Cooling choices (Update)

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My77b
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Cooling choices (Update)

Post by My77b » Fri Aug 14, 2009 8:29 am

My 77 MGB tends to run on the warm side (200 degrees) on 90 degreee days. It will run cooler if i maintain a speed of around 55 to 60. but in traffic it rally heats up (210 - 212 degrees. I have been thinking of what is the best way to provide a little better cooling.

Engine has been rebuilt .030 over, (500 miles ago) new water pump installed, new radiator last summer, and block was tanked and cleaned

Would I best served to recore radiator, bigger cooling fan or an aluminum radiator?

Any help is appreciated.

Glenn
Last edited by My77b on Wed Aug 26, 2009 2:58 pm, edited 1 time in total.
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Re: Cooling choices

Post by Steve » Fri Aug 14, 2009 9:13 am

Hi Glenn, 200 really isn't too hot at all. B-Series engines can run happily at that temperature all day. Assuming you have a bit of coolant mixed in with the water, you can even run at 220F without too much worry, although keeping it under boiling is probably a good idea since some areas heat up more when you shut it down. I like to see 190-200 on the temp gauge in my Bs on hot days and they seem to run best in that range.

I installed one of Darrin Sher's 5-row cores in my '67 B, using the original Mark I upper and lower tanks. The core it replaced was the original one, and it was starting to clog. The improvement was dramatic! The rest of the cooling system is stock, including the metal 6-blade fan. I can sit in traffic on fairly hot days without worry.

If your only problem is sitting in traffic (doesn't overheat climbing hills) then it may just be a matter of air flow over the radiator while at low speed. One way to improve this situation is with an electric fan. Since the stock fan is bolted directly to the engine (or am I mistaken about the 77 MGB), it will run very slowly when the engine is at idle and will offer little air flow through the radiator. Electric fans can spin at full speed at any engine RPM, so cooling is improved. The downside is that you can hear them over the engine and they don't look correct on older cars, although on your 77 it wouldn't really look out of place. I don't recall, but didn't 77 Bs come with two small electric fans? If so, then upgrading to one large modern fan may make a difference.

Aluminum radiators are reported to shed heat very well, but then again so does brass so I've never been convinced that the cost of an aluminum radiator was worth it. The biggest advantage is probably the weight savings, which is arguable on a street car.

Also remember that water cools better than "coolant", so run a mix of mostly water rather than 50/50. I usually fill with a minimum of 70% water, sometimes more, and then top off with coolant for its anti-corrosion properties and to lubricate the water pump bearings. I also use Water Wetter, which seems to help a bit.

Hope this helps!

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Re: Cooling choices

Post by Jimmy » Fri Aug 14, 2009 9:14 am

Try sealing off all the gaps around the radiator to start with, forcing the air through the fins rather than letting some go around.
A shroud for the fan never hurts.
Also quite effective is to create a way for the hot air in the engine compartment to get out.
Then, if you don't mind spending some money, get rid of the stock fan and put a Spal electric fan BEHIND the radiator.
Or, as a last resort, move to a cooler climate - that worked for me.
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But doing the same thing in a car somehow makes it an "accident".

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Re: Cooling choices

Post by My77b » Fri Aug 14, 2009 10:48 am

Steve

The 77 has the small fans on the front of the radiator, they seem to work, but the temp will rise on hot days with the fans running into the +210 range. I drive daily from Ventura and the temp will almost always stay in the 170 - 185 range untill I get neer Simi then the temp rises and pretty much stays up. If I am moving the temp will stay around 200, but in traffic will begin to rise. especially when I accelerate at an intersection from a stop.

Just dont like to see the rise in temp on the guage

Jimmy
Have to stay where I am wish I could move. Gaps around radiator have been sealed as best as possible.


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Re: Cooling choices

Post by Jimmy » Fri Aug 14, 2009 12:17 pm

Glenn,
I'm not convinced that those puny fans up front do much more than block airflow at speed, but then again, that doesn't seem to be an issue in your case.
Steve was spot on with running as little antifreeze as possible, and I also forgot to mention using a "puke can". It doesn't have to be anything fancy, just a plastic bottle or something that catches the overflow from the radiator. Then, when the car cools off, it'll suck the cooolant back into tha radiator, so it's always full to capacity. But, a '77 may already have such a device.
There are two related things that could make your car run hot - timing and fuel mixture. You may want to ensure those are both within spec at low rpm.
Lastly, it's been said that in order to generate heat you must generate power...maybe that's why I don't have overheating issues??

By the way, on the one MG I have that actually does generate some heat, if that single Spal fan can keep a 300-hp engine cool, it should work on yours, too.

Oh, and also, don't ever take anything for granted.
For example, do you know the gauge is accurate? A cheap no-touch thermometer could be helpful for pinpointing the problem either way.
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".

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Re: Cooling choices

Post by My77b » Fri Aug 14, 2009 1:11 pm

Jimmy,

I kind of agree that the fans probubly are not the best, I have looked at the mixture on a co meter and it appears to be in the correct area, I have also switched to a higher octane gas to help stop engine pinging. I have replaced the gauge with one that reads in degrees and I have also looked at the temp of the coolant with an infrared thermometer so I have confidence that the reading is correct on the gauge, and the car does have an overflow tank.

At speed the temp seems to be ok it is just the traffic temps that bother me, I think I may try an electric fan that is larger and pulls more air through the radiator. I drive this car daily and as I mentioned in the area of Ventura and Camarillo it runs quite a bit cooler.
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Re: Cooling choices

Post by Steve » Fri Aug 14, 2009 2:06 pm

Rubber Bumper MGBs also have less air flow and a more cramped engine bay than earlier ones, so increasing air flow in any way you can would be a good idea. The shroud Jimmy mentioned would probably be valuable when combined with a modern high-efficiency fan.

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Re: Cooling choices

Post by Jimmy » Fri Aug 14, 2009 3:26 pm

Ah, I'm overlooking the perfectly obvious...yes, a rubber bumper is detrimental to cooling. And handling, and appearance (oops, now I stepped on several toes. Please forgive me, as I own three of them myself).
But, Steve, the Spal fans come with a shroud of sorts built in - just refrain from mounting them, or any fan, with ties through the radiator's core. Spal sells very versatile mounting brackets for their fans.
In baseball, running into someone is apparently a "collision".
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Re: Cooling choices

Post by kiwimark » Fri Aug 14, 2009 5:28 pm

Hi
it may pay to check the new water pump. The repro pumps have been coming with the impeller improperly positioned on the shart so they tend to cavitate and not circulate the coolant properly. The impeller needs to be pressed in a bit more until it has the correct clearance with the housing. Don't ask me what this measurement is, I am just quoting the clubs MGB tech guru here. I will find out for you this weekend if possible.
Regards
Mark

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Re: Cooling choices

Post by Steve » Fri Aug 14, 2009 5:37 pm

Excellent thought, Mark. There are also many poor quality water pumps out there. If the pump is aluminum then it is suspect. There are aluminum pumps with good impellers but a lot of them also have cheap stamped steel impellers which are less efficient than the originals. If your pump is cast iron then you're safe.

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Re: Cooling choices

Post by My77b » Fri Aug 14, 2009 8:17 pm

Great feedback Thanks guys

Glenn
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Re: Cooling choices

Post by Jimmy » Sat Aug 15, 2009 9:07 am

Glenn,
I don't know why it didn't sink in until now, but if you have to run premium fuel to combat pinging, something's not right in the ignition department.
Unless, of course, the combustion chambers are so full of crud that it causes pre-ignition once the motor's warm.
I'd say forget the timing light/marks and retard the timing a bit. Heck, retard it two bits while you're at it.
It doesn't cost anything to try.
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".

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Re: Cooling choices

Post by My77b » Sat Aug 15, 2009 3:37 pm

Since I had to do the usual maintenance for the 500 mile break in, I changed the oil, and retorqued the head and I realized that I had the valve lash set to .013 not the .018 intake and .020 suggested by the Camshaft mamnufacturer. APT) Set the timing at 14 degrees btdc. After that was completed I took the car for a run and the temp stayed at 180 degrees and the car does not ping at all. I think I may have inadvertedly fixed my heating problem. I just have to wait for a hot day to see how it goes.

The head was rebuilt about 1000 miles ago and I did not see any deposits when it was off.

Thanks for the help
Glenn 8)
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Re: Cooling choices

Post by Jimmy » Sat Aug 15, 2009 4:34 pm

Sorry, didn't realize that it was a fresh motor.
Glad to learn you got it fixed that easily - but I'd still be tempted to play with the timing a bit.
Then again, on my Beater B's original motor, I kept advancing the timing in hopes of more performance. Got it to run somewhat better, but never really good.
With its "new" motor, I started at factory specs and a timing light, then advanced it a smidgen...it runs so nice I never did pursue any extra oomph after that.
Oh, and since you just messed with the valve lash, I'd leave well enough alone for a while. NEVER change more than one thing at a time, I've (finally) learned.
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".

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Re: Cooling choices

Post by My77b » Sun Aug 16, 2009 3:37 pm

Good advise Jimmy,

I will run it this week and see where I stand
Glenn
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Re: Cooling choices (Update)

Post by My77b » Wed Aug 26, 2009 2:57 pm

I put a fan and shroud that I acquired from a junkyard on my radiator on the engine side (Left the original fans) and then purchased a programable fan controller and installed it to operate the fan. I have it currently set to come on at 170 degrees and it keeps the tempurature at 175 degrees no matter what the condition (90 degree plus temuratures outside. and on short grades).

The question is: Is this too cool? The Car seems to run great and no pinging appearant using 87 octane fuel.

Glenn
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Re: Cooling choices (Update)

Post by Jimmy » Wed Aug 26, 2009 3:30 pm

I'd have to agree with Steve, counterintuitive as it may sound, that an engine should run a bit hotter than we tend to strive for.
How about a 185 degree thermostat, and the fan coming on at 190?
About the only advantage I can see with running at a lower temperature is the extra margin when starting up a long hill. But that margin goes away in a minute or two, so why not let the motor run at the temp it was designed for?
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".

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Re: Cooling choices (Update)

Post by Steve » Wed Aug 26, 2009 6:45 pm

I would say that 170-175 is not too cool. If you could keep the engine at 190 all the time, that would be great. But as Jimmy points out, sometimes you need that extra margin of safety on a hot California day while climbing a grade. Running 10-degrees cooler on the flats might buy you valuable minutes before you get into the danger zone on a hill. I run a 165-degree thermostat in my '67 B and it does run around 170 on cool days, and without complaint. In the Summer it never runs that cool so long as the ambient temperatures are above 85-degrees. More like 180-190 on the flats in those conditions.

It would be worth trying what Jimmy suggests and running a higher rated thermostat and see what happens. If you run too hot as you crest your favorite hill, try a cooler one and see if the slightly lower temperature starting up the hill helps you!

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Re: Cooling choices (Update)

Post by My77b » Thu Aug 27, 2009 6:39 am

I currently run a 165 degree thermostat and yesterday stayed in the 180 degree range in the heat (Stop and go driving in Simi) and never went over 190 on short grades. I did notice though when the original fan kicks in the temp goes to 165 almost immediatly. I might try the warmer thermostat, but it sure runs good at the present settings. The only drawback is in the morning, when I go to work (4:30) I dont get above 170 at any time and I am usually at 165 degrees. That may be a reason to use a higher temp thermostat

Thanks

Glenn
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Re: Cooling choices (Update)

Post by Larry Kluss » Thu Aug 27, 2009 10:21 am

Glenn, I don't think there is anything wrong with a 170 water temp unless you are driving the vehicle really hard (i.e. racing). Then it's the oil temp that really matters, Too cold can cause bearing failures. Too hot, oil breakdown. For street driving, it's not all that important. I agree with the others that having the water temp on the lower end under normal conditions gives you margin of safety for the occasional extreme conditions.

For what it's worth, my modified B also runs a 165 thermostat and aluminum radiator without any problems. It generally runs about 170-175 on cool days and 180-185 on hot days. My fan is set about 195 and normally kicks on only at long stop lights or up long canyon roads on warm-hot days. It has been known to get up to 210-215 on very hot days pushing it up long slow canyons. I do not run an oil cooler because my oil temp (I have a guage) runs in the optimum range without one.

I would stay with your current setup as it seems to be working very well. The only thing I suggest is increasing your fan setting to 190-195. There is really no need for it to come on any lower than that. They typically create no more airflow through the radiator than driving maybe 20-30 MPH. If you are running an oil cooler, you may want to get one of those block-off plates that clips on, for cold mornings or winter time so the oil temp is not too low.

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Jimmy
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Re: Cooling choices (Update)

Post by Jimmy » Thu Aug 27, 2009 12:06 pm

Good points about the oil temp, Larry, since we generally don't know what it is.
Perhaps the most elegant solution is to run a thermostat for the oil cooler, too.
That was a necessity on my Jeep in Sweden - without an oil cooler it'd run hot (oil does a lot of the cooling work in an engine) but too cold with an unrestricted oil cooler. And, yes, it has a gauge, or I wouldn't have known.
I know I still have a couple of those thermostats laying around, so I'll be sure to incorporate one when redoing the cooler setup on the V8 car. Glad you reminded me, Larry.
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".

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Re: Cooling choices (Update)

Post by kiwimark » Thu Aug 27, 2009 12:42 pm

Hi
living in socal and driving in 100 deg F plus temps I use a high quality synthetic that will not break down under sustained high temp running. That being said, my B never seems to go over the normal mark even when I wring the guts out of it on an uphill twisty on a hot day. Last year I took a trip to Paso Robles and the car kept its cool hard driving with two up with a load of luggage and wine in 110 deg F temps.I do replace the radiator cap every year to make sure it is good and holds the correct pressure as they do fail eventually. The cars are designed to run just under boiling point with the themostat and pressure cap working togther to cope with spikes and drops in temp so I do not see 180-200 deg being a problem.

Mark

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Re: Cooling choices (Update)

Post by Jimmy » Thu Aug 27, 2009 1:19 pm

Perhaps we should allow at least early MGBs to run hot on occasion - after all, hot flashes are apparently common in those age groups.
Or, avoid most of the temperamental problems by ensuring that you buy a male MGB.
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".

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Re: Cooling choices (Update)

Post by Steve » Thu Aug 27, 2009 1:28 pm

I run a thermostat on my '67 MGB's oil cooler. I don't have an oil temperature gauge but figure that with the thermostat I don't really need one.

See lower left of photo...

Image

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Re: Cooling choices (Update)

Post by My77b » Thu Aug 27, 2009 2:35 pm

Thanks for all the input, I guess I can rest assured that I am not hurting my engine

Glenn
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