[Healeys] Overheating

[Michael Salter]

Bob, I think you may be misinterpreting the figures that you quoted

*At the radiator inlet 134 outlet 85 at high rpms with electric fan
operating.*

*                        inlet 103 outlet 94 at idle rpms with electric fan
operating. *

If the water pump is not circulating enough coolant at idle the coolant
will spend considerably more time working its way up through the radiator
tubes than perhaps it should.

To my mind this would mean that there would be more time for the radiator
to transfer heat from the coolant to the air particularly if the electric
fan was operating at the same speed and therefore would exit the radiator
at a considerably lower temperature..

The numbers above indicate that at idle the coolant is exiting the radiator
at a higher temperature than at greater engine RPM, this absolutely does
not make sense in fact, it would indicate that the coolant is passing
through the radiator core considerably more quickly at idle than it is
higher RPM.

I've given this considerable thought and the only conclusion that I can
come to is that either the fan belt is slipping very badly under load or
the water pump impellor is slipping on the pump shaft at higher RPM.

Have you taken a look into the radiator filler neck while the engine is
running. Usually you can see the coolant passing toward the upper hose and
the rate of flow increases as the RPM increases.

Miche be worth a look.


M

.






On Sat, Mar 6, 2021 at 4:58 PM <rfbegani at gmail.com> wrote:

> Bob & Mike:
>
>
>
> You both may have seen my requests on overheating of my BJ8 and the
> response from the group.  As a result, I purchased an infrared thermometer
> to determine if my water gauge was giving accurate readings.  The
> thermometer gun told me that my water gauge was 30 degrees higher than the
> temperature of the sensor attached to the block.  At the same time, I
> noticed my gauge will show 120 degrees at rest instead of going down to 90
> degrees which would indicate a 30-degree high reading.  In May when I leave
> for cool Michigan, I will send the gauge to Nisonger to be rebuilt.
>
>
>
> I began to test the temperature of the water going through the cooling
> system at the inlet to and outlet from the block, inlet and outlet to the
> radiator and the upper and lower hoses while the engine is running at idle
> and at 2-3 Thousand rpm.  The chart I created to record these temperatures
> allowed me to produce observations or averages because the flow of the
> water is dependent upon the rpms of the engine.  The engine has overheated
> all of the 40 years I have owned it and has only 1000 miles on the new
> speedo since rebuilding to 20 over.
>
>
>
> At the radiator inlet 134 outlet 85 at high rpms with electric fan
> operating.
>
>                         inlet 103 outlet 94 at idle rpms with electric fan
> operating.
>
>
>
> The above temperatures are recorded at the inlet and all along the hoses.
>
>
>
> These temperatures indicate the pump is circulating water with sufficient
> gallons to cool the engine only when the engine is at high rpms.  At idle
> the pump does not circulate sufficient water to keep the engine cool.  This
> is especially true when you have been operating the engine at high speed
> and come down to 30 – 40 mph and stop and go traffic.  Maybe the real
> answer is to install an electric pump for constant cooling water?
>
>
>
> In the past week, I have installed a large Dorman coolant recovery tank
> and a new 7 psi 1 inch radiator cap because I learned that our radiators
> have a long neck.  Both those changes have reduced my problem of very high
> overheating and resulting boiling over.  In addition, when my water gauge
> shows 212 degrees the water temperature is actually 30 degrees less or
> approximately 185 degrees.  Also, I am not boiling over and loosing
> coolant.  Nevertheless, the engine water temperature is still spiking to
> 210 plus degrees true when coming off highway speeds.
>
>
>
> In my review of various sites, the radiator equipment suppliers and others
> are recommending increasing the pressure in the classic car systems to 15
> psi plus, and coolant recovery tanks “if your coolant system, radiator,
> hoses etc. is new” and therefore can hold the pressure.  Unfortunately, I
> have not found any maker of a 1 inch depth x 2.33 inch diameter radiator
> cap except our 7 psi cap so I can try such a pressurized system.
>
>
>
> Another suggestion on an older discussion at the British Car Forum
> indicated some of the Ontario car owners had switched to Evans Waterless
> Coolant rather than 50/50 coolant water mixture.
>
>
>
> I still have no idea why a minority of our group has overheating
> problems.  More ideas?
>
>
>
> Regards,
>
>
>
> Bob Begani 67 BJ8
>
>
>
> *From:* Healeys <healeys-bounces at autox.team.net> *On Behalf Of *Michael
> Salter via Healeys
> *Sent:* Saturday, March 6, 2021 12:20 PM
> *To:* Bob Spidell <bspidell at comcast.net>
> *Cc:* healeys at autox.team.net
> *Subject:* Re: [Healeys] 100 water pumps
>
>
>
> Yes Bob, there is something wrong with our assumptions regarding the
> cooling system not being "large" enough.
>
> My wifes Maxima is around 300 HP and the radiator has less area than the
> 100. Certainly it has a couple of very effective electric fans but they
> really don't cut in very often unless you have the AC on.
>
> I'm suspicious of the rate of circulation but I've talked to Larry Varley
> about this subject and he indicated that increasing the size of the water
> pump annular orifice didn't make much difference when he tried it.
>
>
>
> M
>
>
>
> M
>
>
>
> On Sat, Mar 6, 2021 at 11:42 AM Bob Spidell <bspidell at comcast.net> wrote:
>
> I sold my late father's 1955 Thunderbird to my BFF. These cars have a very
> similar problem to Healeys overheating, esp. at idle. When Ford stuffed the
> 292ci Y-Block into the T-Bird, they found the engine was (essentially) too
> short for the long-hooded car, so they 'engineered'--I use the term
> loosely--a cast iron spacer to move the fan closer to the radiator. The
> spacer had the added 'benefit' of severely limiting coolant flow through
> the pump and radiator; there are some aftermarket fixes and my friend,
> after doing the usual radiator re-core, better fan, etc. installed both a
> better pump (larger vanes) and a re-engineered spacer. Attached pic is not
> of the spacer he used--I can't find the link to it--but it shows the
> general idea (Ford basically put a 'dam' in the cooling system to block
> flow, and the improved spacers mostly remove it). It appears this approach
> has improved cooling, though the engine probably still gets warm if it has
> to sit too long at idle. Link is to one of the improved pumps:
>
>
> https://www.classictbird.com/Water-Pump-Modified-for-Higher-Output-1-Per-car/productinfo/8501HO/
>
> Anyways, after doing all the usual stuff to increase cooling, esp. on my
> BJ8, I've wondered if a similar approach would work on Healeys. Their pumps
> have very small vanes, and the cavity in which the vanes operate seems
> pretty small for such a large lump of cast iron (I'm guessing an uprated
> radiator core won't help much if the coolant flow is still hampered; at
> least, that's what I've found). This is probably not an option as, of
> course, our engines don't have a similar spacer to be improved upon, and it
> would be a major task to increase both the cavity's size and the pump (but
> I can dream).
>
> ps. The overheating issue with Healeys is usually attributed to too big of
> an engine in too small of an engine compartment, and too little airflow.
> But, the engine bay in an old T-Bird is huge by comparison--and the engine
> not terribly larger in displacement--and still suffers the same problem.
>
> Bob
>
>
>
>
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