[Dennis]

...Forged internal pistons (and while you're at it maybe Camshaft, rods... :smile: )
Here's an email I wrote to Probe Industries in Torrance California and Mike Capp's kind response. What do you guys think? I know forged internals are usually a way to strengthen the engine for forced induction, but I want to remain normally aspirated. Would I get a performance boost just from the internals? What cost do ya think?.....
__________________________________________
Dear Probe industries,
I own a new Bullitt and here's my problem...

The new 4.6 Liters coming from Ford have a design problem. Their piston skirts were shortened, for some reason, and now at least 15-20% of the engines knock LOUDLY when the engine is cold, under load from 2,800-4,000 rpm, until the temp gauge gets to mid-arc. Sounds like a diesel truck in any gear with any amount of throttle.
I am left to warm the car up 30 minutes for a 20 minute drive to work, or short-shift most of the way to avoid the death rattle-knock (and avoid half our horsepower!).

Many of us have been to Ford with the problem. One Bullitt owner has had his engine replaced with a new one only to still have the knock in the new one. The regional Engineer told me this is normal piston slap inherent in the design, that no fix is planned by Ford, that this knocking will cause no damage, and that they cannot give me a new engine because no more are available (and I don't want a Ford remanufactured one), and to make me feel better he gave me a free extended warranty.

I don't know what I will do about this, but I'm curious about forged internals as a possible solution. Will your pistons be able to make my engine sing the way it's supposed to? I will remain normally aspirated and not add any other "power-adders"...are their any other benefits to using your pistons for me, other than hopefully losing the piston slap...ie additional power for my normally aspirated engine (maybe with camshaft)?
I'm curious to hear any insight you may have into this problem and so are many of my GT, Cobra and Bullitt-owning friends (the ones with piston slap).
Good luck with your products!
Best regards,
Dennis A. Smith
BULLITT #5578
Arizona Lifeline pilot, Tucson
_______________________________________
Dear Dennis,
We offer replacement quality forged pistons along with rods and or crankshafts---we can sell just pistons--or all the parts. They have offset wrist pins and if run with the proper piston to wall clearance piston slap will not be a problem---any other questions just call 310-784-2977 Thanks Mike Capp

 

['01 Hoofbeat]

First off, I don't believe it is piston slap and it does not sound like a diesel knock at all. It is a ticking metallic sound. There are no horsepower to be gained by going with forged internals. Forged pistons/crank etc. are heavier and will require more hp to move the pistons. If not going with forced induction, forged internals are rather pointless and will cost you some HP. I am an expert by no means, just offering my 2 cents.

Besides, piston slap would be heard at start-up and when revved in neutral. I was told by a Ford tech that Ford knows of the problem and they are working on a fix. If this was a normal noise that is occurring why do only 15% of the Mustangs do it? Why didnt ford tell the dealers/ techs that they are supp0osed to have piston slap(which it isn't) and why are so many techs confused as to what the noise is. I ordered my GT, and if I test drove the car and heard that noise, there is no way in hell I would have purchased the car. There was nothing put out by Ford that the design of the pistons are to induce piston slap.

_________________
2001 Zinc Yellow GT. Side exhaust, 4:10'S, pullies, STB, SFC's, Steeda front splitter, steeda race wing, limo tint, bullitt shock/spring package, JMS custom chip, and some other goodies.

<font size=-1>[ This Message was edited by: '01 Hoofbeat on 2002-02-13 18:37 ]</font>

 

[Bullitt4995]

I also agree that it is not piston slap. I had engines with piston slap, and this isn't one of them. Whatever it is, Ford better get off their FAT BUTTS and take care of the problem, PRONTO! Ford knows of this problem, but what is being done to correct it?

 

[PCRMAN]

I never bought into the piston slap theory. It sounds to me like a rattling of a heat shield-perhaps the catalytic converters? Noise goes away as heat causes expansion. Also, if clearances are that poor when cold, we should be seeing oil consumption. I don't know about the rest of you, but I've got 8600mi on the clock and have not used a drop.

I am getting tired of this topic! But I want an answer from FORD.

Don

Don

Don

 

[DrivingSimulators]

It would be totally cool if the sound is just some component rattling (cats, etc.), but that does not seem likely. The first step to figuring out this puzzle is isolating the source of the sound. So far, no one has done this (I've tried, and will continue to try). Once we've located the source of the sound, then we can make conjectures as to what it causing it.

If I can get Ford to pay for it, I have an expert private+high-perf mechanic who can place a listening device at key locations on the car to locate the sound. I've got mics I can place in the engine bay, but I must keep them away from heat, etc.

Still searching...

 

[Dennis]

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2002-02-13 20:08, PCRMAN wrote:
I never bought into the piston slap theory. It sounds to me like a rattling of a heat shield-perhaps the catalytic converters? Noise goes away as heat causes expansion.
I am getting tired of this topic! But I want an answer from FORD.

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

Hi Don,
I don't think it can be anything outside of the engine or transmission. Many of us have done extensive exhaust modifications (headers, highflow cats, no cats...) and have found the exact same noise after as before.

 

[BULLITT00208]

I finally decided I'm not going to let this bother me anymore. I'm going to drive it like I stole it and then when it blows up it will give me an excuse to build it stronger and more powerful! I've pretty much voided a lot of my warranty anyway

Eric

 

[PCRMAN]

Dennis, good point. I guess that blows the heat shield rattle theory out. Back to square one. I'm with Eric- screw it. I am not going to worry about it, call me stupid and ignorant but I will wait for some response from Ford.

One more thing- we do need a good recording of sound to make sure we all are hearing the same thing. Driving sim has done some great work here, but my crappy sound system cannot discern any death rattle.

 

[strokerswild]

My 2000 F150 with the 5.4L made the same exact sound when cold, so apparently it's something inherent in the late Ford OHC V8s.....

 

[Dennis]

That's what the Ford regional engineer told me a couple weeks ago...Shorter skirt piston design cold engine knock inherent in the 4.6 and 5.4L OHC engines. e also said it would not cause any damage. I just don't know if I believe him (about it being "normal" and about the damage part).

 

[Mus408]

I haven't noticed any real loud piston slap in my Bullitt. But I know about the short skirt deal. When I built up a 408,351W stroker,there wasn't much room left for what you would call a normal looking piston,hardly any skirt at all! These were Venolias,fitted at .0055 clearence,Forged pistons. Couple that with a small 1.55 rod ratio,the piston wants to go out the side of the bore before it goes up. It ran like stink,but had that diesel knock sound all the time! Finaly went back to a 357 setup,very quiet now,runs just as quick!

<font size=-1>[ This Message was edited by: Mus408 on 2002-02-16 09:59 ]</font>

 

[strokerswild]

I doubt damage will occur, unless the driving gets too "spirited" before the engines are hot. The key is proper engine warmup. It's not that hard to get up to highway speed in our cars short-shifting at 2000-2200, staying out of the rattle zone (I know, it's tough). Once warm the sky is the limit. Any engine, regardless of what it is, should NEVER be used hard until it's up to temp. It's not rocket science.....

Engines that have short piston skirts can sound like hammer mills until they heat up, especially strokers like 408 mentions. I've had several cars over the years with piston slap, but this is the first right from the factory. Just heat 'em up before you play.

_________________
Bullitt TB#570
'00 Explorer Sport
'67 Cougar 289-8V
'66 Ford Custom 2-door 460CJ

<font size=-1>[ This Message was edited by: strokerswild on 2002-02-18 09:29 ]</font>

 

[Dennis]

It may be harder than you think.
I have 3.73 gears and many of the guys have 4.10's.

 

[Bushmaster]

That's a fact. With my 4.10s, keeping it out of the rattle range (2200 when it's really cold outside) means shifting into 5th at about 45 mph. At freeway speed (65-70) I'm right smack in the middle of the rattle range. I try and let it warm up before driving it, but one doesn't always have that latitude. Occasionally in my business I'm called upon to get somewhere pretty quickly with short notice and sitting out in the parking garage for fifteen minutes isn't really part of the scheme.
Bottom line is, with brand new $23,000+ automobiles, none of us should have to be dealing with this. We especially shouldn't have to be dealing with it without any support whatsoever from Ford.
The whole damn thing pretty much sucks, IMO.

 

[strokerswild]

Completely true. I'm currently still running stock gearing and live out in the middle of nowhere so I don't have to deal with the freeways, just rural traffic.

I'd like to think Ford would help out, but I don't have a good feeling about it.....

 

[Badkharma]

Driving hard when the engine is cold is not good for ANY engine. I find that all my needles are in the norm after about 1 and a half mins. That seems really short.

 

[MAGRACE24]

On 2002-02-13 22:23, Dennis wrote:
<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2002-02-13 20:08, PCRMAN wrote:
I never bought into the piston slap theory. It sounds to me like a rattling of a heat shield-perhaps the catalytic converters? Noise goes away as heat causes expansion.
I am getting tired of this topic! But I want an answer from FORD.

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

Hi Don,
I don't think it can be anything outside of the engine or transmission. Many of us have done extensive exhaust modifications (headers, highflow cats, no cats...) and have found the exact same noise after as before.

[/quote Gentlemen, did it ever occur to you that there may be (2) different sources causing the dreaded noise in question? There is no way piston slap should be confused with the sound of a vibrating cat-converter or heat shield. I have heard the latter in my car, albeit slightly, but it is in no way piston slap. I always warm my car up before driving it, but since it is a Sunday car, I don't care how long it takes. I have never heard any piston slap in the Bullitt and I know what THAT is because our '91 Crown Vic is the poster child for that little annoyance, but it's at 90 grand and counting. I would wait for dynamic evidence, such as broken rods out the side of the block, then take it to the dealer and say, " See, I told you I would find the problem!"