News

Daytona engine rebuild - how many HPs would you expect?

Discussion in 'Vintage (thru 365 GTC4)' started by Italian Tuneup, May 6, 2020.

  1. gcalex

    gcalex Karting

    Aug 16, 2010
    150
    Mostly New Hampshire USA
    Full Name:
    Alex
    I don't know anything about the original poster, but I will say that just because one bought a Daytona does not necessarily imply that $9k is an expense that one can "shrug off".

    One can argue that it is foolish to buy a car like a Daytona if one does not have a lot of spare cash to give to the Ferrari-restoration-industry left-and-right, but $9k is a sizable amount of money and I (for one) can imagine not being able to afford to just pile that on to what is likely already a pretty sizable rebuild cost; i.e., just because you are in deep does not mean you are necessarily in a position to go in deeper... :)

    Personally, I think $9k is pretty hard to justify, even if the shop had to send the motor out to another facility.

    If it were me, I'd be asking "So how were you planning to tune the engine? Just going to assume you're done if it seems to run without stumbling, or something? Maybe at least check the exhaust gases?"; if their answers are "yeah, something like that", then I suppose that they are no different than most shops that don't have dynos, but it would be an odd attitude for a place that has invested in a dyno set-up...

    When I talked to a few shops about rebuild services, the ones that had dynos generally said that they always test on a dyno before they *risk* putting the engine back in the car, because the last thing they want to do is pull an engine a second time. Places that did not have dynos tended to just do a bench-run for leaks and obvious problems, but it is not surprising that they thought this was "fine", because they obviously thought the expense of a dyno was not worth it.

    If the shop won't include the bench dyno, I would ask what their warranty position is if you take the car to a rolling-road dyno facility to do a few pulls ($300-$600), and the numbers look way off...
     
    Nuvolari likes this.
  2. Edward 96GTS

    Edward 96GTS F1 Rookie
    Silver Subscribed

    Nov 1, 2003
    3,700
    only a couple on hand....
     
    375+ likes this.
  3. 375+

    375+ F1 Veteran
    Silver Subscribed Rossa Subscribed

    Dec 28, 2005
    6,994
    :D:D
     
  4. Andreas72

    Andreas72 Rookie

    Aug 28, 2019
    9
    Thanks so much all for your insights & wisdom. Am definitely going to talk to the shop about the dyno (which they can do in house - they claim to have an old Ferrari F1 dyno setup that can handle 1,000 hp ). Both for initial testing and adjusting the engine as well as for breaking it in. Will keep you posted!


    Sent from my iPhone using FerrariChat.com mobile app
     
  5. Italian Tuneup

    Silver Subscribed

    Apr 16, 2019
    43
    Europe
    Full Name:
    Stefan
    On the dyno they use a special exhaust manifold, which has connections for sensors for each individual cylinder.

    This makes the exact adjustment of the carburetors etc. more accurate because it ensures that the combustion process is the same in all cylinders.
     
    V12addict likes this.
  6. 335s

    335s Formula Junior

    Jan 17, 2007
    864
    SF Bay Area
    Full Name:
    T. Monma
    A couple of humorous points of reference: The "Italian AND German" Factory Dynos both use european horses-they are a tad smaller-so there will ALWAYS be MORE indicated present than in an "American" dyno...:-}
    Additionally-but not surprising is: that as my esteemed Marmon expert so clearly points out: "what does the barometric readings meter indicate?
    While running a research emissions laboratory(5-6 years), which was a Federally certified Testing station, good enough to prep cars for the "Small Volume Certificates of Manufacture Certification" program tested for in Ann Arbor, I frequently discarded ALL testing results when the legends failed to indicate all PERTINENT BASELINE DATA....
    If the barometric pressure is like sitting in the eye of A CATEGORY 3 ATLANTIC HURRICANE....Well, those NUMBERS-WHILE IMPRESSIVE-ARE TOTALLY bogus...
    FURTHERMORE, THE "CORRECTION FACTORS"-IF NOT INDICATED-FURTHER DISQUALIFY REULTS!
    Withe these ground rules stated, it must further be understood that: every test run for power, will be less than the previous-all things being EQUAL-as the dyno AND the test subject vehicle/motor gets HOTTER, further skewing the results...We call this "The deterioration Factor."

    That said, I can offer you some RESULTS-test results-after having been doing this since the early 1970s:
    As for specifics as they apply to "Daytona" tipo 251 engines: stated HP is 351, as my aged addled brain seems to recall....
    Having sone 12+ SPYDERs-which are an EXCELLENT pool of examples, as these cars are essentially required that they be done BONE STOCK, as oppossd to P-6 cammed, 9 x 35 final drives, etc., as lots of coupes were redone in this fashion.
    Spyder values are such that 'KISS' is the order of the day(Keep It Stock Stupid) This said, pre tear down power run tests typically showed 320-ish to 340-ish(pretty healthy mills with no more than 6-8% leak down)
    Post rebuilding results:
    DEAD BONE STOCK
    -valve jobs done with seat/guide machines and 3-5 angle cutters, and a kiss with stones to remove "scraping burrs", NO valve face back cutting, 8MM stem sizes, NO valve seals-intakes at 8 tenths and 12 tenths exhaust, Plateau hone finished liners-all with .09 MM protrusion-ground-and done with a PAIR of honing plates, NO flow benching, and dead bone STOCK cam timing(using throw away precision ground timing discs for half a MM on the cam ramps,) NO modern, "exotic" skirt coatings, no plasma coated low tension, gapless ring packages, no Carillo rods(WHY would you EVER use an H beam rod in one of these?). Using the factory headers(on a dyno previously certified/qualified/calibrated by DOD for a MIL spec testing project, the very reproduce-able results ranged in the 355-365 range...THIS is REAL HP.....with computerized data acquisition: which can easily be manipulated, as in: "what do you want it to read?" Always keep this FACT in mind when reading dyno printouts of results.
    Since there is an economic perspective in all of this which CANNOT be ignored, to a degree, the numbers have to "look good", or at least meet claims prior to "selling the job"
    All of which gets me to the point; What;s the torque curve look like and how and where are the point of inflection/intersection, and how long is the flat ramp for the torque curve? Torque is what gets you there, and HP is what "keeps you there"....but out side of the "old Mulsanne Straight", top end HP is really sort of irrellavent(if you can smoke two cigs from start to finish, THAT'S a long straightway! TORQUE is what wins in racing-plain and simple-especially in old cars where they-in all honesty-don't handle as well as todays grocery getters!

    WITH flow benching, and mods that you KNOW are done, but to the layman: you cant really see whats been done(let alone understand the physics and chemistry), 400-410 no sweat(very expensive to do), and to get to 450+, no problem, but it'll look like, sound like, and drive like a factory Daytona Comp car!
    The math and 50 years of doing this tells me I could PROBABLY get 500+, but why the hell would you want to? The rest of the car could not take the forces in the system. A great example: BBLMs were very prone to breaking stuff in era....materials and ability to manufacture in small lots, parts that didn't break, at a cost affordable to privateers, just wasn't a realistic expectation in those days. Hence the very high rate of DNFs which they experienced-as they were really just road cars being modded to run at: 'big boy', factory Team car events...
    Vintage racing in today's world is another story! Parts are so stout, and so well made, that the cars are faster-way faster-as an entire group of cars, and if done by proficient people, are essentially failure proof.....within the scope of "Vintage Racing."

    In summation: I advise you to re-evaluate the limits of what it is you REALLY want and need.
    yonder this carefully, and then determine if you are WILLING to spend the money. But remember: at the end of the day-HP you cannot use, is HP wasted(wasted$$$).

    PS-and this is critical: all-ALL-results I have obtained are by using a laboratory testing fuel reagent, NOT gasoline, pump gas, or "race gas'-ALL of which can skew one's results. By using a standardized testing reagent, this variable is now a "fixed absolute"...
    Lastly, i would also tell you that its rather unlikely that you could "feel" the difference of 10-15 horsepower, under ANY driving conditions without having had the entire car being completely refurbished...and then, even then, I sort of doubt it-which brings me full circle to the torque topic: you can FEEL torque....the stop watch shows the HP at the track....AND at the dyno....

    PPS: on the dead bone stock config: cam timing of the DOHC is great!
    If I ADVANCE the intake cams 4 degrees, i get more torque for around town driving, but the car is more difficult to "fine tune".
    If I RETARD the intake cams by 4 degrees: my eyes will water standing behind the car, it will idle like glass, ad pull like a train at the top end(sounds Bitchhin'), and burn even more fuel...retarding drops HP output about 10-20, and advance the intake cams will give a slightly less, but similar, INCREASE in top end HP-FWIW.....on the dyno

    My apologies if it sounds like I'm pontificating, its just in my advancing years, I've found that I'm losing ALL filters....
    "Just the facts, Mam."
     
    Nuvolari, 375+, theowinstone and 2 others like this.
  7. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    6,207
    southwest germany
    Full Name:
    romano schwabel
    great writing and explaining ;) and true from my own experiences

    what is this? if you mean play of the pistons in the liners 0,09 is a little on the high side. when I do liners I go to max. 0,08 mm, newer pistons sometimes down to 0.05 mm, motorcycles cylinders down to 0,04 mm
     
  8. TTR

    TTR Formula 3
    Silver Subscribed

    Mar 29, 2007
    2,493
    Riverside, CA
    Full Name:
    Timo
    #58 TTR, Jun 8, 2020
    Last edited: Jun 8, 2020
    Thank you, sir.
    Great summarizing as always.
     
  9. Italian Tuneup

    Silver Subscribed

    Apr 16, 2019
    43
    Europe
    Full Name:
    Stefan
    thank you, great write-up.
     
  10. gcalex

    gcalex Karting

    Aug 16, 2010
    150
    Mostly New Hampshire USA
    Full Name:
    Alex
    I think that there is little that one can do about a shop that is willing to "bend" results to show a given result. At the end of the day, one is always taking the word of the shop that tests were done honestly.

    Personally, what I would want a shop to do is put-on the correct headers and air-filter-set-up; use the type of fuel that I expect to have to use; and then use the dyno to do *quantitative* tuning of the engine. I would like to think that it would be a given that the dyno set-up would not change through the tuning process (though changing temps and atmospheric conditions do tend to make that sort of a challenge), and ideally, I would want the shop to at least bother to talk to me about what sorts of torque/power tradeoffs I probably would prefer. At the end of the day, they could hopefully show me a bunch of different pulls that showed where they started, what happened when they tried this or that, and what they finally settled on.

    I probably would even tell them that I realize that the absolute numbers are neither here nor there, so that they don't have any incentive to try and "bend" any results.

    To me, the shape of the torque curve is the real "finger print". HP curves have sort of had a derivative applied to them, so their shape tends to be more generic. Things being off in the tuning tend to show-up more obviously in the torque curves.

    My experience is pretty limited (and in the context of more modern cars), but at least as far as I have seen, the shape of the torque curve seems to hold-up even if someone monkeys with the usual suspects of dyno-compensation trickery.
     
  11. BMWairhead

    BMWairhead Formula Junior

    Sep 11, 2009
    925
    Portland, OR
    Full Name:
    Ted
    A very interesting and informative post...thank you. However, speaking of physics...the point of intersection...does that ever vary? You have FAR more dyno experience than I have, but I always thought when using the same units, the curve will always intersect at a certain point (e.g., 5250 rpm for hp vs.torque).
     
    375+ likes this.
  12. 335s

    335s Formula Junior

    Jan 17, 2007
    864
    SF Bay Area
    Full Name:
    T. Monma
    TurboJoe: the .08 MM spec I reference is for liner protrusion ABOVE the RE-MACHINED/SQUARED TO CRANKSHAFT CENTERLINE-WITH A 30 DEGREE OFFSET FROM MIDLINE, from the top of the FINISHED, GROUND, liners....This has nothing to do with bore sizing/piston fitment-FWIW...
    Any LESS, and there will be potential problems with fire ring in head gasket achieving a total crush/seal of the cambers.
    any MORE, fire rings crush just fine: but NOW the fibre portion of the gaskets have insufficient crush surrounding the coolant passages, and now you are weeping coolant along the parting line....
    REMEMBER: in the old days, gaskets had asbestos composition, a material eminently suited for that which we are asking it to perform...Everyone here is familiar with the new composition gasket sealing difficulties inherent in "modern" reproduction head gaskets....Precision helps here, but it ONLY....helps....

    GCALEX: "Results" are merely printouts of analyzed, data, AFTER its already happened...moving curves is merely a byproduct of altering the function which draws the graph....I could spend six hours describing what I'm alluding to in far greater detail, and you would have an equally long number of additional questions! This is far more complex "science" topic than most are aware of...
    Since High School auto shop, nearly ALL will remember :"such, squish, pop, fooey" as being an "OTTO" cycle firing sequence of events.
    This, is actually and factually: INCORRECT!
    There is an incorrect and fundamentally erroneous description here: engines NEVER "SUCK" the intake charge into the chamber...WHAT they DO DO" is that they create a LOW PRESSURE zone-and as we ALL know: Nature ABHORS a vacuum! The greatest quantity of intake charge-moles-is achieved by the greatest VELOCITY allowing to the intake chamber via a whole cacophony of variables..
    100% of the time: on the flow bench: I will sacrifice VOLUME of intake VS VELOCITY of the cycle's charge volume...100% of the time...well, nearly 100%...
    It might sound counter intuitive, but EVERY racing guy will tell you, essentially, the same thing-for NO-FORCED induction engines.
    In truth, smaller is usually better than bigger! Additionally, there are a multitude of points where the Bernouli principle is applied as well...Again, I want to avoid descending into an overly technical diatribe, but rather the purpose here is to "dummy" it down such that its palatable to both the Layman, as well as the scientifically educated.
    Besides: I can't tell ALL of my tricks , after all...:-}

    BMWWARHEAD: Please see above....(also, o2 sensors, digitally timed port potl injection, variable xcam timing, variable intake runners, variable exhaust runners .....jeeeez-nothing like having FUEL CONTROL!)
     
    Edward 96GTS, of2worlds and TTR like this.
  13. 335s

    335s Formula Junior

    Jan 17, 2007
    864
    SF Bay Area
    Full Name:
    T. Monma
    I neglected to comment on the issue of fuels-I'm getting "more forgetful"...

    The OP was speaking-specifically-of the 365 GTB/4, engine tipo 251....
    Therefore, my comments as they regard fuels-be they Indolene EEE "clear"(Federally mandated Testing Reagent for an LA-55/CVS, EPA cert driving cycle test, AND, Small Volume Certification Evaluation testing, as well as mileage accumulation "deterioration factor" gradient/"in use" testing), or, any of the VP, Sunoco, etc.all brands that are referred in the vernacular as: "racing gasoline"/for TRACK use ONLY(leaded fuels, in most cases)required some specificity it seems...AFIK-memory is betraying me, again-the Clean air Act Revisions for 1990-ish was the time frame/window when it was NO LONGER legal to sell leaded fuel at filling stations in USA. ,,,it might have been as late as 1995-with 1996/OBD2 just on the horizon, but i seem to remember that it was a bit earlier...

    oopps-airport run-I'll finish this tome tomorrow...
    CIAO

    VERITAS
     
    375+ and TTR like this.
  14. Italian Tuneup

    Silver Subscribed

    Apr 16, 2019
    43
    Europe
    Full Name:
    Stefan
    Regarding the fuel: The car is located in Europe and should run with 98 octane (ROZ) fuel. This is available on every gas station over here. In general I use 100 or 102 octane (ROZ), which is also very common.
     
  15. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    6,207
    southwest germany
    Full Name:
    romano schwabel
    where you get in europe/germany 102 octane fuel? 100 octane not a big problem but 102 octane?
     
  16. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    6,207
    southwest germany
    Full Name:
    romano schwabel
    sorry t.monma, my english is not so good that I understand now what you mean. and when I translate this with google or an other translation program it makes absolutely no sense. could you please write again with "simple" words?

    FWIW: what means this?
     
  17. 375+

    375+ F1 Veteran
    Silver Subscribed Rossa Subscribed

    Dec 28, 2005
    6,994
    For
    What
    It's
    Worth
    ;)
     
    turbo-joe likes this.
  18. gcalex

    gcalex Karting

    Aug 16, 2010
    150
    Mostly New Hampshire USA
    Full Name:
    Alex
    In my case, there is no need to dive in any deeper. I have a mis-spent youth as a physics nerd, and drilled-down pretty deep into such things many years back when I was on a "tuning" kick... :)

    My point was not that I disputed anything that you were saying. I was just conceding that any sort of desire to get absolute/reliable numbers out of any dyno is sort of a fraught thing, and that my conclusion (those many years back) was that for most shops, the right approach to take was to largely ignore the exact numerical values and have the shop treat all the dyno numbers as "befores and afters" that are just indicative of the direction of improvement (in all the various rpm ranges).

    Assuming an honest shop, a bench dyno is a great tool for reducing the time needed to tune an engine, and improve the quality of the final result. I would ask a shop to focus on those things, rather then trying to figure out some way to get their dyno to spit-out the number "350hp"...
     
  19. Italian Tuneup

    Silver Subscribed

    Apr 16, 2019
    43
    Europe
    Full Name:
    Stefan
    At every ARAL station: "ultimate 102". And I don´t know why but it is even cheaper than the Shell V-Power Racing with only 100 octane.
     
    turbo-joe likes this.
  20. 335s

    335s Formula Junior

    Jan 17, 2007
    864
    SF Bay Area
    Full Name:
    T. Monma
    I'm back-but suffering today from "chemo-brain"...

    FUELS-this is the topic which-IMO-requires some specificity for the proper response to the "dreadth and witdth" of subsequent comments
    As far as FUELS, and how they relate to our current topic...I'm going to have to noodle this today, but i promise all, a more precise, yet concise. clarification as all "fuels"- and how they are perceived- is not at all "equal" ...
    CIAO!
     
    of2worlds and TTR like this.
  21. BMWairhead

    BMWairhead Formula Junior

    Sep 11, 2009
    925
    Portland, OR
    Full Name:
    Ted
    Thank you. I have a dusty physics degree and a life-long love of cars...your posts are always interesting to me and very informative. I appreciate your willingness to share.
     
    of2worlds, 375+ and readplays like this.
  22. TTR

    TTR Formula 3
    Silver Subscribed

    Mar 29, 2007
    2,493
    Riverside, CA
    Full Name:
    Timo
    +1,
    except degree.
     
  23. 375+

    375+ F1 Veteran
    Silver Subscribed Rossa Subscribed

    Dec 28, 2005
    6,994
    But are you dusty?;)
     
  24. TTR

    TTR Formula 3
    Silver Subscribed

    Mar 29, 2007
    2,493
    Riverside, CA
    Full Name:
    Timo
    Obviously, but feel rusty and leaky too, although after having spent vast majority of my awaken hours in past 4 decades playing with and/or working on vintage cars, most of which had been born before me, I think it can or should be expected. :rolleyes:
     
    of2worlds and 375+ like this.
  25. 335s

    335s Formula Junior

    Jan 17, 2007
    864
    SF Bay Area
    Full Name:
    T. Monma
    Fellas-sorry for the delay: 2 compound fractures(Hamet bone included, could be a career ender) sustained in my left hand and at my age/advancing years, I have been sitting with my head in a bag screaming in pain for a couple of weeks as I refuse to undergo major surgery to include re-breaks and titanium parts additions-not at my age, when its just a matter of fortitude/adapting to a daily elevated level of additional pain and aggravation..
    That said-I have not forgotten about a fuels discussion, especially as another thread on Daytonas is covering hard hot restarts, which this will help explain... in detail...within the next week or so...???
     
    375+ and of2worlds like this.

Share This Page