Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Crank Whip

Originally posted by 3.0L SVT E0:

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The whole point of these discussions are for people who want to learn, or for people who have questions, etc.

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IMO, this has been one of the best threads in a long time. There was no major flaming, and I learned a helluva lot about crank whip and so on. I have been following this thread from the begining, and wanted to say "Thank You" to all that contributed. This was absolutely educational, and all in all positive. Thanks guys

So is it pointless to DMD an ATX?

I dont think it could hurt. While the ATX has different harmonics, the problem area is the front of the engine, where the distance from the firing cylinder (#1) to the flywheel(or torque converter) is the greatest. So on the face of it, it would have, but may not be a dramatic as the MTX setup. Secondly, reducing the vibration means the drive train is subject to less vibration (Less wear and Tear). This can only help all in all. So i would say the DMD is a good idea for any application.

While this discussion was focusing on the bearing failure aspect, reducing NVH is always pleasant.

If you are inclined to put a DMD on, the ATX application is O.K. (in my opinion, of course).

Not pointless, I installed one in my ATX equipped Contour for the vibration reduction.

But that approx 10hp loss is huge in an atx! Or is that number off?

Originally posted by Tony D:

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But that approx 10hp loss is huge in an atx! Or is that number off?

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HP isn't lost by weight. A 200 HP engine has 200 HP whether it has a 300 lb flywheel or a 3 lb flywheel. The heavier one will just accelerate slower. (being picky here I guess, but an intake mod may increase HP, but not a weight change)

However, The loss in acceleration results in 1/4 mile time reduction which could be compared to an equivalent HP loss. I doubt the DMD affect on accelleration could be measured. And since vibration is an energy loss, reducing it provides more energy for other things, like acceleration. Of course, your mileage may vary.

For practical purposes, it would be interesting to see a consisent driver compare DMD and non-DMD times. A smoother engine may keep traction longer, have more HP available for acceleration than a non-dmd. Of course, I may be wrong, but I don't think you can just weigh the DMD and declare a 1lb increase will decrease peformance without considering the other factors that affect the motor positively.

its weird to find out someone alse has the same problems as dsm's. I thought we were the only ones to get "crank whip" which we call crankwalk, i assume there the same deal. interesting, but shitty. my car "95 talon tsi" crankwalked but now i have a 1st gen battom end which is ammune to crankwalk. find any fixes? i didnt really wanna read the tons of posts. peace

Originally posted by Contouraholic:

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ATX's have torque converter, not solid flywheel. That might change the natural frequency of the crank enough that it isn't the problem it is on MTX's.

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Well, here is my experience with installing a DMD on an ATX. I did notice a reduction in vibration in mid-upper RPMs, but it was not what I would call dramatic. I attribute this to the fluid filled torque convertor acting much as a Fluidampr would.

However, I too have already experienced an engine failure. This happened after having an oil leak fixed at my local dealer. They replaced the oil pan gasket and front main seal. As soon as I picked the car up, I noticed that it seemed down on power. However, the dealership was closing and I figured the power loss might be due to the computer needing to relearn all the sensor calibrations since they had disconnected the battery.

Well, 15 miles later it had even less power. There were no right hand sweeping turns in that 15 miles, much less any taken at high rpms. I tested the engine by holding the accelerator down through first gear. The car held 6000 rpms for about 3 seconds and then shifted into second. Normally it would shift quickly at 6250. Power was way down and at the next stop light the engine was making a mechanical knocking sound and the oil light was flashing. The car now barely had enough power to get to 35 MPH. I stopped and checked the oil which was right up to the full mark.

Eventually the dealership was forced by Ford to replace my engine. I still don't know what they screwed up, since they refused to tear the engine down to inspect it. However, it does seem like this is the same type of failure (from the symptoms) as most Duratec failures. Perhaps they installed the damper wrong? Could they have counter rotated the crankshaft (supposedly a big no-no on Duratecs, as it damages the cam chain drive system), or did they install something in the oil pump/pickup assembly wrong?

I think the latter is the least likely cause, since it should have set off the oil pressure warning light before any damage occured (and obviously it was working, since it was flashing at me at the second stop light).

It's too bad they refused to tear the engine down. I really would like to know what caused my engine to fail.

My opinion? The dealer started the car without oil during the repair. We have had a couple of failures on our service vans. We even had a Ford Service Tech. drop a screw into the intake manifold. He flagged the van, the needed to move it to disassemble the intake to take the screw out. Another tech ignored the tag, started the van to move it and the srew damaged a cylinder and piston. They have detstroyed a couple of engine with the change the oil and forget to refill too.

Not that crank whip couldn't of been the problem, but I would bet on Ford Service Error over crank whip.

DSM's do not suffer from crank whip! The 2nd gen. DSM's suffer from crank walk, they are 2 completely different problems. Crank walk is easier to solve.