daytona engine rebuild

why?
smoke?
knocking?...at idle, or under load, or after you take your foot out of it?
"ticking at idle"(cams bouncing back and forth in the cam "galllies"-only really starts after 40K miles or SEVERE overheating episode...
cosmetically funky?
Mileage concerns?
performance down?

What is your cylinder's LEAK DOWN-when at full operating temp with oil stat open, and fans cycling?

When car fully warm after driving for a half an hour, at a complete stop, in 1st gear, with the steering wheel lock completely in either left or right-full turn...and you SLOWLY let out the clutch..is there a clunk in the transaxle?(HINT: this is NOT a "gearbox" issue)

 

Plan to spend $35-$45K to have it done right.
Strongly suggest you select a shop with a proven track record rebuilding this type of V-12. They are pretty complex and one small error can have disastrous consequences. I had my C/4 motor rebuilt 3 times by the same shop before they got it right......... coolant in the oil supply, disintegration of cam chain tensioner........... the list goes on.

 

Kmartin: You do not need to pull the engine to replace a front crank seal. I would do a leakdown and compression check first before I ever decided to rebuild a street engine. Believe me, if you go looking for trouble, you will probably find it!

 

I just had my Daytona engine done by Patrick Ottis. His work is spectacular. The engine is perfect. I am sure that there are many capable mechanics out there but my vote would be for Patrick.

 

I know this has probably been debated/discussed/written to death on numerous occasions in past 40+ years and should perhaps be posted in "Technical" section of the forum but I'd like to take this opportunity and invite opinions from any of our more esteemed/experienced members, like DWR46, 335s, et. al, to this often referred problem of O.E. (sodium filled) exhaust valve(s) on Daytonas breaking without any predetermined reason, regardless of age, driving style or mileage. How common this really is or has been ? And if common, have other contemporary models (i.e. Dino's, 275's, 330's and/or other 365's) been affected with it ?

 

I am very interested in this too, from my point of view though, if the engine hasn't been opened and you are doing a rebuild one may as well just get new valves as insurance against having to open the engine again if one does go and replacing the valves I reckon would be a lot cheaper than the consequence of a sodium valve failing.

One thing I can say the Daytona engine looks much bigger in the car than it does on the engine stand!

 

For what it's worth: I had an OE exhaust valve break on an 8 year old 365GT4 with about 30,000 miles, properly serviced. It went at during a sustained 6-7000 rpm motorway cruise.

 

If you don't mind telling us how much was that?
Thanks.

 

Sodium-filled exhaust valves are a very real risk item on many old Ferraris. This 308 recently suffered a valve failure. During disassembly, two other valves showed evidence of imminent failure. It's better than new now and the client is pleased but the repair was not cheap.
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Interesting detail photo of the valve that was about to fail. It shows signs of being a fatigue type failure (would need a close up inspection to be positive but the darker area has be cracked for awhile while the small cleaner area was all that was holding it together until you snapped it in half). I would expect imperfections on the valve stem and worn valve guides would contribute to the failure of the valve.

Cheers Jim

 

Those valves broke apart when I knocked them out of the heads. I suspect old age and thousands of heat cycles did the trick on them.

The car is a 1978 with 70K miles. In spite of the poor condition of the valves, the bearings and pistons/cylinders (seven of them anyway) showed very little wear and could have been reused. They were still within spec. Only some light scoring on the affected cylinder necessitated a 0.010" overbore and a new set of pistons. The head was repaired (not always possible) and all new valves (current technology) and guides installed.
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I have a 308 of the same year and similar mileage.
Given its state of robust good health I can't justify a rebuild yet but my fingers are crossed.

 

All of the suggestions above are well taken. I would just add one thing. If possible find a shop within reasonable driving distance.Take advantage of regular visits during the rebuild.There are some mechanics who will actually let you participate in some of the work.What ever the case by getting to know your mechanic, bringing small items of personal interest, show a real interest in the rebuild, make regular visits and do your homework in advance. Don't be afraid about asking questions.It's your mechanics favorite subject, or it should be, so take advantage of the opportunity.You can learn a lot and enjoy the experience. tongascrew

 

early 12s typically used-in many but by no means ALL instances-"inertially welded" valves made by Eaton(look for the "E"...as the implementation of the clean air act progressed, and the thermal loading placed on these due to early oxidation catylzers(air pumps added oxygen to burn off excess long chain hydros at the expense of temperature giving birth to ASTRONOMICAL increases in oxides of nitrogen....high heat in plain english is nthe food for all of this activity....
They valves cant take this environment for too much/too long....70K is well, WELL past any mfg'ers acceptable liability concerns...
"what;s the matter? Can't you afford a new one?"
-I really heard someone say that once....

Ever wonder why 4-cams and DINOs had such valve train failures at rates far greater than ANY other engine families? Dropped valves, broken valves, purported dropped valve seats(a misnomer IMO)
The base circles of the cams are the same for THOSE two, and the acceleration forces placed on the valve train as things stop and start at thousands of times a minute...well, there you have it....One will notice that at the C/4 and everything else SUBSEQUENTLY mfg'ered, they went back to the "smaller" base circle...as time went on, the material science changed and the issue becomes moot by the late 1980s...PARTIULARLY subsequent to 1982(17 digit VINS, and 1984-the Lambda closed loop circuits with 3-way catalysts

 

So if a car had the air pump removed early enough the stress on the valves would be less and their life might not be compromised?

 

they were sketchy to start with, air makes them even sketchier...so to speak...

after 30-50 years, there is no magic sol which can convert a component from a selcted item based on a price point in manufacturing cycle as oppossed to a part selected due to being made to a spec point instead of said price point...
plain and simple...it IS what it is...

 

Some might disagree...
Copyright of yours truly.
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Mechanical jewelry for sure.


Ago

 

here is how I was notified that my engine rebuild time had arrived.
Malcolm
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Over $75k?

 

Quite difficult to answer as there are too many variables, including how extensive services are required, how many parts are going to get replaced vs. reconditioned, quality of parts, etc... not to mention who's doing it and what ? What about removal/installation, reconditioning/replacement/service of external components (carbs, distributors, oil-/fuel lines, etc...), final tuning, etc...? + the unforeseeable "surprises" that are more likely than not...
And all above will probably get amplified on the "full restoration" for the rest of the car...
Best to have in-depth conversation(s) with the person/shop you're entrusting all this to and plan your budget 1 1/2 to 2 times of their well thought out estimate. This way you're fairly well "prepared".

 

always remember that compression is really used more as an indicator of which hole has gone/is going "soft" and requires more intimate scrutiny..in most real world examples these numbers are a relative result as the variables affecting "absolute" values is beyond your likely principle interest: does it need an OH?

since it appears they are all about the same, the relative rate of wear seems, ostensibly, to be well within time, age, and mileage..."norms"
I would examine pumping loss with a HOT leak down next...
what do the plugs look like? Oily or just sooty?
if you are inclined to be ultra conservative, you can perform a measured oil consumption test next, but based on miles-and 40 yrs of experience-I'll bet a stein of grog that the guides and seals are pretty well guaranteed to be worn out.

The problem with one of these is: do you do "just a top end" or the whole shooting match-which gets much more costly in the bottom end than the top assuming all that is largely OK-with top end major components and DIMENSIONS of: width, flatness, surface Ru, Rc hardness, Brinell index for major castings, holes sizing, AND these are also concentric.
If you are in a position to spend any amount of bill that comes your way-then this is all moot-are you price shopping? It "feeels" as though you can afford any ill results which might arise=I repeat, it "feels like",,,,?