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Improving BJ8 Cooling

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AndrewMawson

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Usual thing - overheats in traffic - ok on a run. Whats the best way of improving cooling on a BJ8? Don't particularly want to go to an electric fan - do the 5 and 6 blade fans actually make a differance over the 4 blade standard? Has anyone tried putting a smaller pulley on the water pump to spin it faster?

(Also what are the parameters on ignition and carburation re heating? ie does it make a practical differance retarding the timing a tad or slightly richening the mixture? )
 
A wise old British car mechanic once told me that he solves the majority of overheating problems with one simple fix: install a new thermostat with the appropriate temp rating. "Appropriate" depends on the climate where you live, and I'd defer a recommendation to others in your area based on their experience.

Even if this doesn't solve your problem, it costs so little and is so simple to implement that in my opinion it is well worth a try before to resort to more expensive and/or more complicated modifications.
 
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Usual thing - overheats in traffic - ok on a run. - do the 5 and 6 blade fans actually make a differance over the 4 blade standard? Has anyone tried putting a smaller pulley on the water pump to spin it faster?
(Also what are the parameters on ignition and carburation re heating? ie does it make a practical differance retarding the timing a tad or slightly richening the mixture? )

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You are correct. If it is ok at speed & just overheats at low speeds, a better fan will help a lot. I prefer the 15 inch six blade steel flex fan myself. The blades flex to feather the pitch at higher rpm but they don't flex forward into the radiator.

I doubt if changing the water pump pulley will do anything for you. Electric fans block off quite a bit of radiator surface. You DO have the side air duct shrouds (air deflector assembly) installed in front of the radiator?

Retarded timing will cause more heat. Richer fuel mixture will only help at higher speeds or full power but is not a good thing to do.

I think that changing thermostats will not help much unless it is defective. The thermostat only sets the MINIMUM engine temperature, not the maximum. The maximum temperature is determined by the heat input/output balance of engine & cooling system. A lower setting will give a bit more "cushion" until the temperature rises but no long term benefit. (more than a few minutes)
D
 
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Has anyone tried putting a smaller pulley on the water pump to spin it faster?

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Spinning the water pump faster will generally cause even more overheating, as the flow of the coolant through the radiator is too fast for proper heat transfer.
A larger pulley will help, provided the cooling system is clean, and everything else functions correctly.
A thermostat will cause problems, but only if it is stuck closed. A rare occurence. There are a lot of perfectly good 'stats changed for no reason.
Jeff
 
Hi Andrew and others, To cool a BJ8 requires; 1] Larger size radiator. 2]Texas cooler type 6 bladed fan,or the metal flex type.3] the block must be freed of all silt.4]Run a 3/8" vibration damper on the crank and a Water pump with a 1/2" pulley. Them British mechanics have a gag order on them and can not tell the truth. Well This is improving things isn't it??---Keoke
 
Andrew,

I had a local radiator shop rebuild my radiator with a triple core. The engine temp now always stays at 180 degrees F. This is on a 3000 Healey with a newly rebuilt BJ8 engine.

Larry
 
67BJ8,You probably got four cores./ubbthreads/images/graemlins/thumbsup.gif---Keoke
 
Just my experience, but ... I replaced my original 4 blade metal fan with the "Texas Kooler" ($45.00 delivered) and it has done wonders! I would repeated push 210+ degrees in traffic or on hills and now I never see it top 95.
 
I have tried a Hayden 5 blade flex fan for a Pinto, the Texas Cooler, and the Moss flex fan. The TC and Moss fans are effective but quite noisy. I am returning to the smaller 5 blade if I can find another one. It is not quite as effective as the 6 blades, but flows much more air than stock.
 
One thing that gets overlooked a lot is the good old Radiator Cap. These get 'tired' with age and cant maintain pressure and also the rubber seal gets hard or even damaged. If in doubt, replace it but make sure to get the correct cap. Some of the newer caps do not reach the base of the radiator filler neck and therefore dont seal at all!
 
There are obviously many considerations involved in keeping a Healey from overheating. I think it is important to differentiate between overheating at high speeds versus in traffic--or both.

I solved the former by putting in a larger radiator core--the original had five rows of 30 1/2" tubes and the replacement has four rows of 44 5/8" tubes. The additional cooling capacity allows me to run at sustained high speeds in hot weather without going over 190.

However, even the larger radiator will not keep the car cool on a warm day if I'm stuck in traffic. This is with a five-speed plastic fan supplied by Denis Welch which, I believe, is the same as the Texas Kooler but does not require the additional adaptor. Ultimately, I have an electric Hayden in front of the rad which will keep temps down in traffic but even it has its limits.
 
have had a BJ8 for 9 months over 20 years and put on a Moss 6 blade several years ago and it helped a lot. You did not mention your definition of overheating. Does it boil over or just run too high. Mine runs about 190 in or out of traffic.
 
HI Frank, /ubbthreads/images/graemlins/thumbsup.gif Its a good fan, How ever, it would be a bit quieter if it had an odd number of blades,but you can't hear it in a Healey anyway-so!-Keoke /ubbthreads/images/graemlins/cool.gif
 
/ubbthreads/images/graemlins/savewave.gif Hey Ron, Moss recalled that fan years ago it eats hoods and radiators. If you havent had any trouble you are very lucky fellow. /ubbthreads/images/graemlins/yesnod.gif---Keoke
 
"This is with a five-speed plastic fan supplied by Denis Welch which, I believe, is the same as the Texas Kooler but does not require the additional adaptor."

The Texas Kooler fan ONLY requires an adapter to mount to a 100-4 engine.

See www.ntahc.org Click on the club logo for details.

Tim
 
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HI Frank, Its a good fan, How ever, it would be a bit quieter if it had an odd number of blades,but you can't hear it in a Healey anyway-so!-Keoke /ubbthreads/images/graemlins/cool.gif

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The fan controversy will probably go on & on, with each having their favorite. Mine is 15" six staggered stainless steel bladed flex fan. The blades each have four rivets to a sturdy spider hub. It pulls a "lot" of air at low speeds, doesn't make noise, doesn't flex forward, & is very unlikely to lose a blade. This fan came from BCS in Stockton but is likely made by Hayden.
D
 
I run around 180 to 210...I'll try getting a new cap and see if that helps...doesn't the use of texas cooler fans or 6 blade fans...violate the purist concept of originality with the car?
 
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...doesn't the use of texas cooler fans or 6 blade fans...violate the purist concept of originality with the car?

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Henri,
Some of the more "pure" attributes of the cars "need" violating in the interests of usability & reliability. But you know that.
D
 
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