|
Will more piston 2 wall clearance cause premature wear?
#1118220
11/21/11 12:13 PM
11/21/11 12:13 PM
|
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo
OP
EL Master
|
OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
|
Hi,
Im putting together a stock STROKE 440 and im using KB forged pistons on it. I decided to go with a looser sidewall clearance because I do intend to drag race it every now and then, but it will also be used on the street.
It has stealth heads, 10,5:1 compression
floating pins
performer RPM intake
and this cam:
Summit Racing Part Number CCA-CL21-225-4
UPC 36584046738
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 2,300-6,500
Intake Duration at 050 inch Lift 240
Exhaust Duration at 050 inch Lift 246
Duration at 050 inch Lift 240 int./246 exh.
Advertised Intake Duration 284
Advertised Exhaust Duration 296
Advertised Duration 284 int./296 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.507 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.510 in.
Valve Lift with Factory Rocker Arm Ratio 0.507 int./0.510 exh.
Lobe Separation (degrees) 110
I went with ,0070"
Will this cause premature wear, or is it only that it will be noisy on startup but wear is not really an issue?
Last edited by domingo; 11/21/11 12:53 PM.
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: Challenger 1]
#1118222
11/21/11 12:35 PM
11/21/11 12:35 PM
|
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo
OP
EL Master
|
OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
|
Quote:
Not good, .015"-.002" is what it should be for the street. .007 is way too much. I would never put it together like that.
I am using Keith Black Forged, and 0,0060" to 0,0080" is what they reccommend for drag gasoline applications.
For a street Naturally aspirated build they reccomend 0,0045" to 0,0055"
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: domingo]
#1118223
11/21/11 12:39 PM
11/21/11 12:39 PM
|
Joined: Jan 2010
Posts: 236
upstate, New York
jvcuda
enthusiast
|
enthusiast
Joined: Jan 2010
Posts: 236
upstate, New York
|
Quote:
Hi,
Im putting together a stock 440 and im using KB forged pistons on it. I decided to go with a looser sidewall clearance because I do intend to drag race it every now and then, but it will also be used on the street.
I went with ,0070"
Will this cause premature wear, or is it only that it will be noisy on startup but wear is not really an issue?
Too loose for the street for me
Check KB's installation instructions: KB Piston Installation
john
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: domingo]
#1118224
11/21/11 12:45 PM
11/21/11 12:45 PM
|
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo
OP
EL Master
|
OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
|
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: jvcuda]
#1118225
11/21/11 12:48 PM
11/21/11 12:48 PM
|
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo
OP
EL Master
|
OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
|
Quote:
Quote:
Hi,
Im putting together a stock 440 and im using KB forged pistons on it. I decided to go with a looser sidewall clearance because I do intend to drag race it every now and then, but it will also be used on the street.
I went with ,0070"
Will this cause premature wear, or is it only that it will be noisy on startup but wear is not really an issue?
Too loose for the street for me
Check KB's installation instructions: KB Piston Installation
john
Well, its within spec for drag gasoline. just middle ground at 0,0070". Maybe too loose because it will need a bit to warm out and stop slap, but it is within spec.....right?
D
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: domingo]
#1118226
11/21/11 01:07 PM
11/21/11 01:07 PM
|
Joined: Jan 2010
Posts: 236
upstate, New York
jvcuda
enthusiast
|
enthusiast
Joined: Jan 2010
Posts: 236
upstate, New York
|
Quote:
Well, its within spec for drag gasoline. just middle ground at 0,0070". Maybe too loose because it will need a bit to warm out and stop slap, but it is within spec.....right?
D
Yes,for a "race only" engine.I would still go a little tighter say .0050-.0055 Remember,it's a big block and don't need to spin to 7,000 rpm!
just my .02 worth.
john
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: domingo]
#1118228
11/21/11 01:23 PM
11/21/11 01:23 PM
|
Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
|
master
Joined: Oct 2003
Posts: 7,506
Az
|
It's a little loose for the street, but I wouldn'r worry about it too much. Slightly noisy on start up ( depending on how loud your exhaust system is  ) and piston skirt wear will be up slightly. Why don't you look at having the skirts coated? Might close things up a tho or 2. Knurling might be an answer also.
Fastest 300
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: jvcuda]
#1118229
11/21/11 01:26 PM
11/21/11 01:26 PM
|
Joined: Jul 2009
Posts: 413
Norway (old world)
Oyvind Mopar
mopar
|
mopar
Joined: Jul 2009
Posts: 413
Norway (old world)
|
If it is done, you can live with it. Can be heard as sloppy on startup, but it should take even more clearance to be able to hear it when it is heated/hot. If you hear piston slab in an engine on low idle, it is often from a slack skirt after a seizure, which makes the gap much more than your .007". You can run a hotter thermostat and thicker oil if you have full control on your oiling system, or keep the rpm not too high. Premature wear on a stocker going a high mileage on piston rings due to the piston rocking, but for a hobby car should not be a problem. Let it heat up before pushing it. KB recommends more clearance for marine applications, because boats could be fully loaded before engines are hot, and cylinder walls have not yet grown to hot size. That is not done to optimize on wear, but to avoid a possible scenario giving seizing. You cannot be wrong, it is much worse with too little clearance. My 
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: Oyvind Mopar]
#1118232
11/21/11 01:35 PM
11/21/11 01:35 PM
|
Joined: Jan 2004
Posts: 27,347
Today? Who Knows?
1_WILD_RT
Management Trainee
|
Management Trainee
Joined: Jan 2004
Posts: 27,347
Today? Who Knows?
|
Quote:
If it is done, you can live with it. Can be heard as sloppy on startup, but it should take even more clearance to be able to hear it when it is heated/hot. If you hear piston slab in an engine on low idle, it is often from a slack skirt after a seizure, which makes the gap much more than your .007". You can run a hotter thermostat and thicker oil if you have full control on your oiling system, or keep the rpm not too high. Premature wear on a stocker going a high mileage on piston rings due to the piston rocking, but for a hobby car should not be a problem. Let it heat up before pushing it. KB recommends more clearance for marine applications, because boats could be fully loaded before engines are hot, and cylinder walls have not yet grown to hot size. That is not done to optimize on wear, but to avoid a possible scenario giving seizing. You cannot be wrong, it is much worse with too little clearance. My
I agree 100% Back in the 60's Chrysler set the Hemi's up stock with .007 Chevy & Ford both had similar clearance on forged piston motors... I set my 505 up at .0055 cause I know it'll never see 7000 rpm & I won't have to beat it to hard to get an ear to ear grin...  Put it together & have fun... Oh yeah if you can get the piston skirts coated down there it might be worth it but I don't see that as really necessary....
"The Armies of our ancestors were lucky, in that they were not trailed by a second army of pencil pushers."
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: dartman366]
#1118234
11/21/11 02:27 PM
11/21/11 02:27 PM
|
Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
|
I run about .006 in my eng and my old 440 with the KB pistons had about .005. My pistons in my 493 called for .003 to .005 for street and .005 to .007 for racing and I set them at .006 since I race it some. As was said you will hear some piston slap when cold but mine goes away in a few minutes. You should be fine but if its not together yet you could always do some knurling on the piston skirts. They dont do it much today as it exspands the skirt and you will have to file the knurl to get the right fit but I like the knurled pistons as the knurl holds some oil in it and helps keep the piston a little quieter. I used stock pistons on an old 383 that had almost .005 clearence in a stock bore eng honed out so I knurled them and then they would not even go in the cylinders and I had to fit them to the cylinders to get about .0015 that I ran on stock pistons.
But if it is together I would run it and just use 20w-50 oil. Ron
Last edited by 383man; 11/21/11 02:27 PM.
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: Dodgem]
#1118236
11/21/11 04:34 PM
11/21/11 04:34 PM
|
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo
OP
EL Master
|
OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
|
Yeah its done...I think it will be just fine...
Actually, I dont know why the heck I specified 0.007 at the machine shop....Looking at it again I would have said 0.0055" but oh well....god knows what I was thinking then....
I have been building this engine for quite a while, so its changed a lot since I started it and to where it is now. First I was gonna use stock heads, then I bought stealths for it, I was gonna leave em as is -out of the box- but ended up bowl blending and port matching them, then i got forged pistons, etc.....I think I got carried away in my mind and spec´d some race engine machining tolerances for it. The bearing clearances are on the loose side as well, shy of 0,0030"
Oh well, I think the machining will dictate this build, Im gonna build it with a stouter cam, put some headers, bigger carb, ditch the exh manifolds. And flog the hell out of it...
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: domingo]
#1118237
11/21/11 05:29 PM
11/21/11 05:29 PM
|
Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
|
I know sometimes you can think yourself crazy worrying about every little thing that you say to yourself.........should I have gone just a tad more ?  Dont worry about it as it will be fine. Like I said I run these pistons in my 493 at about .006 and its not that noisey when cold. With 3" pipes and Ultra-Flows you gotta really listen to hear it when cold. And you can always tell them its a Diesel !  Have fun and enjoy it.  Ron
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: domingo]
#1118238
11/21/11 11:22 PM
11/21/11 11:22 PM
|
Joined: Aug 2003
Posts: 43,095
Bend,OR USA
Cab_Burge
I Win
|
I Win
Joined: Aug 2003
Posts: 43,095
Bend,OR USA
|
Don't worry about it, I did a 470 C.I. motor (440 block, 3.91 stroke) bracket race high compression(12.8 to 1, not real high) race gasoline motor that made 720 HP at 7000 RPM, no sealing or noise problems on the dyno I did the same thing on the clearances, added .001 to the minimum To many people think of the Hyper pistons when you mention KB pistons, the forged sereis pistons are not like the hypers at all IHTHs
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: Cab_Burge]
#1118239
11/22/11 12:10 PM
11/22/11 12:10 PM
|
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo
OP
EL Master
|
OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
|
Thanks for all the replies guys. Like I said, I'm gonna run it like that. Its within spec for a drag motor, so I guess it's OK. At least the mfr says it's OK so it must be! Of course this is for a drag gasoline application, so I think Im gonna bump it up some with my cam choice... Like I said it started out as a certain something, and it ended up going somplace else! Right now its a stock stroke 440 10,5:1 compression aluminum 440 source stealth heads with a bowl blend and port match port matched performer RPM intake (I also have an edelbrock TM7 single plane) bearing clearances are loose but still within spec (near 0.0030") high volume oil pump big sump oil pan piston to wall is 0.0070" full floating pins forged pistons stock 3.75" forged crank LY rods with new arp bolts I also have a set of 1.6 roller rocker arms As you can see it' s more like an old school race engine based on the machining specs and parts. So looking at that, Im kinda tempted to ditch that COMP cam I had bought http://www.summitracing.com/parts/CCA-CL21-225-4/ (which is basically an update on the old MP 292° ,509" hyd cam) and step up to a more serious cam given the engine is setup more like a race engine. Also, ditch the exhaust manifolds and buy some nice TTI 2" primary headers.... What do you think? This will go in a 71 4 speed cuda. a833 18 spline dana 60 with 4,10 gears painted in the correct shade of P#uck the world black!!! LOL black billboards black vynil top louvers wing bad ass looks!!! better have a bad ass engine to back up the looks!!!
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: domingo]
#1118240
11/22/11 01:51 PM
11/22/11 01:51 PM
|
Joined: Feb 2007
Posts: 5,080
organ
maximum entropy
master
|
master
Joined: Feb 2007
Posts: 5,080
organ
|
just one more vote to run it. it WILL be fine. a little noisy on start up (i like that sound, it's very comforting. you know you have forged pistons). just don't beat it when it's cold (you shouldn't anyway). i've run more than that in street engines. "it'll be noisy! it'll burn oil! you'll have sealing issues! ring life will be compromised!" none of the above were encountered. in a previous life i had a 340 duster with near .009 clearance, and it was noisy when cold, and you could hear them all the time, but that was one tight little screamer. i put a lot of miles on it, and it saw over 7,000 rpm daily. well over. and i gave it a little squirt of nitrous (this in the 70's when nitrous was scary and friends were blowing their stuff up using it). i put 45,000 miles on that engine before selling it, and leak down was still less than 3% all 8 holes. no freshen up. it went to Minnesota to run in a real race car.
for what is the good life if not doing things thoughtfully?
|
|
|
Re: Will more piston 2 wall clearance cause premature wear?
[Re: dodgeboy11]
#1118243
11/24/11 05:25 AM
11/24/11 05:25 AM
|
Joined: Dec 2006
Posts: 3,667
Arizona
Chris'sBarracuda
master
|
master
Joined: Dec 2006
Posts: 3,667
Arizona
|
I'm running .010 in mine. Drag car with Venolia 4.505 bore x 4.25 stroke.. 14.75:1--B1's.. Aluminum low deck Indy block. 6.535 GRP rod.. When I asked Tom Prock, he said .0085-.011 on my application.. Leakdown has been great, and no smoke..  Also no noise from slap on start up. Chris.. 
|
|
|
|
|
conforting post. LOL
