2v oil scraper ring tension? | FerrariChat

2v oil scraper ring tension?

Discussion in '308/328' started by Ferraripilot, Oct 7, 2024.

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  1. Ferraripilot

    Ferraripilot F1 World Champ
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    John!
    Question for the brain trust. So I've gone through and rebuilt a fair number of these engines now and even fresh 2 valve engines still burn a bit of oil, usually hearing about a quart every 400-600 miles depending on how hard it's driven. I've used Superformance JE pistons and my own designs, they've all used 2.8mm or 3mm oil scraper rings (Hastings type), I believe around 13-14lbs tension or so, light but not crazy light nor tiny. Chevy and some other race motors now running tiny 2mm oil scrapers somehow.

    I suppose I can't be totally certain it's not coming from the valve guides/stem seals, but it doesn't strike me as probable as I always have new guides and stem seals and I've never seen the tell-tale valve guide/seal bad signs.

    Anyone else seeing or paying attention to this? I guess it's not a big deal as that's always about what they've burned.

    SO. I'm wondering if we might try a 4mm scraper ring of standard tension to really get bottom end oil stuff under control. Yeah I get it will add a tiny bit more drag to the rotating assembly. Anyone try this? Bugs me that these things always drink a bit of oil, maybe it's a waste to even try?
     
  2. smg2

    smg2 F1 World Champ
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    I've not seen that on rebuilds typically, but did have a build 8-10yrs ago, JE pistons and their rings that was a nightmare on blowby. Ended up switching them out to total seal, helped but the pistons ended up being replaced as well as CR was not correct. No more problem. I don't have a problem per say with JE pistons but we don't use them. Custom from Carrillo, CPS, RP, etc..

    I've done a few total seal gapless builds and you do notice the increased friction before it's run. But it's not been a running problem.
    Could be their ring supplier/mfg. Everybody has their preference of course. I've had no issues with total seal.
     
  3. Ferraripilot

    Ferraripilot F1 World Champ
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    I always insist on using Total Seal, I source them on my own. The last 2 builds I've actually run the gas ported top rings and they work great, but when they're run hard (which they almost always are) they burn a bit of oil! Standard 20/50 Valvoline race juice. It's only the 2v iron liner engines that have this issue....
     
  4. smg2

    smg2 F1 World Champ
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    Maybe it's the liners
     
  5. Imatk

    Imatk Formula Junior

    May 6, 2007
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    I had no idea these cars burn a quart of oil every 400-600 miles! After reading another thread of misfire I'm wondering how the poor spark plugs function at all with that much oil running through them.
     
  6. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #6 Rifledriver, Oct 7, 2024
    Last edited: Oct 7, 2024
    I wouldn't use JE pistons for free. Junk. There are too many good pistons around to get stuck with crap. Wossner has off the shelf 308 2v pistons in your choice of size and compression. Wossner is the supplier GTO Engineering uses. Good product. Building a 330 right now with Wisecos. Have Wisecos in my 3.5 liter 328.
    There are 2 brands of rings I'll use. Mahle and Nippon. Lots of custom pistons come with Nippon. Wiseco does, a set of custom Italian pistons Scott supplied me came with Nippon rings. Zero issues ever.
     
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  7. Rifledriver

    Rifledriver Three Time F1 World Champ

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    Thats a lot less than from the factory. We had customers with 80-82 308s bought brand new who could not go a full tank of gas without having oil pressure problems from lack of oil. Factory paid for a lot of engine rebuilds.
     
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  8. Ferraripilot

    Ferraripilot F1 World Champ
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    Will give Wossner's shelf stock and shot then. I've used Ross a few times too for custom stuff as their wait isn't nearly as long as others, but never in a Ferrari engine to date. So far so good though in the weird Maserati stuff though.

    Are you seeing zero or very little oil burning with these 2v iron liner motors post rebuild? Do Boxers/Daytona's do the same thing?
     
  9. Rifledriver

    Rifledriver Three Time F1 World Champ

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    If the client ever needs to use the dipstick I have failed in my job. Boxers will always use a little oil. All flat motors do. No excuse for a Daytona to use any degree of oil. We are no longer using Victorian era technology.

    When Ferrari built the 80-82 308 they burned oil like there was no tomorrow. Starting with the 4 valve the problem disappeared. There was one meaningful difference. Mahle rings. Mahle is still the best but there are others who are great and that you can actually deal with. Nippons list of customers is second only to Mahle.
     
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  10. bl10

    bl10 Formula Junior

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    Not a 2v expert by any means however mine, 78 GTS US, 120K + miles which I've had since 1980, uses about 1/2 qt per 3k miles with no oil residue in air cleaner blow by vent in normal around down and freeway driving (not much over 6K and 3/4 throttle ). If driven hard with lots of high RPM (right at red line if not a little above) full throttle up and engine braking down will use the same 1/2 qt in a couple of hundred miles with heavy oil trail on both bottom and top of air cleaner. Don't really see how it can be anything but loss of ring seal.

    I'm currently running Castrol 20/50 synthetic blend with a quart of Lucus oil stabilizer which improved hot around town slow idle (850 RPM with AC and both fans on) oil pressure. (I've never had the oil light come on but it got below the low mark on the gauge). I'm going to change to Mobil 20/50 full synthetic next oil change.

    Back in the day we drag raced Mopar 426 ci Wedge and Hemi NA in NHRA Super Stock, C and A gas classes. At the time we used dykes "L shaped" top ring with low tension tapered scraper and low tension 3 piece oil rings supplied by Chrysler or Sealed Power. We attended all the Mopar seminars and blow by and ring seal was always a hot topic. As a point of reference the Hemi rev limiter was set at 8700 with slick shifted stick shift. Mopar allowed as how there was no way to maintain perfect ring seal and prevent blow by. The standard rule of thumb is don't worry about it unless the valve cover breathers (push on type) moved more than 1/2 inch up on the tube. Kind of crude but a sure sign of trouble. We did lots of leak down testing with the pushrods out and found we would get different numbers at different piston positions. Mopar allowed as how it is impossible to compensate for various engine temperatures as well as head stud, main stud and cross bolt stress even when bored and honed with torque plates..

    The thing we discovered in our NA engines was that the expander in the 3 piece oil ring is critical. To little tension and it will blow oil like a chimney, to much and it would gall pistons.

    Any one interested in this topic should review some of the YTUBE video's on engine rings. Sealed Power has a bunch of them as well as many top engine builders. The thing they keep coming up with regarding oil burning is cylinder roundness, especially in an aluminum sleeved block, and cylinder finish. They are using hones with eight or twelve stones followed by some kind of rubber smoothing pad (stone) followed by electronically mapping the cylinder roundness and finish for the entire bore.

    Just a quick thought when did Ferrari switch to the coated sleeves? Does that correspond to the reduction in oil consumption?
    Barry
     
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  11. mike996

    mike996 F1 Veteran

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    Obviously Ferrari must have improved something about cylinder sealing as time went on - my '89 328 "burns" about 1/2 qt of oil in 3k miles.

    Re Mopars...I wrenched a 340 and 426 Hemi in NHRA Super Stock years ago. A major thing we learned at the Mopar Direct Connection seminars was to look for engine blocks with thicker cylinder walls on the thrust side. Engines with thicker cyl walls on the thrust side maintained their "roundness" at operating temp thus reducing blowby. Since the blocks were cast (iron) there was inherent shifting in the the cylinder wall thickness from block to block during production. This was (is?) common for cast blocks of any manufacturer. So in mass production it was just LUCK that determined if you had a great engine, an average engine, or a (relatively) poor engine. We dynoed many stock Hemis and got numbers from 430 to 510HP for factory "identical" engines. FWIW, IMO the best engine Mopar produced in the muscle car era was the 340, NOT the Hemi though the Hemi gets all the attention.

    The head of the Direct Connection program, at one of the seminars, explained that when he "ordered" his 426 Hemi he actually went to the factory, measured the wall thickness on a bunch of blocks and selected the specific block for his car.
     
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  12. Ferraripilot

    Ferraripilot F1 World Champ
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    Great post thank you.

    It's my understanding Ferrari started using Nikasil coated aluminum liners with the 4v engines.

    I have since checked with a couple mechanics in the UK as well, one notes they use Omega pistons regularly, the other notes they have used a number of different pistons. They've had the same issue which they don't really even see as an issue, it just is what it is with carbureted 308s and Dino engines. They always tell the clients the 2v iron liner motors just burn a bit of oil between changes and depending on how hard it's driven.
     
  13. INTMD8

    INTMD8 F1 Veteran
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    Fwiw, (probably not much here) in my 426 hemi I use total seal .043 AP top .043 2nd napier 3.0mm oil ring 15lbs.

    Lateral gas ports in piston. Vacuum pump. Iron block. Uses no measurable amount of oil. Shifted at 7900.

    For me, always conventional. I do not like any of the gapless rings.

    IMO you would be better off going thinner on the rings for more bore conformity rather than the other way around.
     
  14. Rifledriver

    Rifledriver Three Time F1 World Champ

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    In the dealer network we never used synthetic oil in 2 valve and earlier engines. The piston ring design was ancient. In 4 valve they went to Mahle and it was a very different story. To this day I will not use synthetic in the iron cylinder engines.
     
  15. Rifledriver

    Rifledriver Three Time F1 World Champ

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    Agree.
     
  16. Rifledriver

    Rifledriver Three Time F1 World Champ

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    Are you using big end gaps in second rings?
     
  17. Portofino

    Portofino Formula Junior

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    I gave been using classic mineral 20W 50 in my 77 - 2 V carb based on this ……the iron liners , slack ( by modern stds ) rings.
    It’s changed annually @ 2-3 k kms . It does darken

    The other thing with carbs is potentially oil dilution at start ups fuel washing past these loose rings.More so if a bit of choke is applied
    I think the mineral oils are better coping with this .

    It never needs a top up and there’s no blue smoke - wife has followed me occasionally.
     
  18. Ferraripilot

    Ferraripilot F1 World Champ
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    No no, always check each hole and run appropriate spec. 2nd ring just slightly larger gap than the top ring. Since you mentioned it, it must be that they're just crap oil rings likely with too little tension. Going to Mahle from now on.
     
  19. Rifledriver

    Rifledriver Three Time F1 World Champ

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    Learned from a guy at Honda Racing a long time ago to run 2nd ring gaps at least 1.3 or 1.4 times as big as top ring. Gas trapped between the 2 keeps oil scraper from working.
     
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  20. Rifledriver

    Rifledriver Three Time F1 World Champ

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    The Wisecos I am putting in a 330 right now has .9mm top, 1mm scraper. The last set I installed had .95mm top, 1.1 mm scraper.

    For what its worth, I never tell a shoe maker how to make shoes. I let the piston guys tell me what rings to use. If I was so smart I'd be in their business.
     
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  21. Ferraripilot

    Ferraripilot F1 World Champ
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    Now that is interesting. Honda would know stuff about stuff. In these small bore applications I usually see the 2nd gap about .004 larger than the top, sounds like going to .007 or so would be a good idea then.
     
  22. INTMD8

    INTMD8 F1 Veteran
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    Makes a person wonder about ring packs made with a gapless 2nd ring o_O

    (Still top gapless is trash to me as well)
     
  23. mike996

    mike996 F1 Veteran

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    Main thing we found re rings was re the oil rings - reducing the oil ring friction had a noticeable effect on power output. There was relatively little difference with various tensions of the other rings and even with various gaps, sometimes considerably wider than the typical .004" per inch of bore. I don't know the specific numbers as far as oil ring tension but I remember that we ended up using oil rings that were, per the ring guy, less than 40% of the tension of standard oil rings for the engine application.

    We tried gapless rings but didn't really see any consistent difference in power output. There was a lot more to be gained by careful cylinder wall prep/proper ring material selection.
     
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  24. Ferraripilot

    Ferraripilot F1 World Champ
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    So I did a 308 engine years ago with original Borgo forged pistons from the 'queen mother' V12 engine. These pistons measured out to about 9.8:1 compression and had a massive 5mm (!!!) oil ring. Hastings was the only option I could locate for the oil ring, and thankfully they had a 'standard' 15lbs tension so it wasn't massively draggy, but certainly more draggy than a 2.8mm oil ring. I definitely believe oil ring tension and thickness makes a measurable difference in power. But 5mm for an oil ring??? my gosh
     

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