S4 916 engine - rebuild or….???

[JoeB]

Discovered a few little chips of chrome from the rockers in my oil when I changed the oil yesterday morning. Wasn't real happy about it.

So I'm thinking….

Rockers, yeah yeah..  But given I haven't looked in the top cylinder rocker cover, I figure the cam has probably got a bit of wear.

I am not sure how much has come out. I saved the oil filter so I could look more closely, but havent cut it apart yet.

It was like panning for gold… I saw a few little chrome chips in the oil, and some on the magnetic plug, and only a couple in the gauze.

I've replaced the filter and oil already, and will continue to ride it for a short while - until I work out whether to rebuild the 916 with new pistons, barrels, cams and obligatory headwork and cams - OR - just get a 996 / 998 (or something) and drop it in.. I don't know whats best at this stage - in terms of costs. Availability of parts or spare engines etc is obviously going to be a factor in the choice.

Having said that, anyone got some suggestions???  or feedback from mods to desmoquattro's?

TIA

[J5]

check out the cams and go from there

someone on here is parting out an s4 , maybe go with that motor ?

[JoeB]

It will depend entirely on cost, as shipping engines from overseas to Oz is a huge expense.

[Speeddog]

How much of the work would you be doing yourself?
Are you looking for more power?
How many miles on the motor?

Rechromed rockers can be had for reasonable money.
But don't panic, you need to know what the status of your rockers are,

The engines are capable of going to high mileage without needing pistons and cylinders, etc.
I've got over 50k miles on my S4, and those parts are still good.

[J5]

so check out the cams and rockers

do a compression test and see what it says

[brad black]

i'd suggest seeing if there's anything wrong with it first.

[JoeB]

How much of the work would you be doing yourself?
Are you looking for more power?
How many miles on the motor?

bike has 40,000km on it. it's a 2000 model, so one of the first S4's. always looked after.

oil has always been changed at 5k intervals. always an ester based (silkolene or motul) 10w-40

more than capable of doing the work myself, but I'm a bit short of space at the moment. if I have to pull the engine, then the bike will be completely stripped down, new paint, new tank, triples.... if I do this, the bike will be off the road for a while. I was hoping to leave this for 6 months or so.

back to the rockers... yes replacing rockers is straightforward. and while it's a little bit expensive, the issue is, how much further do you go.
a top end rebuild and some porting? or do I throw some 944 barrels and pistons at it as well?  or do I look for a 996 or 998 engine and play swapsies?

because rockers are only one thing, and if the cams are shot or worn in any way, then the whole top is coming off. that's the logic behind it anyway. I've seen what happens if you leave things too long, but if it is already past saving, then lots of new pieces will follow. the bike is not worth spending huge $$ on as values for ms4's here are sub $10k and closer to half that for a good usable one.

[ducpainter]

i'd suggest seeing if there's anything wrong with it first.

This...^^^^^^^^^^^^^^^^^^^^^

If the rockers have just recently started flaking there shouldn't be cam damage.

[lazylightnin717]

+1 to checking before you jump into engine replacement.

My S4 had 6 openers and 3 closers I had to replace. A few of them were pretty bad. The cams looked ok though so I replaced the rockers, adjusted the valves and called it a day.

[JoeB]

I don't do things by halves, so if 'some' rockers need replacing, then all the rockers and the cams will be replaced also. Like I said before, the problem is just how much further into a top end rebuild… I could do this myself. Right now though I don't have enough space, and my budget needs to expand if I have to 'replace' bits, rather than regrind and reface parts.

The rockers I can get ground, reprofiled and refaced with stellite for about $60 ea, the cam journals  I can have nitrided or hard chromed also, part of the luxury of living near a steel manufacturing industry - plenty of supporting industries with specialized services.

It's also ready for the 2nd set of belts (40,000km) and the vertical cylinder has a small but noticable leak on the base gasket. I didn't mention this before, but it is also partly the reason I'm leaning towards pulling the engine out. and…. well a 944 kit is pretty straightforward from there...

So really in my mind, the engine should becoming out, and there are a few things to do, and I really do not mind pulling it out - BUT, it could wait a few months, until I have budget. Ultimately, If I'm pulling the engine, I'll have the frame soda blasted, and weld some lugs on to hide wiring, and a few other things.

So one little problem can be the catalyst for a huge budget blowout. I'm almost thinking to myself... f- it.

rockers are easy enough. but more to the point, if the cams are stuffed, what spec should I have them ground to, or should I buy aftermarket performance ones?

I'm thinking too much and should just let it go. And sell the cars, buy a Desmosedici and call it a day.

[JoeB]

Here are some pics.

I cut the filter open to see how much metal was trapped. Surprised a little, to see as much as I did.

Still, good to know where it's at.

Some alloy in there as well, so not really sure exactly what else could be worn.

[ducpainter]

Here are some pics.

I cut the filter open to see how much metal was trapped. Surprised a little, to see as much as I did.

Still, good to know where it's at.

Some alloy in there as well, so not really sure exactly what else could be worn.

Crank plug backing out?

[zooom]

I say...if you are going to do it, I would go with a 955 kit and put in some 996 SPS cams unless you want to go hot and nasty and put in a set of Corse 458 G cams in.

[JoeB]

I was thinking about the corse 431 cam and a G. and microtech FI computer.