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Forged, stroker piston "rattle"
#1453208
06/15/13 12:26 PM
06/15/13 12:26 PM
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Joined: Aug 2009
Posts: 740
Anderson, IN
1969RR
OP
super stock
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OP
super stock
Joined: Aug 2009
Posts: 740
Anderson, IN
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Hello everyone! My question concerns the "rattle" noise of my forged pistons. I built a 440 using a 440 Source "512" kit. The block is .040 over. I bought the block from Indy Cyl. The block looked and checked perfect. The kit from 440 Source included the complete rotating assy. I measured everything going together. The pistons are Icon (Keith Black) pistons, dished , -0.010" down. I have between .0045 - .005" piston to wall clearance. Crower hydraulic cam, Harland Sharp roller rockers, Indy EZ heads. Engine runs great, smooth idle, no ping under accel, timing at 12 deg. I'm running TCI headers, dual carbs. My issue, if it even is, is the noise from the engine. Starting to fully warm (200-210 deg) this thing rattles like a diesel. I can hear and almost "feel" the rattle even driving down the road. I've put maybe 500 miles since putting this together. Noise hasn't changed. I've tach'd to 5000-5500 no problems. Like I said, runs fine. I've had one of my machine shop friends that does build a lot of race engines (not so much Mopar tho) tell me it just the pistons. It's almost to the point I can't take the noise anymore! Ready to pull it back out! Is there anything I can do to get rid of the noise, except for changing pistons? I've thought about the high-temp coating, Knurling, etc. What do you guy's think? Thanks in advance! Jeff
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Re: Forged, stroker piston "rattle"
[Re: 1969RR]
#1453209
06/15/13 12:36 PM
06/15/13 12:36 PM
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Joined: Oct 2007
Posts: 288
Birmingham, England
Mick70RR
enthusiast
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enthusiast
Joined: Oct 2007
Posts: 288
Birmingham, England
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I'm using the same stroker kit and can hear the pistons slap when the engine is cold. Seems to almost go away when the engine is hot so I don't worry about it. I have about 10,000 miles on the engine and it still runs fine.
Last edited by Mick70RR; 06/15/13 12:37 PM.
1970 Road Runner
505 cid
MCH CNC ported Stealth heads
MP 528 camshaft
4 speed
GV overdrive
11.98 @ 117 on street treads
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Re: Forged, stroker piston "rattle"
[Re: 1969RR]
#1453210
06/15/13 12:42 PM
06/15/13 12:42 PM
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Joined: Feb 2011
Posts: 1,454
Glendora Ca.
Just-a-dart
pro stock
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pro stock
Joined: Feb 2011
Posts: 1,454
Glendora Ca.
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Does it go away with a little RPM?
"Just a Bracket car dressed up like a streetcar"
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Re: Forged, stroker piston "rattle"
[Re: Just-a-dart]
#1453211
06/15/13 01:50 PM
06/15/13 01:50 PM
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Joined: Feb 2011
Posts: 4,302
Nebraska
72Swinger
master
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master
Joined: Feb 2011
Posts: 4,302
Nebraska
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Sounds like typical piston slap from the short skirt pistons. My 451 even does it and has since first fire. I just tell people to stand back it might blow!
Mopar to the bone!!!
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Re: Forged, stroker piston "rattle"
[Re: 72Swinger]
#1453213
06/15/13 02:30 PM
06/15/13 02:30 PM
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Joined: Jan 2003
Posts: 9,875
Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,875
Weddington, N.C.
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Fairly normal, if everything was machined,assembled and clearened properly and it goes away once you're up to operating temps it's 'normal' for these type forged pistons.
OEM piston typically have a pin offset that reduces 'slap' during warm up. If it makes you feel any better 426 HEMI's used the rattle pretty good (like a coffee can full of Rocks) from the factory, "Typical cold-natured Chrysler Product' the old southern mechanics used to say....
You responded to say you're still hearing it after warm up, you may want an experienced stroker/hp motor guy look at that and advise you, could also be a timing/fuel delivery tuning issue but can't (obviously) diagnose it here.
Last edited by Streetwize; 06/15/13 02:35 PM.
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Re: Forged, stroker piston "rattle"
[Re: MR_P_BODY]
#1453215
06/15/13 04:22 PM
06/15/13 04:22 PM
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Joined: Aug 2009
Posts: 740
Anderson, IN
1969RR
OP
super stock
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OP
super stock
Joined: Aug 2009
Posts: 740
Anderson, IN
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Quote:
Do you hear it on acceleration only or decell also
(once its warmed up)
I hear it all the time. I'd say worse at idle or cruising speeds. Less so under accel and decel. Jeff
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Re: Forged, stroker piston "rattle"
[Re: Laurent]
#1453217
06/15/13 05:16 PM
06/15/13 05:16 PM
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Joined: Aug 2009
Posts: 740
Anderson, IN
1969RR
OP
super stock
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OP
super stock
Joined: Aug 2009
Posts: 740
Anderson, IN
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Quote:
If you've got a 160°F thermostat, you should change it for a 180°F one.
It would reduce noice.
Hello, It is actually a 195 stat. Temps normally run about 195 - 200 depending on the ambient. I've unhooked my electric fans and let it get to about 230, same noise. Jeff
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Re: Forged, stroker piston "rattle"
[Re: Thumperdart]
#1453221
06/15/13 06:18 PM
06/15/13 06:18 PM
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Joined: Aug 2009
Posts: 740
Anderson, IN
1969RR
OP
super stock
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OP
super stock
Joined: Aug 2009
Posts: 740
Anderson, IN
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Quote:
Quote:
To be clear, on an initial cold start a little more pronounced bottom end noise (as compared to an OEM motor) is fairly normal and common, but once the motor is warmed up the bottom end sound should abate considerably (but may not completely go away...again compared to a production motor designed for quiet operation). What you are now describing (on accel and decel after reaching normal oil temperatures) doesn't fall into the realm of 'normal' .
Exactly........guys use to "set em up loose" so they`d rev........REALLY? He has a clearance problem from how it sounds and it`s not gonna fix itself unfortunately......... 
OK, that's my thinking too, but where? Every clearance was double checked. PTW clearance is where the instructions from 440 Source say .0045 -.005". What else could be making this noise? You think a skirt coating would help? Any members near Anderson, IN (north of Indy) that could lend an ear? Boy, would that be great! Thanks guy's! Jeff
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Re: Forged, stroker piston "rattle"
[Re: 1969RR]
#1453222
06/15/13 06:34 PM
06/15/13 06:34 PM
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Joined: Jul 2004
Posts: 19,317
State of confusion
Thumperdart
I Live Here
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I Live Here
Joined: Jul 2004
Posts: 19,317
State of confusion
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Did YOU check clearances or were you told they were within spec?
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Forged, stroker piston "rattle"
[Re: Streetwize]
#1453225
06/15/13 06:56 PM
06/15/13 06:56 PM
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Joined: Jan 2003
Posts: 9,875
Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,875
Weddington, N.C.
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Another clip, idled down Note a hydraulic or hydraulic (as mine is0 roller will be quieter than a solid/solid roller....so the bottom end noise isn't any louder but it's more noticeable than on a solid since the sounds are semi-masked by the valvetrain clicking. http://www.youtube.com/watch?v=lN9uEzqzdA0BTW...regarding "funny noises". Big Roller cams in High compression motors can also typically have a chirping sound through the exhaust, but that's a good sound but you'd be surprised how many people will swear there must be something wrong, 
Last edited by Streetwize; 06/15/13 07:01 PM.
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Re: Forged, stroker piston "rattle"
[Re: Thumperdart]
#1453227
06/15/13 09:37 PM
06/15/13 09:37 PM
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Joined: Jan 2003
Posts: 11,713
Portage,michigan
B3422W5
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 11,713
Portage,michigan
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A short skirted forged piston with excessive clearance in the bore will cause " piston slap" which is basically the piston rocking in the bore. When the piston warms up it swells in the bore taking up clearance and the condition may lessen or pretty much completely go away.
If it doesn't go completely away, it can and will cause excessive and premature wear in the bore. The only fix is either new pistons or perhaps a coating.
Both Subaru's( which the car dealership I own specializes in) and GM 6.0 liter v8 engines are notorious for this malady. Both utilize a short skirt relatively high compression design
I stay away from any such cars that exhibit this trait if it doesn't go completely away almost immediately after startup.
In a race motor where long term high mile use isn't the norm, I would be less concerned.... But the piston rocking in the bore to that degree definately isn't a good thing
It's definately because the piston isn't sized correctly if it's a new motor....
For whatever reason, Marvel mystery oil seems to help this condition, at least to the ear.
Why I don't know... Lol
Last edited by B3422W5; 06/15/13 09:51 PM.
69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight
418 BPE factory replacement headed stroker, 565 lift solid cam
Best so far, 10.40 @127 1/4
1.41 best 60 foot
6.60 at 103.90 1/8
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