Re: Piston Wall Clearance
[Re: GTMaracucho]
#110369
08/25/08 11:03 PM
08/25/08 11:03 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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everything expands when hot. if the ring gap is to tight, it will bind up and lock the pistons in place.
The specs for kb pistons and ring gaps are on the kb site. just search it
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Re: Piston Wall Clearance
[Re: GTMaracucho]
#110370
08/25/08 11:04 PM
08/25/08 11:04 PM
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Joined: Jun 2004
Posts: 6,780 Alabama
Mopar-Al
master
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master
Joined: Jun 2004
Posts: 6,780
Alabama
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Quote:
.012".
Why??
I think thats around 4-6 thou too tight if not more.
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Re: Piston Wall Clearance
[Re: Mopar-Al]
#110371
08/25/08 11:26 PM
08/25/08 11:26 PM
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Joined: Jan 2003
Posts: 309 Maracaibo,Venezuela
GTMaracucho
OP
super street
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OP
super street
Joined: Jan 2003
Posts: 309
Maracaibo,Venezuela
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Quote:
I believe minimum clearance in .0015
But if your ring gap is too tight, a kb hypo will expand more and can bust the rings
But what about Piston Wall to Cylinder??? .007" It's OK???
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Re: Piston Wall Clearance
[Re: RapidRobert]
#110373
08/25/08 11:31 PM
08/25/08 11:31 PM
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Joined: Jan 2003
Posts: 309 Maracaibo,Venezuela
GTMaracucho
OP
super street
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OP
super street
Joined: Jan 2003
Posts: 309
Maracaibo,Venezuela
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Quote:
From KB site: "street normally aspirated" forged pistons top ring-.016" 2nd ring -.012"
Thanks....but I'm using total seal ring, is same??
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Re: Piston Wall Clearance
[Re: GTMaracucho]
#110374
08/25/08 11:32 PM
08/25/08 11:32 PM
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Joined: Jun 2004
Posts: 6,780 Alabama
Mopar-Al
master
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master
Joined: Jun 2004
Posts: 6,780
Alabama
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Quote:
Quote:
I believe minimum clearance in .0015
But if your ring gap is too tight, a kb hypo will expand more and can bust the rings
But what about Piston Wall to Cylinder???
.0015 thou
I do believe. This card says .0015
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Re: Piston Wall Clearance
[Re: Mopar-Al]
#110377
08/25/08 11:48 PM
08/25/08 11:48 PM
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Joined: Jan 2003
Posts: 309 Maracaibo,Venezuela
GTMaracucho
OP
super street
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OP
super street
Joined: Jan 2003
Posts: 309
Maracaibo,Venezuela
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Quote:
Did you make sure you had good engine/body ground cables and the right size? This particular question can bite a lot of people in the but.
I have the battery in trunk, and have only one ground cable, because the motor mount are metal without rubber.
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Re: Piston Wall Clearance
[Re: RapidRobert]
#110381
08/26/08 12:20 AM
08/26/08 12:20 AM
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Joined: Jan 2003
Posts: 309 Maracaibo,Venezuela
GTMaracucho
OP
super street
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OP
super street
Joined: Jan 2003
Posts: 309
Maracaibo,Venezuela
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Quote:
In your 1st post you have .007" ptw with forged pistons. What do you mean "in resume"?
I'm confuse, .007" PTW is goood?? or .015" is the correct clearance??
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Re: Piston Wall Clearance
[Re: RapidRobert]
#110383
08/26/08 12:33 AM
08/26/08 12:33 AM
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Joined: Jan 2003
Posts: 309 Maracaibo,Venezuela
GTMaracucho
OP
super street
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OP
super street
Joined: Jan 2003
Posts: 309
Maracaibo,Venezuela
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Quote:
in your 1st post you have .007 piston to wall clearance with your forged pistons, & in the next post you have .012 top ring end gap clearance, correct so far?
Yes sir
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Re: Piston Wall Clearance
[Re: RapidRobert]
#110385
08/26/08 01:32 AM
08/26/08 01:32 AM
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Joined: Jan 2003
Posts: 309 Maracaibo,Venezuela
GTMaracucho
OP
super street
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OP
super street
Joined: Jan 2003
Posts: 309
Maracaibo,Venezuela
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Quote:
on their(KB) site they want .004 piston to wall clearance on the top ring for each inch of bore with forged(not hypereutectic) pistons(If I am reading their site correctly,it was a little confusing) which would put you at .016" for a street normally aspirated application(the top ring). At .012 you are tighter than they recommend but I dont know if your rings are butting & causing the problem or not but the more I think about it I would be inclined to think the rear mounted battery & long cables are the culprit. When its warmed up it cranks too slow & this is the issue right? At that point in time could you pull the plugs & see how it cranks & also with the plugs out put a socket & breaker bar(or torque wrench) on the front harmonic dampener bolt & see how hard it is to turn ? or easier yet at that point in time get a jump directly to your starter & dont use your trunk battery & see what it does. It is midnight here & I am going to have to sign off. I will get back to you tomorrow. Post what you find out.
Thanks for your help..... Now I have in my hands somethink to do tomorrow
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Re: Piston Wall Clearance
[Re: GTMaracucho]
#110387
08/26/08 02:48 AM
08/26/08 02:48 AM
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Joined: Feb 2007
Posts: 2,315 MOPAR HEADQUARTERS IN ALDEN NY
hemigod426
top fuel
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top fuel
Joined: Feb 2007
Posts: 2,315
MOPAR HEADQUARTERS IN ALDEN NY
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ptw on kbs is 2-4 thou there designed to be tighter than forged i set up at 4-6 thou ptw, its where the top ringland in piston is machined that it comands twice the end gap for expansion if you dont follow that piston top will break off when under load and up to temp
MOPAR OR NO CAR
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Re: Piston Wall Clearance
[Re: hemigod426]
#110388
08/26/08 08:54 AM
08/26/08 08:54 AM
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Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
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I Live Here
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Posts: 16,376
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You didn't read the original post. He says the pistons are KB FORGED. He says he has 0.007" piston-to-wall clearance, I think that's too much, but it's the maximum in the KB chart for drag racing, 4" piston. He says he has ring gap of 0.012". The chart says 0.004" per inch of bore diameter, that would be 0.016" so the ring gaps are too tight.
R.
Last edited by dogdays; 08/26/08 08:58 AM.
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Re: Piston Wall Clearance
[Re: dogdays]
#110389
08/26/08 10:18 AM
08/26/08 10:18 AM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Marysville, O-H-I-O
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he also said hard turning when hot...could it be a timing issue instead of a clearance issue?
**Photobucket sucks**
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Re: Piston Wall Clearance
[Re: RapidRobert]
#110391
08/26/08 11:13 AM
08/26/08 11:13 AM
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Joined: Feb 2003
Posts: 12,675 Columbia, CT
moper
I Live Here
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I Live Here
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Posts: 12,675
Columbia, CT
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.007 on the pistons is ok, loose and mabye noisey when started cold, but ok. .012 on the top ring is bad, and technically, leaving the 2nd ring a little bigger than the top will help ring seal. So with a 360 (4.03 when bored .030 over) I'd be setting the top ring at .017 and the 2nd ring at .020. Also, always round up when you get a "point something" (4.03x.004= .01612, or .017). You want to err to the large side on any performance engine.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Piston Wall Clearance
[Re: RapidRobert]
#110392
08/26/08 01:03 PM
08/26/08 01:03 PM
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Joined: Jan 2003
Posts: 309 Maracaibo,Venezuela
GTMaracucho
OP
super street
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OP
super street
Joined: Jan 2003
Posts: 309
Maracaibo,Venezuela
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Quote:
Quote:
he also said hard turning when hot...could it be a timing issue instead of a clearance issue?
excellent idea! Could it actually be something thatsimple as overadvanced timing On our stock car we had to engage the starter THEN switch on the ign to get it to crank when things were hot. If he grounds the coil wire & then cranks we'll have the ans to that.
I have 34° and MSD 6 Digital Plus with retard option
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Re: Piston Wall Clearance
[Re: RapidRobert]
#110399
08/26/08 09:55 PM
08/26/08 09:55 PM
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Joined: Jan 2003
Posts: 27,421 Balt. Md
383man
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Posts: 27,421
Balt. Md
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When its hot and cranking slow unhook the MSD box and then crank it to verify if it is an over advanced ign. You have forged pistons and not hypertech pistons so then I agree the top ring gap should be .016 to .017 and the .007 Piston to wall clearence is a bit on the loose side at .007 but it will work. Will most likely be a bit noisey when cold like was said but it will be ok as it's not to tight. If you find the eng is tight and its not the ign then I would think about that .012 top ring gap you have in it. Good luck , Ron
Last edited by 383man; 08/26/08 09:56 PM.
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Re: Piston Wall Clearance
[Re: 383man]
#110400
08/27/08 07:18 PM
08/27/08 07:18 PM
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Joined: Jan 2003
Posts: 309 Maracaibo,Venezuela
GTMaracucho
OP
super street
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OP
super street
Joined: Jan 2003
Posts: 309
Maracaibo,Venezuela
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OK Gents.... Today I talked with my mechanic and he said that the first ring is .017" & second is .022". I started and warm up the engine, then I pull out all spark plugs and turn manually and the engine is very..very hard to turn. Maybe on this week end we pull out the engine and check everything again. I'm thinking go to more clearance on Piston to wall, what about .010"??
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Re: Piston Wall Clearance
[Re: hemigod426]
#110405
09/10/08 09:56 PM
09/10/08 09:56 PM
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Joined: Jan 2003
Posts: 309 Maracaibo,Venezuela
GTMaracucho
OP
super street
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OP
super street
Joined: Jan 2003
Posts: 309
Maracaibo,Venezuela
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Hi, I made new electric system (new cables, relays, etc) and BINGO the car can start OK. Thanks a lot for the support, and this weekend I will test the car in the race way. Regards....Jose
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