Trying to understand my cooling system

[Randy Forbes]

Being retired allows more time for "science projects". Ask me how I know.

Better I think than some of the other marque-specific boards I frequent, and always fascinating (not just the outcome, but imagining your thought-process throughout too)!

 

[Healey Nut]

A 20$ harbour freight IR gun will be no where near as accurate as a meat thermometer in the actual fluid .
IR guns measure surface temperature and the reflectivity of the surface you are measuring drastically affects the accuracy of the reading .
I have IR guns costing hundreds of dollars for my regular HVAC job but they are only a guide if you want true accurate temperature you have to measure the fluid directly
Just as an experiment take your IR gun and measure the temperature of something and mark the area you measure , now place a piece of flat black tape or draw on the item with a black marker in exactly the same spot and remeasure from the same distance ...I would bet dollars to donuts the readings will be a lot different ..

 

[Jim 58 BN6]

A 20$ harbour freight IR gun will be no where near as accurate as a meat thermometer in the actual fluid .
IR guns measure surface temperature and the reflectivity of the surface you are measuring drastically affects the accuracy of the reading .
I have IR guns costing hundreds of dollars for my regular HVAC job but they are only a guide if you want true accurate temperature you have to measure the fluid directly
Just as an experiment take your IR gun and measure the temperature of something and mark the area you measure , now place a piece of flat black tape or draw on the item with a black marker in exactly the same spot and remeasure from the same distance ...I would bet dollars to donuts the readings will be a lot different ..

You're probably right, but mine isn't the Harbor Freight model, I got it from an electronics supplier as an "incentive", so It's probably worth all of $40.00, and still made in China. You can enter a calibration number to account for the differences in emissivity of different materials - which I don't think the HF ones have - so it isn't completely sleazy. I checked it through a temperature range against a known good thermometer, and it was close - they were probably within a couple of percent of each other, which I thought good enough. YMMV.

 

[Michael Oritt]

You can get a more accurate reading of a liquid's temperature with an IR gun by immersing something in the liquid and after a few minutes shooting the object's temperature than the liquid itself. Or shoot the header tank of the radiator rather than the liquid at the radiator neck.

 

[Deleted member 21878]

been a couple of good days now for trying some test drives. unfortunately, yesterday, i spent on replacing the alternator which quit working. but all back together now. also did a couple of other projects i was needing to clean up.

so today i figured i would take a couple of test runs. weather was a little warmer and i had the afternoon free. So i get in the car and take a run up to the gas station. just a couple of miles with a couple of stop lights. by the time i get there the gauge is at 190. shut it off to put in gas and when i start it up, it drops to 180. i took off down the highway and soon it is back up to 190. the next light i am sitting it, it goes up to maybe 200 or so but cools back down to 190 after getting moving again. in all i rode about 12 miles or so. i have been having an issue with a sticking throttle and it was being a pain so i turned around and headed home. again mostly highway driving. got home and it was still at 190, maybe to the high side. pull it in the shop and shut it off.

the engine is off and i am watching the gauge as it climbs. the gauge goes up to i'll say 220 or so. at that point i hear water blow out the overflow and in to my overflow bottle. did not think any more about that because i knew i had added some extra coolant to bring the level up to the neck. so not surprising.

at this point i am figuring ok, it did not go above 190 while driving so i just need to get used to that. but this is where it gets funny. i am fiddling with the throttle linkage and trying some things. the car is cooling down some. after some adjustments to the linkage i figure i will go back out and test it. by now the the guage is about down to 190. i fire it up and go for another 15 mile ride. the gauge started out going right down to about 180. it never went up from there. thru the whole ride and even sitting at stop signs. it may have once gotten to what i would call 185? while i was waiting on some traffic. but went right back to 180.

in fact i went on a number of runs, maybe a few miles each time, making adjustments to the linkage. never did it run hotter than 180. when i would shut the car down after a run, even the 15 mile one, the gauge never went above the 212 mark.

So maybe it just needed that burp... it will be interesting to me to see if it acts the same way on a new day or will it now stay at the 180 mark when i run it. i am not going to add any fluid to it or even pull the raditator cap just to see.

below is a picture of the of the overflow bottle after the burp. the tape i had put on there to show the starting level. i wanted to see if it would put out any fluid while i was driving. it did not. none until the big burp. i mean by "the burp" that is what it sounded like. not only fluid blowing out but it sounded like air with it. of course that could have just been air in the line or the fact that the bottle has a smaller vent hole that the line coming in.

so needless to say i am pretty happy it ran at 180 for the rest of the day. if it started like that i would never have started this thread.

i do appreciate all the help and comments you all offer. i know i probably seem to worry too much about this but this is like a couple with their first born. you just worry about everything that does not look right at first glance. partly because you have no history to compare it to. overheating the engine could be a big issue and a very exspensive one. So i am a little extra cautious. i do plan to grab a meat thermometer and give that a check just out of curiosty, as soon as i get the chance.

for now we shall see what the next road test brings.

 

[Deleted member 21878]

the has been a week of testing. i want to run the car to a car show next weekend about 30 miles from here.

on engine temp: i did the meat thermometer test on Monday and it showed exactly what the gauge showed or close enough. i started the car cold and ran for probably 20 minutes at about 1200-1500 RPM. of course the gauge never ran hotter than 175 in that time and sitting in my garage. but the meat thermometer was reading exactly the same. so i assume the gauge is fine.

once i accepted this i went back and read threads on cars running cool and hot. at idle they heat up as air recirculates around the radiator. So while it was raining one day i decided to try and make a cover to keep the air from coming back over the top. my piece fits inside the factory air deflectors and closes off the top of the radiator at the fins. took a couple hours of messing. pop riveted in place. before i had it in place, sitting at a light, the car had edged over 200 in not so long a time. since i have installed it, i have not had it run more than a couple degrees over 190. So maybe it helped. i have tried to run the same routes and the same stop lights. see pic.


the other problem i read was the air coming in under the car at speed. i already have a panel to block the air between the frame and the radiator. so i made a flat panel that covered from frame rail to frame rail and back to within 6" of the oil pan. i have made a few runs (OS temp 65*) and i have not seen any difference in the engine temp with it on or off. every time the gauge slowly climbs to the needle covering the 1 on the 190. after maybe a stop or two and sitting a little the gauge climbs to 190. when i get moving again it goes back to the needle being between the 1 and the 9 on 190 and stays there. i have been doing what i call "spark plug runs" so the routes and amount of the run have been the same. right now i have the panel off as i was going to paint it. but unless i start seeing higher temps, i will not use it.

spark plug runs:
my spark plug runs, as i call them, are to check the look of the plugs for seeing if i am running lean or rich. since lean can cause extra heat i figured i would make some runs and see what they showed. bascially i run 10 miles out from the house and 10 back. the route i use only has one place i really have to slow down coming home. i try to keep the car rpm's up most of the trip but the way home i keep them at least 2500. right up until i pull in the driveway and then i shut the engine off and coast to the shop. let the car cool down some and then pull plugs to see how they look. each time i pull three. one from each carb. each time if the plugs looked clean, i would drop the jet one more flat and do the run again. i got it out to the point where the idle was getting hard to keep smooth. then i worked them back in about a 1/2 flat trying to get a balance between good idle and good looking plugs. may need another run or two to see how the plugs look.

while messing with this i wondered about the balance of the carbs. i can tell you pulling the breathers on these tri-carbs is a real PIA. so during some more rain i made a little turtle cap to try and check the balance. you know... i think it worked ok. at least for a quick check. see pic. tri-carbs are close on that front fender brace so i may try a different bowl at some point that is not as deep. main thing is the seal covers the whole breather.


Also while doing all these runs i felt like my oil pressure was dropping to lower than what it had shown before. i have put about 150 miles so far on this engine. So i decided to run thru the easy fixes first. i pulled the block fitting for the gauge and cleaned it up. i pulled the oil pressure relief valve and made sure it looked ok. then i changed the oil filter. the oil pressure looked better after that.

so right now, if nothing screwy happens, Lilly should make the show next weekend.

 

[Deleted member 21878]

one more thing on the cooling.

i was sitting in front of my car making some notes about one of my test runs. starting looking at the driving lights and the Healey badge on the front. i would think they must cause some turbulance which prevents a smooth air flow in the front grill at speed.

wondered if the car might run cooler with them removed?

Also wondered what might change if i plugged the small top grill or the front grill outside of the air deflectors? anyone tried this to see if it has any affect?



thanks

 

[steveg]

one more thing on the cooling.

i was sitting in front of my car making some notes about one of my test runs. starting looking at the driving lights and the Healey badge on the front. i would think they must cause some turbulance which prevents a smooth air flow in the front grill at speed.

wondered if the car might run cooler with them removed?

Also wondered what might change if i plugged the small top grill or the front grill outside of the air deflectors? anyone tried this to see if it has any affect?

Thanks

I've done a lot on this subject. See my gallery at:
https://www.pbase.com/stevegerow/healeyaircontrol

 

[RAC68]

A couple of points.

Overflow Container Placement
You are using an overflow non-pressurized container placed quite far from the radiator. This would require the vacuum of the radiator to suck back the coolant from a distance that may be too far away. Although some coolant will probably return to refill the cooling system, I am not sure you will receive a full measure and over time diminish your cooling capacity.

Air Recirculation
Steve has done quite a bit of work on eliminating the porosity of the radiator bulkhead to eliminate this condition. Although cooling air recirculation is a condition that is dominant when the car is not moving forward, it is the condition that most dramatically shows the engine temperature increasing. This condition in combination with a non-existing fan cowl resulting in the elimination of major air pull through the radiator are 2 of the primary changes that could help the Healey better control operating temperature. Although you have mentioned the elimination of some of the porous bulkhead points, the area around the steering box is a major opening that is much more difficult to address.

Recirculation has been with us for decades and accepted and only recently I have come to find the condition was known to Geoff Healey through a document posted by Patrick (I believe). Although known however, neither of these 2 major issues were addressed with production changes but were address in their racing modifications on company vehicles.

Based upon Geoff's racing modifications, I have come to believe, and will try when I get sufficient time, to install a enclosure surrounding the radiator core area and extending forward to the grill opening. This enclosure would eliminate recirculating air from easily being redrawn through the radiator when stopped and should also improve directional air flow at speed combined with a shallow cowl enclosing the fan to increase air pull efficiency is another factor that, I believe, will substantially improve temperature control. Keep in mind that the effects of these modifications must be tested to validate their effectiveness.

Just my thoughts,
Ray(64BJ8P1)

 

[Deleted member 21878]

Steve and Ray,
Thanks for the info and help. i have read all of what you all say and more. in fact while under the car the other day i was thinking i could make a pan that would again mount to the original air deflectors and run from the bottom of the grill to the bottom of the radiator. thus enclosing the passage without having to deal with the steering box area.

as you suggested, i have seen that the system will not pull back fluid from the overflow bottle. as it is, it serves more for keeping any coolant from blowing out on the ground. i have thought of moving the bottle up to the fender brace and see how it works there. but i want to wait before i do any other changes to see how much worse things gets if it gets hotter out.

my questions above were more of a "am i do all the simple things i can do" to help with cooling the car.

as it stands right now, i am fine with how it works. as long as it stays in the 190 range, i can't complain. it gives some room for the temp to rise without an issue.... as long as it can come back down when moving. that is the one thing i see with this car. once it gets to a temp, it does not seem to recover easily. just not enough cores in the radiator i guess.

it is supposed to get in the mid to upper 80's here this week so i will be able to get a feel for how it does in those temps. once it gets in the 90's around here, with the humidity we have, it is likely i will be in a vehicle with AC... Or on hotter days i still have the TR6 to keep running.

really just curious on simple things i could be doing.... thanks.