Rattling DOHC

[ausie]

I am not offended Shannon,
Piston slap it is. At least the issue is identified and that letting the engine warm up prior to putting it to load will reduce any excessive wear. I have been doing some digging into the issue.

One question to ask: if your motor has piston slap as is the case on cold starts, will that occur every time the motor is cold at start up? I only have it once in a great while. It is more apparent when I have synthetic 20w-50 oil in the motor and does not occur until about 2000 miles after the oil change. Ford attempted to identify other possibilities such as using an incorrect oil filter (one that is lacking a good reverse flow valve). Let me re-phrase that, I can only hear it once in a while.

I have heard this rattling noise while sitting at a stop light, but it goes away after I push the clutch in. I am baffled as to what the issue may be. However, I have also heard the same noise described in many of the piston slap threads on other sites.

It makes me wonder if I could find metal deposits in the oil filter. The next thing to do would be to drop the oil pan and inspect for fragments.

What other issues did you have with your 01? Just curious I guess probably more so since I have that year Cobra. I was considering on trading mine in for the 04 SVT but now I am not sure that would be a good thing to do.

[Firme]

some good info in this thread.

one thing to note. I am convinced that the move to 5w20 was strictly due to EPA and Gas Mileage figures. I had a bunch of link (that I feel like digging up unless someone really wants me to) to .PDF files on EPA.GOV website send out to car manufacturers recommending that they switch to 5w20 due to the fact that the engine will warm up quicker, reducing NOX, and the "thinner" oil producing better gas mileage. The funny thing is back when a bunch of us were looking into this on Stangnet, including a petrolium engineer (guy really knew his oils), we found one of the original drafts of the document that stated "even though 5w20 causes quicker engine wear, that is offset by its benifits of less polution" , they since removed the document, guess it was too incriminating.

Although the heads on the DOHC 4.6 have been said to not bee able to move 20w50 well enough to oil the engine at a good rate (at startup and high RPM), 5w30 has done just fine. That is why I use AMSOIL Series 2000 0w30, the stuff is pure AWESOME in a bottle.

[34Ford]

Since the warmer temps mine is not as bad. Winter, its very noticable.
But you hear mine right when you let off the throttle to get another gear.
If your accelerating, or decelerating (sp) its quite. Its right at that moment when theres no load.

Or if in any gear, give it the gas and just lightly lift your foot, it rattles, let all the way off it quits.

Dennis

[NO 5 OH]

Originally Posted by ausie

I am not offended Shannon

I probably did come off a little harsh... sorry if I did. You know this is the internet and what you say can always be interpreted totally different than what you intended

Originally Posted by ausie

Piston slap it is. At least the issue is identified and that letting the engine warm up prior to putting it to load will reduce any excessive wear. I have been doing some digging into the issue.

It is identified... but I hate there's nothing you can really do about it. Letting Ford replace the motor (if they'd go that far) won't fix the problem... you'll get the piston slap back eventually. The best thing to do is as you said let the motor warm up... you don't physically have to let it get to operating temp before you move it. As a rule I don't turn mine past three grand on the tach (sometimes not even 2500) until the needle on the temp guage is straight up in the middle.

Originally Posted by ausie

One question to ask: if your motor has piston slap as is the case on cold starts, will that occur every time the motor is cold at start up? I only have it once in a great while. It is more apparent when I have synthetic 20w-50 oil in the motor and does not occur until about 2000 miles after the oil change. Ford attempted to identify other possibilities such as using an incorrect oil filter (one that is lacking a good reverse flow valve). Let me re-phrase that, I can only hear it once in a while.

Both my new one and old one "slap" after sitting overnight... or if driven to work and they sat for a period of eight hours or so. I ran 5w-30 Amsoil in the old Cobra for the longest time... switched to Motorcraft synthetic blend before taking it in for warranty work and it wasn't as noticeable. I actually traded the car the day it went in for it's last warranty repair. I recently switched the new Cobra to 5w-30 Amsoil after a sufficient amount of miles... it's made no difference in the slap at start up. I'm not so sure if I'd personally run a 20 weight oil in my car... that seems a bit thick in my opinion.

Originally Posted by ausie

I have heard this rattling noise while sitting at a stop light, but it goes away after I push the clutch in. I am baffled as to what the issue may be. However, I have also heard the same noise described in many of the piston slap threads on other sites.

I actually heard this noise off and on if my old car was sitting idling with the clutch out. I never really checked this one out... but I'm pretty certain it's the throw out bearing making this noise. This makes sense as in your case and in mine the noise goes away when the clutch is engaged. It's either that or something in the tranny would be my guess. You can take that for what it's worth... I'm no expert by any means

Originally Posted by ausie

It makes me wonder if I could find metal deposits in the oil filter. The next thing to do would be to drop the oil pan and inspect for fragments.

I don't know if I'd go to this extent... dropping the pan with the motor in the car requires totally dropping the ENTIRE front suspension from out underneath it. I'd only do this if you were doing headers I actually have a Canton 7 qt pan on my car now due to the long tube installation... rolling the motor over by jacking up the oil pan didn't work for me Ask anybody that's done headers and they'll probably tell you the easiest way is to get the k-member out of the way.

Originally Posted by ausie

What other issues did you have with your 01? Just curious I guess probably more so since I have that year Cobra. I was considering on trading mine in for the 04 SVT but now I am not sure that would be a good thing to do.

Oh lord... this is turning into a novel

Piston slap on start up
Oil smoke out the tailpipes on start up, if sat over night (probable valve seal failure or oil getting into combustion chamber)
Vibration in driveline in 3rd gear (they never heard this noise )
Transmission grinded into 2nd and 3rd when cold, until car up to operating temp (tranny was on it's way out when it got traded... would pop out of 2nd gear sometimes when accelerating)

I think there might have been a few more things... but I've forgotten them since it's been long gone now. The new Cobra helped me forget about the bad things wrong with it Trading mine in on the 03 was the best thing I could have done... I got a Cobra with a blower from Ford with a warranty This one has been much better than the last one... I'm very happy with it. Trading in your case may not be the best thing... I'm sure you really like your car and I bet it looks cool as hell with the BBS wheels on it

Shannon

[ausie]

Shannon,
Ouch, it sounds like you had a few problems with it. If I ever decide to trade in my 01 for an 04 SVT, I still have all the stock parts to put back on. The good thing is that my cat-back and wheels will fit an 03-04. Eventhough I put down $10,000 cash and got a $1500.00 rebate along with ford 0% financing, I would brake even if I traded it in. I have seen rebates offered by the dealer on the 04 model I would still loose money on the trade. My car is in very good shape with 25k miles. I had to do a few adjustments to it so it runs better (new EGR valve, IAC, and altered the throttle stop since the tps was off when the throttle plate was closed). The only complaint I have is that it still has that 4x4 stance it came with. It would be hard to part with (unless I test drive a new SVT).

This past thursday I changed the oil from 20w-50 to 0w-30 to see if there is any difference. In physical appearence, the series 2000 AMSOIL 20w-50 is very much the same as the 0w-30. The 20w-50 poured like water as did the 0w-30. The only difference is that the 20w-50 will cling longer. I would not use conventional 20w-50 oil since it is thick as moleassiss.

I have been doing some more digging, I cannot find many links directly associated with a 2001 Cobra (probably due to the smaller production numbers). I have heard some sound clips on the pistonslap.com web site from a GM vehichle, It sounded worse than a Cummings (sic) deisel. Ever hear piston slap in a deisel? lol....

One thing for sure, abnormal oil consumption is associated with piston slap as well as the rattling sound. That would at least explain the carbon buildup in the motor which is one of the main issues with the 01 Cobra.

However, the plugs did not show the characteristics of burning oil. Flat black plugs may indicate running too rich, but oil burning is also a cause of carbon build up. I tracked my problem down to a faulty EGR valve which was not functioning. After replacing the EGR valve, and installing a free flowing cat back, my plugs exhibit normal characteristics. Prior to that, they would get fouled up within 500 miles.

I think I am getting way off topic here. Sorry about that. I have not yet learned to get the point across in a few sentences.

I have seached the topic until I got sick and tired of openning up the same pages. I did however find some marketing hints that the MACH 1 motor was supposed to be improved as not to experience piston slap. I guess they were wrong.