big displacement Desmoquattro engines, any experiences?

Ben710 · #1 (**permalink**) 09-17-2008, 08:56 PM

Has anyone of you any experience with a biggger displacement Desmoquattro engine? I read about 1080cc Desmoquattros with a 2v crankshaft. Someone had a 1036 built...

Does that work well? Has anyone gone bigger and how about reliability in street mode?

hubert · #2 (**permalink**) 09-17-2008, 09:48 PM

Hey Ben, check out this thread.

Ben710 · #3 (**permalink**) 09-17-2008, 10:04 PM

That was a really good, informative posting.

A pity that there´s not more info about the 1000 crank in the 996, making it a 1080 or whatever it was going to be.

Maybe nowadays someone has some info?

ubermensch · #4 (**permalink**) 09-18-2008, 02:46 AM

here's one in the classifieds.

Ducati 996 916 748 race & Corse parts

foggy123 · #5 (**permalink**) 09-19-2008, 04:20 PM

My bike is still being tuned and broken in so results are preliminary.

The mechanics at Seattle Ducati are very impressed with my 1080 motor. It's got a little more torque than a 1098 but not quite the hp (because of a limited topend rpm). While there I watch them tune both cylinders at 60% throttle position. The bike fired immediately at startup, idled easily, and accelerated hard.

To install a 1000 crank, you have to clearance the inside of the cases abit and may have to shim/adjust the jackshaft. Mine had the cylinders shimmed 3.0mm for the extra stroke. Belts and pulley selection becomes an issue because of the extra length. To balance the motor you have add weight to the crank if you use the stock pistons and rods. Compression will depend on your heads etc.

brad black · #6 (**permalink**) 09-20-2008, 09:00 AM

a 1036 is with 2mm bigger bore - it's only 40cc bigger, or 4%. if the pistons are the same weight or lighter then there's no change in crank reliability. and the gearbox, etc, aren't going to notice an extra 4%.

i did a 1026 (900/st2 crank) that i didn't see the point of as it was a perfectly good 996 to start with, but if you were rebuilding a 996 down to crank out level then it's not a bad way to go. you add another std 0.6mm base gasket (2 in total) and the squish is then bang on 0.90 - 1.00mm and the comp around 12.7, no clearance issues, good belt tension with the heads 0.6mm higher, same piston to valve clearance as before - it's a good way to fix the squish and comp. still undervalved, but it should make a bit more than a comparable 996, again without stressing anything. you could pull the limiter down a bit for the extra stroke if you wanted to.

foggy's motor has the clearance issues with the 1000 crank, but apart from that i don't think there'd be any reliabilty issues. it's really revs that kills them, and with a 1080 peaking at 8,000 it's not going to get revved hard.

ElPrebZi · #7 (**permalink**) 09-23-2008, 11:14 PM

why not use a 998cc testastretta engine with 102 mm pistons -> 1038 cc

I did mine last year - works perfect

I think the dynograph still is on the forum somewhere

Ben710 · #8 (**permalink**) 09-23-2008, 11:19 PM

Because you need so much stuff from the 998 if you have an older chassis. Airbox, wiring loom, injection manifold, ECU, engine, etc. Way more expensive.

chris steedman · #9 (**permalink**) 09-24-2008, 12:53 AM

I installed a 996sps 66mm stroke crank into my 998s 3 years back making it 1027cc. This engine now lives in an old 888 strada

I had issues with a 1026 using ti-rods. I had to machine the cases as the rod bolts were hitting the cases. The jack shaft had to be cylindrical ground by 1mm in diameter to clear too.

Stroked a 748r to 772cc and that had belt tension issues. The rollers needed to be made smaller in diameter.

This week im stroking a 06 999r to 1079cc. Thats 998 crank installed. Custom 2.5mm base plates and again the rollers need to be cylindrical ground smaller then cam timing re-set.

A question why go back to the old motor. I thought you had a 998r with be-faster heads that you just bought

Ben710 · #10 (**permalink**) 09-24-2008, 08:59 AM

It is a 999R engine that I had in my bike. The heads weren´t mine, they now go back to the owner. Parting out the bike because I go back to University.

brad black · #11 (**permalink**) 09-25-2008, 01:08 PM

i get paranoid about the pistons sticking out the bottom of the cylinders too far when lifting them, but that's just me. up to 1mm higher hasn't given me any "too tight" belt tension issues, and if you can machine the valve reliefs and piston crowns a little you can get more comp by sticking the piston up higher negating the need for anything more special there.

748 pistons you can machine a bit off because they're so tall, 916 not so much. that sort of thing.