348 Compression & Leakdown #s, Thoughts? | FerrariChat
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348 Compression & Leakdown #s, Thoughts?

Discussion in '348/355' started by itsablurr, Jan 7, 2016.

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  1. itsablurr

    itsablurr Formula 3
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    Matt
    #1 itsablurr, Jan 7, 2016
    Last edited: Jan 7, 2016
    I've been on the hunt for a 348 for a few months now, and have a deposit on a '92 TS with 37k mi, in excellent condition (http://www.ferrarichat.com/forum/348-355-sponsored-bradan/509481-well-just-made-deposit-down-my-first-ferrari.html). Car went to its PPI with John Tirrell at IFS this week. Received his report back this morning.


    "Overall a good car save the compression leak down numbers. They could possibly be improved with a valve adjustment and some miles put on the adjustment".


    Compression (PSI):

    Bank 1:

    Cyl 1: 200
    Cyl 2: 200
    Cyl 3: 190
    Cyl 4: 200

    Bank 2:

    Cyl 5: 195
    Cyl 6: 160
    Cyl 7: 155
    Cyl 8: 160


    Leakdown (%):

    Bank 1:

    Cyl 1: 6%
    Cyl 2: 8%
    Cyl 3: 20%
    Cyl 4: 8%

    Bank 2:

    Cyl 5: 16% - Intake
    Cyl 6: 45% - Intake, some Exhaust
    Cyl 7: 55% - Intake, some Exhaust
    Cyl 8: 48% - Intake, some Exhaust


    waiting on a call back to discuss, but perhaps valves adjusted too tight/deposit buildup on seats on that bank?
     
  2. vinny84

    vinny84 Formula Junior

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    #2 vinny84, Jan 7, 2016
    I'm not an expert, but I would be concerned on anything showing more than a 20% leak per cylinder.

    Do you know it's service history? When was the last major service performed?
     
  3. itsablurr

    itsablurr Formula 3
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    #3 itsablurr, Jan 7, 2016
    Last edited: Jan 7, 2016
    Last documented service 11y, 10k mi ago. Long overdue.

    Of course, the numbers warrant some attention for critical analysis and differential diagnosis for likely scenarios that may fit the pattern of evidence... disclaimer being, you never know until you're "in there".
     
  4. vinny84

    vinny84 Formula Junior

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    #4 vinny84, Jan 7, 2016
    Oh yeah, she's going to need an major service and then some sounds like.
     
  5. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    Brian Crall
    #5 Rifledriver, Jan 7, 2016
    Might be from tight valves, could have been maladjusted. Leaking from an intake valve is unusual otherwise.

    Getting debris from the plugs on valve faces is not uncommon. I'd rerun it for a minute and retest.

    As a data point I have a 67,000 mile Mondial QV here that lost a belt and bent a bunch of valves. The guides are still perfect and except for being bent the valves were too. So were the pistons/cylinders/rings. QV motors go a long time unless someone screws something up.
     
  6. ///Mike

    ///Mike F1 Veteran

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    #6 ///Mike, Jan 7, 2016
    Last edited: Jan 7, 2016
    Nothing that a valve job won't cure, and a valve job is pretty straightforward on a 348. I'd be far more concerned about the paint and interior since those areas are more expensive to repair. If the rest of the car is nice and you can come to terms on price then I personally would go for it. At worst you may have to buy a few new valve$ but if you can use the PPI results to negotiate a bit off the price then your risk is relatively low and the upside is that you'd have an essentially fresh engine when it's done. Being that it's a later car makes it more desirable to me (especially if it has the later rear suspension geometry) and the color helps as well, so assuming the rest of the car is clean and straight the leakdown numbers would not deter me. If the rest of the car is tatty I'd likely punt unless the asking price was too good to pass up. My two pesos, for whatever it's worth...

    Good luck and let us know what you decide.

    Edit: Just saw Brian's post above mine. Words of wisdom from someone who knows, and advice that's well worth heeding. The fact that the intake valves are leaking is indeed odd and could easily be indicative of some grit on the sealing surfaces of the valves.
     
  7. plugzit

    plugzit F1 Veteran
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    #7 plugzit, Jan 7, 2016
    One side crud. Per Rifledriver, Italian tuneup, retest.
    348s are VERY robust, but this one hasn't been properly driven (was the PO a poser?). Drive the pee out of it, then retest. I'd wager that with 10 trips to 7500, it'd improve considerably.
    Me, I'm an idiot. I'd buy it with those numbers knowing that's what would happen. But, I'm an idiot.
     
  8. ///Mike

    ///Mike F1 Veteran

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    #8 ///Mike, Jan 7, 2016
    Not sure I'd bounce it of the redline once, let alone ten times, on ten year old belts. But otherwise I agree.
     
  9. itsablurr

    itsablurr Formula 3
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    #9 itsablurr, Jan 7, 2016
    Thank you for the input, gentlemen. Much appreciated. I just heard back from John, and discussed the car at length. His opinions follow much of the same, being likely that the valves could be maladjusted tight, and some proper mileage after its major service should likely resolve, which is good to hear. He confirmed no leaking past the rings was detected, and the numbers are not indicative of a more severe issue on the top end (ex: bent valves).
     
  10. dapper

    dapper Formula Junior

    Nov 10, 2003
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    #10 dapper, Jan 8, 2016
    Get an agreeable price adjust sorted then go for it, the motor needs to be dropped out in any event for belt change and tensioners etc.
     
  11. ahsan127

    ahsan127 Karting

    Jun 28, 2015
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    #11 ahsan127, Jan 8, 2016
    As a reference. After my major including valve job the leak down is 2-3% all cylinders. 20k mile 355
     

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