Engine Overheating Question

[The New Guy]

Hey, we are preparing for West and we are wondering what is an acceptable operating range for the F4i?

What are the failure temps for the engine and oil?

Thank You

[The New Guy]

Hey, we are preparing for West and we are wondering what is an acceptable operating range for the F4i?

What are the failure temps for the engine and oil?

Thank You

[exFSAE]

Well.. I'll say you probably won't have issues if you keep it under 220F for coolant.

[screwdriver]

I know our maximum recorded engine temperature so far, I could also tell you the temperature when our telemetry system starts displaying an error message or the temperature at which the warning lamp on our steering-wheel lights up. All that doesn't matter for the competition though. You just run it until it breaks. You haven't got much choice.

[A Richards]

When your slugs start looking like this and grip the cylinder wall you have gone a little to far, http://fsae.com/groupee_common/emoticons/icon_smile.gif


http://i197.photobucket.com/albums/aa249/deakinracetechnologies/Picture060.jpg

[The New Guy]

screwdriver,
what's your max engine temp so far? Ours is 122 C
Also for oil we hit 162 C yesterday.

Any thoughts?

[Maverik]

162 C on oil! Holy smokes! Check your engine... Overheating is addressed many places on the forums, with an excellent picture above of what could happen... I'd shoot for 110 oil and 90-95 water if you can get it down there. However, As long as your clearances are sufficient it would be "safe" to run hotter temperatures providing you are truly ejecting the excess heat.

[Wesley]

While you get higher thermal efficiency with increasing coolant temp...

We generally run ours between 100 and 80ºC. The fans kick on at 100, and back off at 82.

(Or 210 on and 180 off)

Most factory engines run in that range.

[exFSAE]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by The New Guy:
screwdriver,
what's your max engine temp so far? Ours is 122 C
Also for oil we hit 162 C yesterday.

Any thoughts? </div></BLOCKQUOTE>

WOW. Time to upgrade your cooling, dude. And check some of your engine internals.

[Chris Lane]

We haven't got our SAE engines running yet, but as a guide we run our Formula Ford motors at around 95deg C. 110 is too hot for these

[screwdriver]

122? Ours was higher than that. I won't give you the exact number until after comp though, since you'd just get funny ideas.

But you do know that water evaporates at 100?C. Give it 110 under slight pressure but that's just asking for it. I mean you only have so much water in the system. I give you about 2 maybe 5 minutes of running like that until all the water is gone. After that you probably have about a minute, probably a lot less until your engine buys the farm.

You really, _really_, REALLY need to do something about your cooling system!

[fart can]

Our fan comes on at 180 F. We try to keep the coolant below 220 F. We use water plus water wetter, mixed to spec by the rules.

If you are overheating you probably have air somewhere in your system that is incapable of being bled out. We had a similar problem, which was resolved by tilting our radiator parallel to the ground to allow air to escape. And clearly, you need your fill point to be the highest in the system.

Once you perform your initial fill you will need to run the motor for a while, work out the air, and then refill.

If you do not correct the air problems you will eventually cook off all of your coolant.

The honda service manual has a coolant system chapter, where the detail desired operating ranges.

http://fsae.com/eve/forums/a/tpc/f/125607348/m/96510947...10947341#96510947341 (http://fsae.com/eve/forums/a/tpc/f/125607348/m/96510947341?r=96510947341#96510947341)

Best case you have air, worst case your cooling system is inadequate. What are it's specs?

[Superfast Matt McCoy]

The fan on my '01 F4i kicks on at 225. We ran those engines beyond 235 several times for several laps without incident, then once with a major incident. If you're looking for a maximum I would say 240 is right at the edge as long as you have an oil cooler and a high pressure cap.

[Chris Lane]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Superfast Matt McCoy:
The fan on my '01 F4i kicks on at 225. We ran those engines beyond 235 several times for several laps without incident, then once with a major incident. If you're looking for a maximum I would say 240 is right at the edge as long as you have an oil cooler and a high pressure cap. </div></BLOCKQUOTE>

That sounds about right.

[blister]

Our fan kicks in at 105 C and cools down till 95 C.

We use an additional pressure bottle to compensate for vaporized water. So we don`t loose water into the overflow bottle.
Additionally we use an electrical water pump, which can cool the engine down even while driver change.

[screwdriver]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by blister:
We use an additional pressure bottle to compensate for vaporized water. </div></BLOCKQUOTE>
0_o
I really need to take a look at your car at comp. Hope we're pit-neighbours again.

[Mike Hart]

Make sure you're running WITH the thermostat. For some reason, there is a school of thought that believes it's best without it but I can guarantee you it isn't. Running with it drops an otherwise constantly 100deg C engine to a more realistic 85-90deg C engine which is about right for max power. If your running a 1.1bar pressure cap, you should be good for 110deg C but do you really want to be running your engine up there? I'd say keep it below 100 or you're asking for trouble!

[HenningO]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mike hart:
Make sure you're running WITH the thermostat. For some reason, there is a school of thought that believes it's best without it but I can guarantee you it isn't. Running with it drops an otherwise constantly 100deg C engine to a more realistic 85-90deg C engine which is about right for max power. </div></BLOCKQUOTE>

Any clues on what the reason might be? I'm not an engine guy http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Poe]

At least on the F4i, the thermostat closes the recirculating loop as it opens to the radiator.

[Maverik]

What's the thermostat do? It helps warm the engine up by blocking flow until it's hot enough... how in the heck would it help cool the car? True, your car will warm up a lot faster, but I guarantee you it won't help cooling other than to keep you in a range once your system already OVERcools.

[Wesley]

Agreed, we just talked about this today at the shop as I threw the stock t-stat across the shop.

Thermostats serve two purposes:
Warm the engine block and oil up fast, since you only have to heat the water that is in the block, and not the whole capacity,

Keep engines in temp range and prevent overcooling at high air-flow, low power demand situations (i.e. highway driving)

On a race car, we warm them up before hand, and almost never see an overcooled situation - if you do, you've overdesigned your rad system and can lose some weight.

[VFR750R]

Isn't everyones fan their thermostat? No thermostats in any racecars i know of.

i better not hear anything about too much water flow, no restriction ect.

[Poe]

Not sure about other engines, but if you don't run a thermostat on an F4 or F4i, you'll need to block off the hose going from the bottom of the thermostat housing back to the water pump, otherwise that much water is just going to bypass the radiator and cause the engine to run hotter than if a thermostat was in place.

[fart can]

Has anyone tried running with no thermostat at FSAE ?

[Chris Lane]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
Isn't everyones fan their thermostat? No thermostats in any racecars i know of.

i better not hear anything about too much water flow, no restriction ect. </div></BLOCKQUOTE>

I agree with you there, never seen a thermostat on a dedicated race engine. Sometimes if its a colder day the Formula Fords run a tad too cold, so we race tape some of the sidepod air intake off so there is less air getting to the rad.

[Maverik]

I have an answer... the thermostat causes a lower flow rate in the water, meaning it will spend more time in the radiator and lose more heat ;-)


Please don't take my drunken ramblings seriously... please

[Wesley]

On that same token, really we should run radiator temperatures as high as humanly possible. A higher temperature gradient across the heat exchanger will increase total heat transfer, yes?

Molten sodium coolant? I think so!

[Pete M]

I'm with VFR, we've never run a thermostat and have never heard a good reason to run one either.

You want fast warm up? Use an electric pump and PWM its power supply.

[Mike Hart]

Typical assumptions that lower flow rate is worse. The thermostat serves a number of purposes:

a) It helps the engine heat up more quickly (admitedly not that important in our application)

b) It helps maintain a constant temperature. Whilst you may think your fan alone can do this, in reality, it's effect is not seen soon enough by the engine, so you may well see water temperatures that continuously vary by 5deg of more.

c) The thermostat introduces a flow restriction. Without this restriction your water flow rate through the block will be too high. Yes you read it right. Too high! You can splooge water through at 300l/min if you want, but it won't necessaraly help you. The block is designed to run at some degree of pressure with a controlled flow rate. Without this, you're likely to get boiling spots, may see some errosion and will most likely not be utilising the full heat capacity of your water.

If you really don't want to run the Stat, then at least stick in some kind of flow restriction plate. You'll find something similar in a race tuned engine to maintain the block pressure. I don't know about you though, but I'd rather spend my time doing other things than measuring the flow through a thermostat, and the ability to maintain a steady temp is a plus IMO.

[Chris Lane]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mike hart:
Typical assumptions that lower flow rate is worse. The thermostat serves a number of purposes:

a) It helps the engine heat up more quickly (admitedly not that important in our application)

b) It helps maintain a constant temperature. Whilst you may think your fan alone can do this, in reality, it's effect is not seen soon enough by the engine, so you may well see water temperatures that continuously vary by 5deg of more.

c) The thermostat introduces a flow restriction. Without this restriction your water flow rate through the block will be too high. Yes you read it right. Too high! You can splooge water through at 300l/min if you want, but it won't necessaraly help you. The block is designed to run at some degree of pressure with a controlled flow rate. Without this, you're likely to get boiling spots, may see some errosion and will most likely not be utilising the full heat capacity of your water.
</div></BLOCKQUOTE>

a. Agree, fast warmups are not important.

b. the radiator maintains the temperature, not the thermostat. If the cooling system is designed properly, your water temp shouldn't vary too much when you're racing. Due to the nature of the course, plus or minus 5deg sounds acceptable to me

c. Yes the thermo introduces a flow restriction. This in my eyes is bad! Having a high flow rate of water through the block would be a good thing as the radiator/fan will be able to better regulate the system. With high(er) flow rates boiling spots wouldn't be an issue since you're pumping coolant through faster. Erosion? Really minor issue in my eyes. It would be a good thing if you're not using the full heat capacity (latent heat?) of the water! If you were you would be pumping the water too slow and boiling the water which in my eyes is FAR worse than over-cooling the water.

My vote is overdesign the system and have your car overcool itself rather than cut it fine and have it overheat at the first whiff of sunshine. Overcooling can be regulated, undercooling cannot.

[Wesley]

I was under the impression that most of the pressure in the coolant system was generated by the radiator cap... and the water pump just pushed water around. An impeller type pump like that can cavitate pretty easily at high pressure ratios.

[Mike Hart]

Well Chris, you can say what you want, but the results are clear to see. The thermostat reduces our block temp by 10-15deg in a steady state situation on the dyno where we're running a tube type water to water heat exchanger and electric pump.

The reduced pressure of taking the Stat out can result in air pockets in the head causing boiling. Slow the flow down a bit and increase the pressure to what it was designed to run at and you get rid of them! Remember that the manufacturers don't put at Stat in for fun. It's there for a reason and the whole cooling system of the bike is designed around the assumption it'll be there. I never understand why so many teams feel the need to reinvent perfectly good things that exist already. Why try and change everything when you've already got a system that works. By all means fit an electric pump so you can cool your engine after a run and increase the radiator size if you feel it needs it, but why go adding oil coolers and removing the stat when the bike will happily sit at 10k rpm plus all day long on a track? OK, so our overall speeds are lower, but you can overcome this with some appropriate airside design.

If you wish to read some more on the issue check out this very useful thread on Ten-Tenths:

http://www.ten-tenths.com/forum/showthread.php?t=86215&...=bike+engine+cooling (http://www.ten-tenths.com/forum/showthread.php?t=86215&highlight=bike+engine+cooling)

Whilst admittedly a lot of it is opinion rather than proven fact, there are a lot of people agreeing on there that taking the stat out is a bad idea including someone who claims to have worked on tuning numerous BTCC, WRC and Super1600 engines all of which HAD A STAT!

[Mike Hart]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Wesley:
I was under the impression that most of the pressure in the coolant system was generated by the radiator cap... and the water pump just pushed water around. An impeller type pump like that can cavitate pretty easily at high pressure ratios. </div></BLOCKQUOTE>

Yes, you're quite right, the whole system will run pressurised to around 1.1bar if that's the pressure cap you have on and your temps are greater than 100deg C.

The stat however causes a build up of pressure in the head caused by the pump. Although, since most bike pumps are centrifugal, they cannot build up masses of positive head, they will build up a fair few PSI which helps to prevent boiling since it ensures there are no air pockets in the head.

[MalcolmG]

FWIW, Carroll Smith states in (Engineer?) to Win that he always used a venturi type restrictor on the outlet of the engine, which increased the block pressure, he claimed reducing the likelihood of air pockets, localised boiling and hot spots occuring. Not to say that his word is gospel but one must assume he has a pretty good idea of what he's talking about. We don't run a thermostat in our R6 as we have a PWM controlled water pump, but we will definitely be investigating the effects of a cooling system restrictor.

[Wesley]

So why not put a couple PSI higher cap on it if it's just the pressure that prevents steam pockets?

Where was the block temperature measured at? What were the inlet and outlet temperature differences at the engine? At the heat exchanger? Do you have any data graphs? With a water-water heat exchanger, heat rejection is very high, realistically leading to low inlet temps as compared to an appropriately sized radiator system in a transient environment.

Is the thermostat truly the restriction in the cooling system? Are there any areas in the cooling system with a similar cross-sectional areas to the open stat? If so, the restriction point is moot.

Could not radiator return lines be sized appropriately to maintain coolant flow rate? Since we are changing the parameters the radiator is operating under (low speed, high temperature, possible packaging issues mandating a smaller or parallel radiator design,) does it make sense to leave in a system that is no longer operating under design intent of the original OEM parts?

[Chris Lane]

Sorry Mike, I'm still not convinced.

In my eyes the thermostat is a tool used to facilitate fast warm-ups on road-going engines. Is the common consumer going to warm up their engine to operating temp for 15 mins before EVERY drive? The select few might.

In FSAE (and indeed any racing condition) the engine has been removed from normal operating conditions where the car is carefully warmed up to temp before competing. Therefore the thermo is just dead weight in my eyes.

There are only two situations I can think of now where you might run it;

1. The regs stipulate that the motor must be unaltered in some ways, which I suspect is the case with some production rally classes (not sure though)

2. Fast warm up before the enduro event to minimise fuel wastage

If I see some data that proves conclusively that the thermo actually does some form of good in our application, then I might think about it. Until that time, I'm not convinced it's even remotely needed.

[VFR750R]

There is alot of work done by oem's and race teams to make sure heat rejection is the same for each cylinder and eliminate hot spots ect. It would be interesting to know if the oem's race thermostats in their CBGSXZXR1's in road racing that were orginially designed with them vs motogp where i'm sure it never even crossed their minds.

Generally the more power more water. I've never heard of voluntary restriction, it is true that water pump pressure increases pressure in the block and therefore decreases localized boiling. But, running the entire system under the higher pressure results in higher water pump and radiator efficiency as well as the boiling protection. I heard aston martin's gt1 car had 180gpm water flow for 600hp.

Q goes up with water flow in both the radiator AND engine. As water flow goes up though, the increase in heat from the engine does not match the increased efficiency of the radiator resulting in less difference between the point of highest water temp and lowest. Since the high water temp is what maters you can shrink the cooling system and run a higher average temp for the same peak temperature. The limit as water flow goes to zero is zero heat transfer and melted engine. The limit as waterflow goes to infinity is zero temp delta across the engine and radiator, allowing the smallest system possible for the peak temperature. Although it would take a larger radiator to allow the higher flow rate.

Oh and who cares how consistent water temp is. Show me a blown engine that was the result of no thermostat and the resultant water temp variation. But, if you dont' have a thermostat you can't fail endurance because of a broken or stuck one.

I'm also curious, did carroll smith also say to put the radiator cap tube at the throat of that venturi? Where does everyone put their radiator caps?

[Pete M]

Again, I second VFR.

It seems to me that people are being overly paranoid about these engines. Seriously, put a radiator on it that has a hope in hell of cooling the engine sufficiently and make sure you've tuned it right. Make sure you drive on it sufficiently before comp to show you aren't overheating. Your engine package is seriously f-ed up if you destroy an engine with the tiny amount of time these cars drive, especially if you're NA and aren't pushing the redline, etc.

The only downside i can see to excessive flow (as in flow that has reached the point of diminishing returns, not flow that is somehow harmful), is that it means you invested to much mass in a water pump.

I like the sound of that radiator cap at the throat of a venturi idea, VFR. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[ad]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Pete M:
I like the sound of that radiator cap at the throat of a venturi idea, VFR. http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

Me too http://fsae.com/groupee_common/emoticons/icon_smile.gif

Steam ahoy

[screwdriver]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Pete M:
The only downside i can see to excessive flow (as in flow that has reached the point of diminishing returns, not flow that is somehow harmful), is that it means you invested to much mass in a water pump.
</div></BLOCKQUOTE>

That's kind of hard since they don't come in any mass you like. In our case, the available pumps are either too small (Honda related OEMs) or too big (BMW/MINI).

On a sidenote, I advise you to check the data on your pump thoroughly. We've ran into cooling issues last season, too. After Hockenheim, we've worked quite a bit to track them down. As it turned out our pump only puts out it's rated performance at 30V (Don't ask me why.) and with minimum backwards pressure. We solved the issue by slapping a sledgehammer of a pump from a MINI in for Australia. And guess what, all was fine.

Conclusion: It's nice buying OEM and racing stuff nice and cheap second-hand but paying the price by not having proper data about the parts costs you more than you save.

[ad]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by screwdriver:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Pete M:
The only downside i can see to excessive flow (as in flow that has reached the point of diminishing returns, not flow that is somehow harmful), is that it means you invested to much mass in a water pump.
</div></BLOCKQUOTE>

That's kind of hard since they don't come in any mass you like. In our case, the available pumps are either too small (Honda related OEMs) or too big (BMW/MINI).

On a sidenote, I advise you to check the data on your pump thoroughly. We've ran into cooling issues last season, too. After Hockenheim, we've worked quite a bit to track them down. As it turned out our pump only puts out it's rated performance at 30V (Don't ask me why.) and with minimum backwards pressure. We solved the issue by slapping a sledgehammer of a pump from a MINI in for Australia. And guess what, all was fine.

Conclusion: It's nice buying OEM and racing stuff nice and cheap second-hand but paying the price by not having proper data about the parts costs you more than you save. </div></BLOCKQUOTE>

I think what Pete was suggesting is that the OEM component can be swapped for either a similar mechanically driven pump, or lighter electrical pumps.

Dont forget you should also consider the effect of the different final drive ratio on FSAE application vs standard bike too (for mechanical pump).

[Drew Price]

[QUOTE:a) It helps the engine heat up more quickly (admitedly not that important in our application)
[/QUOTE]

This has been mentioned a number of times, but I personally saw a very large percentage of teams rolling into dynamics at East this year without warming the engines up. Same thing on the dyno.

I don't know about the rest of you, but we had morning test sessions in April where the temps were down in the 30's and 40's. Some days the engine would barely warm up to 160* with the thermostat. We also had to bench tune the engine against the open door to our garage this winter - and it's pretty chilly in Chicago.

Best,
Drew

[Wesley]

A couple bits of cardboard duct taped over the rads ought to fix that in short order.

Also, teams that don't warm their cars up won't benefit from having a thermostat that much. You just give up power due to fuel condensation, loose bore clearances, viscous oil, etc. and may reduce your longevity of motor life. I doubt the teams that don't warm their cars up drive the things again anyways.

[VFR750R]

i second the cardboard. Our temp control is tape over the grill opening.

the only time we start an engine below 140F water ever, is qualifying. the cars go out with cold water, but they also start with 280ish oil temp. The oil doesn't stay that hot, but it stays 200 plus.

Water is preheated before starting in the garage, or on the dyno. The highest levels of motorsport all preheat engines.

[Chris Lane]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
Water is preheated before starting in the garage, or on the dyno. The highest levels of motorsport all preheat engines. </div></BLOCKQUOTE>

I guess that allows you to run much closer tolerances throughout your engine build, yes?

I'm interested to know how do you achieve this preheat at the competition? Just cycle your coolant through an external heater of some sort, or even block heating using electronic elements?

[exFSAE]

VFR doesn't do FSAE anymore..

But, if you wanted to preheat your deal at comp.. wouldn't be too hard. I'd cycle through an external source.. use quick disconnect fittings all over the cooling system so you can just unsnap from the radiator and pump hot water through the system for a bit, then snap the radiator back in place.

Why no one uses QDCs is beyond me.

[Mike Hart]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by exFSAE:
Why no one uses QDCs is beyond me. </div></BLOCKQUOTE>

They cost about $100 each......

[VFR750R]

http://www.crracing.com/custom_built/check_valves.shtml

http://www.crracing.com/checkvalveCustom.shtml

These work really nice.

http://www.speedpartsinternational.com/images/Kit_Engin...lor_front_May_06.pdf (http://www.speedpartsinternational.com/images/Kit_Engine_Heater_Flier_Color_front_May_06.pdf)

All of these are reproducable for a lot cheaper then they cost. There's also one that uses deisel that heats water faster and without 220v.

http://www.crracing.com/custom_built/diesel_heaterNewProduct.shtml

[exFSAE]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mike hart:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by exFSAE:
Why no one uses QDCs is beyond me. </div></BLOCKQUOTE>

They cost about $100 each...... </div></BLOCKQUOTE>

Must be some fancy ones for $100 each...

The nice anodized aluminum aeroquip ones are much cheaper than that..

http://hydraulics.eaton.com/products/pdfs/fc/A-SPPE-MS003-E.pdf
http://www.bsrproducts.com/index.php?cPath=12
http://www.bakerprecision.com/aqp6.htm

Plastic ones are much cheaper still (check something similar to McMaster 51545K32)

They seriously rock. Screw having to drain and reprime the cooling system if you have to make changes or preheat the block or do anything. Hell you could basically prime each part individually, and just snap it all together. No mess, no (or very little) air.

Been tryin to get my team to use these for some time now.. and hard line aluminum tubes as well.

[Wesley]

We put one of those on our fuel system and never looked back. It's the handiest thing ever.

[bigtoyota9]

I'm not discounting designing your coolant system properly. BUT... we had a failure in our coolant system in 2004 during the endurance event on the second lap. I got an engine temp. alarm when the temp. went over 220F. I slowed down for a lap before the driver change so it wouldn't spit water everywhere when we turned it off. Amazingly the engine and the car lasted the complete event. After the event we looked at the data and the oil temp was in excess of 300F and the water temp. was probably reading steam temp. I thought for sure that the engine would definitely lock up after we turned it off, but we started it right back up before we put it in the trailer, and (correct me if im wrong Poe) that engine was used as a test engine for a good bit after that.

The moral of the story is that Hondas can take a terrible beating before you see a failure.

[Pete M]

I second the strength of the hondas. Only parts we've ever really got to break are pistons and one shifter fork and both were under rather unusual conditions (heh, heh, no comment). We've seen:

<UL TYPE=SQUARE>
<LI> Oil temps north of 150?C (if i remember right, the sensor clipped at 150...).
<LI> Water temps in excess of 130?C, or maybe 150?C (i forget, wasn't on the team then).
<LI> Zero coolant flow in the middle of an SCCA run (failed water pump).
<LI> Engine started and idled without oil (before my time, they went on to win the comp a couple of days later with the same engine).
<LI> 105?C intake temps on the dyno for a brief period.
<LI> Harsh bang bang anti-lag with EGTs in excess of 1100?C, clipped and failed the type-K thermocouple.
<LI> Repeated launches on 15+ psi of boost on stoichiometric mixtures (bad alternator reg and terrible injector voltage compensation). I turned about as white as the spark plugs when i saw the log...
<LI> Spikes of upwards of 270 kPa absolute manifold pressure on a launch (~25 psi of boost), on 90?C intake temps with the stock 12:1 compression.
<LI> Heaps of WOT shifting with a pneumatic quickshifter (the broken fork was with a manual shifter, funnily enough).
<LI> Months and months of driving on 18 psi of boost, MBT timing and LBT mixtures (or leaner when we were worried about our fuel tank size in the enduro at the last comp), making approximately double stock torque with stock internals, on 98 RON fuel, 12:1 compression.
[/list]

We've never had an engine failure in a car, and average about one engine failure a year on the dyno, mostly due to mistakes (the dyno is much less forgiving), and most of those were just a minor rebuild, not engine destruction.

[Poe]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">After the event we looked at the data and the oil temp was in excess of 300F and the water temp. was probably reading steam temp. I thought for sure that the engine would definitely lock up after we turned it off, but we started it right back up before we put it in the trailer, and (correct me if im wrong Poe) that engine was used as a test engine for a good bit after that. </div></BLOCKQUOTE>
That might have been '05, but you're right, it was about that hot. There was also the '00 or '02 car that ran the coolant completely dry in endurance and still runs.

[Wesley]

Hondas can take a beating, but they do have limits:

We've thrown a rod through the crankcase and caused the oil to ignite due to temperatures (see OU fire on youtube for the California '07 explosion)and we've spun 5 rod bearings in the time I've been on the team (2 years) in 5 different motors, on course.

But, as a testament to their strength: We've run an entire competition on a fuel map that was in the 15-17:1 AFR range. We won fuel economy at the Goodyear event with an F4i... and still run that motor in this years car, a year later.

We've run on a burned clutch for over a day of testing, with oil temps in excess of 300ºF, and also literally slagged a clutch on the dyno and had to pull solidified aluminum globs out of the oilpan. That motor ran for a good while before giving up.

We ran a motor with mismatched bearing shells, half an F4 gearset, and missing bolts and it would run and drive fine but wouldn't restart when it was hot.

Our '06 car has been running since competition in '06 with nothing but a new clutch and an oil change... it's "Old Faithful," and has more drive time every year than our new car.

We've never had a catastrophic dyno failure, it's always a track failure.

[fart can]

Our F4i was diassembled, then reassembled sans oil pick up or oil pressure relief. Ran for about two weeks on the dyno while we were troubleshooting the dyno under little to zero load. Cams started squeeking and that's when nightmare started. Metal debris in the sump everywhere, very hard to put that metal back where it came from. Destroyed.

Also exploded a clutch on the dyno. Other than that we've run our headers glowing red from primary to the muffler outlet when playing with timing. I did not know aluminum end caps glowed red. Hindle makes a good muffler.

[Pete M]

One of our failures years ago (2003 i believe) was the pressure relief falling out of the block into the sump due to them using a modified relief with the stock sump on the dyno. Minced the big ends nicely.

Oil pressure idiot switches are mandatory. Or better, run a proper proportional oil pressure sensor. We've run one ever since that failure. The stock idiot switch is only really meant to detect total absence of oil pressure, not just dangerous pressure (or it'd be on all the time at idle). I forget what the switch threshold is but it's low.

[Mikey Antonakakis]

I'm going to make a nice bump to this thread. I was messing with the tune on our '09 car tonight (F4i). I was mostly adjusting idle and warmup compensation. I then remembered that the radiator fan switch was set for 170F. I did some quick googling and found that the F4i fan seems to kick in around 220F. I went back and changed it to 210F. I let the engine warm up, and as it approached 200F it started to slowly overflow the reservoir cap. I think the cap is 16 lbs (is this force or pressure?). I kept my eye on it as it warmed up while only idling. Fan switched on like it was supposed to and it cooled back down to about 200F, but it kept slowly overflowing. I probably lost 4 ounces of coolant over the course of 5 minutes. The flow would fluctuate from a slow drip to a small but steady stream. I just recently bled the system (bled it then capped it off while cold and haven't touched it since). You think its just too much air in the system, or a bad radiator cap, or what? Any ideas I've missed? Once it cools I'm going to run the engine with the cap off for a bit and maybe just flush the system since the coolant came out pretty brown.

EDIT
Ok so I let it cool down, then did another bleed. This time I let the engine warm up with the cap off. I opened the bleed screw occasionally on the radiator, lots of air bubbles came out. Then I capped it up, continued to let it run, and waited for the fan to come on at 215F. The fan cycled on and off several times, not a drop from the overflow http://fsae.com/groupee_common/emoticons/icon_smile.gif

EDIT #2
Okay so I ran the engine again just now. It started slowly overflowing again. After studying the cooling diagram, I can see that the system we have on the car SHOULD be almost the same. The main difference is that the fill cap is on a remote reservoir instead of the top of the radiator. I'm going to try to explain this as clearly as I can, so bear with me.

On the stock system, the water pump pumps to the engine block. Coolant cycles through the engine, and exits through the thermostat housing back to the water pump. This is set up identical to the stock configuration on our car.

From this point on, I'm going to talk about each of the errors I think we made. Feel free to validate or correct me on what I consider to be an error.

Error 1:
Water is pumped through the oil cooler, then to the cold side of the radiator. We kinda have the same setup as stock there, except it is pumped to the top of the cold side of the radiator. Also, on the line going from oil cooler to radiator, we have a t-fitting connected to our reservoir. The reservoir is the highest point in our system, but I think we messed up by not putting it on the hot line to the top of the radiator. I think ideally we would want this t-fitting just before the hot inlet to the radiator, right?

Error 2:
So also coming out of the thermostat housing is the loop for the fast idle wax unit. We do not have one of those on our car, so we have simply closed this loop. However, I think we made another error because the air bleed line coming off of the thermostat housing is connected to this loop with a t-fitting. Would I be correct in saying that the air bleed hose should connect to the top of our reservoir, just under the cap?

Error 3:
So the final part of the stock cooling system is the line from the top of the thermostat housing to the top of the hot side of the radiator. Water flows through here when the thermostat opens. We messed this up too. It connects to the bottom of the hot side of our radiator. It should connect to the top, right? Also, as I mentioned before, I think because we are running a remote reservoir, the t-fitting to the reservoir should be placed just before the hot inlet to the radiator, right?

Finally, we have the overflow hose, which should go to our water catch can. We have that set up correctly.

I'd appreciate your comments on our current system. At least from what I can gather, I think what we need to do to fix it is:
1. Move the hot inlet to the radiator to the top of the hot side instead of the bottom.
2. Move the t-fitting for the reservoir to just before the hot inlet to the radiator.
3. Move the bleed line to the top of the reservoir, under the cap.

What do you guys think?

[BuckeyeEngines]

When water heats, it expands thus the overflowing into the catch can. When it cools back down you need a siphon tube in the catch can so the coolant will go back into the engine. Take a look at a car.

The rating on the cap is the amount of pressure it will allow to build in the system before it will "blow". We are running a 27-29 lb cap which will keep the water from boiling until a much higher temperature.

The F4i likes to run at 180 F. This is the point in which the thermostat opens which if your radiator is sufficient you should run right around 180.

[Poe]

The thermostat begins opening at 180, but is not fully open until 190-195. Ours always ran right around 200F (except when we were having cooling problems, then it was higher).

[VFR750R]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BuckeyeEngines:
When water heats, it expands thus the overflowing into the catch can. When it cools back down you need a siphon tube in the catch can so the coolant will go back into the engine. Take a look at a car.
</div></BLOCKQUOTE>

True story, I think this is what was happening to you.

I'd look into a closed system where the expansion tank is in the system rather then connected through the radiator cap. It will allow for expansion without letting any water out to have to suck back in later. It also allows you to precharge the system with pressure which is a lot better way to prevent localized hot spots and boiling in the engine should you run hotter then 212, which you all should be doing.