456M high oil consumption - Ferrari Life
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post #1 of 96 Old 08-17-2013, 06:17 AM Thread Starter
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456M high oil consumption

I'm working with a recent arrival that came in with a high oil consumption concern (1 quart/200-300 miles) and significant smoke, particularly out of the left side pipe, when the engine is cold or has been sitting for a few hours. Interestingly, the (visible) smoke appears to subside after about 5-10 minutes of driving.

When starting from dead cold, the engine soundslike she isn't firing on all 12 cylinder, although OBDII data showed no evidence of a misfire. Idle quality was not what I would expect and have experienced in the past from these cars. After 5-10 minutes of running, the idle quality improved steadily.

Preliminary tests done by another shop indicated "good" compression in the 225 psi range, with minimal variation. Oddly, no leak down was done at this point.

Oil type used and quantity (in the dry sump tank) were verified. Both OK. Although some of the hoses to the/from the oil/vapor separator are a bot old and hard, the system was found to be free from any sort of obstructions. Next, a leak down test was done, revealing leakage from 18-33%, with the intake and exhaust valves being the predominant leak source. Oddly, on some cylinders, leakage was stable at 2-3% for a few seconds and would then steadily rise to 30% and level out. This was noticed on several cylinders. There was evidence of "wetness" on one of the spark plugs that may prove to be troublesome as the repairs progress. Upon teardown, the intake ports revealed some evidence of oil/carbo blow back. However, most of the exhaust ports were heavily encrusted in an oily/carbon sludge. When the heads were finally removed from the engine, it was found that some of the exhaust valve guides were worn so badly that, even with the heads fully assembled, the top of the valve could be moved approximately 1/4" with just thumb pressure!

With a mere 15,000 miles on the engine, no less....

The last two photos are proof positive on just why it's so important to replace the coolant hoses (particularly those in the valley of the beast). There was evidence of coolant seepage and that coupler hose sure doesn't look like there's much life left in her!
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post #2 of 96 Old 08-17-2013, 07:36 AM
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Glad to see you posted on this one David; the community needed to hear about it.

David & I were sorta working in parallel on exhaust manifold & head removal techniques over the last week, and it's been fun (well maybe there's been 5 minutes of fun.....) I had a "head" start on David (that was pretty poor wasn't it?), as I'd already managed to get the right head off, but I had been dreading trying to get the left off until David remotivated me. Together we (unsuccessfully) explored several ideas and approaches to get to the pesky rear outboard head nuts, and we both contributed a quantity of busted knuckle tissue and blood to the cause.......

Finally David came up with a brilliant idea to get to the rear fasteners, and managed to get both heads pulled the same day, while I'm still sitting here with the driver's side head still on. That's the difference between a pro & a DIY'er!

Whoever owns this 456 ought to be VERY thankful someone of David's calibre is working on his car. It's just a pity the heads are in such poor condition and it was obviously misrepresented by previous shops.

'99 550, Rosso Corsa / Nero, S/N:114654, Assy: 31836, Engine: 52084

High mileage, low compression, and missing on a few cylinders.....just like my cars.

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post #3 of 96 Old 08-17-2013, 09:47 AM
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Quote:
Originally Posted by David @ FluentInFerrari View Post

Preliminary tests done by another shop indicated "good" compression in the 225 psi range, with minimal variation. Oddly, no leak down was done at this point.


Sorry, I feel like I am coming in at the middle of the story.

When you say preliminary tests, does that mean another shop was trying to diagnose the oil consumption? Or was it just a test for general condition prior to a sale?

In either event I suppose it highlights two things

a. The real lack of diagnostic abilities of most that work on cars, both professional and not.
b. The widely held belief, spread in large part by internet experts claiming compression and leak down tests are redundant.


In the case of this car the high compression figures were because of the oil consumption. It is one of those cases where the test actually provided a false sense of good engine condition.

Your experience with the slow change in the leak down measurement is actually quite common on a car with high oil consumption.

Last edited by Brian; 08-17-2013 at 09:59 AM.
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post #4 of 96 Old 08-17-2013, 09:50 AM
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It's just a pity the heads are in such poor condition and it was obviously misrepresented by previous shops.


Sorry, again feeling like I came in at the middle of the story, why do you say "it was obviously misrepresented by previous shops".

I heard no evidence of misrepresentation by anyone to anyone.

There is an accusation someone in the car business screwed someone either by omission or commission and zero back story to support it. Just curious.

Last edited by Brian; 08-17-2013 at 10:09 AM.
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post #5 of 96 Old 08-17-2013, 10:10 AM Thread Starter
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Quote:
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Sorry, I feel like I am coming in at the middle of the story.

When you say preliminary tests does that mean another shop was trying to diagnose the oil consumption? Or was it just a test for general condition prior to a sale?
Sorry for the confusion. The documentation is such that it appears that the compression test was done to specifically determine the engine condition as the owner had previously mentioned a high oil consumption concern. A reference was made that it was 'likely valve guides', but a leak down test should be done to verify. Hence, my question as to why not just do the tests concurrently, versus duplicating labor later on the customer's dime.

Quote:
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In either event I suppose it highlights two things

a. The real lack of diagnostic abilities of most that work on cars, both professional and not.
b. The widely held belief, spread in large part by internet experts claiming compression and leak down tests are redundant.
I agree!

Regarding your salient point b; in the one test is static and the other is dynamic, one would hopefully presume that they would serve different diagnostic purposes. But since the Internet has also seemingly changed the basic laws of physics and gravity, I guess anything is possible.

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post #6 of 96 Old 08-17-2013, 10:17 AM
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Quote:
Originally Posted by David @ FluentInFerrari View Post
Sorry for the confusion. The documentation is such that it appears that the compression test was done to specifically determine the engine condition as the owner had previously mentioned a high oil consumption concern. A reference was made that it was 'likely valve guides', but a leak down test should be done to verify. Hence, my question as to why not just do them the tests concurrently, versus duplicating labor later on the customer's dime.

[

I agree!

Regarding your salient point b; in the one test is static and the other is dynamic, one would hopefully presume that they would serve different diagnostic purposes. But since the Internet has also seemingly changed the basic laws of physics and gravity, I guess anything is possible.



David, I have a little insight here, but only a little. Well meaning shops all to often get caught up in following the direct instructions of the guy paying the bill. Some cars turn into the poster child of poor, deferred or improperly performed service due to an owners need to dictate what will be done, when and how.


The very fact that the service order notes another test should be done supports that. You own a shop, how many tests and service procedures do you perform when not authorized? When you suggest them and not authorized do you note it on the repair order?


Cars go unfixed and badly fixed all the time, blaming it on a repair shop that was not paid to do the work isn't OK.


This just may be one of those cases. I sure could not at this point condemn any one of the places that have worked on this car.

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post #7 of 96 Old 08-17-2013, 10:35 AM Thread Starter
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Your insights are appreciated, Brian. My intention was not be be accusatory...as it could be construed. With the blatant symptoms recently presented and the somewhat lacking (or perhaps non-conclusive) documentation provided, I personally feel that this situation could have been handled in a more definitive manner.

In retrospect, I don't doubt that the previous shop's intentions were well-meaning. However, my thoughts are that customers look to us for answers, not more questions.

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Last edited by David @ FluentInFerrari; 08-17-2013 at 10:42 AM. Reason: grammar
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post #8 of 96 Old 08-17-2013, 10:39 AM
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Quote:
Originally Posted by David @ FluentInFerrari View Post
Your insights are appreciated, Brian. My intention was not be be accusatory...as it could be construed. With the blatant symptoms recently presented and the somewhat lacking (or perhaps non-conclusive) documentation provided, I personally feel that this situation could have been handled in a more definitive manner. My thoughts are that customers look to us for answers, not more questions.

In retrospect, I don't doubt that the previous shop's intentions were well-meaning. However, my thoughts are that customers look to us for answers, not more questions.


I agree but like I said I have a little insight here and it trumps by a large margin any evidence I have yet seen to the contrary.
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post #9 of 96 Old 08-17-2013, 10:49 AM
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David- Sounds like this M got one of those sets of all copper valve guides. We once wondered it any of the Ms received sintered steel valve guides from the factory, since Ferrari pumped out a service bulletin about installing the sintered steel guides in the 456M and 550. It now appears Ferrari continued with the bronze guides, some good, some bad batches apparently, until 456M production ended in 2004. Even though they were installing sintered steel guides on 575M heads at the same time, no change was apparently made. And that was happening even though they changed the parts catalog to show the replacement guides on the 456 and 456M as the sintered steel guides. Talk about stubborn.

Brian- Interesting point on oil deposits leading to high compression readings. Had not thought of that, but it makes sense. I do remember some high performance cars with cold plugs that developed preignition problems in the olden days, likely from the same cause of essentially a smaller combustion chamber, plus possibly hot spots on carbon deposits acting like a glow plug.

You pros keep teaching me stuff and maybe one day I can be one of those internet experts who causes no harm.

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post #10 of 96 Old 08-17-2013, 11:05 AM
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Quote:
Originally Posted by Brian View Post
Sorry, again feeling like I came in at the middle of the story, why do you say "it was obviously misrepresented by previous shops".

I heard no evidence of misrepresentation by anyone to anyone.

There is an accusation someone in the car business screwed someone either by omission or commission and zero back story to support it. Just curious.
You're right Brian; at the crux of it was some data that David & I corresponded about privately, which would indicate either proper testing wasn't done, or if it was, the results were skewed.

I shouldn't have brought it up and I'll leave it to David to expand on it further if he chooses.

'99 550, Rosso Corsa / Nero, S/N:114654, Assy: 31836, Engine: 52084

High mileage, low compression, and missing on a few cylinders.....just like my cars.

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post #11 of 96 Old 08-17-2013, 05:54 PM
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John- How is your valve job coming? Did you get the errant head removed?

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post #12 of 96 Old 08-17-2013, 06:49 PM
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Taz, my shop is still sourcing the guides. Apparently there's not many 550's that have had their valve guides replaced, so it's tough to find anyone that has them as a standard item. Mine will probably have to be made, but it should be easier & cheaper for the next guy. We've hit all the usual sources, ie CHE, Ferrea, Supertech, Xceldyne and others and are just comparing offers.

The driver's side head is still on the block David has kindly offered to make me one of his tools to get the thing off, and more importantly, be able to get it back on and torqued properly.

The Hill head nut tool is a beautiful piece of work and works pretty well either alone or with its 90 degree extension for 26 of the 28 head nuts, but it just won't fit on the two outboard rearmost nuts. To get to those requires one of David's tools or some redneck techniques which I'd rather not discuss here

'99 550, Rosso Corsa / Nero, S/N:114654, Assy: 31836, Engine: 52084

High mileage, low compression, and missing on a few cylinders.....just like my cars.

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post #13 of 96 Old 08-17-2013, 10:06 PM
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John- Dave to the rescue. My passenger visor still works like new, so he helps all of us.

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post #14 of 96 Old 08-18-2013, 02:26 AM
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John- Dave to the rescue. My passenger visor still works like new, so he helps all of us.
Taz, different David; I was referring to the David who started this thread

Dave B. & I collaborate on skunkworks stuff, while the head nut removal tool is David F.'s brainchild. Both great guys.

'99 550, Rosso Corsa / Nero, S/N:114654, Assy: 31836, Engine: 52084

High mileage, low compression, and missing on a few cylinders.....just like my cars.

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post #15 of 96 Old 08-18-2013, 06:35 AM Thread Starter
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Quote:
Originally Posted by cribbj View Post
..The Hill head nut tool is a beautiful piece of work and works pretty well either alone or with its 90 degree extension for 26 of the 28 head nuts, but it just won't fit on the two outboard rearmost nuts. To get to those requires one of David's tools or some redneck techniques which I'd rather not discuss here
Yankee ingenuity to the rescue...Is that what I'm hearing? Honesty, I must give some credit to both Brian and David Moore of Moorespeed, as both of them gave me the mental inspiration to get the job done, without yanking the lump. For the many of us who are engineers, this is one job where over thinking the problem just makes the solution that much more difficult to see, Those gents just gave me the gentle whack upside of the head to get the job done in an efficient manner. There's nothing like a bit of outside confidence to help one see through the trees...For that alone, I thank them both!

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post #16 of 96 Old 08-18-2013, 11:24 AM
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John, David- I see, said the blind man.

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post #17 of 96 Old 08-20-2013, 08:12 AM Thread Starter
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Little good news to report, but what was discovered was expected...
Intake valve/guide clearances are in the 0.006" range
Exhaust valve/guide clearances are in the unbelievable range, where a proverbial ruler could have been used to measure the slop,

Next up is to do a leak down test on each cylinder to ensure that there are no ring (or liner) problems.

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post #18 of 96 Old 08-20-2013, 05:29 PM
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Every engine I've ever replaced valve guides in read high compression on at least a couple cylinders. In fact, I've seen a few engine have good leak down numbers and high compression on a cylinder or two. Those of us who have worked with sued car dealers know the old trick, artificially saturate the rings with high to get a false but good compression number on a weak engine.

If the shop that did the compression was on point, they have have reported the compression numbers as indicative of the need for the heads to come off and gave the owner the option to stop there, or proceed with an expectation to rebuild.


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post #19 of 96 Old 08-22-2013, 08:28 AM
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On my 456MGT 1999 (113811) 2/3 of the valve guides looked or rather felt like that:

456 worn valveguide - YouTube

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This was found after one valve was hit by the piston resulting in parts of 4 valves beeing reaspirated in the left head. I turned the engine off immendiately when I noticed that something was wrong. Funny: The slow down light came on :-). However I was traveling a about 280km/h on the German Autobahn. Luckily nothing else was damaged I could stop the car safe at the next parking area and wait for a flatbed.
The engine was complely rebuild.

Btw: I had no increased oil consumption. But the milage was ridiculous round about 35l/100km = 6.7 miles / gallon (US).

Last edited by mehl; 08-22-2013 at 08:34 AM.
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post #20 of 96 Old 08-22-2013, 11:26 AM
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Christian- That consumptions is about as bad as my old 67 427 (7 liter) Corvette that had been hot rodded.

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