F355 Compression & Leakdown test advice | FerrariChat

F355 Compression & Leakdown test advice

Discussion in '348/355' started by CCWillF355, Mar 16, 2020.

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  1. CCWillF355

    CCWillF355 Karting

    Nov 14, 2019
    105
    London
    Full Name:
    Chris Williams
    As the world is about to go on lockdown, it doesn’t seem appropriate to be raising this, but life does need to continue somehow and I imagine there’s a few of you bored at home. Would be very grateful for any advice on the below.

    Have looked a few F355’s now and pretty much all have had some kind of issue with the engine. I’ve walked away from 4 cars already and think I need to do the same with this recent car. As always, had a PPI with Compression test done and below are the findings.

    Cylinder compression test results in psi:

    1. 180 psi
    2. 180 psi
    3. 180 psi
    4. 120 psi (40% difference)
    5. 180 psi
    6. 190 psi
    7. 185 psi
    8. 185 psi

    Obviously cylinder 4 is worrying and above finding were relayed to the dealer and owner. These came as a shock to the owner who then carried out another compression test, but this time with a leakdown too. See below:


    Cylinder compression test results in psi:
    1. 180 psi / 14% leak off
    2. 180 psi / 16%
    3. 180 psi / 15%
    4. 160-175 psi (Lowest and highest readings) / 14%
    5. 190 psi / 15%
    6. 180 psi / 21%
    7. 185 psi / 17%
    8. 185 psi /12%

    As you can see most of the readings are the same, but cylinder 4 is a lot better. Still on the low side but if I had low and high readings across all cylinders, the comparison could look better or worse. It’s also interesting to see that cylinder 4 leakdown test resulted in one of the lowest.

    Both tests were carried out on a warm engine.

    Any advice on the above compression and leakdown tests would be very much appreciated.

    Thanks.
     
  2. Ferrarium

    Ferrarium F1 Veteran
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    Jul 28, 2018
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    #2 Ferrarium, Mar 16, 2020
    Last edited: Mar 16, 2020
    Compression tests are about relative reading to each other. Some cars run higher than others, maybe its climate maybe its procedure who knows. Mine was 190-195 for all and a leak down was 5% - 8%.

    For me anything 10% or more is an issue as it tends to get worse if there is an issue. Some folks say up to 20% is acceptable. You need to fdecide waht range is acceptable. You can use the leak-down to pinpoint issues rings are wore than heads for example
    • Intake valve : Air whistling out of the intake, carburetor or throttle body indicates a leak at the intake valve.
    • Exhaust valve : Air heard hissing out of the tailpipe, turbocharger or exhaust manifold means an exhaust valve leak.
    • Piston rings : Whistling or hissing out of the PCV valve, oil filler cap hole or dipstick tube means the air is pushing past the rings. Suspect ring or cylinder wall wear.
    • Head gasket : Air bubbles in engine coolant seen at the radiator filler cap could mean air escaping into the coolant past the head gasket.
    • Cracked cylinder head : Bubbles in coolant or coolant being pushed up out of the radiator neck can also indicate cracks in the cylinder head or cylinder walls.

    There are threads out here with others having done tests, run some searches and see what came of those discussions as well.
    Google these
    "ferrari f355 leak down site:ferrarichat.com"
    "ferrari f355 compression test site:ferrarichat.com"

    Good luck on your search!
     
    Qavion and CCWillF355 like this.
  3. CCWillF355

    CCWillF355 Karting

    Nov 14, 2019
    105
    London
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    Chris Williams
    Have read a huge amount on here and else where on compression / leakdown results and what is good and bad. I don't have any more information on the leakdown test as this was done by the owner. I will require more info.

    Tend to agree with the 10% variance as a good guide, which makes the readings the owner and I received annoying. 7 out 8 cylinders are good, it's just one which isn't. What kind of repair bill could this be. I've had someone suggest a rebuild of one side to be 3K. If that was all the car needed, then I'd be happy to negotiate. I suppose we would never know till it's opened up.
     
  4. Ferrarium

    Ferrarium F1 Veteran
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    If its heads its different than if its rings. Part of the leak down should be to determine where the issue is. If its a head, doing it at the time of a major is not absurdly prices but if not you have to pull it it will cost, may as well do a major while at it if its coming due. The issue as you say is once you open it you never know what you will find, because of you find issues unrelated it makes sense to fix that too.

    Maybe, assume its the heads (not uncommon) then get a quote for the dealer or who ever then negotiate that in perhaps? Then wait until a major to have it done when the engine is out already.
     
  5. johnk...

    johnk... F1 World Champ
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    Jun 11, 2004
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    John Kreskovsky
    No need for discussion. I'd walk away from this car.
     
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  6. CCWillF355

    CCWillF355 Karting

    Nov 14, 2019
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    Chris Williams
    This is my initial thinking. But it's the spec I've been looking for and I've been looking for over a year. If it's fixable, is it not worth giving it a new lease of life?
     
  7. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    Mitchell Le
    I have never seen a bad valve guide on C4 but it's possible. It has always been C1 or C2 for me. The bit of information you are not getting from the test is where the leak is going. The shop should have told you where the air is leaking to. Very often, it is the exhaust valve that is leaking. Exhaust valves live a harder life than anything else.

    Assuming it is the exhaust valve or guides on the head that is leaking, repairing it is called a valve job. While many will perform valve job on both heads, it can also be done on only one head. In the US, that repair will run $10K easily. It involves:

    Engine removal from the car, Yes Virginia, the engine must come out for this.
    Removal of everything from the front and the top down to the one head.
    Send it out for valve job. Some shops will replace the bad valve, some shops will recut the affected valve.
    Replacement of valve guides and seals
    Installation of head(s) with new belts, bearings (maybe), seals, cam timing (don't even think about skipping that step), and anything else that is questionable.
    Putting that engine back.

    In the UK where you are, I have heard that mechanics work for peanuts, so maybe that job is a $5K job.

    Negotiate from there if you love everything else about the car. I can tell you this, years ago when I bought my first 355, I walked away from a bad cylinder but I really liked that car. Knowing what I know now, I would have negotiated hard and brought that car home. It's just a car that needs repair. It is not a basket case.
     
    drbob101, GSF355 and brian.s like this.
  8. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    Brian Crall
    Its all about the value of the car. If it can be discounted enough to pay for the work, great you'll have a good car when all over but if the seller doesn't see it that way move on. There are more cars and time is on your side.
     
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  9. yelcab

    yelcab F1 World Champ
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    Ain't that the truth.
    For what I just lost in the stock market during the last hour, I wished I had bought that 355.

    But, at least I bought two Ducatis. I'm back on a Duc and it feels GREAT.
     
    taz355 likes this.
  10. emac

    emac Formula Junior
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    ernest
    If it were me and the car was a very nice, clean,no other issue, with a recent major and ran great (no smoke, misses, etc) I would be in for the right price. Drive it for a while, fix it right and be done. It may just need an italian tune up!
     
  11. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    As soon as this stupid paranoia is over the markets will be back. I was thinking more generally. 355s market value isn't going anywhere, not for some time if ever.
     
    JLF likes this.
  12. CCWillF355

    CCWillF355 Karting

    Nov 14, 2019
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    Chris Williams
    Car is listed at 80K, there are other things the PPI raised, but I see those more as maintenance and TLC.
     
  13. kenneyd

    kenneyd Formula 3
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    Sep 30, 2014
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    I would be hesitant to buy a car with issues.
    However, I have a hunch based on personal experience that many of these compression related issues can be attributed to carbon build-up. If it was my car, I would just romp on it track day style to burn all that gunk out.
    I worked on planes for years, and that was the first go-to when a aircraft had low compression on a annual inspection. And 9 times out of 10 it was due to a valve not seating due to carbon build-up.
     
  14. emac

    emac Formula Junior
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    ernest
    I dont have a good feel for the current market, but I would expect an 80K car to be pretty close to perfect. Maybe things have gone up in value more than I thought.
     
  15. yelcab

    yelcab F1 World Champ
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    While it solves many things, there are some 355s with real problems that the right foot tune up job will not solve. But, I would at least give it a try.
     
  16. yelcab

    yelcab F1 World Champ
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    No it has not...
     
  17. emac

    emac Formula Junior
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    Market has not increased because I haven't sold my car! I can list several cars that I sold right before they went crazy in value.

    1. 88 M5 with 49k miles in perfect condition sold for 16K in 2010
    2. Fully restored 71 204z sold for 8.5k in partial trade for F355 in 2015

    Both cars I had owned for many years and really didnt have a reason to sell them. I will let everyone know when I sell the 355!
     
    FourthAlfa likes this.
  18. dwhite

    dwhite F1 Rookie

    Great advice! Just what I always wanted a mechanic and finacial advisor. What time frame do you expect the markets to be back to the highs and please explain to everyone how you come up with this brilliant analysis.

    I love a person who believes their expertice in one area is given over to all areas. What I refer to as the Wile E. Coyote syndrome: the super genius with zero credentials.

    Ignore enacted.
     
  19. malex

    malex Formula 3
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    Dec 5, 2007
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    OP is in the UK. Market prices for 355s are higher in the UK/Europe than in the US/Canada.

    And fwiw, I'm guessing he means £80k (~$97k), not $80k. But I could be wrong.
     
  20. CCWillF355

    CCWillF355 Karting

    Nov 14, 2019
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    Chris Williams
    Sorry not clear, I'm talking about the UK market, which does have high valuations than the US. The Uk seems to be around the below, but obviously this is dependent on mileage.

    100k-110K - concours
    80k-100K - excellent
    70-80k - good
    50-70K - fair

    It's whether to take a risk or just wait, waiting I don't mind, it's just finding the spec I want. Don't think there's actually that many in the spec I want in the UK.
     
  21. taz355

    taz355 F1 Veteran
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    Feb 18, 2008
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    Based on above, now ask the question when next major is due.
    If due in 2 years I would buy it and due the Italian tune up.
    Drive it for the two years likely less that 5000 miles then fix it when you pull the engine.
    Only if it’s not burning oil etc. And running good.
    That’s what I would do but I am not you.
     
  22. CCWillF355

    CCWillF355 Karting

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    Major was done last year and very little miles done on the car after. So not needed for a few years really. Personally I’d want to know the car is ok as soon as possible. Or have some reduction on the asking price to cover my risk.
     
  23. greyboxer

    greyboxer F1 World Champ

    Dec 8, 2004
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    #23 greyboxer, Mar 19, 2020
    Last edited: Mar 19, 2020
    I hear your concern but given the lack of recent miles (especially if they have been soft or urban driven) and the unusual cylinder an Italian tune up sounds a good starting point as noted in the post above (which in turn echoes 13 & 15)

    If not then it gives a couple or more years to save for the eventual rebuild whilst enjoying the fact that it is still running fine

    Meanwhile a renegotiation is always possible especially if its a dealer SOR sale with a motivated private seller
     
  24. taz355

    taz355 F1 Veteran
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    If it was me I would base it on what’s out there and cost. That cylinder is not that bad but is an anomaly for some reason.
    All I can comment on is my car as I have not owned others. My compression and leakdown were very close and repeatable around 195 to 200 and less than 5% from what I remember since it was a long long time ago.
    Others I know of who did look after cars but drove them spiritually just about every drive also had similar numbers.
    For me it would not be a deal breaker but since it is a used car I would negotiate a reduction unless I really wanted the car.
    The other question and I think the most important is how long are you going to keep it.
    If that answer is 10 plus years then the small reduction in price in my opinion is irrelevant if it’s the car you really like.
    Of course just my opinion.
     
  25. CCWillF355

    CCWillF355 Karting

    Nov 14, 2019
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    Have read a bit about an Italian tune up, if that's all it needs then great, but I very much doubt it. Need to be prepared for the worse case.
     

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