456 Valve Job

My engine is taken out, and the heads are taken off.
The dealer took off my clutch, and found that the contact surface for the clutch plate on my flywheel is not at all flat as it should be.
The clutch plate has been worn, because of this, only on the outer side.
This means, new flywheel, and complete new clutch system.
Cylinders are all 100% percent, and so are the crankshaft bearings.
I will keep you informed on the progress.
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Thanks for posting the pics, but I'm curious, how many kilometers are on the car?

 

50.000 km

 

hans, why did the heads come off? Valve guides, or?

 

The car was using 1 litre of oil per 1000 km while driving long distances.
When started cold, it smoked like hell after 1 minute idling.

All bronze valve guides wil be replaced by sintered ones.
At the same time I will use the opportunity, to let the head and valves be flowed.

 

Are you sure it was smoke, all cars I've owned do this I assune it's just steam, which dissapears after 5 mims.

 

It is a bit late to put this question, isn't it.

 

Can he not resurface the flywheel?

 

According to the Ferrari workshop manual, the maximum allowable you can take from the flywheel surface is 1 mm.
I do not know how much has to be taken off here, but according to my workshop it would pass this limit.

 

Hans, 1mm is quite a lot: hard to believe that would not make the surface true again!
Since the flywheel has to come off anyway, I would have the workshop go through with the resurfacing and see how it looks; before buying a new flywheel.

 

The flywheel has already been taken off, look at the pictures at the beginning.
I will let myself inform what the price difference is between a new flywheel and resurfacing the old one.
Thank you for the tip.

 

It's not that removing 1mm wouldn't make the flywheel true again, but rather once a 1mm is removed the flywheel isn't thick enough and is now out of spec.

my guess anyway...

 

That is exactly what the workshop just told me.
The second reason is that there is a huge amount of tension buid up in the flywheel to make it out of true. When making it true again, changes are that this tension will cause new trouble in future.

 

There are ways of making that work, though... well.. let's not go into the details... who knows knows =) some would call it half ass job, but it works. =)

 

The only thing that may go out of spec is the travel of the pressure plate that would be 1 mm longer and would require compensation on the spring plate, in order to keep the loading of the clutch within specs.
Shaving 1 mm from the flywheel on the lathe does not build up any significant amount of heat and the flywheel is built to whitstand heat anyway.
The reduction of weight would also be negligible.
Just my 2 cents.

 

The cylinder heads are now ready to be retrofitted.
All valve guides, plus four exhaust valves that where no longer within the specs, have been replaced.

Since I could not get any feedback on this forum regarding the need for balancing the Flywheel/Pressure Plate, I will have the new ones mounted as they are supplied by Ferrari.
The workshop manual does not indicate that any balancing has to be done, so I´ll thrust everything will be O.K.
The engine mounts are still in perfect shape, so are all the water hoses.

As soon as I have new pictures from repairing my cylinder heads, I will publish them.

My workshop will need another 3 to 4 weeks to finish their job completely.

 

What year and how many miles on this 456?

 

1999, 50.000 Km

 

Here are the pictures taken during the restoration of my cylinder heads.
As you can see on some pictures, the valve seats have angles now of 30-45-60 degrees instead of 45 degrees only. This improves flow.
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How come there is so much pitting on the cylinder heads? When I had mine done they were totaly smooth.

 

That was my first impression also. What you see are alu debris from machining.

 

Ah Ok. Thanks.

 

You were right about the pitting. Spoke to the guy this morning who did the heads, and who also made the pictures for me.
He told me that this pitting is very common in F heads, that it looks a bit worse on the pictures then it really is, but that this is absolutely harmless.

 

Glad to hear it. As long as he sees no issues.

 

Got my car back this morning. Runs absolutely fumefree now when idling cold or hot and also under the fastest possible acceleration.
The valveguides were the one and only cause for fuming and for using substantial amounts of oil when driving.