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MG MGB Technical - Fan Blade Nick - Long
Hello, Took advantage of the great weather to do the routine oil change, lube, etc. on my 72B roadster. I was putting things back together and had a bit of a freak accident. The engine was running and I leaned over the engine from the side and my glasses slipped off. Of course they took a bounce and landed on the fan as it was running launching them into the back yard. I have yet to find one of the lenses but... My concern is that the collision left a nick in one of the fan blades about 1/4" long. The nick is bent out as if someone did it by grabbing it with pliers and bending it. I have a few questions: In my old flying days a nick that deep in a prop would have meant "no-go" until it was properly dressed. I bent it back easily enough but should I be concerned? Having read some of the posts here about folks losing fan blades through the bonnet I'm a little worried about it being unbalanced. Also, if I should replace the fan - which one should I use? I ask because my engine - 18V584Z-L4979 has a 3-blade metal fan and the catalogs all show this as the fan for a much earlier car. Any suggestions? Thanks alot! -Greg |
Greg Smela |
Greg, A hefty pair of glasses you had there! Yeh, the three blade fan IS from early engines, but I believe the six blade is interchangeable -- regarding mounting holes, etc. With any regards to parts -- my peace of mind is more valuable then the price of parts. IOW -- I could not enjoy the drive wondering if or when the fan blade might pop out of the hood. The three blades are wide and 1/4 inch is not that big. Go with your best instincts. glg |
glg gimbut |
For anyone wondering about 'dressing a prop'... Prop nicks are dangerous because the nick is a stress point in the metal which is more likely to develop into a crack. If the nick is properly radiused (filed) the stress is spread out over a larger area and thus less likely to develop problems. Not a siutable repair for props but most metal fatigue cracks can be halted or slowed from progressing further by drilling a hole at the end of the crack. This causes the metal (or plasic, glass, plexi, etc.) around the radius of the drilled hole to absorb the energy and not focus on the point of the proceeding crack. This is also why you always want to bevel the edges of mounting holes drilled in plexi. Mike |
Mike Phillips |
Greg, I can't tell you how pleased I am that you avoided injury as the result of flying glasses. I think, it might not be best to test the benevolence of the Good Lord Almighty. You've been spared danger from your fan once. Why take a chance that the next incident will be a fan blade flying off just as you're concentrating on the timing mark? I don't know exactly what a new fan costs, but I doubt it's worth more than your safety (or insurance against a hole in your hood or radiator). Note that in "Safety Fast", the word "Safety" has been given first billing. Oh, and get a croaky for those glasses while you're at it. (Most parts suppliers could probably tell you which blade is correct for your motor. I think I'd just go for the 7-blade plastic fan unless you're a racer. They don't have tales of losing blades and cool better at low speeds.) |
Matt Kulka |
Couldn't agree more - bin the fan. The plastic fan seems not to fail, but best option is an electric fan. I fitted one taken from a small Peugeot in front of the rad. The engine seems smoother without the engine fan, and the electric fan is super efficient at cooling the rad when needed. Mike |
Mike Howlett |
Thanks all, a new fan has been ordered. Unfortuantely this is going to lead to a series of "might as wells" while the fan is off! -Greg |
Greg Smela |
Greg, It's those might-as-wells that make such a great car. Anytime you break one thing and fix two, you're just improving the quality and preventing a breakdown. It's my opinion that the people who have the self-control to avoid the might-as-wells also have the most trouble with their cars. |
Matt Kulka |
Yeah Matt, the more I get into it the more I get into it. I haven't worked on cars since one of my first - a 67 Pontiac when I *had* to work on it to keep it going 27 years ago. Now I'm finding that working on my B is true low-tech relaxation. I work with computer systems all week and the B is a great way to decompress. Over the weekend I replaced my steering gaiters and brakes and decided to replace the fan. Now it's on to recoring the radiator and replacing the fan. I'll also do the oil cooler cuz one of the hoses has a serious looking crack. The writer Mark Helprin participated in an online discussion a few years ago. In that discussion he made the following comment that stuck with me: "I have a car that allows me to adjust the radio, change CDs, set the speed limit, with my fingers on the steering wheel. The air conditioning is perfect, the mirrors tilt down when I back up, and every possible little thing has been taken care of. In 1956, I learned to drive in a surplus WWII Jeep that had no top, a brake, a clutch, a shift, a steering wheel and lights. I had a helluva lot better a time in that jeep than in my current swept-back, ultra blue, air conditioned Lizard. This is a lesson which I urge, to the extent that I may, upon everyone who is entranced with incremental advances in technology as it relates to human comfort or ability. The source of joy and fulfillment is not in the machine, and comes not from the characteristics of the machine, but it is rather in the human action when a human being is challenged and responds to whatever situation he finds himself in. Witness the little boy in the WWII Jeep and never to be so excited again by driving." For what it's worth! |
Greg Smela |
Good Greg, "I have a car that allows....... so excited again by driving." Now that, was worth reading. |
AJ Munro |
This thread was discussed between 22/03/2003 and 26/03/2003
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