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#1
03-28-2013, 08:30 PM
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butler ross 4.155 piston measurements?
Anyone use a set of butler forged stroker pistons and mic them. Mine are coming up about 4.148 to 4.149 just wondering what everyone else is getting. I think my machine shop has my bores to tight for these pistons.
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#2
03-28-2013, 08:44 PM
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They measure 4.150 with my mic. They will live happy anywhere between .0045 and .006 clearance. Mics may vary. Set the mic to the piston, set the dial bore gauge to the mic. This way it doesn't matter what the number on the mic says. The dial bore gauge will show your actual clearance. If your machinist has any questions, have him call me.
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#3
03-28-2013, 09:29 PM
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Where are you measuring the pistons? That can make a difference. Measure the skirt (90 degrees from pin) about an inch up from the bottom of the skirt. Should measure 4.150". Bore to 4.155". I personally don't think I've ever recieved a set of Ross pistons that were off more than .0005", but that doesn't mean it can't happen. What did they bore it to if you don't mind my asking?
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#4
03-29-2013, 08:11 AM
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bore
Bored by a reputable pontiac engine builder but it appears to be 4.152-4.1525 checking with a mic on the pistons and a dial bore gauge I can only get .002 to .0025 clearance. Was bored and honed with a torque plate. Looks like another 3 hour trip each way to the machine shop to get right. I wish I had the money to buy my own machine equipment. Thanks, Paul.
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#5
03-29-2013, 10:43 AM
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Measure twice - bore once
Measure twice - finish hone How can a machine shop finish hone without measuring?
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GT37 3625lbs..Fastest bench seat, column shift, all steel,no power adders car at Norwalk 1.35 w/29.5x10.5x15 6.42 @ 109 10.09 @ 133 |
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#6
03-29-2013, 01:58 PM
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I think Ross has different spots to measure depending on the piston blank used so be sure you have the correct one.
Some old Venolias I got in a motor take 0.008 at the oil ring. They look kind of heavy also.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
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#7
03-30-2013, 02:14 AM
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Whittmore has my Butler Ross 4.155 pistons and has the clearance at.006. Block
filled up the the bottom of the bottom of the water pump holes as per instructions. The ring gaps had to be opened up .002 also. Thing is, if I wanted to run NO2 I would have had to run .002 more clearance on the pistons the ring gap too. Heat does some things too rings and pistons. .008 is a lot but that is what I would have to do unless I wanted to have the end gaps touch and the top ripped off the pistons. Dan said that at .006 it would rattle a tiny bit until warm but that is the price you pay if you want to bottom fil the block. The manufacturers instructions are there for a reason. |
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