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355 Challenge durability

Discussion in 'Technical Q&A' started by Aircon, Dec 31, 2003.

  1. Aircon

    Aircon Seven Time F1 World Champ

    Jun 23, 2003
    77,463
    Melbourne, Australia
    Full Name:
    Peter
    Please don't bother answering this question unless you have had specific involvement in 355 Challenge racing..I'm not looking for guesswork!

    At what sort of mileage (racing) would you expect that compression/leakdown/wear and tear etc would mean that a rebuild or refresh would be due and what would normally be done? Just rings and seals? Bearings? Valves/guides?

    Speaking of valves and guides, did the mythical head/valve guide issue raise its ugly head often in the 355 Challenge series?

    Thanks.

    Peter
     
  2. Dr_ferrari

    Dr_ferrari Formula 3
    Professional Ferrari Technician Consultant

    Nov 2, 2003
    1,064
    Pocono Sportscar
    Full Name:
    Jim McGee
    Basiclly, the engine would be "refreshed" once a year before the start of the season.

    pre-teardown compression and leakdown tests would be done.

    Cylinder heads would be check and repaired as necessary, lower end and rings/cylinder liners checked. Refresh all seals and water pump.Check and clean oil pump and replace oil chain tensioner guides if worn. Check and replace any worn componets.

    Complete reasssemble and cam timing adjust with all new belts. Complete engine adjustment.

    break in and shakedown of engine and chassis on a dyno or test day at the track. and then follow-up with a compression and cylinder leakdown test.

    Replace all filters and check all systems (ie....cooling, ignition connections, oil, etc...)

    As for the valve guide problem, yes it was an issue untill we replaced the guides with the improved steel sintered type.


    best regards, Jim
     
  3. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    1,572
    Kalamazoo, MI
    Full Name:
    Rob Schermerhorn
    I concur with Jim. If you want to run up front, this is the plan.

    I did have customers who would accept more wear (cylinder leak %) and delay refresh to save a few $$.

    Durability is high, for sure. Challenge racing gives competitors a lot of track time. We'd log over 100 hours on engines easy each year. I know of a few F355's going years without rebuilds, but they'll leak down 10% or more.

    Without crash damage, Challenge cars are relatively (for purpose-built race cars) low maintenance.

    Best regards,

    Rob Schermerhorn
     
  4. ferrarifixer

    ferrarifixer F1 Veteran
    BANNED

    Jul 22, 2003
    8,520
    Melbourne
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    Phil Hughes
    And not to forget, that although nearly all parts are road car parts, the extreme use and heat cycling causes increased wear when racing road cars.

    Using datalogging it's possible to calculate average rpm per lap/km etc. Overlay a race cars average rpm to a road cars average, and you'll see that actual km is almost meaningless....how many high load revolutions has the engine actually done???

    Race engines have copper/alloy/steel combustion sealing rings and rubber o rings on oil and water ways in place of a conventional head gaskets, and non stretch, use once only, head studs....just for random example of heat cycling management.

    A previously raced, but now roaded challenge will give years of useful life, but niggles due to vibrations and heat cycling will frustrate more than a road only car might.
     
  5. Dr_ferrari

    Dr_ferrari Formula 3
    Professional Ferrari Technician Consultant

    Nov 2, 2003
    1,064
    Pocono Sportscar
    Full Name:
    Jim McGee
    Good points,
    Honestly for the customer who wants to run club events, these are an excellent choice for a first track ferrari.

    As the guys have said, they will give good dependable service.

    Suggestion would be to have a tech checkover before each event due to the fact that most all events require a tech inspection, you can kill two birds with one stone.

    Best regards, Jim
     
  6. FLATOUTRACING

    FLATOUTRACING F1 Rookie

    Aug 20, 2001
    2,684
    East Coast
    Full Name:
    Jon K.
    Hi Peter,

    What Rob S. and the other posters have said is right on the mark. My car is for sale as you may know and we just did a compression and leakdown test.

    My car had about 8000 miles before it was converted to a Challenge car and an additional 5000 miles on the track show 13,000 miles on the odometer. If you have seen any of my vids I run the car pretty hard but it has never had any engine or gearbox issues.

    Although my engine may not be typical, we got on average 8% leakdown for cylinders 1-7 and right at 10% for cylinder number 8 which Ferrari of Washington indicated is excellent for a 13,000 mile engine.

    Except for last year I did a precautionary engine service (15K service) each season and I am sure it had some positive effect.

    The main wear items are the drive shafts, gearbox, and engine mounts. Also weak points are the rear wiring harnesses which can be easily fried.

    As long as you maintain your engine it can last a very long time. Remember, the guys rebuilding their engines each year are the front runners who are looking for that extra 5-10 hp and are willing to spend a fortune to get it.

    I'll let Rob S. answer the valve guide question but my car has had no such problems whatsover and it's a 1995 model.

    Regards,

    Jon P. Kofod
    1995 F355 Challenge #23 (for sale)
    www.flatoutracing.net
     
  7. Aircon

    Aircon Seven Time F1 World Champ

    Jun 23, 2003
    77,463
    Melbourne, Australia
    Full Name:
    Peter
    Yes well that's the thing, Jon, I'm only using it for club days 4-5 times a year and on the road the rest of the time. I'm not really interested at all in the last 5-10hp and it sounds like your car is a long way from needing a refresh and the work it's done (mileage) is a little more than mine about 7500mi). Sounds like I should be pretty right for a while. I think all the talk about 3000mi rebuilds of 360CH cars has made me nervous! My car runs perfectly, and I guess I should go by that, really.

    Thanks guys.

    Peter

    p.s. You're really going to miss that car when it's gone!
     
  8. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    6,333
    As an avid high performance F355 driver who does not have a challenge, but has followed the conversations over the last couple of years:

    The 100 hour number is a good number even for track drivers not in a real racing situation. But consider that in a typical club event you might get 4 20-25 minute sessions per day. Considering the warmup lap, the cool down lap, the occasional blockage by slower vehicles, this may only be 1 hour of high RPM motor time per day at the track. So, if you took you car to the track regularly, you should consider that 100 track days will basically require a top end rebuild. At 1 track day per month, this is 8 years, at 2 per month, 4 years. For a race motor, this has to be considered excellend durability.

    But, once you do have to pop the heads to do anything inside, you might as well do the whole number, checking everything, and putting it back to freshly built status. This way, you get another 4-8 years of running the snot out of it regularly before you have to do anything serious to it again.
     
  9. Aircon

    Aircon Seven Time F1 World Champ

    Jun 23, 2003
    77,463
    Melbourne, Australia
    Full Name:
    Peter
    Makes sense to me! My car's due for another major in 4 years. Going by your reasoning and additions, that should be around the right time to do some mechanical refreshing too. And i thought the LAST one was expensive!
     

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