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View Full Version : Lesson of the day for 9/11/06



Steve_S
09-11-2006, 09:18 PM
Today's lesson: Follow your own advise.

I took a friend for a ride up the coast in my MGA to buy some parts for his MGB at Moss Motors. It was a lovely day and all was well in the world. We bought parts, ate some lunch in Santa Barbara and then headed home.

Half way home there was a large BANG and then heavy vibration. I immediately pulled it out of gear and put my hand on the key, ready to shut it down. But something didn't feel right. It didn't feel like internal engine. All gauges were good and idle was normal. Still coasting at 40MPH I decided to slip it into 4th gear and see what happens. It went right in and the car drove fine, but still a heavy rapid vibration. I would think broken crankshaft except the engine was running fine.

I took it back out of gear and revved a couple times easy. The engine revved normally but RPMs affected the vibration greatly. So this eliminates the transmission, U-joints and drive shaft.

The only things I could think of were engine mount and fan blade. I drove it easy, finding an RPM which minimized vibration and pulled to a safe place off the freeway. Popped the bonnet open and what's this? Missing fan blade! I had a heat flash as I inspected the radiator and hoses for damage. Nothing. And no slice in the bonnet. Boy was I lucky! The only damage was a scratched bolt on the steering column bracket. And there sitting on the crossmember was a bent up fan blade. Cool, a souvenier! /ubbthreads/images/graemlins/laugh.gif

So there were now two options. Remove the opposite blade and hope the fan would balance enough to drive the 30 miles home without damaging the water pump, or remove the fan entirely and hope it doesn't overheat. MGAs don't have very good air flow as it is and this engine is 300cc larger than stock. But once my co-pilot du jour pointed out how thick the metal on the fan was, I decided that I liked option two best. So I removed the fan and began the drive home.

It ran hot on the two big grades and nearly overheated once when I got stuck in some traffic, but the car made it home like a true champion without nary a complaint. I love these cars!

So the point of this thread is that when you know that 40-year-old metal fans can fly apart without warning, and you drive at high RPMs daily, and you warn other owners about the damgers of old metal fans, and you know you should be running a plastic fan... replace your fan, dummy!

This fan was 23 years old and I'm a big dummy for letting it stay in the car this long.

One interesting note... on the drive home, the engine was noticably smoother than before the fan incident. I now highly recommend removing the fan from any engine to see if it makes a difference. If it does, your fan is out of balance which can stress the water pump and introduce vibration into the steering wheel and pedals. I had only the slightest vibration which felt completely normal, but now you can barely tell the engine is running!

https://www.mgnuts.com/temp/fan1.jpg

https://www.mgnuts.com/temp/fan2.jpg

https://www.mgnuts.com/temp/fan3.jpg

kennypinkerton
09-11-2006, 09:35 PM
Interesting!

R6MGS
09-11-2006, 10:10 PM
Wow!....I should probably change the fan on SWMBO's MGA....It looks kinda rough...and she drives it daily...Another weekend job.

thanks for the heads up.

Steve_S
09-12-2006, 12:53 AM
Yeah, it has me thinking of replacing all my metal fans, regardless of age or condition. I hate to think of what could have happened, had the blade gone another direction. Radiator, coolant hoses, oil hoses, aluminum bonnet, fan belt, wiring harness, etc. They were all in the line of fire!

tony barnhill
09-12-2006, 09:41 AM
At the Townsend, TN show a couple years ago, there was an Austin Healey with the fan sliced into the hood - guy kept the hood on the car - fan sticking out & all.

swift6
09-12-2006, 09:43 AM
The same thing happened to friend of mine in his MGA. He wasn't as lucky though because it destroyed his radiator. He replaced the radiator and went to an electric fan.

My Cortina used to have the 2-piece four blade fan. Their nicknamed 'suicide' fans. I adapted an eight blade Triumph plastic fan to it and have had no problems since doing so.

Steve
09-12-2006, 10:35 AM
Man, with that kind of luck you should have bought a lottery ticket!

martx-5
09-12-2006, 12:06 PM
Just one more reason to install an electric fan!!

Glad that there was no damage. It coulda gotten real ugly.

Banjo
09-12-2006, 07:28 PM
/ubbthreads/images/graemlins/eek.gif /ubbthreads/images/graemlins/eek.gif /ubbthreads/images/graemlins/eek.gifNot cool! Glad all tuned out ok.

Steve_S
09-12-2006, 09:09 PM
Despite their obvious superiority, I can't stand the look and sound of electric fans. But I did buy a 7-blade plastic MGB fan which I am going to paint and adapt to the MGA. It will look nearly stock since the original was a 6-blade unit.

tony barnhill
09-12-2006, 09:37 PM
The TR fan I adopted to fit my Rover V8 engine:

https://www.theautoist.com/tr7fan001.jpg

https://www.theautoist.com/tr7fan002.jpg

https://www.theautoist.com/tr7fan004.jpg

https://www.theautoist.com/boxerv8.JPG

https://www.theautoist.com/enginein3.JPG

Steve_S
09-12-2006, 10:44 PM
Oh man, Tony! That's a great idea!!!

UPDATE: The MGB fan does not fit the MGA. MGA fans hold the bulk of the fan back over the hub. The MGB fan puts the mass of the fan forward, and there is not enough space to the radiator even if I space it forward all the way to the front shelf. Looks like I'll have to do something custom, or buy a new metal fan.

max71
09-12-2006, 11:24 PM
Tony. Want to make one like that which will fit my B. I have to take the Moss "shroud" into account for blade clearance though.

Steve_S
09-13-2006, 12:16 AM
Except that I don't want 13 blades! /ubbthreads/images/graemlins/laugh.gif

tony barnhill
09-13-2006, 10:00 AM
I built my adapter plate so that the fan sits back over the end of the water pump - barely clearing the belt.....here's an old photo

https://www.theautoist.com/enginein6.JPG

R6MGS
09-13-2006, 02:40 PM
[ QUOTE ]
Despite their obvious superiority, I can't stand the look and sound of electric fans. But I did buy a 7-blade plastic MGB fan which I am going to paint and adapt to the MGA. It will look nearly stock since the original was a 6-blade unit.

[/ QUOTE ]

/ubbthreads/images/graemlins/iagree.gif I wouldn't convert an A over to electric...Either adapt a plastic fan or get a new metal one and keep a close eye on it.

Steve_S
09-13-2006, 11:24 PM
Well, the old metal one lasted 43 years so a new one should be even beter. But I still want to reduce the rotating mass so I'm going to keep trying to find a plastic one that will fit.