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Off the Record Answer from _o_ _

updated 5/15/02

(Name withheld by request)

My question is how where these cars driven prior to the gear/sprocket failing?

I think a lot of people bought these cars thinking they are designed to be torched and beat on. Ford builds mustangs for that. Ford built these things for the person who wants to feel like he has a fast car, but can lug kids and old people around too.

Ford didn't stop selling the option because of the engine problems, they stopped because so few where being sold, The boasting V8 was unimpressive in the shadows of the competition. Not to mention, for the same $ you could get a crown vic with a 4.6, police suspension, and more room from the same dealership.

The Phenomenon your speaking of (in my own opinion) wouldn't be specific to ford sho motors. It is a problem experienced by a lot of overhead cam engines driven very hard.

If the car was constantly full throttled since it was new, the gear could easily break by 20k miles, and ford would warranty the work. Not too many people drive their new cars like that. So the problem usually occurred after warranty ended. That's probably why ford denies the problem.

The truth is, that with any performance rated car, from a sho to a corvette, there are going to be people who do buy the car and beat on it from the time they get it, until they break it. Then when it breaks, they act like it shouldn't have broken.

But any real mechanic knows that if you full throttle anything all the time, it will eventually break.

The cam sprocket transfers a lot of torque to the cam-a large mass. Often, the gear is made of plastic, where all the other components are steel, and is a weak point in the valve train. This is not just a problem with fords.

After a lot of abuse, teeth on the gear can break off, causing the valve timing to slip. At worst, the gear completely shatters at high rpm, and the cam stops after the chain binds up and strips the lower gear too. In this case, if the engine is not a free rolling motor (meaning that if the crankshaft is not free to rotate when the camshaft is not rotating), the pistons will hit the open valves, bending, or most often breaking them, and usually destroying the piston and sleeve. High grade cam gears are a no-brainer when building high horsepower engines. Sure, ford should have made this gear stronger, but shouda, woulda, coulda costs a lot.

same thing happened to my co-workers BMW M3. Cost him about 16k. eight on the first hi-po motor that lasted him 13k miles when the ALUMINUM gear literally shattered. And, eight to build it again after the gear failed. The gear had about 80k miles on it because when he had his motor rebuilt the first time he didn't replace the cam gears. He drives his car like it is a race car.

My advise is depending on how you drive, and the mileage of the car you bought, it might be a good idea to replace the gears (and chain while your there) before they have a chance to fail-if it has over 80-100k miles on it. That would be a costly, of course. But a engine would cost a lot more, if that is the only fix.

The history of the car...who owned it, how they treated it is important obviously. if you think it was treated nice, and for the most part your a average driver, then I would say not to worry about it.....But if your right leg spasms every time the light goes green, you might want to invest in a new gear.

Hope this mini essay helps a little...

(Name withheld by request)

Tim, it seems to me that the individual that wrote the mini-essay "off the record" (4-26, V8SHO)- "the reason the V8-SHO motors cam sprocket fails", is not very familiar with the SHO motor design or the specific numbers (mileage, age, demography or quantities) on these failures.

First, our cam gears and the shaft itself are in fact made of steel, not plastic or aluminum as suggested in the essay. It is of the same design as the newer Mustang motors of which better then 90% of are driven much harder and more frequently at WOT then the SHO. I have seen little in their list's postings that deals with any type of cam issues other then the adjustments, grind and timing. Why I ask do the Mustang motors with multi-overhead camshafts, driven hard from day 1 not fail as the SHO? Or does Ford know something that they could share to let us know that they have a greater then 10% failure of cam sprockets on the Mustang engines? Consider this, the Cobra motor cost less then the SHO motor. I have not read that the Mazda, Honda or Nissan's succumb to the same sprocket failures even though a bulk of their motors are double-over-head cam motors and mounted in sport-sedans and coupes that are driven hard. I would very much invite the author to submit the documentation of the "other" overhead camshafts experiencing the same sprocket failures.

In response to the profile or demography of the people that have experienced this failure, I know of at least 3 failures to cam sprockets here in Ft. Smith that occurred to 2 old ladies and a very conservative older gentleman. None of these people had driven their cars in the manner the essay author described as reason for the engine failure. The older woman had her's repaired at 38,000 miles as she recalled. Then there are others who have flogged their car from day one with no ill effects with nearly 100,000 miles.

This list is not an exception or anomaly or pervasive to the trend of the failures, but rather a limited, and I feel that needs to be stressed, A LIMITED collection of the knowledge to how many have actually failed. Of the close to 20,000 V-8 SHO's produced, we have only around 500 of them posted to this group. Many, many more SHO owners know nothing of this list, the NHTSA data base or anyway to be heard since our production numbers don't even show up as a blip on the radar to one of the top ten largest corporations in the world, Ford.

I would hazard a guess that the person that wrote the essay is in fact a warranty issue or customer service Ford employee with very little if any engineering or metallurgical design training. If they did, I would at the very least feel we would have received an explanation as to why technically this is in fact the only automobile engine to have the cam sprocket not "shatter", "break off" or "fall off" but just have the slave sprocket loose bonding to spin free on the second most important rotational component in the motor. Then to allow this design to cause catastrophic damage. The concept that the "large mass cam" is responsible for this failure would be in direct contradiction to the design by not attaching the gear to the camshaft by the usual tried and proven methods of either a bolted flange incorporated into the casting itself or to the primary drive sprocket. I would also expect to have it explained why this problem does not occur on the other Ford performance engines of similar camshaft design.

So this is what a "possible" Ford response could be expected if they were to supply any acknowledgment that this problem really does occur?

That would be very disappointing from such a World Class Corporation.

Carter Fujibayashi
'97 ES
Greenwwod, AR.
Cam sprocket failed November, 2001 at 94,000 miles


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