i have purchased a 916SP engine from a very good mate.
It is a bit of a bitsa engine i think?
The heads are definatly sp with the v4 missing of the casings and the 1mm bigger valves.
The rods are the titanium H section.
The altonator cover has been butchered a little and had the front sensor moved backwards!
Questions:
The flywheel is lighter? so that would possible explain the sensor! so are the altonator casings differant on the sp?
How can i tell if the fly wheel is the lighter sp?
How can i tell if the crank is and sp?
Are the engine casings differant and if so what should i look for? will it be identified by the numbers?
Sorry for so many questions.
The idea is to find a doner 748 and build a trackday fun sunday bike.
Was looking at a 955 big bore but its a little out of budjet at the moment
The 916 SP’s originally came with “H” section steel Pankle conrods, not Titanium items of any shape or form!
The flywheel is steel and is the same as a 851/888/916 Strada, but with several big holes in the back plate to lighten it, making it the same as those fitted to the 851/888 SP’s/SPS’s.
The alternator cover should also be the same as these models, as in it should have two pick ups to suit the P8 ecu.
You might have a standard/later 916 cover that’s been modified to take the two pickups?
The single front pickup on the later bikes 9*6 Bip’s (to suit the 1.6M ecu) was in a different position, but all the mounting bosses are there on both types of cover only they’re not drilled and tapped to suit.
It’s a pretty easy job to modify a later single pickup cover to suit the earlier twin pickup system.
The inside of the “Bob weights”/ears on the SP cranks are scalloped out on the inside faces to lighten them and they have large round pieces of “Mallory Metal” (heavy metal) set into them, standard 916 items are solid/the same thickness across the width of these (not scalloped out) and don’t have the Mallory Metal inserts in the bob weights/ears.
Bip’s have 20mm small end/gudgeon pins, the SP’s have 21mm items.
Pukka SP crankcases have larger bores/crankcase mouths to accommodate the thicker muffs on the genuine SP barrels (102mm OD IIRC?), this was to allow an overbore to 96mm giving 955cc’s.
If you have the genuine 916SP barrels? (As rare as Rocking Horse Shit, but I’ve a pair )These can be bored out/re-plated to suit 96mm pistons, 916 Bip’ barrels are too thin at the muff to take anything more than a 95mm overbore which would give you 933cc’s.
I don’t know for sure? But I think the SP cases (and the very 1st 916 Strada’s) possibly had stronger/possibly sand cast crankcases.
If you contact Ducati in Italy with your engine’s number they can confirm what model they came from.
If you really want this motor to fly you should invest in a set of “T1” 9*6 SPS cams and then time them at 107/107 center lines.
These cams work very well with 916 SP heads, I use them myself in my 916cc 851 motor, but have 35/30 valves in the heads instead of the stand SP 34/30’s.
Please feel free to contact me if you want anymore info’, I love building/tuning this kind of motor and I’m happy to share my experiences/knowledge.
Edit…Sorry for the delay in replying, but I’ve been trying to post this answer since you 1st posted your questions??
Yes you are corect H section steel rods, dont know why i was thinking titanium!
Not sure about the flywheel will check tomorrow, if i get some gas for the workshop froze my nuts off earlier.
The cover has been modified:
The heads are the SP item with the bigger valve and the missing casting marks.
And yes will probably need more info.
Have valves to grind in and tappets to set and then after a bit of paint and a few missing bits (and you never know the rocking horse crap!), it should be then in a place to go back togther
All 4V Ducati cams are marked, the 916SP’s had “G” inlet and “A1” exhaust cams*.
The Desmoquatro 748,851,888,916 and 996 Strada’s all had “A/A” cams as standard.
The Corse/customer race bike 888,926 and early 955’s all ran “G/G” cams, later race Desmoquatro’s 955/996’s ran “431” inlets and “G” exhaust cams.
The “OA”, “OS”, "VA"and “VS” markings denote the position in the heads, “OA” being horizontal head inlet and the “VS” vertical exhaust etc.
These produce good power but at the expense of pretty poor low down power, they give a 2 Stroke like kick when they come “On Cam” piling on 20+ rwbhp in a 1,000 rpm “Powerband” from around 7,000 rpm, this makes for an exciting ride and feels very fast however…
The later “T1” cams that were fitted to the 916/996 SPS’s actually make more power throughout the rev range (than the SP "G/A1"combination), with the added bonus of making their peak power at under 9,500 rpm.
It’s quite easy to build a powerful 916, the trick is to be able to build a powerful and reliable motor that won’t blow up or need rebuilding every other meeting.
The 916SP’s suffered from crankcase failures/cracking between the “V” of the cylinders*, this was/is caused by the higher rev ceiling needed to make maximum power.
The Corse/Race bikes of the period used to have their crankcases changed at 500 race mile intervals.
The cams are SP G/A1.
I poped into my secret supplier of all things Ducati as i needed and opening and closing rocker and picked up new for £75 for the pair
And after moving a few boxes i found me some of that rocking horse crap… yep a 916 SP barrel in good nick so i now have a pair
So valves cleaned and ground in heads decoked.
Just need to throw it in the ultrasonic tomorrow and it will be ready for paint and then a rebuild.
Just need: a top end gasket set, and a clutch hub and we are done.
)These can be bored out/re-plated to suit 96mm pistons, 916 Bip’ barrels are too thin at the muff to take anything more than a 95mm overbore which would give you 933cc’s.
