888/926 racing head, how to recoginze?

workslorenz

Hello,
I have at home two heads empty, one marked in the top 92 and one marked 93, they appear like racing heads because the combustion chamber is different from road models and the valves seats are very big, seem suitable for 36-30 valves.
How to recognize if are 888 racing or 926 heads?
I have a complete set of inlet (36mm) and exhaust (30mm) valves new from Menon for this heads, so I'm thinking to complete them but before I would like to know what they are...
Thanks

Ducal

I think from memory the race heads had copper beryllium seats.

BABA

Originally, they were using 92 stamped heads, with a big S on the top.

36/31 valves on R93 bikes, and 37/31 valves on R94.
May be replaced to use 996 valves (36/30) which are easier to find and cheaper than original ones ???

Inside the combustion chamber, it looks like the photo below.

(36/30 Chrome Menon valves are the 748RS valves, replacing the previous nimonic valves version)

workslorenz

Here the photos, no berillium seats or S stamped on the top.
What for me is strange is the top of the horizontal head marked 92 that is short and without the Desmo 4v Dohc lettering, I see this kind oh heads only years later. Also the combustion chambers for me have a strange design.
What you think?
The head gasket sign the head with a diameter of 96mm inside.

BABA

916 heads for me, maybe used on a modified 955 engine and 996 valves.

The inside combustion chamber design is a common modification.

I had also started to made it on mines (but with std valves).
First time I made that, and I've had no good pics of details of Racing/prepared heads at that time.

to finish finally more hemispherical

workslorenz

Maybe but 916 started his life in 1994 and these are marked 92 and 93. I have 916 heads marked 94 so something is strange.
I never look inside an 888 Sp4 or Sp5 so I don't know the combustion chamber of these.

ajcorse

926 or 955

Hi, I see this heads with stamp G and withou letering on Ducati 916 SP from 1994. this bike have frame nummer 00043. But there is bore 94 mm. Ducati made also 916 SPA with engine 955. They used for 955 engine same /G/ heads like normal 916 SP but with big valves.

BABA

First moulding weren't from 1994.
I think I remember reading they began to study a new head "lower" in 1991. But I don't think it was used before the 916.
I should have precised that the head without desmo 4V DOHC are used on 916 SP and R/F.
I don't know what "B" originally means, but "G" is a classic cylinder head with 34/30 valves (so it could be an SP5 head, I don't remember if the rear 916SP head is the same as the 888, which I think could be the rear and front of an 916 SP)
The manufacturing of SPs bikes was started at the end of the previous year of the MY in question, so first 916 SPs have been produced at the end of 1993.

workslorenz

Ok thank you very much for your help.
I have a 916sp head casting so I can check the dated stamped and also the later.
In the evening I will update the post!

😄

ajcorse

916 SP Heads

Only front head on 916 SP1-3 is without letter. Rear is same like SP5 or SPS with 34/30 valves

outtacontrolla

According to my notes B on head is 916 SP !
using G and A cams .
Cheers steve .

workslorenz

yes, I have another 916sp head and on the top is marked B and 94 year.
What is strange of the other head is that it is marked 92 so probably is one of the first head done for the test.
The G head sure are 888 SP5 heads (probably also 888 SPS head) and used also on the rear of the first 916SP.

Mr.R

I've a pair of modified 916SP heads on my 851/916cc motor, they're both marked (have cast into them) '94 and both have the sloped down exhaust rocker boxes, with the narrower valve covers.
...and they both came from the original 916SP motor.
I've also a pair of NOS "G" heads that I've modified to take 37/32 valves (these have '00 cast into them), I went for the bigger exhaust valves as the "G" heads had much wider ID/bigger ports than the 916SP heads.

Steve R