1998 550 Maranello "sorting" thread--DIY

Walnut shell, FTW! I had this same treatment done to my 90,000 mile Range Rover (with shells) and the "seat of your pants" difference was noticeable.

 

+1 walnut

 

Pete,

Walnut shell blasting is so easy it will now become a part of my major service like sending out fuel injectors to be cleaned. The cool thing about DIY Ferrari service is much of the cost is my free labor. But actually I expect that with good mixture control my valves will look clean. I don't know what my valves will look like in 5 years.

The only fear is getting stuff in the cylinder. Interestingly, when I was developing my cleaning protocol the 1st valves I cleaned with gumout solvent. Out of curiosity I filled the a bowl with solvent and it sat there overnight! All the solvent was still there in the morning, our valves seal that well. I tried it more more valves and the same result perfect seal so I felt confident I could clean the valves and get all the residue out. With the size of walnut shell particles it is even easier to get those out. Here is a typical cold leakdown for me very similar to one of your cylinders.

Also, there is a universal problem with fouling in today's direct injected cars. Walnut shell is the method chosen to remedy that. This method is the industry standard.
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FBB- Very ingenious.

 

Carl & Pete, maybe I should ask by PM or start another thread, not sure. Carl is using an aircraft leakdown tester and Pete is using an automotive leakdown tester. The bleed orifice in Carl's aircraft style tester is 0.040", aircraft engines have *huge* jugs. What is the orifice size for Pete's automotive tester? Cars have much smaller cylinders. If the automotive tester also has a 0.040" orifice, then we're comparing apples to apples. If not....

 

Hi,

If you go down this path you open up a leakdown tester holy war. There are many controversies too long to discuss in this thread. I use an FAA tester because I'm not willing to invest the time to figure it all out thus using a standardized tool is a no brainer choice for me that works fine on our smaller engines. The 040 orifice standard FAA tester is within the displacement capacity of our motors. You can read about that here:
Leak-down tester - Wikipedia, the free encyclopedia

 

Wil, start a new thread, this will be good......I'll bring the popcorn!

 

John & Carl, oh hell no I ain't starting anything that needs popcorn! BTDT. I will keep looking around and see if I can find one or two specs on the automotive leakdown tester orifice size. If they're different, then maybe start a thread. For instance, an aircraft tester might say an automotive engine is 'less leaky' than it actually is (did I get the reasoning right?, hm)....whoa--stop right there podnuh....that's another thread.

 

Pete, the next questions I'd be asking myself are:

1. Why only #7?

2. Where did the carbon/coke come from - was it oil from the head (running down worn guides or worn stem seals), or the intake manifold (blowby, oil overfilling, etc.)

How do the intake port & valves look for #6?

 

John-Quit trying to goat Pete into go in deeper...

 

Busted! Aw come on Pete, I'm sure you're curious.......

You know, where you are right now, with the cams out, you "could" change the stem seals on those two #7 intake valves without too much grief. All it would take is a valve spring compressor and a bit of rope.......

(I know, I ought to be ashamed of myself for even suggesting it. I probably should say 10 Hail Enzo's and offer a blood sacrifice to the Ferrari Gods......)

 

easier than that. compressed air in sparkplug hole.

Actually, I forget the leak numbers you got but if you clean the intake and ensure good seal, easily seen with a puddle of gumout cleaner still sitting over night, I would redo the leak test. If is is good then you know it is all about carbon fouling. If bad maybe in the exhaust side. Then you can be pretty sure it is a mixture problem. Fouled injector comes to mind. By chance was there a report from RC based on injector number before cleaning? Or we never saw the other intakes were they all about equal with #7 being the worst? If so no worries then.

 

John- That stuff on the valves probably comes from the oil in the intake manifold the 550 gets from the blow-by system.

 

A thing done in the aircraft world for leaking valves is to 'stake' them. It has worked for me a few times, usually no difference though. Staking is just whacking the end of the valve sharply with a plastic hammer to snap the valve open, then it snaps closed on the seat. It sometimes breaks up a tough carbon crust. Don't know if being an automotive valve makes any difference.....

 

Taz, agreed, and that was one of the possibilities I suggested in post #810, but then, why only one cylinder? We could possibly say "....well, #7 is at the rear, and since the engine is canted up a bit at the front, it's the low cylinder of the system so it'll ingest oil pooled oil in the manifold before the front cylinders. But then why is #6 OK? Or maybe it's gummed up too, as Pete hasn't shown us pics of #6 yet "

 

Pete- That really does a good job. Combine that with an Italian tune-up to get the small amount of crud between the valve and valve seat and you should be set.

In the olden days the Navy used walnut shells on turbo-jet engines to clean off carbon. Believe it or not they were put down the intakes with the engine running. If you did that with a modern turbo-fan, it would trash the engine. Those old turbo-jets were tough and the clearances were not so tight because of material properties.

 

Those big Moroso's are the best. Even Stevie Wonder could time an engine with those.

 

So as I approach degree ing in my cams...I have a question...do I have to be concerned with oil left in the hydraulic lifter? Will it give me the wrong number as the lifter begins to move because of possible oil in the hydraulic chamber of the lifter? When performing this task, with American V8s, I would always use a solid mechanical lifter to degree the cam.

 

It must be a tooling issue. All I used plus the blaster was an equally sized blow gun to blow all the shell out as I sucked with this tip that is soft rubber than fits perfect in our intakes. You stick the blaster or blowgun tip in there and the rubber tip surrounds the blow gun tip and seals real nice. No mess at all and complete removal of residue less than what you see in your photo 3.
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