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#1
05-06-2003, 05:13 PM
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So I lube up the bearings, give the main bolts a swipe with some 30w on a rag, trim the BOP seal to .018" and put the silicone in the anti-rotation holes and a little bit on the ends of the seal, lube the seal lip, install the crank, torque everything down and check the endplay.
.016"!! Holy Crap! Now what? Is this crank toast? If so, I might just have to throw it through the window of the shop that did the work on it. It was a virgin 428 crank with no signs of abnormal wear when I took it to them, got it back .020" under on the mains (they couldn't tell me why) and now this...  ---------------------------- '72 Formula 400 12.77 @ 108 / 234/244 cam / Q-jet / 3840# / 3.23s / street tires (not DRs) '73 Firebird 400/4-speed
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---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
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#2
05-06-2003, 05:13 PM
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So I lube up the bearings, give the main bolts a swipe with some 30w on a rag, trim the BOP seal to .018" and put the silicone in the anti-rotation holes and a little bit on the ends of the seal, lube the seal lip, install the crank, torque everything down and check the endplay.
.016"!! Holy Crap! Now what? Is this crank toast? If so, I might just have to throw it through the window of the shop that did the work on it. It was a virgin 428 crank with no signs of abnormal wear when I took it to them, got it back .020" under on the mains (they couldn't tell me why) and now this... ---------------------------- '72 Formula 400 12.77 @ 108 / 234/244 cam / Q-jet / 3840# / 3.23s / street tires (not DRs) '73 Firebird 400/4-speed
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---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
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#3
05-06-2003, 05:23 PM
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What does the thrust surface on the crank look like. Is there a groove in it or something or maybe the bearings are the wrong ones or something. Try a diff set of thrust bearings. You should always test fit everything before final assembly.
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#4
05-06-2003, 05:31 PM
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Thrust surface on the crank looks fine, no grooves or anything. It looked fine when I took it into the machine shop too. As mentioned, this looked like a perfectly good 428 crank that I fully expected to clean up with just a polish, or maybe a .010" turn.
As for checking before final assembly, that's what I'm doing. But, it didn't make much sense to me to lube up all the bearings and install the crank only to have to pull everything apart again to install the rear seal if everything checked out fine, which it always has before. Not sure how the bearings could be the wrong ones. Aren't all the large journal engines the same when it comes to bearings? ---------------------------- '72 Formula 400 12.77 @ 108 / 234/244 cam / Q-jet / 3840# / 3.23s / street tires (not DRs) '73 Firebird 400/4-speed
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---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
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#5
05-06-2003, 06:41 PM
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I recall reading an article on a 455 rebuild where the crank endplay fell out of spec and was corrected with a different thrust bearing.Not sure if it was just from a different set or a special order. I wondered how you could adjust end play with bearings as I would assume that they were all quite precise and identical
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#6
05-06-2003, 06:44 PM
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Check with your parts dealer to see if you can get the thrust bearing with the thrust surface over size. If I can remember I'll look in my bearing book in the morning.
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#7
05-06-2003, 07:28 PM
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I can't help you. Pull out a copy of your favorite Indian mag and check in the back for some Indian rebuilders. Call the best.
connman
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connman |
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#8
05-07-2003, 01:17 PM
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Get some shim stock and make a shim to go under the thrust side of the bearing. Nunzi told me to do this many years ago.
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It's ok, I understand, this ain't no never never land.... |
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#9
05-08-2003, 06:31 AM
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Hey Will I have two crank that have this exact problem, the worst one I welded up and it's at the machine shop being turned. I'll let you know how it turns out. It's kind of a bitch to get to the thrust flange, I was going to use my small welder but didn't have the wire on hand so I used my 250 amp Lincoln which was not the best choice. Anyway I got plenty o bead on the surface. I used a copper shim wrapped around the journal and a hose clamp on top that to keep from FUBARing the surface while welding.
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#10
05-08-2003, 07:10 AM
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Have seen a couple of "virgin" 428 cranks come in right at .012". It is possible that the machinist "brushed" against the thrust surface when turning the crank and opened up the clearance some. Found the same thing last year on a 455 crank I bought "fresh" from the machine shop. I would not run the crank, about the only option is to weld it and regrind the thrust. I'm not aware of any oversize thrust bearings available.....Cliff
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If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
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#11
05-13-2003, 06:55 AM
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Ok I got the crank back, it cost me 120 bills to turn because the machinist was probably not used to doing this and it took longer than expected. Arrgh! I though he would have used HSS to rough it in then switched to carbide but the "pros" all use indexable carbide inserts on every job that comes thru the door. Chipped a lot of inserts..duh. And they don't have toolpost grinder. So anyway the lesson is to get the shop to grind it, I thought I might be able to avoid a crank grinding fee but I guess not. Oh well I learned something new from my adventure. Good news is it's in spec but the surface is not exactly true due to the inclusions in the deposited material. I'm running it though. It's a 350 Chevy so you don't have to worry
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#12
05-13-2003, 11:53 AM
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King Bearings are available with oversized thrust. I measured the crank end-play of my 400 at .008" with new FM bearings and .004" with King. King states on their site that this is a feature of their bearings, to compensate for some thrust wear.
67 GTO, 428, Q-Jet, TH400, 3.42, 12.50/107.5, whisper quiet 67 GTO, 400, Q-Jet, M20, 3.23, 14.02/98.7, loud & obnoxious |
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#13
05-13-2003, 12:24 PM
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What is KINGS website address.
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#14
05-13-2003, 12:43 PM
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12.84 @ 106.89 with street radials. 12.63 @ 108.39 on drag radials. |
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#15
05-13-2003, 12:46 PM
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Look for the MaxFlange line. That appears to be the one.
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12.84 @ 106.89 with street radials. 12.63 @ 108.39 on drag radials. |
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#16
05-13-2003, 06:47 PM
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Will you sure seem to have rotten luck on these things !! I sure hope you get something to fix it. Let us know how it comes out.
1977 TA SE y82 I think. T-tops Black on black best ET [email protected] on DR's |
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#17
05-13-2003, 07:16 PM
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I know you need the large journal bearings but the part number for small journal King main bearings is: MB5523AM 0X0 where x = undersize. The AM suffix denotes the bi-metal (no copper) construction.
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