456 Valve guides

...and were replaced with sintered steel ones. Running perfectly ever since (11/2002)! Currently @ 56K miles.

Good luck!

Konstantinos
'99 456M GT Black-on-Black

 

I do not know if this is a US problem only, but mine (000114781) did 30K Miles, and seems to be doing fine.

 

Hi,

I think I'm having the valve guide problem on my 94 456 Gt.
I've a slight misfire at idle and engine is not running 100% at medium/full throtle.
I just took out the spark plugs and the nº 8 spark plug shows some oil on the pole. The other 11 are okay with the brownish color.
Could be the problem or am I beeing pessimist?
Of course I will have new sparks from NGK (DCPR9EIX), I've been told that these are much better than the Champions. I will clean the VAE sensors (idle sensors) and the throtle bodies and see what happens, but...

I just saw the prices for new guides and valves.
Could, please, someone explain to me, in case I have the problem, what guides should I buy? Ferrari have two parts numbers for those but one reference is for oversize guides. Are these the new guides (not bronze)?
I'm a bit confused.
Also, the valves could be Eaton or Intervalves. The Eaton are much more expensive. I guess that Intervalves were first used, beeing a 94 model I guess that mine are Intervalves. What shoul I buy?

Any help will be much appreciated.

 

I never buy Ferrari valves. For a lot less money I have them made out of superior materials. If your machine shop is careful oversized guides will not be needed. The bronze guides are no longer offered so even if you order by that number it will be superceded to the iron guide.

 

Thanks,

If I understood, oversized guides are needed if something goes wrong taking out the old ones?

Mont

 

...attributed to the high sulfur content of our fuel (...at the time; I think the sulfur levels in fuel -gas&diesel- have consistently decreased, esp. the last couple of years here in the US). Hopefully, if a problem has not surfaced up until now it may never appear in the future because of this decrease in the sulfur content. My 2c.

 

It is not a US only problem.


Ferrari's crap valve guides have been trouble all over the world.

 

...So Brian do you think I'm facing the problem? Does an oil fouled spark plug mean a badlly worn valve guide?

 

I was not aware of these issues on ex-US cars...

 

It's possible but justifies some diagnostics before taking it apart or losing sleep over it.

 

29k miles on my 95 with no valve guide problem. I was having some other issues (mainly check engine lights and poor running), but we resolved those and it wasn't the valve guides. The last year or so, the car has been fantastic.

 

What was it, then?

 

That is correct. I do this for a living and I'm rebuilding a set of 355's right now with a set of 308s waiting on the bench. Whoever wrote that the oversized guides are needed if there is a problem taking out the old ones is correct. If you just drive out the old guides often they will "gall" and pull aluminum from the head out with them leaving behind a torn up guide bore. The trick is to bore the guides out till they're just a few thousandths wall thickness, but don't bore them all the way through, this relieves the press fit so they can be driven out without damaging the head. Also, whoever wrote do not buy Ferrari replacements parts... also correct. Don't replace a crap guide with another crap guide. I'm not sure on the 456 and 550s, I haven't done any yet, but the 355 and 360 parts are available aftermarket and there is no problem using and after market bronze guide, as all bronze are NOT created equal. Those stock guides are a copper alloy, and they are actually copper colored (you wouldn't believe how soft they are, it's like machining aluminum). Manganese bronze is what you want and it is bright colored like brass. Iron is a good material too, just harder sometimes to install becasue they are brittle.
Signs of guides being worn are: A little smoke at start up, but clears right up, rought idle, eventually valvetrain noise, although I've not seen a Ferrari get that bad.
I have some pics and a little more info on my site if anyone is interested:
www.FerrariPerformace.com

 

What you should have said is "Nothing wrong with iron guides as long as they are not Ferrari iron guides".

 

are the IRON Ferrari guides failing too? I have not seen that.

 

No but they are not exactly an example of great engineering or wrokmanship.


Ferrari valve guides are and always have been subcontracted to the low bidder. I think it must be someones cousin. In the old 4 valve motors they survived OK but every motor before and after sure have or are having problems. Back in the early 80's when we were doing all the warranty rebuilds about 1 in 8 guides were in spec for concentricity. Their response was to change the spec. It has not changed.

We are doing a 355 valve job right now whose original seats were machined to guides that were as far off of concentric as .020.


Ray Charles could have made better guides.

 

After endless troubleshooting, the problems went away after we replaced the battery. Go figure.

 

That makes sense... I've never checked them before (it's hard to get an accurate reading when you've got .012 of clearance) but the seats are always way out after the new guides are in. Thanks for the tip.
I've only had two heads in the shop with iron guides, one with about 10k miles, the other with around 20k, both were wearing nicely and did not need to be replaced.
I think I read somewhere that Ray Charles did some subcontracting with Ferrari in the early 90's. It may have been in the valve guide facility.

 

Louthancomp, you have a Private message.

 

Someone was nice enough to PM me and let me know the link that I left to my site didn't work... looks like I'm still learning how to spell!
Thanks for the "heads" up!
The address, for those who are interested, is www.FerrariPerformance.com

 

Nice website, very impressive.

 

I see you're in Salem, OR, have you posted in the NORTHWEST section? There are a number of interested parties that migt be keen to find you're in their backyard.

 

Looks like great work!

(Your price sheet page [http://www.performancecylinderheads.com/exoticpage.htm] is "busted" [using Firefox].)

 

Having gone through the unfortunate situation with bad valve guides on my 97 F355 Spider I'm reluctant to purchase a 456M (but still may since due to my fondness to the car).
My question: are the late model 2001-2003 M models suseptable to this same issue??

If anyone knows of any other intrinsick issues with the late model cars pls advise.

Tanx, AL