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Main Bearing Clearance; Am I too tight ???
#540798
11/30/09 01:02 AM
11/30/09 01:02 AM
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Joined: Jul 2006
Posts: 4,319
Puyallup, WA
StealthWedge67
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,319
Puyallup, WA
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This 451 will be a 10.25:1 street strip motor with a goal of around 500hp, and will likely see between 6000 & 6500 RPM.
413 crank turned down to "B" std.; 400 Block w/ fresh mainline hone.; Cleavite P bearings, std.: ARP main studs.
I don't own a micrometer & bore guage. Plastiguage says I'm between .015 & .020, and is consistant at all journals. Am I too tight? Should I take the crank back to have the main journals polished a bit?
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: Main Bearing Clearance; Am I too tight ???
[Re: StealthWedge67]
#540801
11/30/09 01:11 AM
11/30/09 01:11 AM
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Joined: Aug 2003
Posts: 43,180
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,180
Bend,OR USA
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I would run .003 and have ran .0038 with no problems on full groove sets. Are the "P" bearings full groove or 3/4 or 1/2 groove? You probally need to have some with a set of inside mikes and outside mikes or a dial bore gauge measure it for you  Don't take a chance on anything your not sure of,  it could kill you if it fails while racing 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Main Bearing Clearance; Am I too tight ???
[Re: Cab_Burge]
#540802
11/30/09 01:18 AM
11/30/09 01:18 AM
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Joined: Jul 2006
Posts: 4,319
Puyallup, WA
StealthWedge67
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,319
Puyallup, WA
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Yes, I did mean .0015 & .002. And yes, P bearings are full groove.
I was also hoping to see .0025. You guys seem to be of the same opinion as I. Hmmm. I think I'll take the block & crank back to my machinist & have him measure it. If my plastiguage is accurate, can polishing get me to where I need to be?
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: Main Bearing Clearance; Am I too tight ???
[Re: TS3303]
#540804
12/01/09 01:50 AM
12/01/09 01:50 AM
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Joined: Jul 2006
Posts: 4,319
Puyallup, WA
StealthWedge67
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,319
Puyallup, WA
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I called the machinist today..... He was a bit insulted at even the thought that I would trust a piece of plastigage over his work. He said his "journal" on my motor showed .0023 - .0025 on the mains. "Bring it down here if you want, I'll mic it for ya.... maybe I'll charge ya, maybe I wont, depends on what sort of mood I'm in" was his comment.  I don't want to insult the guy, but I also want to be 100% positive that the motor I'm assembling is correct. Hope he doesn't get all pissy with me... Question is, if clearances are a bit under where they should be, what can be done about it? 
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: Main Bearing Clearance; Am I too tight ???
[Re: Triple Threat]
#540806
12/01/09 02:35 AM
12/01/09 02:35 AM
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Joined: Apr 2004
Posts: 1,981
SE Michigan
TS3303
top fuel
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top fuel
Joined: Apr 2004
Posts: 1,981
SE Michigan
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if he doesn't respect your fears it's time for another machinist. Tell him you can only afford to do this once and you want to make sure it's right. my machinist is a "confident" sob  , but neither of us are afraid to tell each other what we think. Then we go out to the track and have a good time. work is not personal it's professional.
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Re: Main Bearing Clearance; Am I too tight ???
[Re: R70RUNNER]
#540809
12/01/09 09:20 AM
12/01/09 09:20 AM
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Joined: Jan 2003
Posts: 21,072
Niles , Ohio
therocks
oh wait.but hey.lets see.oh yeah.
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oh wait.but hey.lets see.oh yeah.
Joined: Jan 2003
Posts: 21,072
Niles , Ohio
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My machinist is just the opposite.If I have any questions he will double and even triple check it.He spent like 2 hours just checking the keepers and springs on my new Stealth heads even though I wasnt going to use them.He just wanted to do it for his own knowledge.A good machinist is priceless.That and his prices are super reasonable.Some Ohio guys here know him and all say the same thing .He is one of the best.Rocky
Chrysler Firepower
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Re: Main Bearing Clearance; Am I too tight ???
[Re: StealthWedge67]
#540811
12/01/09 10:00 AM
12/01/09 10:00 AM
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Joined: Feb 2004
Posts: 1,093
Long Beach, CA
Mike Swann
super stock
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super stock
Joined: Feb 2004
Posts: 1,093
Long Beach, CA
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The present machinist's attitude is unaceptable and you should tell him that. At this time, I would find another competent machinist, tell him to check the work that was done and offer to pay him for the inspection. If it is that tight, there is a good chance it will eat a bearing.
8.30's @3400 lbs
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Re: Main Bearing Clearance; Am I too tight ???
[Re: StealthWedge67]
#540812
12/01/09 11:05 AM
12/01/09 11:05 AM
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Joined: Jan 2003
Posts: 75,012
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,012
U.S.S.A.
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Quote:
I called the machinist today..... He was a bit insulted at even the thought that I would trust a piece of plastigage over his work. He said his "journal" on my motor showed .0023 - .0025 on the mains. "Bring it down here if you want, I'll mic it for ya.... maybe I'll charge ya, maybe I wont, depends on what sort of mood I'm in" was his comment.
I don't want to insult the guy, but I also want to be 100% positive that the motor I'm assembling is correct. Hope he doesn't get all pissy with me... Question is, if clearances are a bit under where they should be, what can be done about it?
guess what , that's his problem , not yours . I have a block here that needs to go to the next overbore and a set of file fit rings that are useless because the guy that assembles the blocks at the shop I USED TO USE didn't check the bosses work ... hourglass bores .0025 OVERSIZE  ...
I don't care who does the work ... CHECK IT ... if the guy gets insulted then that's his problem , even the best make mistakes ...
but he does have a point , checking his work with PLASTIGUAGE ... 
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Re: Main Bearing Clearance; Am I too tight ???
[Re: StealthWedge67]
#540813
12/01/09 12:20 PM
12/01/09 12:20 PM
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Joined: Feb 2007
Posts: 5,080
organ
maximum entropy
master
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master
Joined: Feb 2007
Posts: 5,080
organ
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Quote:
I called the machinist today..... He was a bit insulted at even the thought that I would trust a piece of plastigage over his work. He said his "journal" on my motor showed .0023 - .0025 on the mains. "Bring it down here if you want, I'll mic it for ya.... maybe I'll charge ya, maybe I wont, depends on what sort of mood I'm in" was his comment.
I don't want to insult the guy, but I also want to be 100% positive that the motor I'm assembling is correct. Hope he doesn't get all pissy with me... Question is, if clearances are a bit under where they should be, what can be done about it?
i wouldn't be surprised if your machinist is right- plastigage ain't worth a damn anymore, imo. in fact, it's decline is responsible for me running out and getting myself a dial bore gauge. in the olden days, plastgage was different. now it just feels like a piece of wax or some such nonsense.
for what is the good life if not doing things thoughtfully?
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Re: Main Bearing Clearance; Am I too tight ???
[Re: B G Racing]
#540815
12/02/09 02:52 PM
12/02/09 02:52 PM
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Joined: Jul 2006
Posts: 4,319
Puyallup, WA
StealthWedge67
OP
master
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OP
master
Joined: Jul 2006
Posts: 4,319
Puyallup, WA
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Well, chalk one up for the machinist in this case. Just got back from the shop, we torqued up the mains & rods, and measured all the journals.... Clearances at mains were between .0021 & .0023. Rods were all at .0022 or .0023. I'm new at this, and its important to note that prior to machining, I never gave him any specific clearance requests. He said with a performance motor, he shoots for the high side of the bearing manufacturers reccomendations, which is exactly where its all at. I'm satisfied. And its also worth noting that he treated me very well when I showed up for the double-check process. In the words of Emily Litella: Never Mind 
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: Main Bearing Clearance; Am I too tight ???
[Re: StealthWedge67]
#540816
12/02/09 03:08 PM
12/02/09 03:08 PM
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Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
B G Racing
master
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master
Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
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Quote:
Well, chalk one up for the machinist in this case. Just got back from the shop, we torqued up the mains & rods, and measured all the journals.... Clearances at mains were between .0021 & .0023. Rods were all at .0022 or .0023.
I'm new at this, and its important to note that prior to machining, I never gave him any specific clearance requests. He said with a performance motor, he shoots for the high side of the bearing manufacturers reccomendations, which is exactly where its all at.
I'm satisfied. And its also worth noting that he treated me very well when I showed up for the double-check process.
In the words of Emily Litella: Never Mind
Did he actually mic each or did he plastic gage them?
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