Massive performance loss & misfirings | FerrariChat

Massive performance loss & misfirings

Discussion in '365 GT4 2+2/400/412' started by vespasian, Mar 1, 2012.

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  1. vespasian

    vespasian Karting

    Nov 28, 2011
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    Germany
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    Alex
    #1 vespasian, Mar 1, 2012
    Last edited by a moderator: Sep 7, 2017
    Today, I've put my 400GT w/Carbs on a dynanometer. Background was simply to get a "status quo ante" which can be compared to the status quo after finishing all maintenance works.
    Sadly though, the performance diagram not only showed massive misfirings starting at around 4.000rpm, but also a performance drop from the original stated 340PS down to a mere 228 PS.

    The car was more or less stationary for about 5 years: last oil change in 2007 stated a mileage (obviously in kilometers ;-) which is just a couple of hundred km away from todays numbers. Until today, I've driven the car (I bought it in the middle of this winter...) just around a corner, no longer routes whatsoever.

    Apart from the obvious ones - spark plugs, carburettors - do you have suggestions?
    Thanks in advance, Alex
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  2. Crowndog

    Crowndog F1 Veteran
    Rossa Subscribed

    Jul 16, 2011
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    Robert
    Distributor/s might need a going over. Advance mechanisms also.
     
  3. hoverland

    hoverland Formula Junior

    Aug 14, 2010
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    Norway
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    Harald Ø
    Stock ignition?
    Is engine running effortless without vibrations up to 4000rpm?
    Is misfiring also present above 4000rpm without load ?
    -If so, ignition is probably the problem.

    -Do the easy steps first before you start to rip things apart;
    1 > hook up a dwellangle meter and check reading -should be around 37-39degrees and same value for both banks, (if much lower -there will not be enough energy from stock coils at high rpm.)
    2 > Check static ignition to be 11deg both banks.
    3 > Connect a stroboscobe-lamp cyl 1 and 7 and check ignition advance at 5000rpm to be 30deg
    4 > Airfilters not clogged?

    My experience is that DCOE's are basically good as "open throttle devices" and normally gives you trouble on low power settings, so I would not suspect them before items above is checked OK.

    Good luck and keep us posted on progress.
    Harald
     
  4. 180 Out

    180 Out Formula 3

    Jan 4, 2012
    1,206
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    Bill Henley
    I have found at least 50 of the missing ponies. Yankee gearheads generally assume a parasitic drivetrain loss from a TH400 or other old school Detroit automatic of 20% to 25%. That is, rearwheel hp equals 75 to 80% of flywheel hp. If I read your printout correctly, your Dynojet run measured 214 rearwheel hp. Applying a 75 to 80% conversion factor (divide 214 by .75 and by .8) gets you up to 268 to 285 flywheel hp. You're still missing between 55 and 75 ponies, but that's not quite as bad as 125.

    I wonder how your tech gets "clutch" hp of 228 hp out of 214 rwhp. That's totally unrealistic.
     
  5. vespasian

    vespasian Karting

    Nov 28, 2011
    55
    Germany
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    Alex
    @ you all - thank you for your hints, very helpful indeed for more detailed discussions with my garage guys. Harald, very very valuable!

    What kind of power metering car manufacturers will post regularly as the "power" of their cars? Flywheel oder rearwheel power? I always thought hp numbers obviously would adress rearwheel power because that's the only thing that matters for customers?

    Bill, based on your calculation, this would be flywheel power instead? Confused right now...
     
  6. vespasian

    vespasian Karting

    Nov 28, 2011
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    Alex
    I wouldn't say engine is running effortlessly at all. There also is a huge lag between throttle and response from the engine especially at low revs. During this lag, revs are going further down instead of increasing.

    "Misfiring without load" - could yo clarify this, how can I rev above 4000 without load / or how do you define 'load' in this context? (sorry to be that dumb)

    In my initial post, I didn't mention the quite massive oil loss during the dynanometer test - seemed for one part to be oil out of the automatic gear box. But also the engine itself - cause unclear right now - showed a dinstinctive oily skin underneath. I actually did a compressiontest before buying which showed quite balanced results within 1 bar for 11 cylinders, one cylinder was down by 1,5 bar which didn't seem so bad to me.

    Well, this can get nasty or easy ...
     
  7. hoverland

    hoverland Formula Junior

    Aug 14, 2010
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    Harald Ø
    Misfiring without load, means revving engine with gear-selector in neutral.
    -Reason for asking that is that with no load -the fuel consumption is relatively low, so if engine still misfires, fuel starvation probably not the problem.

    The "lag" you describe, could be a combination of several things, but I would again recommend to check ignition as described as 1st step -before targeting carburettors.

    Also please note that any single cylinder misfiring will cause noticeable vibrations.
    If one complete cylinderbank is off -engine is still running quite smooth. This due to the fact that "engine control"-systemwise the engine is actually two independent straight six'es sharing the crankshaft. (makes troubleshooting a whole lot easier ;) )

    Harald
     
  8. vespasian

    vespasian Karting

    Nov 28, 2011
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    Alex
    ok, understood, thank you.

    I had a spark plug pulled out and measured the elektrode gap: a good millimeter instead of 0.6-0.7mm. So, there the journey begins...
     
  9. hoverland

    hoverland Formula Junior

    Aug 14, 2010
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    Harald Ø
    The devil is in the details!
    And with 12 cylinders, 6 carburettors, 2 fuelpumps, 2 ignition systems and the built-in Italian surprises there's a lot of details :)

    Anyway -good start on "the journey" with the sparkplugs.
     
  10. vespasian

    vespasian Karting

    Nov 28, 2011
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    Alex
    That was a nice one :)
    And the best side of the story is: these Italian surprises came for free and are still functional after 30+ years ;-)
     
  11. 180 Out

    180 Out Formula 3

    Jan 4, 2012
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    Bill Henley
    Advertised hp has always been flywheel hp, measured with a test engine hooked up, usually, to a water brake dynamometer, with or without mufflers and accessories like alternators and smog pumps in place (net hp vs. gross hp). The 340 hp and 310 hp numbers Ferrari advertised for the 400 and 400i, respectively, are net flywheel numbers.

    The Dynojet measures rearwheel hp. All chassis dynos, by definition, are measuring output at the rear wheels (although most brands other than the Dynojet measure torque and calculate hp). All the components between the crankshaft's output flange and the dyno rollers are turning the kinetic energy produced at the crank into heat energy. The torque converter, the transmission, the differential gears, the bearings, the U-joints, even tire flex, are subtracting from the output at the crankshaft.

    Therefore, in order to compare rearwheel hp as measured on a chassis dyno with advertised numbers as measured on an engine dyno you have to apply a conversion factor. For Detroit cars we gearheads have always used 20-25% for a 3-speed auto and 17% for a 4-spd stick. That's why I say the numbers on your printout, of 214 hp at the wheels and 228 "clutch" hp, don't make sense. That's just a 6% conversion factor. No drivetrain is so friction-free that it would subtract only 6% of the crankshaft output.
     
  12. vespasian

    vespasian Karting

    Nov 28, 2011
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    Alex
    Bill, thanks a lot for your detailed explanation!

    Today I also asked the guys who did the dyno test about the odd numbers. They explained that "clutch power" is an unhappy if not totally wrong term because the clutch hp show the total output of the engine/gearbox-combo. The difference between rearwheel hp and clutch hp numbers is only caused by the drivetrain, these 6 odd percent are fairly common after their words. Also, this seems to be different to most american setups, their dynanometer just uses one roll for both rear wheels.

    To me, it made perfectly sense. Hope you are on my side on this?!
     
  13. 180 Out

    180 Out Formula 3

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    I think all Dynojets use only one roller. It is a massive unit, of a *known* mass. The raw data that the system measures is the rate of acceleration that the test car is able to exert on this known mass. That's the definition horsepower.

    If you go in for more Dynojet runs as you chase your missing ponies, I suggest you apply the conversion factor to the advertised number of 340 net flywheel hp, and use that result when analyzing the Dynojet rearwheel results. In other words, when you are able to achieve somewhere between 255 and 272 rearwheel hp on the Dynojet, you can conclude that you are getting 340 at the flywheel.
     
  14. vespasian

    vespasian Karting

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    Alex
    #14 vespasian, Mar 6, 2012
    Last edited by a moderator: Sep 7, 2017
  15. ricar116

    ricar116 Formula Junior

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    Sorry that is a bummer. Dont make your decision too quickly.
     
  16. Ashman

    Ashman Three Time F1 World Champ
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    Wow! Sorry to hear that. Let us know what the full teardown (assume you'll do that just to confirm what it would cost to rebuild the engine) shows you. Then you can figure out whether this engine can be saved or if you'd be better off buying another 400/400i with a rusted/crashed body and starting with that engine as a donor for your car.
     
  17. samsaprunoff

    samsaprunoff F1 Rookie
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    Jun 8, 2004
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    Sam Saprunoff
    Good day Alex,

    Yikes... that is indeed very disheartening!

    Although as John commented, investigate first and then explore your options and in fact finding a used engine may be a viable option.

    I wish you better luck!

    Cheers,

    Sam
     
  18. Highmiler

    Highmiler Formula Junior

    Dec 8, 2010
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    Greg
    I agree with the others.
    The grit might just be carbon.
    The magnetic stuff may just be an accumulation of wear.
    The orange stuff is probably bad news but it looks like gaskets to me.
    It is even possible that an oil change and run up will flush all that junk out. Since there was grit on the uptake screen in the photo it could be that the motor went nuts because of a pluged uptake screen
    As a second ditch effort, pull the engine apart and see what ails it. Even if it is dead the internal parts still have value.
    Then as a last resort do as suggested, buy a junker and save the engine.
    I wouldn't give up on the dream.
    Greg
     
  19. Highmiler

    Highmiler Formula Junior

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    #19 Highmiler, Mar 7, 2012
    Last edited: Mar 7, 2012
    I sent your information to my engine guy who is also the guy who sold me my 400i. His business is building road race car engines.
    He agrees with what I suggested: clean out the junk, put it back together with fresh oil and filters and warm it up.
    Then play with O2 sensors on each side, in the tail pipe or at header bungs, to find out which side is leaned out. He suggests that your power loss above 4,000 comes from weak fuel pumps, obstructed in line fuel filters or both.
    Whatever it is will probably be simple and obvious. If the engine were really on the verge of total failure, it wouldn't run well at any RPM let alone 4,000.
    Good luck on the hunt,
    Greg
     
  20. 180 Out

    180 Out Formula 3

    Jan 4, 2012
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    Bill Henley
    Now that Highmiler has chimed in with some optimism I will join him. General engine wear is usually indicated by bad oil pressure. An engine's oiling system generally consists of a single network of galleries which connect the oil pump to oiling holes located at each bearing. The pressure of the entire system will fall if the gap between the bearing surfaces increases due to wear. Therefore, if you've got good oil pressure it means that your bearings are not excessively worn.

    The other tests of wear are a compression test and a leakdown test. The compression test will tell you if the piston rings and cylinder walls are not excessively worn. The leakdown test will tell you the same thing, and also whether the valves are sealing.

    If your engine is running and not making anomalous sounds, like a timing chain hitting something that it shouldn't be hitting, then you can assume the reciprocating assembly is sound. If you've got good oil pressure, compression, and leakdown, and no anomalous sounds, then the poor running is more likely due to ignition or induction than to a problem with the long block. So I would certainly do the compression and leakdown before I would tear into the long block.

    There are also oil analyzing services that can tell you exactly what is in that oil, e.g., aluminum or iron or other stuff. I did a Google of oil analysis services germany and I got some promising hits of vendors of this service. You can probably do better if you use German words.

    We amateurs always assume the worst when things go mysteriously wrong with our cars. But try to get some easy to find facts before you tear into the engine.
     
  21. alastairhouston

    alastairhouston Formula Junior

    Apr 19, 2009
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    Alastair Houston
    Sound advice
    dont panic there could be a really easy solution to your worries. I have been told the engine has a lot of tollerance compared to modern engines so what looks like a disaster might be an accumulation over a long period.
    junk sitting in your sump isnt doing any damage to the working bits!
    Good luck
     
  22. vespasian

    vespasian Karting

    Nov 28, 2011
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    Germany
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    Alex
    Thanks for your words of comfort ;-)

    Well, the work so far has been carried out by a real crack with over 25 years of experience with old Ferraris and Alfa Romeos and a undisputed reputation. He's specialized and totally focussed on restoring & improving old engines. So, I take his word quite seriously.
    As he opened the oil cover, he simply said: "Never seen anything like this before!". He's totally sure that the materials are in part from the bearing shells (correct expression? it's where the crankshaft is mounted). The bigger red parts are just sealing material from the oil cover mountings, no problem with these.

    He's sure too, that this grit is just a small portion and that the rest was been washed out by emptying the oil before unmounting the oil cover. And he simply said: "can you imagine what these hard metallic particles (up to 1 - 1.5mm in diameter!) already had done to the engine? And imagine - crankshaft and so on are parts with 1/100 of a milimeter in tolerance - this parts here are way bigger. So - total engine overhaul is a Must."

    I asked him what he would do if it would be his car. He said without a trace of hesitating: "I'd do everything to return that car to its seller. Period."

    I've to add here that he isn't especially interested in acquiring this job - he already said there would be others who can do this job way faster and that it would take him around a year because of all of his pending work.

    Today, on my inquiries (he said this would be a waste of time hence the result is absolutely clear already), he'll unmount further parts to reach and to inspect some of the bearing shells so that we can see wether there's already visible harm done to them or not.

    I'll keep you posted.
     
  23. ME308

    ME308 Formula 3

    Nov 5, 2003
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    Alex, I feel your pain :(

    think you don`t mind if I post the sound file of your engine - so the guys here can listen

    (that was before and the reason why the oil pan was taken off in the first place)


    [ame]http://www.youtube.com/watch?v=wEnttoGCWaI&feature=player_embedded[/ame]
     
  24. wrxmike

    wrxmike Moderator
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    Mar 20, 2004
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    Mike
    I think the most likley source of those metal particles is a disintegrated tensioner for the cam chain which has led to the chain skipping a tooth and then hitting othe rparts of the timing case. These engines will run (poorly) with the chain one or two teeth out ( this won't cause a valve to hit a piston.

    A second, less likely source of the material is the earings for the water pump that which are driven by the lower cam chain - have a look at a 400 parts manual in the water pump and engine oil pump section. If the problem is in this area, it will most likley hav been caused by coolant leaking through the water pump seal and corroding the bearings, leading to their failure.

    There is a good chance that the rest of your engine is actually ok. The large bits were filtered out by the screen on the oil pickup and the small bits by the engine oil filters.

    To establish wether or not the debris has contaminaited the oil passages of the engine you can remove a couple of the camshaft caps and see if there is any evidence of metallic fragments in the bearing caps.

    I would also perform a leakdown test on each cylinder ( as opposed to a compression test, which would require turning over the engine using the starter motor, you don't want to do that anymore....)

    Also, an endoscope camera will let you have a look at the timing system from the sump.

    If both tests are OK, then it's probably worth pulling the engine out and attempting a repair ( engine needs to come out to open the timing cover).

    M
     
  25. vespasian

    vespasian Karting

    Nov 28, 2011
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    Alex
    #25 vespasian, Mar 8, 2012
    Last edited by a moderator: Sep 7, 2017

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