Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Crank Whip

Originally posted by Terry Haines:

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FWIW the 2.5 in USA is now a 'dead duck' to Ford.Its production is only for vehicles built in Europe,also funny how its only the SVT motors have this problem ...wonder why...don't se many,if any Std 2.5's with spun bearings or oil starvation issues.....higher CR's ?....greater load on crank??.....same pan ,same oil pump,same bearings,'selected' cranks(yeh right!)..same rods...

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Plus I am sure SVT owners spend alot more time near the red line. People buy these cars for performance "acceleration, handleing"!!! I mean look any any performance 6 or 4 cylinder.. The most recent RX-7 didn't last much over 50,000 miles before gernading, givin its a rotary engine!!!! It all comes down to if you wanna play, you gotta pay!!!! You can pay by buying a DMD for a $100.00 or by replacing your engine!!!!! However I am willing to bet, if these cars wern't drivin like there stolen all the time and well maintaned they whould stand the test of time "100,000+ miles"!!!!
Just my .02

If you do eat a bearing what options do you have as far as getting it fixed??? And how much could you expect to pay????

Originally posted by Terry Haines:

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funny how its only the SVT motors have this problem ...wonder why...don't se many,if any Std 2.5's with spun bearings or oil starvation issues.....higher CR's ?....greater load on crank??.....same pan ,same oil pump,same bearings,'selected' cranks(yeh right!)..same rods...

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...........more revs....more whip...(&less oil getting back to pan??)

Actually, I have seen a pretty good number of reports of spun bearings in non SVT. Difference is in SVT its usually about 40-60K miles, in non SVT 80-100K miles (still young). I believe the same process (whip, oil starvation) occurs in non SVTs but takes longer because on average they see less revs...SVT hits peak power at or near peak power (and revs faster). Regular Duratec peaks around 6K ...little need to flog it to 7K!!! Thats just my theory though.

OK,so the order of events is -at high revs the crank starts to whip and all the oil is in the heads-the whip distorts the crank to take up running clearences-the bearing liners start to move in the caps and the oilways are blocked of by the soft bearing matl and the bearing is toast...so what causes the bearing to spin, the whip or the oil in the head?...and what is the fix??

Originally posted by Terry Haines:

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and the oilways are blocked of by the soft bearing matl and the bearing is toast...

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Terry, out of curiosity, have you observed this on tear downs?

Why bearings spin...not enough oil film quantity/quality on the bearing surface! Why not is the real Q!

Yes,on many 2.5 teardowns,not just oil,if the running clearence is taken up by a whiping crank the oil goes,as does the clearence.the only retainer for the bearing liner is the 'tang' & the amount of 'nip' that is designed in between the I/D of the rod end or main bearing cap and the O/D of two liner halves,in the case of these rods the 'nip' is minimal so any distortion that cuses a metal to metal touch condition at high load/rpm, be it whip or lube , can cause a bearing to spin.......

I wanted to mention something that I skipped over when I was reading this topic over. Dan Nixon made a post about what cars have the DMD and what cars don't. I belive that a mfg. will add the DMD if they think that they need it to take care of NVH issues in a certan chassis. Maybe Ford was unhappy with the way the motor felt in the new Mondeo, or they couldn't add the level of refinement the X-type has, so they added the DMD. Where as the new X-Type may use a different hardness rubber in the motormount if not a different design. You have a slightly different design. The X-Type is a much more expensive car so the quality of the materials may be different to. There are alot of variables there. I think that is one clue to why the DMD is there mainly for NVH. If it was there to save the motor from shaking it's self to pieces then why isn't it there on every duratech motor? Why take the chance if you are the manufacturer? You're playing russian roulette with every motor you place in a car without this damper. What about the rental companys who buy thousands of Tauruses? those cars get hammered non stop. Everyone plays the rental car game. How about the Soccer mom who stomps on the gas to pass someone on a 2 lane road with a load of kids? It may not happen often, but it does. These motors have to stand up to alot more abuse then they are intended to see if they are maintained properly. With preventing 'crank whip' the maintaince of the motor seems to be irrelevent(other then maybe changing the weight of the oil?). 'Crank whip' may be why the redline is lower on the non SVT duratech motors. Ford just took a gamble with the SVT. That would mean 'whip' was a problem mainly past 6000 rpm. That means you wouldn't see standard duratech motors failing, just SVT's like Terry said. But Dan Nixon says he has polled the fourms and found that the SVT cars seem to fail earlier. I believe the SVT cars may get driven harder, but everyone on this fourm is an enthusiast. They all bought contours because of how well they go, stop and handle. I'm sure the majority get driven hard at one point or another. What seems strange to me is how Dan Nixons (I'm not questioning the results of the poll or attacking Dan) poll results say roughly 40% of the enginge failures were similar to mine(Oil starvation), and roughly 40%+ there were "no turns prior, good oil level, no signs of oil starvation found". It sounds to me like bearings may have been damaged by oil starvation previously and after a little time they let go. I believe that you can hurt a bearing and have it go for a time before it causes a 'rod knock'. It depends on how badly it is hurt. I'm pretty sure that once it smacks, grazes, taps, etc. the journal it's done for. It is just a matter of time before it spins if it doesn't happen immedately. A spun bearing is exactly that, spun. The bearing comes in contact with the journal, the tabs that hold it in place pop out and it spins freely inside the rod or main journal. I am curious about how someone can tell how this happened. I know when a gearbox lets go there is almost no way to tell what happened first. It is possible get to the root of the problem (I.E. a gear pair). You just can't say gear A failed before gear B. You can make an educated GUESS, but you can really never know unless you witness the the event happen. It's just to destructive. I have my 3.0L apart in containers on the floor of my garage. I'll take some pictures and post them tonight and show everyone what I'm talking about.I'm not sure if there are any good parts in that. Another thing is woudn't a tougher bearing not wear as much? Why would it prevent you from spinning a bearing? As far as I know when a bearing hits the journal that bearings life is over. A harder bearing would LAST LONGER so it wouldn't get the loose tolerances at higher mileages that a softer bearing would. I could be wrong. I'm looking to learn just like everyone else. thanks for listening again

Roger

Originally posted by 3.0L SVT E0:

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1) Dan Nixon made a post about what cars have the DMD and what cars don't. I belive that a mfg. will add the DMD if they think that they need it to take care of NVH issues in a certan chassis. .... If it was there to save the motor from shaking it's self to pieces then why isn't it there on every duratech motor? .... What about the rental companys who buy thousands of Tauruses?

2) It sounds to me like bearings may have been damaged by oil starvation previously and after a little time they let go. I believe that you can hurt a bearing and have it go for a time before it causes a 'rod knock'. It depends on how badly it is hurt.
Roger

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In the post you refer to I was making a point that DMD correlated with MTX (Mondeo, Mazda6) and no DMD with ATX(MPV, Taurus)...which fits with my RPM=whip comments. I think ATXs are protected from whip cause they rev much less. The "exception" to the rule is Jag..which can be had with MTX. I just remembered 2 things here...1) I recall the 3L S type with alot of engine failures of ? etio..anybody else remember this..further info??. 2) apparently the Jag V6 is undergoing numerous revisions for 2003..will be interesting to see if DMD is one. Also, again perhaps the Jag gets trimetal bearings or "another" solution to whip...just a thought.

2) You can just as easily say that "the bearings were damaged by crank whip and gave out when subjected to minor, brief oil starvation... circular arguement without data one way or another..

Again, I believe both oiling and crank harmonics are in play. We may never know as the experts have different opininons (Judge, Terry, Procyon.. all of which I respect), and Ford has adressed BOTH issues and moved on. I think we should address both and move on to. I notice the only resistance to this comming from persons with UDPs. With all the discussion at least you that keep the pulleys know the score...but for those without......think very carefully about that mod.

Why would an automatic car be protected from 'whip' more? The auto car CAN rev just as high as the manual car can. Like I said in the post,
"There are alot of variables there. I think that is one clue to why the DMD is there mainly for NVH. If it was there to save the motor from shaking it's self to pieces then why isn't it there on every duratech motor? Why take the chance if you are the manufacturer? You're playing russian roulette with every motor you place in a car without this damper."

I think that placing the DMD only on cars that are available with manual transmissions doesn't make sense to me. The ATX car can and will rev just as high as a manual car if the pedal is pushed to the floor. This is why I am of the opinion that the DMD is for dealing with NVH issues, not the cure all for internal vibration problems.

Roger

Originally posted by 3.0L SVT E0:

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Why would an automatic car be protected from 'whip' more? The auto car CAN rev just as high as the manual car can. Like I said in the post,

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Torque Converter.

What he said.

The torque Converter, because of the contruction, acts like a hydraulic damper. It changes the natural frequency of the crank assembly.