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MG MGB GT V8 Factory Originals Technical - I finally did something right cooling-wise ...

... and it certainly wasn't hard. I have had a summer of terrible cooling frustrations. The motor in my car is a 3.9 but it has been stroked -- I don't really know what the total displacement is -- and otherwise warmed over quite a bit. There is a plain old factory V8 rad on there. I just did two things that made the car run -- on hot sunny days in stop-and-go traffic (formerly my nemesis) -- just to the right of N, or about 190-200 degrees, which seems OK. They are:

1. follow George's suggesion and build an air duct to the bottom of the rad, leading back from those two holes in the valance -- sealed to the front of the rad with some foam Home Depot pipe insulation; and

2. lose the flex-fan, and install two 8" electric fans (rated at 800 cfm each; that seems pretty optimistic though) on either side of and below the water pump pulley (i.e. just up from the sway bar). There is plenty of room to do this with the motor in the stock V8 location; it's not a tight fit and this is a hell of a lot easier than fiddling with the flex fan and cowling.

Occasionally the yellow pushers click on in front but the car does not overheat now. Clearly it might be better to put a bigger rad on the car, but with this setup it does not seem to overheat under the worst possible conditions. I believe it once briefly touched the hash-mark halfway between N and H for some reason (215 degrees), but it went right back down to 195. It had always been running at 210 and well above. I am just reporting this not out of narcissism but rather so that someone scanning the archives might be saved from having to waste a lot of time and money, as I have.

Harry

Harry-
For posterity's sake, could you give a detailed description of exactly how the duct is configured, contructed, and installed? It would save a lot of people a lot of grief!
Steve S.

Pretty basic steve, just take a piece of thick sheet aluminum, bend in the shape of the lower rad, and then trim to fit behind the valance with tin-snips. One screw on each side holding it to the underside of the horiz panel behind the grille. Put the pipe insulation on the back where it hits the rad so it basically seals. I didn't really go for the super-clean look -- which I usually make at least some attempt at but I was too impatient in this case -- however it isn't exactly prominent and in any case it seems to help.
Harry

Harry, can you share what brand/model of fan you used and where you got them? Did you wire them to always be on, or only once the engine reaches a set temp?

I can forsee having some heating issues and it would be nice to have a plan in place if I do.
Larry Embrey

Harry-
"Simplicity is the essence of Genius." Perfectionist that I am, I would had been thinking of something more elaborate, tapering outwards from the ducts to the radiator. Your design works on the principle of captive pressure to force the airflow through the radiator instead of allowing it to flow around it and thus can use simple-to-bend right angles and parallel sides. This simple homemade fix might spare a few people the cost of recoring their radiators with aluminum cores. I think I'll add this idea to my Roadster as a back-up for those truely hot days. Thanks!
Steve S.

Glad you got it sorted out. I've noticed a sort of 'thermal runaway' on these engines where once they get above some fairly specific temperature I've pretty much had to shut down to get the temp to drop. Anyway, sounds like a good combination.
Jim Blackwood

8" or 10" cooling fans from Scotts Fans, Valencia, Calif 91355
800-544-5596 or 805-295-9340
I bought some and have been very satisfied.
I have 2 - 8" pullers and a 12" pusher. I have made no mods to the radiator panel or mounts but I am using a Buick 300 water pump.(short snout for air con. car)

Martyn.
Martyn

Harry - what is the distance between nose of your pump and the rad core, and what is the depth of your pullers? I'm looking at an 8" Pacet that is 2.5" deep at the centre and praps about 1" at the edge, with a fairly straight graduation from one to the other. Do they attach through the core or ... somehow else?

PaulH.
Paul Hunt

Paul, it's about 1" from pulley to core. The pullers are probably 7/8" deep at the edges, and 1-1/2" deep at their centers. I mean, just eyeballing things. They just attach through the core with those plastic jobs. I think the brand is Perma-Cool. They are whatever they sell at Jeg's. Too expensive though; there may be cheaper ones out there. Again, it's not a particularly tight fit; they will go right in. I gave them their own circuit so that if the yellow pushers crap out due to an electrical snafu, these mightn't. Relay & all that crap. The best way to do it would be to put each on its own circuit but that seemed tedious and it was getting dark ...

I may replace the yellow OE pushers with two more of these Perma-Cool fans. I think they draw less current for one thing. Plus, the Perma-Cool units actually see to work. Sometimes when those yellow fans are on you can feel air blowing out the front of the grille! (no, they're turning the right way) Bottom line is, I detest those yellow pushers.
Harry

This time I got it in the right thread!!

3 years ago I had my radiator for my standard 4 cylinder recored to a 4 row radiator versus a 2 row radiator. The upgrade only costed 180 bucks, and the cooling difference is INCREDIBLE. In the past week of driving (80-90ºF) the temperature needle has only gone out of the "C" range twice! One of those times, I intentionally left the car idling for 20 minutes just to see what would happen. The needle creeped about 1/4 of the way up the scale and never went any further. As soon as I started driving again, it immediately fell back into the "C"!! I called my radiator shop and they gave me some specific information which should be of benefit to everyone.

The stock 1977-1981 mgb radiator has a 14" x 17" core with 2 rows of 5/8" tubes, and 5/8" inners, and 10 fins per inch.

The uprated core is still 14" x 17" has 1/2" tubes with 3/8" inners and high density fins. This radiator is 1/2" thicker then the stock radiator, and has 4 rows of tubes versus 2.

I paid around 180 bucks for the recore 3 years ago, and loosing 1/2" of depth at the front of the engine bay is a cheap price to pay for the incredible gain in cooling efficiency. Hopefully this information will be enough for any good radiator to come up with this core, and if not, e-mail me and I can connect you to my radiator shop and they could probably do it via mail..

FWIW
Justin

Justin

Harry - thanks, although the only 8" fan I could find on the perma-cool site (http://www.perma-cool.com/Catalog/Cat_page18.html) claims to be 2-1/4" max depth.

PaulH.
Paul Hunt

Has anyone seen or made a shield or housing for the little yellow fans? Without a housing around the ends of the blades and fan is just going to throw air all over rather than pushing in the direction desired. If a housing was built around the edge of the fane and then sealing up to the width of the radiator (much like is done with todays engine mounted puller fans) I am betting the stock fans would really prove usefull.. I really wish I had the fiber glassing skills to make one..
Larry Embrey

The downside (maybe) would be limiting the air coming into the radiator core which could restrict flow of a puller fan if used as a backup or additional fan.. But It probably would not be too bad.
Larry Embrey

Paul H,

8in Kenlowe fans are 58.9mm in middle and 38mm at edge.

Larry,

Roger P reckons those yellow fans with cowling would be improved no end. The question is how to form the required cowling.

Paul
Paul

Larry-
Here's an idea for a simple ducting shroud for your pusher fans that might work: Measure out a strip of heavy gauge aluminum that is the same width as the distance from the leading edge of the fan blades to the trailing edge and as long as the circumference of their arc (3.1416 X Diameter), then lay out mounting straps perpendicular to the strip. Cut it out, wrap it around in a circle, and bond the ends together, then bend the straps toward the middle of the motor and mount it to the motor. Crude, but effective. Unfortunately, I don't have these fans on my car (My fan is engine mounted), so I can't look at one and tell you how to mount it to the motor. Anyway, you get the general idea. Don't forget to use a sealing strip along the top of the radiator so that the air pressure during forward travel won't be lost flowing over the top of the radiator instead of passing through it.
Steve S.

Paul Who the heck is Roger P.?
j

That alum strip idea is pretty simple and should provide a noticable enhancement. I will try that when I get things sorted.
Larry Embrey

Roger Parker

Paul
Paul

Larry E. I used heavy gauge aluminum to make shrouds to go around the two stock fans. I aluminum strap was 1 ½” wide and was shaped like the Greek letter Omega. A full circle would have been too close to the fan at the bottom. These were placed flush against the radiator but not sealed to it and extended past the sides of the radiator as the stock fans do. The result was a small improvement in the amount of air flowing through the radiator with no air thrown outward, but most of the air moved by the fans took the easy route along side the radiator. The radiator mounted aftermarket fan I use now works much better.
George Champion

George,
Thanks for the info. I am thinkging about maybe adapting the "ring" idea to make a full shield that would cover the radiator and force all the air to go through rather than around. My concern is that it will limit overall air flow
Larry Embrey

I have found ring style fan shrouds (original equipment and aftermarket) to be very efficient. My concern is when sitting at idle the air that is pushed or pulled through the radiator has more difficulty going past the engine block and out the bottom than it has going backwards through the radiator next to the shrouded fan. Not only has the air gained heat from its first pass through the radiator, but radiated engine heat may also cycle through.
George Champion

I know what you mean george, that is why I think making an "enclosure" is the way to go. Much like modern cars have. the only way in/out of the radiator is through the fan blades... I really think those fans push quite a bit of air. Maybe not as much as a fancy new Kenlow, but they move air which is what matters.
Larry Embrey

This thread was discussed between 27/07/2001 and 03/08/2001

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