998 Bayliss - Blown Piston

safetyfish · 26 Apr 08, 02:48 AM

I recently was lucky enough to buy a Bayliss edition off a guy who had money issues. Lucky for me.
The bike was in pretty good nick, but it needed attention. First order of business was a new set of belts. The bike has 3200 km on it and it is still running on its original belts.....

Fitted the belts, cleaned up things like air filters and greased up suspension parts and other small bits and bobs while I had the rims off to fit a new set of Bridgestone 015's.

The morning broke and I was out the door like a rabbit with its tail on fire. I just could not wait to finally start her up and hit the road. I noticed that the oil level is high.... strange? Never touched the oil....
Start the bike up and let it tick over for a minute. Switch it off, and check out the oil level... Back to normal?

She was handling completely differently to my 999, a more involved experience. Took a few turns to get used to the quirks of this bike and new started to step things up a notch.

Bang!!! Sound of metal doing something and then nothing. I wheel to a stop with the clutch in and my first thought was the bike is on fire. Take a few steps back and realise it is all steam....thank goodness for small concellations.
But the steam was coming out of the exhaust pipe also, now that is not good. There is coolent everywhere, it is even running out of the joints on the exhaust pipes.

Got home with some kindly help and took the bike apart.

After having driven it for less than 30 minutes or 25 km's, this is what we find.

If you look closely, you will see the exhaust valve imbedded through the piston.
The titanium conrod is bend to hell and gone and the engine can not turn over with the amount of metal inside of the gearbox. It was somewhere around here when I said FAAAAARK!!!

This is going to hurt financially.

SF

andyb · 26 Apr 08, 01:51 PM

"The bike has 3200 km on it and it is still running on its original belts.....

Fitted the belts, cleaned up things like air filters and greased up suspension parts and other small bits and bobs"

Who fitted the belts?

safetyfish · 26 Apr 08, 02:08 PM

I fitted the belts.

Before taking it apart the general concensus was that I did not tighten the belt tensioner pulley properly when I changed the belts. (Ducati Master Technician helped me to take the thing apart)
Big surprise, everything was exactly as it should have been.
Pulleys were torqued as per spec and were still good when we opened it up.
belts were tensioned correctly
The timing marks on both the horisontal and vertical cylinders all alligned perfectly..... The cuase of the failure could not have been the belts.

Before the failure, the bike started first time. It idled perfectly. No backfire. Linear power throughout the rpm range. No stuttering or stalling. It picked up nicely when accelerating from one gear too low. The only difference too that bike was that I removed the intake restrictors, which gave it a louder intake growl. That is it.

I am currently looking at the cost of replacement head, conrods, piston, valves, rollers etc. ooouch!!!

SF

andyb · 26 Apr 08, 02:46 PM

"Before the failure, the bike started first time. It idled perfectly. No backfire. Linear power throughout the rpm range. No stuttering or stalling. It picked up nicely when accelerating from one gear too low."

"The cuase of the failure could not have been the belts."

Hmmmmm, it may be a hard pill to swallow but that does appear to be the only variable factor...........sorry. I guess it matters not now as your faced with a big bill....

safetyfish · 26 Apr 08, 03:29 PM

I went through the whole installation process in my mind thinking if and where I messed up. The evidence is just not there. Not that it is any concellation because the repair bill is going to be huge regardless. But it would be nice to understand what went wrong though.....

The only thing I can remember that bugged me then was the fact that the oil level was perfect in the sight glass before I went on holiday two weeks back. When I came back from holiday I changed the belts and noticed that the oil level covered the whole sightglass screen. I did start the bike, let it idle for 10 seconds and then switched it off and checked the sight glass again. There was no milk in the oil and the level eased out at the top mark having left the bike standing for about 3 to 4 minutes. (My thought was that the water pump seal may have allowed water to pass into the gear casing causing the rise in the oil level.) If that was the case then the oil should have turned white almost instantly if the engine was allowed to run for a few seconds.

SF

matt#corse · 26 Apr 08, 06:03 PM

Try contacting this guy to see if he has engine kit for your 998

Ducati 748 916 996 Pankl Titan racing con rods Pleul on eBay, also Ducati, Motorcycle Parts, Motorcycle Parts Accessories, Cars, Parts Vehicles (end time 26-Apr-08 17:24:08 BST)

Hope this helps,Matt.

ducati2242 · 26 Apr 08, 08:22 PM

Never seen valves snapped like that without pistons hitting them first. The rest of the damage will of occurred later.If belts are still intact then I think that there must be a serious timing problem.Which obviously reared its head at some revs.Cant think how water leaking into the crankcase would cause the valves to snap.

Mr.R · 26 Apr 08, 08:59 PM

Originally Posted by safetyfish

I went through the whole installation process in my mind thinking if and where I messed up. The evidence is just not there. Not that it is any concellation because the repair bill is going to be huge regardless. But it would be nice to understand what went wrong though.....

The only thing I can remember that bugged me then was the fact that the oil level was perfect in the sight glass before I went on holiday two weeks back. When I came back from holiday I changed the belts and noticed that the oil level covered the whole sightglass screen. I did start the bike, let it idle for 10 seconds and then switched it off and checked the sight glass again. There was no milk in the oil and the level eased out at the top mark having left the bike standing for about 3 to 4 minutes. (My thought was that the water pump seal may have allowed water to pass into the gear casing causing the rise in the oil level.) If that was the case then the oil should have turned white almost instantly if the engine was allowed to run for a few seconds.

SF

Hi,
I'm sorry to hear about your trouble.
The water pump seal failed on my bike (851/916sp) and the fully snth' oil floated on the water, raising the site glass level.
The oil didn't go milky...
I knew I'd put the right amount of oil in the motor so popped the rad cap off and put my finger in, which came out dry.
Fortunatly I check my oil level before and after going out for a ride, so no damage was done.
I stripped out the alternator case and changed the seal only cost apart from the seal was that I had to throw away the contaminated new oil and filter.
As i've said the oil floats on top of the water, your oilpump picks up from the bottom of the sump, so your pump was pumping water to the bigends...
Not good!
I think the 30 min's and 25km's were enough to shag your bottom end which let go causing the rest of the damage.
The knackerd bigends allowed the piston to hit the valves, which let go falling into the combustion chamber.
Which then caused the rest of the damage.
Of course I might be wrong here but...
If anyones got a better idea I'd like to hear it??

Steve

P.S. I've got a good pair of Ti' SPS rods going spare, which you could have cheap, but I think you'll need a lot more than just those.
I'd be looking for a complete new engine if I were you, it'll be a lot easier/cheaper than trying to salvage what's left of your motor.

andrewmc83 · 26 Apr 08, 09:03 PM

Originally Posted by Mr.R

The water pump seal failed on my bike (851/916sp) and the fully snth' oil floated on the water, raising the site glass level.
The oil didn't go milky...
I knew I'd put the right amount of oil in the motor so popped the rad cap off and put my finger in, which came out dry.
Fortunatly I check my oil level before and after going out for a ride, so no damage was done.
I stripped out the alternator case and changed the seal only cost apart from the seal was that I had to throw away the contaminated new oil and filter.
As i've said the oil floats on top of the water, your oilpump picks up from the bottom of the sump, so your pump was pumping water to the bigends...
Not good!
I think the 30 min's and 25km's were enough to shag your bottom end which let go causing the rest of the damage.
The knackerd bigends allowed the piston to hit the valves, which let go falling into the combustion chamber.
Which then caused the rest of the damage.
Of course I might be wrong here but...
If anyones got a better idea I'd like to hear it??

Steve

me too! if its gotta top that!

jordy27 · 26 Apr 08, 09:40 PM

been studying your post for a while now,there seem to be a lot of damage to head and valves and block,if the valve timing was wrong it would show up as soon as you started it,so i think you can rule that out seeing as you have double checked the timing,it looks like the whole barrel,piston, head has been subjected to a whole lot of pressure.
heres the scenario, your riding your bike at x mph and suddenly one of your cylinders induces a significant volume of engine coolant ,as water cant be compressed it puts enormous pressure on the con rod bending it(ive seen it on cars)and in turn totaly distroying piston and head,that would account for the steam out of exhaust
just a possibility
andy

Mr.R · 26 Apr 08, 10:28 PM

Hi Jordy,
What your talking about is called hydrualic lock, the thing is when the motors running the pressure from the combustion chamber is trying to get out not suck in water from the cooling jacket.
So the engine pressurises the coolant not the other way round, hydrailic lock normally happens when the head gasket fails, the head or barrels cracked and the water seeps in when the motor cools down,
The bending of the conrods happens when you try to start a motor thats suffered this, as as you've said you can't compress a liquid.
But this failure happened after 30 min's of ridding?
I think the rod bent when it tried to compress the broken valve heads.
Of course I may be wrong again, but when I've suffered a blown head gaskets I've been covered in green coolant, from the expansion tank.
I did think about the hydrualic lock theory before posting my thoughts though.

Steve

stevel · 27 Apr 08, 08:21 AM

Some ugly scenes on those pics SF, sad story which I hope you resolve soon. I think MrR's theory sounds closest, especially as it took a few miles to develop. A timing issue would arise straight away? My only query would be based on my own experience of the failed pump seal.......in that case, the water did get to the sump and increase the level slightly, but the oil went very milky and totally opaque rather than the situation MrR describes where the oil and water sit in the sump one atop the other.
In my case it was a slow leak that I spotted as the coolant level dropped, the oil level increased and the colour changed at same time. ......I suppose that if a lot of water got through and the bike was left several days, the water would settle and cause that water to go through the pump first?
Good luck with the fix mate

ducati2242 · 27 Apr 08, 10:41 AM

We`d have heard it rattling over here if the big ends were that knackered that the piston had hit the valves through a worn crank. Its dropped a valve. Either by snapping or by lost collet but one way or another its been a valve problem.

frenaugo · 27 Apr 08, 12:42 PM

Originally Posted by safetyfish

I fitted the belts.

Before taking it apart the general concensus was that I did not tighten the belt tensioner pulley properly when I changed the belts. (Ducati Master Technician helped me to take the thing apart)
Big surprise, everything was exactly as it should have been.
Pulleys were torqued as per spec and were still good when we opened it up.
belts were tensioned correctly
The timing marks on both the horisontal and vertical cylinders all alligned perfectly..... The cuase of the failure could not have been the belts.

Before the failure, the bike started first time. It idled perfectly. No backfire. Linear power throughout the rpm range. No stuttering or stalling. It picked up nicely when accelerating from one gear too low. The only difference too that bike was that I removed the intake restrictors, which gave it a louder intake growl. That is it.

I am currently looking at the cost of replacement head, conrods, piston, valves, rollers etc. ooouch!!!

SF

I am amazed the belt driving the camshafts with the failed valves was still intact.

looking at the pictures the inlet valves are still in place and there is quite a bit of hammering damage to both the piston and the head indicating the engine did not come to an instant stop. This damage would have taken place whist the engine was still rotating.

It would be reasonable to assume that if the engine was rotating after the exhaust valve heads where broken off, the inlet valves, if still operating, would have also been contacted by the flying broken internals and themselves also been contacted and broken off

I can see how the the water in main journal theory would be possible. In my experience (not with bikes) water in the sump normally results in highly emulsified oil/water mix, which still provides a degree of lubrication, obviously this is not ideal but probably would avoid a catastrophic failure of the main bearing shell.

I have only ever seen one engine where the shell/bearing was ejected from the bearing cap allowing that sort of clearance increase and that was a 600HP v8 which did not allow it to seize/lock and 'spat' it out instead

safetyfish · 27 Apr 08, 04:08 PM

It was autopsy time again today between race 1 and 2 at Assen. (Wont spoil it if you have not watched the SBK race yet)

All theories went on the table, and then we looked at what is there to support a theory.

Unfortunately for me, and this is a hard one to admit, it would appear that I did mess up the belt change.
Looking at the piston face itself you can see two neat little circles where both the exhaust valves made contact with the piston face for an extended period of time. The circles have carbon deposits in them (difficult to see after the fact with all that metal flying around in there at 8000 plus rpm) and all the damage is super imposed on top of the circles. AT 8000 plus rpm that piston and exhaust valve was making contact at in excess of 130 times a second. From the time when that exhaust valve finally snapped and started to do its thing until the engine reduced its rotation to zero was enough to cause a lot of damage.....to the engine, to the bank balance and to my pride.

In the end, I must have slipped a single tooth on the belt change and when the engine was doing top rpm all hell broke loose. Now that is an expensive lesson to learn......there is not much to say other than "you stupid bloody idiot!"

I now have to go and humbly appologise to the bike

SF