Great pictures there Dropping in them pistons so close to thee piston bore oil jets can be a sod, there as brittle as **** But you probably know this by now Thanks for posting.
Very nice pics of very nice work. That should be one strong 355 when it's done. Thanks for sharing the pics.
manganese-bronze alloy guides. They are undersized on the internal diameter, which enables us to run tighter valve to guide clearances-specifically at the lower end of the Ferrari specs.
I suspect the wear was due to the fact that the engine had 30,000 miles on it and that the guides were completely shot. The valve stems were literally flopping around inside of the guides allowing the excessive wear to the valves.
Thats what happens when the valves don't seat completely and allows for oil and gas residue to form on the valve stems over time. Keep in mind that this engine is 20 years old with over 30,000 miles on it. I suspect that the guides went out of tolerance a LONG time ago, so the end result shows in the valves.
Not sure what you see Bob, maybe i am missing it, none of those stems seem smaller just bigger with the buildup.
Ya i see that and not trying to be a dip **** but when i look at the stem it looks normal with build up. Also i did not think valves in guide would corrode. I guess saying that if they sat for a long period of time maybe if the chemistry works, did not think it would though.
Grant. I didn't say they looked smaller, I said they looked like they could snap off. My deduction on that is as a result of this: Motorsports - Failure Analysis of a Pitted Automotive Racing Valve
Good info Dr Bob, never seen it in such detail. Always something new to learn about. Thanks for posting.
I'd like to know that too. The intakes look different (flat top) compared to the usual 355 intake valves which have a conical depression. Must be "high compression" valves. Wink, wink, nudge, nudge.
