Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Crank Whip

I have asked this before, but I just wanted to hear again what this crank whip is. From what I understand "crank whip" is vibration from the crankshaft on the duratech motors that causes bearings to spin at high rpm. Do people really belive that this is the primary cause of engine failure in these motors? I was just wondering. If this is what crank whip is that means EVERY TIME YOU REV YOUR MOTOR up to the rpm that this "crank whip" becomes a problem you run a chance of blowing it up. I just don't see how ANY motor could make it very far at all in a car with this problem.

Roger

You summed it up right.

All engines,all cranks have degrees of whip...must have as the 'firing order' dictates the loads will never be 'opposite & even' on an engine......its the degree of crank whip that can cause a problem.I dont think the 2.5,now only produced in Ford of Europe, would have had a DMD fitted 'as standard' if there was no problem...Ford dont spend on parts just for the sake of it!

Terry - you have all the data. But an ignorant guy like me sees that the competition Ford Europe's Mondeo is going against is what - the BMW 3 series? And don't all BMW's have smooth revving DMD damped engines as well? We all know how much work (and money) goes into making cars sound and feel just right - all that sound deadening, rubber isolation mounts, hood blankets, soft rubber bushings... sure don't help performance and they arean't cheap either - but they are standard items on every car you buy.

Remember the last year of the SVT - one of the auto mags reported the engine felt "over worked" and somewhat unrefined. Hardly a characteristic that would help it fight against a BMW. Then you look here in the US, no 2.5L duratecs (MPV, Cougar) get the DMD. Look at the 2.5L Jaguar which has the same block and crank (Maybe different bearings????), no DMD there either.

Obviously the DMD is a huge step up in refinement and NVH, and for the price of only 1 lb of extra weight it's not a huge power dropper either. But, I guess I'm still not convinced that the primary goal of the DMD is not just noise and vibration handling, with maybe a small bit of reliabilty thrown in for good measure. Even the engineer at Adams software who worked on this project with Ford:

http://support.adams.com/kb-files/id_9358/Ford_Complete_Engine_2001_NAUC.pdf

indicated (in typical "not going to tell you much about this subject" fashion) that DMD dampers served to reduce noise and vibration in the 3-400 hz region, and "that's all I know about it".

I know there have been a LOT of blown SVT engines, but way back when on the American.edu mail list, before the SVT's were around much there were almost NO stories of low mileage blown 2.5's (even with a bunch of us having MTX's). Brad Hall has mentioned he heard rumors that early cranks may have had more treatment (nitriding? or something) but he never had that verified. Anyway - you obviously have the data and I'm just rambling here. But, I am curious, did you hear about the crank whip problem and DMD solution from internal Ford research, or did it come about from your own research on dead SVTs after you left Ford?

Thanks - Scott Kauffman

I know why the cranks whips,I can also tell you that the brg mfg had problems during the develpment of the Modular V6,the overall lenght an stiffness was reduced from the Porsche Proto V6,early protos also HAD to be run on Mobil 1 synth,the first batc of 2.5's ever out of C/land Engine plant were QC rejected the day before they were sent to K/C Assembly, all the cranks were changed etc etc...Yes I know what happened!

Originally posted by ScottK97SEMTX:

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I know there have been a LOT of blown SVT engines, but way back when on the American.edu mail list, before the SVT's were around much there were almost NO stories of low mileage blown 2.5's (even with a bunch of us having MTX's).

Thanks - Scott Kauffman

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Scott, I think its true that initially we saw the SVT failures at about 40-50K miles and I actually was talleying them. But I have noticed a second pattern emerge. Several Contours and now Cougars with somewhat higher miles (but still low for a modern car) about 70-90K with the spun bearings/broken rods. My theory is it is all high RPM area under the curve (the bending danger zone). SVTs have peak power at 6600-7000 RPM and they pull hard to redline. They are run up high and often. Normal duratecs peak a good 800-1000 RPM lower. On average, you will be less tempted to run up to 7K. No need to either with a sub 6K power peak. So SVT accumulates more RPMs faster and thus fails earlier. But, it seems that eventually many normal Duratecs get there too.


This is my speculation about why SVTs have had problems quicker. I have no data myself but this theory fits the data available. Only other possibilty I have figure is the oil cooler as a restriction. But this makes no sense as it is on Euro Mondeos which are doing about as well as regulaer Duratecs when I checked with Mondeo.org. You REALLY should talk to Judge about the issue of crank whip. I have, its scary. But in view of the fact that his job is an issue, it can't be discussed here by me. Talk to Judge....or just get the DMD..


One more thing, I think the DMD may actually gain power over stock. The 1 extra pound of such small radius is negligable BUT the reduction in crank whipping in the bearings MUST cut down on frictional power loss. It is not a small difference, you will feel it..

Dan,

I know you and Terry (and just about everyone else on the board) are probably right. Maybe I'm just slow

- on a related note -

I finally got off my @ss and emailed blackstone-labs for a test kit. In the not too distant future, I (actually "we" since I will tell everyone my results) should see how much tin or aluminum (whatever it is) bearing material I have floating around in the oil after 48,000 miles of running an UDP. Anyone want to make any bets how much higher than average my reads will be - I really have no clue???

{I had a boss back at Xerox - he was a great guy, but a real hardass. No matter how much sense something you told him made, he'd flat out refuse to accept it untill you could "show me the data". }

Is it possible that all the crank whip could cause the platic water impeller the crack and fail?????

This is one of the scariest subjects I have seen on this forum in a while. How the Duratec is still in production with such a fatal flaw is amazing to me. Can someone please tell me what the DMD thing is and if anyone has upgraded? Rather drop a bit of cash now than a lot later.

Between the water pump and now this... I'm scared to rev my motor anytime. How does one go about measuring crank whip? I've heard that the Eclipses have the same problem.

Originally posted by ScottK97SEMTX:

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I finally got off my @ss and emailed blackstone-labs for a test kit. In the not too distant future, I (actually "we" since I will tell everyone my results) should see how much tin or aluminum (whatever it is) bearing material I have floating around in the oil after 48,000 miles of running an UDP. Anyone want to make any bets how much higher than average my reads will be - I really have no clue???

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I wondered the same thing when I sent my first sample in.

Verdict? No signs of bearing wear after 1.5 years with the UDP.

Doesn't mean I'm not concerned about crank whip, just some interesting data. I've got another sample to send in, I'll do it soon.

-Lance