308 2v sodium valves | Page 2 | FerrariChat

308 2v sodium valves

Discussion in '308/328' started by AREA, Jan 21, 2015.

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  1. vvassallo

    vvassallo F1 Veteran
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    Aug 4, 2006
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    Vince V
    I am doing larger valves in my 348, particularly the exhaust side and discussed this very subject with my machine shop. Bottom line is I'm swapping the sodium exhausts for solid steel. I don't race the car. It doesn't see redline more than a few times per drive. It is not turbocharged and is designed to shed heat pretty well (because it's a 348!). If any of the foregoing were different, I'd retain the sodium design spec. I am sure the engine will be fine for many years to come.
     
  2. yelcab

    yelcab F1 World Champ
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    You're in a valve job now?
     
  3. NoGoSlow

    NoGoSlow Formula Junior
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    I thought the sodium valves were only used on the 2V 208/308 engines, and were phased out around 1980. This is the first I've heard that the 348 engine might have had them as well.
     
  4. nerofer

    nerofer F1 World Champ

    Mar 26, 2011
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    At Ferrari, phased out with the introduction of the four-valve engines.
    Two-valve engines (carbed an injected) have them (exhaust valves only); four valve engines don't.

    Rgds
     
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  5. vvassallo

    vvassallo F1 Veteran
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    Well, yeah. Stooge skunksworks project. For the upcoming major so later this year, maybe in a month or two.
     
  6. guygowrie

    guygowrie Formula 3

    Sep 19, 2011
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    Yes.
     
  7. GordonC

    GordonC F1 Rookie
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    I will post this again, it's quoting a Rifledriver post from 2013 - it's not just sodium as a factor on the exhaust valve failures, Brian notes that Ferrari's valve stem diameters were narrower than pretty much every other sodium valve used.

    https://www.ferrarichat.com/forum/threads/would-i-have-sodium-valves.395864/#post-142044367 (The below text is post #18 by Rifledriver in this thread)
    Sodium valves typically have very large stems. The German valves I have seen for Mercedes and Porsche ranged from 10.5mm to 12mm in diameter so that there was a useful hollow space and enough stem material to be strong. The American sodium valves I have seen were 3/8's....same idea.

    Alfa used 9mm stems on theirs but for the most part those motors had lower redlines and the power was in the lower part of the range so seeing redline was far less common.


    Ferrari used 8mm stems with minimal wall thickness and yes, I suppose you could say they weren't very good as evidenced by the fact that they have a reputation for breaking.


    With valve stem diameter never entering into the discussion comparing Ferrari valve breakage to German or American uses of sodium is just silly.

    For those that want to feel safe because of the idea that only worn guides are the cause of valve breakages. Sorry, not the case. I have seen motors break their valves with perfect guides. The very first Ferrari motor I ever took apart was a low mile Lusso motor with a broken, recently replaced OE valve. I have seen many more since.​
     
  8. derekw

    derekw Formula 3
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    Good point- the smaller cross sectional area means higher stress concentrations even with perfect guides. The weld being in the hottest part of the stem doesn’t help. With the guide holes not being concentric with the seats, if you don’t index the new guides off the seats or don’t lap the seats, you’ll have the same additional bending stresses.
     
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  9. NoGoSlow

    NoGoSlow Formula Junior
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    FWIW, Brian is currently replacing the sodium valves on my 1975 308 GT4. I find Brian to be carefully deliberate... there wasn't a knee-jerk phobic reaction for removing the sodium valves, although he agrees they are a weak point in that engine's design. In my case (44 years old, 36K miles), the engine has never been apart and is really tight... solid numbers for leak-down and compression. I have a long-term plan for maintenance and restoration, and we decided to pull the heads and deal with the valve risk along with other items on my laundry list.
     
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  10. tuttebenne

    tuttebenne F1 Rookie

    Mar 26, 2003
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    Those folks who have replaced their 308 2v sodium filled exhaust valves with stainless versions, where did you get them?
     
  11. waymar

    waymar Formula 3

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    There are a few places. Aw Italian in NJ, SI valves in CA, and a few more.
     
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  12. tuttebenne

    tuttebenne F1 Rookie

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    Thanks !
     
  13. derekw

    derekw Formula 3
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    I still have lots. Both inlet and exhaust are $12ea plus post and they are 21-4N. I have a range of lengths (plus or minus a few thou) so can compensate for the rest of the geometry if needed.
     
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  14. Nabga

    Nabga Rookie

    Oct 31, 2017
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    all need some help!!!
    I found a 75 GT4 in a garage in queens NY...
    The car had sat on a lift for 8 years, a Jag collector bought it at auction. He passed away leaving the car at the shop.
    I paid the shop owner 7K which was the storage fee
    It sat in my garage for an additional 3yrs. This winter I had a Major done and rebuilt the carbs. Car ran great when started and short 10 min rides.
    This Sunday went for a 30 min ride in the morning, car ran great.
    took one last ride in the evening, running up thru the gears i heard a pop and then the sound like a baseball card in the spokes trick.
    limped the 1/4 home and shut down.
    Monday night I ran A boroscope in the cylinder, the face of the exhaust valve looks like a potato chip. Intake is fine.
    The exhaust moves up and down as the crank is turned. There seems to be 4 small grooves on the piston dome, but it looks as there are no holes.
    I cannot see if the valve seat has drop
    Any insight why the valve would drop low enough to hit the piston????
     
  15. absostone

    absostone F1 Veteran
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    Timing belt skip? Tensioner fail? Sorry to hear. Good luck
     
  16. Patrick Dixon

    Patrick Dixon Formula 3

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    Are you sure it's valves hitting pistons? I had a transfer gear tooth shear off in my gt4 many years ago. Do you still get the noise if you turn it over with the clutch depressed?
     
  17. Nabga

    Nabga Rookie

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    Thanx for the replies
    Engine still feels smooth
    The horoscope confirms there is an issue with the exhaust valve
     
  18. Nabga

    Nabga Rookie

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    Also no vacuum on the NBR 1 cylinder
     
  19. derekw

    derekw Formula 3
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    The head will have to come off but to diagnose the cause check the timing marks on the cam when you have the cover off. Since it was only one valve and the valve head is still attached, I suspect the tip broke and collets (keepers) came out or just a bad spring broke (less likely.) Worth doing both heads if you can stomach it. I can send you some valves but check the guides and reline them if required (don’t replace unless you can cut the new ones concentric with the seats as guide holes and seats are not concentric.)
     
  20. Patrick Dixon

    Patrick Dixon Formula 3

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    I guess it was just born unlucky.
     
  21. Smiles

    Smiles F1 World Champ
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    What’s your sign? And your ascending sign?

    :)

    Matt
     
  22. Nabga

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    Meant boroscope!!!
    I see exh valve moving up and down using the scope
    Removed all components and now down to the head removal.
    Won’t budge!!!
     
  23. derekw

    derekw Formula 3
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    Borrow or build a lifting plate and get some PB blaster down the sides of the studs (which are why heads are usually stuck.) Thick plate with holes drilled to line up with studs, weld nuts underneath and then bolts though holes/nuts to push on studs. Bolt on or weld on side straps to latch onto manifold studs. Tighten main bolts evenly and use fan heater, hair drier etc to heat head. Be patient, may take a while. Come back after a while and give bolts another half turn...
     
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  24. Nabga

    Nabga Rookie

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    finally got head to move....end result
    comments????
     

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