Engine temps vs. wear
So I am curious on theories for engine wear vs oil temp vs coolant temp.
Currently I am running a no T-stat reroute and an oil cooler on the car. Generally speaking on track my oil temps will get up to 190-ish, while coolant temperatures will run between 120-180 depending on the track and speed. should I be worried about engine wear if my coolant temps are running low, even though oil temps are normal? I am assuming oil temp is a pretty good indicator of bearing temps, and coolant is probably more accurate for piston/cylinder walls, etc. what do you guys think? Also, what do you guys think about methods of blocking off the mouth of the car? does one method work better than another? for example taping off the outside vs. making a block off plate directly in front of the radiator? |
I told you over this weekend that operating the engine below 170F or so will greatly increase piston ring wear and that you'll wind up killing a few orders of magnitude for "cycles" (like 10^6 vs 10^9). I know just enough to get me into trouble when it comes to material science/engineering, so I'm hoping that a few guys come in and drop some knowledge bombs.
|
Originally Posted by Track
(Post 1081406)
Also, what do you guys think about methods of blocking off the mouth of the car? does one method work better than another? for example taping off the outside vs. making a block off plate directly in front of the radiator?
|
Originally Posted by Dunning Kruger Affect
(Post 1081407)
I told you over this weekend that operating the engine below 170F or so will greatly increase piston ring wear and that you'll wind up killing a few orders of magnitude for "cycles" (like 10^6 vs 10^9). I know just enough to get me into trouble when it comes to material science/engineering, so I'm hoping that a few guys come in and drop some knowledge bombs.
|
Originally Posted by thenuge26
(Post 1081408)
You'd probably have to run a bunch of CFD sims to know for sure, but my guess is that the difference in drag in blocking off the mouth vs the rad will negligible. I don't see why one way would be more or less effective as the other as far as cooling (or lack thereof) effect.
The easier solution to this problem is to install a thermostat. |
|
sounds like a headache dealing with a t-stat in the back of the engine. what do you guys do when you need to replace it? is there a way to add a t-stat to another location?
|
if you have the m-tuned reroute, the t-stat is in line so you can place it in a more accessible spot.
|
This stuff has been studied countless times for roughly a century. There is no mystery.
There is a good relationship between ECT and cylinder wear. The difference between 140F and 180F is probably a factor of 2 or 3 times the wear. |
Originally Posted by Full_Tilt_Boogie
(Post 1081531)
This stuff has been studied countless times for roughly a century. There is no mystery.
There is a good relationship between ECT and cylinder wear. The difference between 140F and 180F is probably a factor of 2 or 3 times the wear. So, is the suggestion to buy an inline t-stat housing? In that case, the gutted t-stat in the back of the engine becomes useless (so I should remove it the next time the engine is out)? |
Do you expect to have regular issues with the thermostat going out? I know they will die occasionally, but in the 15 years I've been driving I've never had one go out. I wouldn't think it's really a wear item that you'd expect to be replacing regularly or anything.
Even if it does go out, or you want to replace it as a preventative measure, getting to it on the back of the head isn't so difficult that it's worth being concerned about, IMO. |
Yeah, my 160f never failed in 5 years (drivability sucked), so when I finally replaced it with a 180f unit, the trick was taking off the three PPF bolt on the back of the transmission and jacking it up there, which pried it away from the fire wall. Worked like a charm.
COPs help too, which give you a little extra room. |
Originally Posted by Track
(Post 1081515)
sounds like a headache dealing with a t-stat in the back of the engine. what do you guys do when you need to replace it? is there a way to add a t-stat to another location?
|
dunno, t-stats seemed like a once every year or two item (to me initially), but with everyone else it seems much longer. So if they do last longer, I am sure you will pull the engine out atleast once every few years.
I think if I was running enduros I would probably run an inline or a gutted t-stat. With that said, I am going to try curly's suggestion and see if that works well for replacing it. |
What kind of thermostats are you using? Do they have "slick 50" stamped on them? I've never had a problem that was fixed by replacing a thermostat - I have replaced many thermostats, using different temperature ranges, different flow-through hole sizes, etc., and they have never fixed the problems; they have only ever shifted the symptoms. I know of *one* person who has had a thermostat fail on them *one* time.
Thermostats really are the one good *solution* to thermal issues with your engine and cooling system; they are rarely, if ever, the problem. Engines love thermostats; get that engine a thermostat. |
Originally Posted by fooger03
(Post 1081969)
What kind of thermostats are you using? Do they have "slick 50" stamped on them? I've never had a problem that was fixed by replacing a thermostat - I have replaced many thermostats, using different temperature ranges, different flow-through hole sizes, etc., and they have never fixed the problems; they have only ever shifted the symptoms. I know of *one* person who has had a thermostat fail on them *one* time.
Thermostats really are the one good *solution* to thermal issues with your engine and cooling system; they are rarely, if ever, the problem. Engines love thermostats; get that engine a thermostat. Usually they fail open but in the event that the car overheats, the wax element inside the thermostat can get stuck closed and you'll see temps starting to climb. |
Originally Posted by fooger03
(Post 1081969)
Thermostats really are the one good *solution* to thermal issues with your engine and cooling system; they are rarely, if ever, the problem.
|
1 Attachment(s)
|
Good timing for this thread. I have not been running a thermostat and just replaced my motor with a stout build. New thermostat is on the way. Do most of you guys run 180's?
|
180 or 190 here - put a 160 in at one point to try and correct problem; the engine and oil simply warmed up more slowly, and the problem remained unchanged. 180-190 is probably the sweet spot.
|
Originally Posted by k24madness
(Post 1082390)
Do most of you guys run 180's?
|
Stant 180 is what I have always used since that handsome model Joe Perez did a video on them.
|
Anywhere from 180-195° should be fine. My M-Tuned Reroute has a 195° thermostat in it, makes the heater nice and hot.
|
Originally Posted by Track
(Post 1081406)
So I am curious on theories for engine wear vs oil temp vs coolant temp.
Currently I am running a no T-stat reroute and an oil cooler on the car. Generally speaking on track my oil temps will get up to 190-ish, while coolant temperatures will run between 120-180 depending on the track and speed. should I be worried about engine wear if my coolant temps are running low, even though oil temps are normal? I am assuming oil temp is a pretty good indicator of bearing temps, and coolant is probably more accurate for piston/cylinder walls, etc. what do you guys think? Totally in agreement with the use of a coolant thermostat to get the engine up to a proper temp. The comments and graphs verify what I've known intuitively and read elsewhere. However, everyone seems to talk about optimal coolant temp, not including the oil. Tere is a "lead/lag" relationship of water/oil temps. By this I mean proper guages will show a coolant temp rise before oil temps go up. Once the engine is fully up to running temperatures, the oil temps will be higher than the water. Pushed hard, ie, on the track, oil temps in a non oil cooler equipped Miata will spike quickly ahead of the water temp rising. Temps we saw on our Spec Miata were ~280F momentarily which is the actual limit of the guage scale (Mechanical 270 degree sweep AutoMeter). Water temps at this time were 220F. Ambient Air temp was close to 100F. I think these elevated oil temps are from the oil squirter system all 1.6 & 1.8 Miata engines come with. It seems your oil cooler equipped system is doing a bang up job of keeping things cool. I suggest maybe a bit too cool. Running ITA and FP now, we have the ability to run an oil cooler. We also have an oil thermostat in the system - ours is a MOCAL. With an oil cooler we've now got water temps at the 190-200 range and oil runs from 220 - 230. On a race car the oil thermostat isn't totally necessary - on cold days you can cover the cooler. I like the flexibility to keep the oil temp where it needs to be. Also I am not sure why you think an engine pull is required to change the coolant thermostat if you have a coolant reroute. Or why SixPack has to drop his PPF to do the same. We use a 1.6 thermostat housing on the head with the fan switch bung cut off. This gives is plenty of room between the thermostat housing on the back of the head and the firewall. On the 1.8 car pulling the coil pack off (if you don't have COP) is needed and pulling the CAS or the coil pack from a 1.6 makes lots of room. I really don't understand why Mazda didn't keep the T'stat back there to begin with. |
All times are GMT -4. The time now is 03:46 PM. |
© 2024 MH Sub I, LLC dba Internet Brands