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Discussion Starter · #1 ·
In the unlikely event that you haven't read the topic I am referencing, it is at: Scary, Ridiculously Annoying Sound Topic

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>Bullitt#0685:
Official word from ford is "probably piston slap". </BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

First of all, let me just have a moment of emotional expression here.


[rant]
I'm angry that the dealer did all that to his car, for no real benefit. I'm angry that Art Hyde didn't reply to my email, or forward it to someone who could, and I'm angry that neither the dealers nor Ford seem to give a sh*t about this. There have been a few issues raised at bullittclub that, honestly, I thought people had gotten a bit overly bent out of shape over. However, THIS is really beginning to chap my ass.
[/rant]

Now, if it IS piston slap, it's been implied by a couple of people in different threads that although piston slap sounds bad, it is nothing to worry about. I've asked a couple of times how it could be harmless when both the sound and the description imply a "loose" (I realize that loose is relative) piston rattling loudly inside a cylinder wall. The metal to metal contact that must be necessary to make this sound seems INHERENTLY bad to me, or at least wear-accelerating. Someone made reference to piston slap being normal in top-fuel dragsters, but my guess would be that they rebuild their engines alot more often than any of us would like to.

SO, here is my official appeal:

If it can't/won't be fixed by Ford, I'd love to have an explanation of why piston slap is nothing to worry about. I don't mean this to "challenge" anyone's opinion. Rather, this is an appeal to those of you here who are old salts, true motorheads, and have the experience with an engine to have some knowledge or educated opinion on this.

Can anyone shed any light on this? I can live with the annoyance factor if I can feel comfortable about not harming my engine.

Thanks!
Joe


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Dark Highland Green #1934

Bone Stock except for a deep Zaino Shine!

1995 4.6L Thunderbird LX in Electric Red -- R.I.P.






<font size=-1>[ This Message was edited by: DHG-1934 on 2001-12-05 20:07 ]</font>
 

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First off, piston slap is a rather new phenomenon in all newer cars; nearly all car makers have this problem. it is due to dissimilar materials in the piston and block.

It is not harmful to the motor because it is a temporary condition.

in fact if your car is like mine you can totally alleviate the noise by either warming the car up, or shifting below the rpm where the noise develops.

the gap required for piston slap is also another reason why it is not real harmful. it is moving thousanths of an inch, its actually vibrating.

also the engine block is really a tough customer, the cast iron doesn't chip away or bend (warp) real easily.

those are the reasons i've come across...

one more thing: piston slap isn't really all that bad of a problem becuase of what it implies. It implies that the pistons were designed to fit the engine block at a certain temp (operating temp). anything below that the piston shrinks. so... if the pistons were "tight" when cold and didn't make noise, then they'd REALLY be tight when warm. this could lead to: overheating, hard starts, ping, cylinder bore scoring, excess piston ring wear.

i'll take piston slap any day compared to that.

and maybe if we bitch loud enough ford will hand out some extended warranties for free.
 

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Discussion Starter · #3 ·
<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>also the engine block is really a tough customer, the cast iron doesn't chip away or bend (warp) real easily.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

But don't we have sleeved cylinders? I don't know what the sleeves are made of, but my bet is that they aren't cast iron. I don't necessarily picture them chipping or bending, I picture them developing wear in the areas that receive the slap, and eventually blowing by.

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>It is not harmful to the motor because it is a temporary condition. </BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

As is oil starvation at startup, but isn't it widely regarded as fact that this is the source of much of an engine's wear?

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>if the pistons were "tight" when cold and didn't make noise, then they'd REALLY be tight when warm. this could lead to: overheating, hard starts, ping, cylinder bore scoring, excess piston ring wear.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

I'm fairly well educated on the effects of thermal expansion. But if materials have changed so much that these types of cold tolerances are necessary, then why isn't every new car owner complaining of this?

Joe





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Dark Highland Green #1934

Bone Stock except for a deep Zaino Shine!

1995 4.6L Thunderbird LX in Electric Red -- R.I.P.


<font size=-1>[ This Message was edited by: DHG-1934 on 2001-12-05 20:36 ]</font>

<font size=-1>[ This Message was edited by: DHG-1934 on 2001-12-05 20:38 ]</font>
 

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many new car owners complain of this.

Ford seems to have the most problems with this piston slap stuff.

you're right about oil starvation at startup.
it contributes wear to the motor, but is there anything that can stop it?

piston slap, if it gets progressively worse, will ruin the cylinder and cause blow by.

but it usually stays constant.
 

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Discussion Starter · #5 ·
BTW, Fixer, please allow me to say that your explanation has been reasonable and makes sense. I don't doubt that you know what you are talking about. I just want to be certain that this is something I can choose not to worry about. I DON'T think that "shift before 3k" or "warm your car up 10 full minutes every day" are acceptable answers. However, I suppose I will do these things anyway, and if I can go 100k without a rebuild then what can I really say? :smile:

As a side note: There are accumulators that can be purchased which provide immediate lubrication upon startup (don't remember the brand name), and they are reasonably priced. So while oil starvation at startup is generally considered to be unavoidable, it can be alleviated for a modest investment. If I can get ahead of the game financially while the Bullitt is still low mileage enough to be considered to have a "fresh" engine, I plan to get one of these AND a bypass oil filter. Admittedly, both of these items seem alot less cost-efficient if you don't plan to keep a vehicle forever, but I do plan to do so with the Bullitt, hence my concern with the piston slap.

Joe
 

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i hear ya on the warm up and short shifting. i hate having to treat my brand new (graduation present btw) car as a 25 yr-old pickup truck.

i'm still taking it to the dealer to see if they, by some miracle, have an answer, but after 0685's travails, i'm sure they won't.
 

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Let me just start off by saying that 'piston slap' is not a good or 'normal' condition nor is it a 'new phenomena' or common place in newer engines from any manufacture. If this situation exists in your engine, it will be trouble in the future. Engines are not built in any tolerance level to compensate for varying differences in metal composition to promote piston slap as a normal condition. It is caused by a loose tolerance between the piston skirt and the cylinder wall. In other words, the tolerance measurement between piston and cylinder wall is out of spec causing the piston skirt to bang or slap against the the cylinder wall as it pivots on the wrist pin. This condition is NOT ACCEPTABLE in any new engine sold to the public. As far as dis-similar metals are concerned, the measurements or tolerance levels designed into the engine are their to eliminate things like piston slap, rod knock and the like. Since I am a mechanic by trade and have rebuilt my share of engines over the years, I can tell you first hand the effects of piston slap which normally occurs on high mileage engines. As the piston skirts wear, the tolerance between the pistons skirt and the cylinder wall become looser and as I said before, the piston starts to pivot on the wrist pin and thus the skirt starts to bang or slap against the cylinder wall. As this condition continues, the stress on the skirt begins to cause metal fatigue in the skirt the result of which are cracked or even broken skirts . I have seen this many times in the past while inspecting pistons for wear. The bottom line here is if you do have this condition in a brand new engine, it needs to be remedied. It will not get better but it will get worse. Take it back to Ford and tell them to fix it.
 

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<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2001-12-05 23:04, RenegadeBullitt wrote:
Let me just start off by saying that 'piston slap' is not a good or 'normal' condition nor is it a 'new phenomena' or common place in newer engines from any manufacture.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

Ford, GM, toyota and chysler have all had their fair share of this problem in recent memory. It is a new phenomenon because hypereutectic pistons are basically industry standard. and this type of piston has only been in major usage in the last 10-12 years.

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>If this situation exists in your engine, it will be trouble in the future.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

if it gets worse than a little rattle then yes, it will.

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>Engines are not built in any tolerance level to compensate for varying differences in metal composition to promote piston slap as a normal condition.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

correct. nobody builds motors with the direct, premeditated, intention of having piston slap; its a common byproduct of the design.

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>As far as dis-similar metals are concerned, the measurements or tolerance levels designed into the engine are their to eliminate things like piston slap, rod knock and the like.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

actually i'd figure the tolerances are maximization of friction forces.

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>I can tell you first hand the effects of piston slap which normally occurs on high mileage engines.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

exactly... high mileage engines.

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE> the stress on the skirt begins to cause metal fatigue in the skirt the result of which are cracked or even broken skirts .</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

detonation does this as well if someone stays on the gas while detonation occurs...

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
Take it back to Ford and tell them to fix it.
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

If the solution is to keep swapping motors and pistons till they get it right, forget it, i'll deal with a little piston slap.

<font size=-1>[ This Message was edited by: fixer on 2001-12-06 02:48 ]</font>
 

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Guys, I don't think the noise we are getting is piston slap, at least in my car. It sounds more metallic. I can vary the throttle causing the noise to come and go. This just started, but now I am getting the noise in neutral when cold, but it doesn't last that long. I have been trying to isolate it. Very hard to do. :sad: In the meantime, if anyone finds the problem, please post your findings. Having a brand new car make that type of noise if VERY IMBARRASSING! :oops:
 

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Perhaps my own experience is of further diagnostic value to those that really understand piston slap well.

We all understand the role of cool temps in promoting the sound and mine dissappears after full warm up, like most everyone. I'd like to describe the 'exact moment' in engine operation at which this noise presents for me.

Before full warmup, I can drive in order to alleviate the sound or to promote it, at will. The sound in my Bullitt is only evident when the engine is freewheeling, in the RPM range we've all described, when the driveline is loose and not torqued with the forces of accelleration or decelleration. This happens momentarily between shifts or at any time that I stabilize the throttle, as if on a plateau. The sound is not evident if I am on the throttle increasing my vehicle speed and it is not evident if I am using the engine to slow the vehicle down. The brief period between accelleration and decelleration is where the pistons loosen up.

So, it makes sense to me that the pistons are at a 'high-centered' point on the piston pin and in a loose state in order for the slap vibration to occur. Cylinder compression, when 'leaned upon' by the driveline seems to tighten up the pistons. Maybe it causes them to lean one way or the other and prohibit the back and forth vibration from occurring.

I've chosen to limit engine freewheeling during engine warm-up. I also will not seek a cooler running plug, or any other device that tends to decrease engine operating temperature significantly. I would rather keep the motor on the warm side to be certain that the slap isn't given much opportunity to do its evil.

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<font size=-1>[ This Message was edited by: 01GTCOUPE on 2001-12-06 09:49 ]</font>
 

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From day one.

Ford, give me a 100k warranty. Do NOT give me a new engine. What happened to rebuilding? Rome doesn't need that many failed engines.
 

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Well, 01GT, all I can say is "You're VERY lucky"...
My "diesel truck from hell" sound happens when the engine has been running less than 15 minutes, between 3,000-4,000 rpm, no matter where the throttle is. In fact it's LOUDEST when ON the gas, accelerating. How embarrasing. And since 90% of my drives are only 20 minutes long I NEVER get to enjoy the Bullitt! Not unless I warm it up for 10-15 minutes for a 20 minute drive.
Can you say "Rediculous?!"
 

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Discussion Starter · #15 ·
<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE> Question for the cold start scary noise people out there...

Has it always done it from day one or did it develop?
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

I suspect that some who say it "developed" may in fact realized the the development of the sound just coincidentally happened when the temperatures started to get colder. The first time mine did it was the first time we had a <40F night, and I got in it the next morning to drive. Temps have been fluctuating alot since then, and it seems like only when it actually gets CHILLY does the engine loosen up enough to do this. Maybe that is only my own experience, but since most of us got them when it was warm out, I could see it masquerading as a developing problem when actually the conditions weren't there early in life.

Joe
 

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<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2001-12-06 08:47, DHG #1302 wrote:
I believe it developed.
I don't remember it doing this in the beginning.

Jim
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

It was warm when I got the car May 10.
That may have covered up the issue until later when it started to get cooler outside.

?????

I just wish Ford would come forward and tell us what IT is!

Jim
 

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if you engine is slightly tapping during cold start up and maintains that till it warms up, my thoughts is a different oil might be in order. here is how that works, some oils are low quality base stocks and can shear real easy. this is when an oil's base stock is squeezed out between to high pressure or shear zone thus leaving virtually no lubrication to protect your parts. one reason is your base oil is a 5wt and once warmed up the viscosity improvers "thicken" the oil to a 20 or 30wt (which ever you have) thus damping the noise a little better. in a good quality lubricant, you also have an additive designed for this called a barrier lubricant that will keep momentary shearing down to a minimal and depending on what type of barrier lubricant can even help prevent cold dry starts like some of you are concerned with. in some cases synth oils tend to be a little more prone to allow this to happen since synths flow easier than mineral oils. what you have to do is determin what type of oil your using and make adjustments, so if your useing a synth try a good grade mineral, and if mineral, consider higher grade mineral or synth.

for those of you that jackrabbit starts and stops, your shearing your oil and that causes excessive wear. case in point,
little lady from texas never hammers it, car runs forever, take same car put young guy who jackrabbits from light to light, car won't last. this is due to the shearing of the oil. i cover that on my site. look under states of lubrication to learn more on that.

now one experiment you could do is try this to see if this is where your problem is comming from. i don't advise leaving it that way but it will give you a clue as to if it's that or not.. try going to a 20w50 racing oil. now don't leave it in there for 3,000 miles because it being a racing oil, it's tbn's are going to be lower, but for the purpose of seeing if the oil is shearing because they are using a 5wt oil at start up this should help prove this theroy.

bob
Member STLE
Lubricant Specialist
http://www.bobistheoilguy.com
 

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<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2001-12-06 07:40, Mid Life Crisis #388 wrote:
Question for the cold start scary noise people out there...

Has it always done it from day one or did it develop?

</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

about two weeks ago is when the temps in the valley went from say 65-70 in the morning all the way down to low fifteis in a weekends time.

at that time is when i noticed it.

right when the temp got chilly/cold.
 

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I think I will chime in here since I believe I was one of the first people to report this problem back in july. you can see the thread here:
http://www.bullittclub.com/phpBB/viewtopic.php?topic=902&forum=9

I bought my car July 5th and my post was on July 23rd so I would have to say it started from almost day one. I am somewhat concerned about the possibilty that this may cause excessive engine wear, but I drive pretty hard so I don't have an expectation of the engine lasting forever. My problem is that it is really embarrassing! The engine sounds like it is going to rattle right out of the car. It is loud enough that if people outside the car are within 20 feet they turn and look. I recently swithced to 5w-20w Amsoil synthetic so I will see if that improves the noise or makes it worse.


To me this definitely seems related to looseness in the engine before it reaches operating temp. I believe this appears at a certain engine rpm because of harmonics. I also think that it is more pronounced on our vehicles because of the aluminum intake.(I have noticed Cobra owners complaining of the same noise elsewhere)

I will eventually take my car to the dealer and take a mechanice for a ride so he can hear the noise. I'm just not in any hurry because I know the answer is going to be "that's normal, they all do it". The reason I think it is important to have the mechanic confirm the noise is so down the road if it gets worse and causes a failure you have it on record that the problem first surfaced at 5K miles. I will update if I find anything out.

Eric
 
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