,
--Stuart

Author:  graeme [ Thu Jan 05, 2012 8:41 pm ]
Post subject:  Re: 1985 F1 cylinder head modification question

Hello Stuart,
I used a 650 Alazzurra rear head, similar to F1, and had the 14mm plug welded and re made as 10mm to get more room for bigger valves.
Also used 900ie cams.
The donor engine was a '95 SS 750, so the Ally head's combustion chamber was also welded up and shaped to match the SS bathtub shape of the front head.

Image

Image

Image

Hope this helps
graeme

Author:  duck-stew [ Fri Jan 06, 2012 12:17 pm ]
Post subject:  Re: 1985 F1 cylinder head modification question

Re: the above photos: :shock:

Damn... Amazing... What valve diameters are you running in those beautiful heads?

Author:  618F1 [ Sat Jan 07, 2012 1:47 pm ]
Post subject:  Re: 1985 F1 cylinder head modification question

And, this is what NCR did during the days of the TTs: 41 & 35mm conversions to the Pantah head for TT2s, and later as big as 44 and 38mm valves for TT1s and F1/Endurance racers. One set here has the 41/35mm version that was later converted to 42/37mm and dual plugs. Notice that on the biggest-valve versions the chamber is cut to 105mm wide, for BIG (92mm) pistons, on the one in the middle it is 100mm for the standard 88-90mm pistons. Ports were monsterous too, which is contrary to modern thinking (volumn vs. velocity). MikeV
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Author:  loudbike [ Wed Jan 11, 2012 2:49 pm ]
Post subject:  Re: 1985 F1 cylinder head modification question

I should point out that within the next 2 weeks, we'll be offering conversion services; taking Pantah and other 'big plug' heads and converting them to later F1 'small plug', 41/35 specification. We're just nailing down the pricing now, so stay tuned - or PM me to get on the list.

Regards,

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