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Any advantages to a missing thermostat??

Discussion in 'Technical Q&A' started by christopher, Jun 14, 2004.

  1. christopher

    christopher Formula 3

    Nov 29, 2003
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    Christopher
    Hello "F"-Chatters,

    While installing a new water pump I realized that the thermostate was missing. Is there any advantage to why it isn't present? I live in a smog state where a few degrees engine temp. could make a difference in readings.

    What I find interesting is that when the engine is warm, the cooling fans "kick" on as if the cooling sytem is cycling through the radiator.
    Interesting.....

    Thank you,

    chris.
     
  2. dm_n_stuff

    dm_n_stuff Global Moderator
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    Dec 10, 2003
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    Dave
    Um, what car?

    Some cars use the thermostat to channel water in multiple directions, or so I'm told, others it is an on/off proposition.

    It would help to know which car you're talking about.
     
  3. christopher

    christopher Formula 3

    Nov 29, 2003
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    Thanks Dave,

    It's a 79 308GTB, wierdest thing, didn't skip a beat.............
     
  4. milstanselnino

    milstanselnino Formula Junior

    Jan 8, 2004
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    I am not a mechanic. That said, a missing thermostat affects the coolant flow, even when the car is warmed up. DO NOT operate without it. IMHO
     
  5. ferrarifixer

    ferrarifixer F1 Veteran
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    Jul 22, 2003
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    A missing thermostat can cause flow problems. Water flow is increased without the restriction of the stat, so cavitation in the pump at high rpm is a possibility. This can put air in the system and/or cause hot spots in the block and heads, that go un detected while causing damage.

    It's probably ok for styreet use though, but I'd advise fitting a stat asap.

    The fans cycle due to natural rises and falls in temperature within the radiator, and has no bearing on the stat being fitted.

    Usually, the engine will take much much longer to get to proper working temp without the stat. This causes extra wear, wasted fuel and dirtier emissions for longer. You'll also probably think the heater is pretty crap.

    308's with healthy cooling systems require no modifications to components. The only mod required to run cool in even extreme conditions is the extraction ducts as used on QV and 328 bonnets.

    The later QV style wide cooling fan blades are slightly more efficient, but this just means they are on for shorter periods, the peak temperature will not change.
     
  6. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
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    The 308 has a recirculation type system to aid in warm up. The disc on the bottom of the stat seals this recirc. port when the stat opens. Without a stat in place, a good amount of coolant flow never makes it to the radiator. It is surprising the engine doesn't overheat without the stat in place, unless the recirc. port has been plugged (common mod for racing). Want a thrill? Check out the current price from Ferrari for a new stat!
    Dave
     
  7. christopher

    christopher Formula 3

    Nov 29, 2003
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    Hello Dave,

    Where would I find this if my vehcile was fitted with such a device?
    After I install the thermo. I 'll want to insure that the recirc. port hasn't been plugged as to prevent coolant cylcing through out the entire system.

    Please advise, I appreciate all help!

    Thanks, Chris.
     
  8. gabriel

    gabriel Formula 3

    As far as engine temps are concerned the thermostat brings the engine up to operating tempertures far more quickly. Below this temperture the fuel air mixture is incompletely burned which results in some additional cylinder wear due to the unburned fuel washing the clyinder walls. I suppose there are emmisions considerations as well. I don't know about the coolant flow considerations in your engine, but I'd replace the thing.
     
  9. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
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    If you look at a new thermostat, there is a plastic disc on the bottom of the stat. This moves down to cover the recirc port directly below where the stat is mounted, as the stat opens to allow circulation to the radiator. If this lower port is not covered then some of the flow will be back through the engine and some to the radiator.
    Dave
     
  10. dm_n_stuff

    dm_n_stuff Global Moderator
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  11. ernie

    ernie Two Time F1 World Champ
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    Nov 19, 2001
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    In a normal car you need the thermostat as other have said. However a friend has a South West NASCAR team. I was at his shop one day and noticed that the engine had no thermostat, but had a little peice of metal splitting the inlet for the coolant. I asked him what it was for. He told me that you could make extra power by rerouting the coolant. I was puzzed as to how. He explained that the by making the the flow split it caused the top of the cylinder to cool faster than the bottom. As a result the piston had less resistance at the top of the stroke because of the difference in temperature. He said you could make about an extra 20hp just by putting the little splitter in there. So that is one advantage to not having a thermostat. But the way a Ferrari V8 routes coolant isn't the same as a Chevy V8. So keep using the thermostat.
     
  12. christopher

    christopher Formula 3

    Nov 29, 2003
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    Thanks Guys for your valuable "feed-back", I figured that I'd put one in regardless, but I wanted to insure that no damage could have happend.

    One of you Gents, suggested hot-spots on the inside of the block and/or heads, anyway to visual on this?

    Thanks again Guys!

    chris.
     
  13. jselevan

    jselevan Formula 3
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    Nov 2, 2003
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    Christopher - I have a different perspective on the thermostat discussion. First, you should find in your owner’s manual a "flow" diagram of the coolant system. Look carefully at thermostat housing and determine whether the thermostat simply opens and closes a single port. If it simply acts as a on/off valve for coolant to flow through the engine, then you have several options.

    I believe that the thermostat is inserted in the system for one reason only: To hasten achievement of operating temperature. If you subscribe to this theory, then for those who live in a warm climate, and do not need cabin heating, the thermostat offers only the opportunity for it to fail.

    The radiator and cooling fans/thermal switch act as a feedback control system to maintain operating temperature during driving. The thermostat will remain open during normal operation. Should the thermostat fail, there will be trouble in River City.

    Now, truth be known, automotive thermostats have been around for 100 years, and this technology is pretty well established. Thus, potential for failure is real, albeit remote.

    The other reason to consider losing the thermostat is flow resistance. The various items discussed, from excessive gasoline-washing of the cylinder walls, to increased horsepower resulting from cylinder wall temperature differential, to pump cavitation, are, in my opinion, unfounded and undocumented. As anyone who has taken a course in fluid dynamics will tell you, if you introduce a partial obstruction or narrowing into a conduit, the pressure proximal to the obstruction will increase. Total flow will decrease.

    In summary, as I believe that the thermostat is introduced to enhance creature comfort and reduce warm-up time, and as most Ferrari owners, by definition, are not concerned about creature comfort (otherwise they would have purchased a Honda for far less money), the thermostat only reduces flow and has the potential for failure. If it's not there, don't replace it.

    Jim S.
     
  14. christopher

    christopher Formula 3

    Nov 29, 2003
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    Jim, Thanks for you feed-back, you seem very well read on the subject.

    I appreciate your insight and will consider your take in this area.

    Thank you very much!

    Regards,
    chris.
     
  15. resnow

    resnow Formula Junior

    May 21, 2001
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    Jim S.

    A few more points . . .

    The thermostat's most important function is to keep the engine at a particular temperature. Yes, it hastens warmup, but more importantly, it keeps the engine at a high enough temperature to operate more efficiently. It also helps keep it from getting too hot and causing damage. The thermostat sets minimum engine operating temperature - the radiator and fans limit maximum temperature (unless the thermostat sticks in the closed position). If the thermostat is not present, the engine will run too cool for maximum efficiency and minimum emissions.

    Bob
     
  16. gabriel

    gabriel Formula 3

    Have to disagree with you that it's unfounded that lower than correct tempertutres being maintained does not cause incomplete combustion and it's attendant problems.

    It's pretty basic auto shop 101, and you can find it documented in any number of auto tech school textbooks. Optimal tempertures are needed for optimal combustion, and that is partly a function of the thermostat. Any cooling system would be enginerred to take into account what you call "decreased flow." That's not decreased flow, that's normal flow; the system is designed for the flow characteristics with the stat included, and assuming that it and the other cooling sytem components are clean and correctly functioning.

    Taking parts off of a street cooling system is, IMO, unwise in the long run.

    After all, you really don't need the fans either if you are careful.
    Heck, on the strip they remove the water pump and install a blockoff plate.
     
  17. kverges

    kverges F1 Rookie

    Nov 18, 2003
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    Excessively low engine temperatures also accelerate engine wear. Below abot 170 deg F or so, engine wear increases exponentially, at least with normal lubricants.

    Also, while a thermostat increases pressure ahead of the obstruction, this can be a good thing. A water pump can cavitate if it does not have adequate pressure to work against; in essence the cavitation "bubbles" are suppressed by the greater dynamic pressure.

    Bottom line, use a thermostat in a street car. In racing conditions, pulling the 'stat can help reduce overheating, but even that is trial and error.
     
  18. davewapinski

    davewapinski Formula Junior

    Nov 24, 2003
    276
    I have not yet had time to learn about the Mondial t cooling system, but I know much about thermostats. The Mondial t also uses the oil system to help the cooling.

    In the vast majority of vehicles, the thermostat just controls coolant going to the cooling system. It helps in cold weather and helps the heater. Do not yet know about the Ferrari.

    Years ago, in August I went to Ft. Irwin just south of Death Valley in CA. I helped design their systems, helped order their equipment, and helped train their staff.

    The old timers there normally ran their vehicles without a thermostat. However, daytime temps were about 110 to 120 F.

    Thermostats have improved, but the old wisdom is to change them once or twice a year. For an average vehicle they are about $10.

    There are now two versions for normal vehicles: old type that can fail in either the open or closed position. For a few dollars more, the new type has an extra spring and can only fail in the open position. Do not yet know what is available for the Ferrari.

    I would make sure you have adquate cooling. If not the head can be warped or the engine ruined.

    I once had the old style fail in the closed position in a 4x4 in a desert in the middle of nowhere and nowhere. I had to have the engine rebuilt.
     
  19. jselevan

    jselevan Formula 3
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    Gabriel and Resnow - appreciate the debate. Always something to learn with constructive discussion.

    More on the topic. While combustion chamber temperature will influence extent of combustion of hydrocarbons, I offer that thermostat and radiator do not influence the combustion temperature. Combustion chamber temperature far exceeds that of the block and coolant temperature, hence the transfer of heat from hot to cold (consistent with the 2nd Law of thermodynamics). Block and bearing temperatures will correlate with coolant temperature, and consequently, oil characteristics (e.g., viscosity). However, coolant temperature, even in engines with coolant/oil heat exchangers, will always be cooler than oil. Air cools coolant, which cools oil, which cools metal of internal components (crank, bearings, rods and bearings, etc.).

    All this to suggest that yes, engines are designed to run at optimum range of temperature. However, the maintenance of this range of temperature is not a function of the thermostat. Once at operating temperature, in a temperate climate, the thermostat will remain open. It is the fans and radiator working double time to keep the sucker under control (design temperature range). Left to its own devices, without cooling, the entire hunk of metal would achieve combustion chamber temperature.

    Now, in frigid climates, like San Francisco, the engine could, in fact, run too cold. Witness the need for those in severe climates to use that high-tech device (cardboard) to restrict radiator airflow. Think about this. In steady state without thermostat, the coolant temperature might be 190 degrees. Now drop ambient temperature by 100 degrees from 80 degrees to -20 (sound familiar Chicago?). Without a regulating mechanism, the system temperature would drop 100 degrees as well. Here the thermostat maintains the 190-degree coolant temperature, implying that the system has near infinite capacity to generate heat.

    Long winded, but fun to think about this stuff. If one of us do-it-yourselfers had left a wad of chewing gum in our coolant hose, we would have a fit for fear that it would obstruct flow. But the thermostat, despite being wide open, represents a significant obstruction. Yes, this is designed into the system, but as rubber hoses crack on the inside, and pipes develop corrosion, the resistance to flow increases throughout the system. The absence of the thermostat helps mitigate this time-related phenomenon.

    Conclusion - I would not purposely remove the thermostat. But, if it were out, I would not go out of my way to put it back in. If I lived in a very warm climate (like Death Valley), I would remove the thermostat when the system was open for another reason.

    Jim S.
     
  20. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
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    IMHO, there is way too much smoke inspired conjecture about the advisability of a thermostat.
    STREET CARS, (as opposed to theoretical or racing cars), need a thermostat, because:
    they frequently operate at cold, warm up, or less than "normal" ~190 degree temp.
    At these temps, combustion generates a lot of water and unburned hydrocarbons, (read : raw gas). This junk does nothing for the quality of the oil, the rings or the corrosion that probably takes place. I defer, as quickly as posssible, and with great respect to the oil engineers out there, who, I think, will agree with me about the need to get the oil up to a STABLE, design operating temp. Our oil coolers are a part of the cooling equation, as well.
    I encourage you to review the well thought out posts of Mr, or is it more probably "DR" Haas, with respect to the efficiency of lubrication of overly hot or cold oil or his concerns about cold oil, in particular.
    If we leave these considerations for a bit and ponder the effects of the over cooled or undercooled engine, we need to look at two areas: combustion efficiency, hence power, (a subject near and dear to all ferraristi), and the thermodynamics of the infernal combustion engine, to be brief, metal, of all types expands when hot, ENGINE(ers), have fought out and pretty much mastered this carefully ballanced compromise between clearances, alloys, material cost, light weight and durability. THE ENGINE is necessarily designed to operate in varying conditions or load, temperature, and cost. Hence a thermostat .
    Design performance is not achieved at 130 degrees farenheight.
    Cold oil flows slowly and poorly lubricates parts. cold pistons rock in their bores, no good things happen with a cold engine, except that it gets you to the down the road for an espresso.
    When operating at design temp, all clearances are as designed, friction is as low as the engineers can make it, power is as good as it can get, wear is realy minimal, fuel economy, while minimal, is aceptable.
    If we look at the good sounding cars, the carbureted cars, (no slight intended to you guys that have efi), NO thermostat means we see a lot of fuel washing down the walls, diluting the oil, (making a lot of wear), Poor performance because of poor fuel air mixing, sluggish oil, because it's cold and oil that must be heated enough to try to evaporate the dilutants, to prevnt further damage.
    I love my 308, I hammer it down the road, HARD, but if you try to run the car without a thermostat, ENZO will personally come down and ICE PICK you in the forehead, while you sleep, no doubt dreaming about the $33 you saved on the THERMOSTAT.

    With LOTS of malice aforethought,
    i remain,
    chris
     
  21. davehelms

    davehelms F1 Rookie

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    Some good arguements pro and con, if the design of the system followed that of a 70's Chevy. That old domestic car had the miserable little formed hose that was impossible to get to behind the water pump. That hose consituted the recirc. system of the time. Fact is that port is now internal on the 308's and needs to be covered when the coolant is flowing to the radiator. No stat on this type of system will cause overheating.
    Even on the race cars with the stat removed, usually a "restrictor plate" is installed (a gutted stat was often used) to slow the flow of the coolant enough to help eliminate cavitation and allow the coolant ample time to pick up and dissipate the heat.
    Ferrari engines are designed and machined to run at a given temp. Consider the main bearing clearances of an engine being assembled cold. These are in the range of .0008" to .0011". These clearances are set as such with the anticipation that at running temp the block and heads will "grow" until these are in the .003" range. Aluminum is not a "stable" material.
    Cast iron technology of the 70's is not applicable to the big lump of aluminum used in the Ferrari's. Try to get an old 250 or 275 to idle smooth with no cylinder head temp. Hell, we used to see carb iceing on the old 250 race cars in the middle of the summer until they were up to full operating temp.
    We had to run the GTO and TR on jack stands in the paddock until it was just starting to overheat, just to get ready for a race. Thin out the 300W goo in the diff., bring the gear luble up to a point where is would allow the trans to be shifted, and allow all of the engine components to expand to their running clearances.
    With aluminum engines, heat, at a stable temperature, is a good thing.
    Dave
     
  22. jselevan

    jselevan Formula 3
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    Nov 2, 2003
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    I believe that we all know the answer to this conundrum, we simply can't agree on what it is!

    Okay, you've all beat me into submission. That said, here is more food for thought.

    I am full agreement that too many spend too much time trying to cool their engines - aluminum radiators (misguided), bigger fans, etc. The internal combustion engine is a heat pump, and the cooler the combustion chamber the lower the efficiency. In theory, heat left in the combustion chamber is available to do work (in expanding gas against the piston). With efforts to lower engine temperature, we bleed heat away from the combustion chamber. Stated differently, heat of combustion is used to heat metal and a fluid (coolant) rather than to expand gas.

    So, absence of a thermostat would, it might seem, reduce engine efficiency. I am merely trying to suggest that with ambient temperatures that most of us drive in, engine temperature is achieved with or without the thermostat. It simply takes longer without it.

    I give up. Please don't beat me anymore.

    Jim S.
     
  23. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
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    DANGER, WILL ROBINSON, DANGER!

    The 308 'stat is not a simple on/off device, nor a simple valve as in "regular" cars. Lacking at the moment proper wording, I'll describe it as more of a 'diverter' valve. W/O it, coolant will tend not to reach the radiator and will, for the most part, simply recirculate inside the engine - probably resulting in an overheated engine. I'd guess that some sort of permanent restrictor/baffle gizmo could be fabricated to replace the stat while retaining proper flow to the right places.
     
  24. 4re gt4

    4re gt4 Formula 3

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    BTW, as a side note, when we used to race flat head Fords, you had use a large washer if you wanted to eliminate the thermostat. W/O it, the motor would overheat very easily.
     
  25. davehelms

    davehelms F1 Rookie

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    Taken wrong. I think you have many good points.
    When the facts are applied to the Ferrari one has to look closer. Aluminum needs a stable heat source, that gets hot quickly, is the only point I was trying to make. Block the recirc port with a pipe plug, and install a small restriction and eventually all will become stable at a constant load.
    Dave
     

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