https://www.ferrarichat.com/forum/threads/95-f355-valve-guides-fact-vs-fiction.5554/
I would guess (but have no evidence to back it up) that Manganese-Bronze guides would give just as much longevity as steel and be easier on valve stems. I'm a little skeptical of steel as when it comes to metal parts that wear against each other you want one to be softer than the other so the softer part wears. In this case steel valve stem on steel guide is not as good as a slightly softer guide. The problems with factory guides (just as in 911's) had more to do with poor fitment at the factory than material choice.
Would Steve be able to remember what transpired with the heads/guides? It would be nice to know exactly happened to an engine with steel valve guides installed from the factory, which some have argued here is the gold standard. Steel guides are also significantly more expensive than after-market manganese bronze guides. Come time to do guides on my other 355, I will use after-market m-b guides for material, design, and perhaps costs reasons. I believe they will suffice if sourced from a reputable place.
Readers should be mindful when reading the first post of that thread, it was written in 2004.. only 5 years after the last 355 made. 5 years is not enough time to see how things will unfold when it comes to the 355 at least. “Myth #1: All 1995 F355 have valve guide issues and need their original valve guides replaced Fact: Completely false. According to FNA technical director Adam Williams, only about 20% of all95-model year 355s experienced excessive valve guide wear and needed them replaced. And in fact, about half way through the 1995 model year the factory changed over to a different type of valve guide (the ones that they replaced the old ones with on the early cars). Myth #2: Some have stated that since the valve guides were not sintered (formed and hardened by heat and pressure) then accelerated wear will also be seen later. Fact: FNA confirmed that this has never ever been anissue. The problem stemmed from improper seating of the guides and if no problem occurred early on then it will not be a problem in the future other than normal wear associated withrunning the car. PERIOD, END OF STORY! Myth #3: Valve guide issues can occur at any time during the life of the car and are more prone to experience these issue in higher mileage cars. Fact: According to the Ferrari factory in Italy and re-affirmed by Adam Williams, 90% of the valve guide issue occurred almost immediately or within the first two years of ownership. The few that have occurred in higher mileage cars cannot be confirmed to have happened at a specific point in time and likely could have been present for quite some time. Certainly the older valve guides may wear out faster but they dont go from being in good shape to wearing out overnight. Myth #4. This is only a US problem due to the high sulpha content in our fuel and that Euro cars had different valve guides. Fact: Sorry but totally false. It was a small problem on Euro cars as well and the gas issue is inaccurate. Myth #5: Valve guide issues were only present on 95 models. Fact: Also false. Even with the newer valve guides post 95 production 355s problems arose. A bad batch of valve guides found its way into several 97s and at least two 98 355s. Ferrari of Washington alone had two 97s and one 98 355 that had valve guide issues discovered when each of those cars had higher than normal oil consumption. Myth #6: If the valve guides were changed on a 355 by the dealer then there must have been a problem. In other words why would the dealers change them free of cost if there wasnt a problem. Fact: The amount of disinformation being spread in the past few years made it impossible for dealers to move 95 model year 355s, even ones that had later production dates and didnt even contain the old style valve guides. FNA finally decided to have all early production 95s changed over even if there were no problems. Myth 7: Only 95 model year cars had any engine problems. Fact: I have already mentioned a bad batch of guides in other production year models but in addition some 96 and early 97s cars had connecting rod failures (issues with the connecting rod bolts). There are also a few 98 specific engine related problems.”
““Myth #1: All 1995 F355 have valve guide issues and need their original valve guides replaced Fact: Completely false. According to FNA technical director Adam Williams, only about 20% of all95-model year 355s experienced excessivevalve guide wear and needed them replaced. And in fact, about half way through the 1995 model year the factory changed over to adifferent type of valve guide (the ones that they replaced the old ones with on the earlycars). ” On 95’s I’d say it’s more than 20%. Not enough time has passed when that was written. Plus, not everyone reports their issue to the FNA.
“Myth #2: Some have stated that since the valve guides were not sintered (formed and hardened by heat and pressure) then accelerated wear will also be seen later. Fact: FNA confirmed that this has never ever been anissue. The problem stemmed from improper seating of the guides and if no problem occurred early on then it will not be a problem in the future other than normal wear associated withrunning the car. PERIOD, END OF STORY!” Apparently, not the case here .
“Myth #3: Valve guide issues can occur at any time duringthe life of the car and are more prone toexperience these issue in higher mileage cars. Fact: According to the Ferrari factory in Italy and re-affirmed by Adam Williams, 90% of the valveguide issue occurred almost immediately or within the first two years of ownership. The few that have occurred in higher mileage cars cannot be confirmed to have happened at a specific point in time and likely could have been present for quite some time. Certainly the older valve guides may wear out faster but they dont go from being in good shape to wearing outovernight.” Myth #3 has proven to be … not a Myth .
I read that the same way John did. This post talks about a 99 car with valve guide issue? Interesting so it seems, how there are all these "myths" yet it is just the 355 with the valve guide issue yet people keep saying in not an issue. I can count the number of 328/348/360 I have read having this issue on one hand and using no fingers. The 355... the forum is lousy with the talk. I have read of some cars having it done twice. Kind of like how the manual says its normal to burn up to a quart of oil every 1000 miles. Avoid liability. None of that takes away the 355 awesomeness in my mind, its just a thing with the car, most have have some character issue, like the diff on a Testarossa.
In cases like this where it’s not a safety issue, like for instance faulty airbags that can kill a consumer. Manufacturers are definitely best of: deny, deny, deny. Ford did it for some time with the 6.0 diesel, Toyota with their oil control ring issue, on and on and on.
My personally am referring to #7. One of those "facts" about the "myths" busted, not sure which... probably like 4 of them. Plenty of cars have no issues, ever as well. Its a crap shoot is what it comes down to. Italians, gotta love them. https://www.ferrarichat.com/forum/posts/148325355/
Wouldn't carbon build up also cause a similar leak down to worn valve guides? I would think the only real way to check valve guides would be to tear down the motor and measure them.
I'm not an engine builder, but I did speak to the owner of the shop that Ferrari of Washington used to do all their head work years ago. He indicated that carbon buildup was a common byproduct of not driving the car hard enough. He also recommended periodic Techron or BG44K fuel treatments. This is why I will always drive a Ferrari throughout its rev range after a proper warmup. Cars that see frequent short-tripping or engine lugging are more likely to experience these issues.
BG44k is a great product use it at every oil change on my daily drivers and every fill up on my toys with fuel additive when storing them The only other thing I would believe to produce carbon build up is not using oil that meets or exceeds Ferrari standards and the PCV system crank case gas will flow into the intake after the engine is turned off there’s not much you can do about it with out letting the crank case vent to atmosphere which is a EPA violation and fail at any inspection But I do feel that driving the car often is probably the best way to keep carbon from building up to much Sent from my iPhone using FerrariChat.com mobile app
My car is a 1998 model, build date was 04/98 to answer that question. I did question carbon build up as the reason/explanation of the leak down test results. But when the heads came off, there was clear wet oil (plus some carbon) on the exhaust valves on the rear cylinder on one bank and the front cylinder on the other bank. So it was not just carbon build up causing the bad leakdown test numbers. I did get 67k miles out of the engine before this happened. So I don't know if this is within the range of acceptable for a high-revving, high performance engine. I for sure use the whole rev range, and as you should be able to tell from the mileage on the car, the car does get driven regularly, including long trips (OC to Monterey many times for car week). So this isn't a case of non-use. A good friend who races a spec racer, which uses a Toyota Atlantic engine, says he has to rebuild the engine every few years-- his comment is you can't live at 9,000rpm and expect an engine to last so long. Lastly, I am feeling a bit better about the whole experience as some time goes by. Driving the repaired car has helped me to see what my money got me! If I hadn't had to deal with the first guy disappearing with some of my money, it would have been just a bigger-than-usual major service. I had done 3 majors before this one, so I am well attuned to the cost and incidental findings of a major service. So I suppose adding a valve job to a belt service without the drama of the disappearing mechanic would not have taken so long or have caused as much anguish as I experienced. Thankfully, in my case, the failed smog check coincided with the timing (well, a few months early, but close enough) of the scheduled major service. So the engine was coming out last year anyway.
