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Minimum bearing clearance for 7200 rpm or so

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Author	Topic: Minimum bearing clearance for 7200 rpm or so
n2oMike Gearhead Posts: 2419 From: Spencer, WV Registered: Jan 2001	posted 03-04-2005 11:52 AM The shortblock is done and I'm getting ready to bolt the heads on and button the thing up... but I'm paranoid. I've got just a touch under 0.002" and would like to have 0.0025" to 0.0030". (got screwed by the crank grinder) Okay... What's the verdict? Should I run thinner oil? I usually use Mobil 1 15/50. It's a Boss 302 crank, and is already 0.030" on the mains and 0.020" on the rods. To fix it, I'd have to get it welded up and reground, and buy new bearings. Of course, I'd also have to disassemble/reassemble the engine again. ------------------ Mike Burch 66 mustang real street 302 4-speed 289 heads 10.63 @ 129.3 http://www.geocities.com/carbedstangs/cmml_mburch.html http://www.fortunecity.com/silverstone/healey/367 http://www.mustangworks.com/cgi-bin/moi-display.cgi?220 IP: Logged
Mpcoluv Gearhead Posts: 1278 From: Charlotte NC usa Registered: Apr 2001	posted 03-04-2005 12:03 PM Why can't you polish the crank? IP: Logged
Hans olsson Gearhead Posts: 622 From: Sweden Registered: Apr 2000	posted 03-04-2005 12:19 PM Take the rods big end to the max. Hans ------------------ VIN 1F05M139343 71 Mach 1 Ram-Air 351C 4V 285 HP F-G/Stock Aut Stockers are way cool! IP: Logged
89_coupe Gearhead Posts: 228 From: Ontario (Upstate), NY Registered: Mar 2001	posted 03-04-2005 12:22 PM I would definitely use 10/30 oil or something thin along those lines. I specifically made my bearing clearances tight .002-.0025 rods/mains with a known shift point of 7500-7800 RPM with my 393 using 10/30 oil. My oil pressure is good and even when fully warmed up it is maxed at 65PSI at idle or 7800RPM. I use to run .003" on my rods/mains with 20/50 oil but I prefer better oil control from tighter tolerances. Mine are the 3" mains and 2.31" rod journals so your small 302 journals I think are just fine with .002 or a tad under using 10/30 or even 5W30 oil. I wouldn't worry one bit as long as all the clearances are uniform. Just don't use thick oil in there. ------------------ Kent '68 Falcon wagon stock 289 '65 Fairlane 500 wagon 10.5:1 351W '78 Fairmont wagon 10.5:1 302 '76 Pinto wagon 392 stroke '01 Focus SE DOHC 2.0L '04 Explorer XLT 4.6 3.73 trac lock What is this FE fixation for which there seems to be no real cure? Something about wanting to spend twice as much money to go half as fast for one third the number of passes between explosions and not being able to find parts to fix it when it does explode. Pinto 392W 15:1, Iron Pro Topline 64/215s ported to 237cc, angle milled .115" to 52.5cc chambers with 2.08/1.6 valves, ported Super Victor, 1.72 rockers, Isky solid roller (290/300 adv, 256/266 at .050", .650" net lift, 108LSA/108 ICL), Crane Pro Series solid roller lifters, 9375 1050 Dominator, Victor water pump, billet 9 key timing set, custom 1 7/8"-2" step headers, 3.5" H-pipe and Hooker Aero Chamber mufflers, C4 w/9" 5000 stall, 4.30 gears, 28/10.5/15 MT ET Drags, 3200#s w/o driver. IP: Logged
Moneymaker Administrator Posts: 25883 From: Lyons, IL, USA Registered: May 99	posted 03-04-2005 12:22 PM Well Mike, for starters you know that you can't break it in on synthetic oil. I would get some "looser" bearings if it were me. Try these guys http://www.kingbearings.com/ ------------------ Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,'04 &'05 First SS/MA in the TENS! IHRA division 5 Superstock Champion Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked." Quote #2: "Make sure brain is in gear before engaging mouth!" Quote #3: "If you can't run with the big dogs, stay on the porch!" www.moneymakerracing.com IP: Logged
89_coupe Gearhead Posts: 228 From: Ontario (Upstate), NY Registered: Mar 2001	posted 03-04-2005 12:25 PM quote: Originally posted by Hans olsson: Take the rods big end to the max. Hans That just causes less crush on the bearing shells giving a greater chance of a spun bearing. Always keep the big end at the middle of the tolerance range or tighter for maximum bearing crush. Maybe some undersize bearings are availabe in .001" oversize increments? ------------------ Kent '68 Falcon wagon stock 289 '65 Fairlane 500 wagon 10.5:1 351W '78 Fairmont wagon 10.5:1 302 '76 Pinto wagon 392 stroke '01 Focus SE DOHC 2.0L '04 Explorer XLT 4.6 3.73 trac lock What is this FE fixation for which there seems to be no real cure? Something about wanting to spend twice as much money to go half as fast for one third the number of passes between explosions and not being able to find parts to fix it when it does explode. Pinto 392W 15:1, Iron Pro Topline 64/215s ported to 237cc, angle milled .115" to 52.5cc chambers with 2.08/1.6 valves, ported Super Victor, 1.72 rockers, Isky solid roller (290/300 adv, 256/266 at .050", .650" net lift, 108LSA/108 ICL), Crane Pro Series solid roller lifters, 9375 1050 Dominator, Victor water pump, billet 9 key timing set, custom 1 7/8"-2" step headers, 3.5" H-pipe and Hooker Aero Chamber mufflers, C4 w/9" 5000 stall, 4.30 gears, 28/10.5/15 MT ET Drags, 3200#s w/o driver. IP: Logged
Hans olsson Gearhead Posts: 622 From: Sweden Registered: Apr 2000	posted 03-04-2005 12:39 PM TRW rod bearings number CB 948P has .001 more clearance. Hans ------------------ VIN 1F05M139343 71 Mach 1 Ram-Air 351C 4V 285 HP F-G/Stock Aut Stockers are way cool! IP: Logged
Moneymaker Administrator Posts: 25883 From: Lyons, IL, USA Registered: May 99	posted 03-04-2005 12:40 PM quote: Originally posted by Hans olsson: TRW rod bearings number CB 948P has .001 more clearance. Hans There ya go. That's a start. ------------------ Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,'04 &'05 First SS/MA in the TENS! IHRA division 5 Superstock Champion Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked." Quote #2: "Make sure brain is in gear before engaging mouth!" Quote #3: "If you can't run with the big dogs, stay on the porch!" www.moneymakerracing.com IP: Logged
n2oMike Gearhead Posts: 2419 From: Spencer, WV Registered: Jan 2001	posted 03-04-2005 03:44 PM I wasn't going to break it in with synthetic. I had just planned on running it later. I'll have to check in to those rod bearings. I wasn't aware of any FORD bearings that gave EXTRA clearance. Does anybody offer them for the mains? Does King? The 0.030" under mains and 0.020" rods might be tough to work with. I know the 3/4 groove racing bearings are no longer available in those oversizes. After getting the crank back and finding it wasn't ground down enough, I went back to the shop to have it ground down some more. They acted like it was not enough to grind, but too much to polish. They went ahead and ground the mains a tad and polished the rods. This brought the clearances up close to 0.002". As much as I hate to, I guess I'm going to have to pull this engine back apart. One part of me just wants to dog the crap out of it until it flys through the fenderwells! Another part doesn't want to get killed by an engine grenading in front of a 4-speed, spilling oil all over the road and possibly locking the rear tires up. I'm also thinking about getting a different camshaft for it. This one measures 242/254, and I don't think I need that much of a split... even with the nitrous. You can probably see why I haven't been that motivated to get this thing finished. TONS of problems with that #$%^$ engine. I hate even looking at it. Oh well. The sooner it dies, the sooner a stroker takes its place. ------------------ Mike Burch 66 mustang real street 302 4-speed 289 heads 10.63 @ 129.3 http://www.geocities.com/carbedstangs/cmml_mburch.html http://www.fortunecity.com/silverstone/healey/367 http://www.mustangworks.com/cgi-bin/moi-display.cgi?220 [This message has been edited by n2oMike (edited 03-04-2005).] IP: Logged
Butch Jennings Gearhead Posts: 624 From: No. California Registered: Apr 2000	posted 03-04-2005 11:23 PM Why not build the stroker now and sell off the crap that's got you so pissed off? Seems cheaper in the long run than building this one hoping to blow up so you can do the stroker. Butch IP: Logged
n2oMike Gearhead Posts: 2419 From: Spencer, WV Registered: Jan 2001	posted 03-05-2005 12:24 AM It pisses me off, but it has me determined all at the same time. I will win. The engine will end up doing what I want, or I'll kill it trying to make it do so. It's a crazy world between these ears... You think I'm stubborn... You should see my 3yr old daughter! Everything has to be just so. She's a freakin' RAIN MAN or something. Thanks for all the advice, and any more that happens to come along! ------------------ Mike Burch 66 mustang real street 302 4-speed 289 heads 10.63 @ 129.3 http://www.geocities.com/carbedstangs/cmml_mburch.html http://www.fortunecity.com/silverstone/healey/367 http://www.mustangworks.com/cgi-bin/moi-display.cgi?220 IP: Logged
rustang@home Journeyman Posts: 94 From: Clarion, PA Registered: Jan 2004	posted 03-05-2005 05:51 AM I know it's too late now, but for the next crank you have done, make sure the machine shop writes down on there work order that you want your crank turned for .0025-.0030 clearance rod and mains. That worked out for me once, when they hadn't put enough clearance in there, I took the crank back, we looked at the work order and clearly the clearance note was on there. they took more off the crank and never questioned it. IP: Logged
n2oMike Gearhead Posts: 2419 From: Spencer, WV Registered: Jan 2001	posted 03-05-2005 11:57 AM I did. ------------------ Mike Burch 66 mustang real street 302 4-speed 289 heads 10.63 @ 129.3 http://www.geocities.com/carbedstangs/cmml_mburch.html http://www.fortunecity.com/silverstone/healey/367 http://www.mustangworks.com/cgi-bin/moi-display.cgi?220 IP: Logged
Moneymaker Administrator Posts: 25883 From: Lyons, IL, USA Registered: May 99	posted 03-05-2005 12:50 PM Mike, I really feel for you buddy. And people wonder why I send my stuff all the way to Arkansas. Accu-Crank is dead nuts everytime! ------------------ Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,'04 &'05 First SS/MA in the TENS! IHRA division 5 Superstock Champion Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked." Quote #2: "Make sure brain is in gear before engaging mouth!" Quote #3: "If you can't run with the big dogs, stay on the porch!" www.moneymakerracing.com IP: Logged
n2oMike Gearhead Posts: 2419 From: Spencer, WV Registered: Jan 2001	posted 03-05-2005 02:37 PM I see King sells 0.040" over bearings... I REALLY hate to tear this engine apart again, but it looks like I'm going to have to before I feel safe flogging the sh*t out of it. I ran the other engine like it was some sort of dirt bike. It got run as hard as it would possibly run everytime it hit the street. It's a hotrod.... no sense in puttering around like some sort of 'poser'. If this engine is going to live through that abuse, I might as well tear it down and do it right (while its out of the car) than have to do it again later. There's a talented machinist semi local here who does good block and crank work. A buddy of mine has a 383 chevy built by him that has lived a LONG hard life and still runs great. The guy builds dirt track engines that live, so I might go have a chat with him and feel him out about the crank. He might also get the nod for the bottom end of this 427 FE stroker (428 crank) that I've got myself into building. I got commited to it a long time ago, and we've been gathering parts for quite some time. He finally bought a Fairlane to put it in, and wants it by the end of the summer. Thanks! ------------------ Mike Burch 66 mustang real street 302 4-speed 289 heads 10.63 @ 129.3 http://www.geocities.com/carbedstangs/cmml_mburch.html http://www.fortunecity.com/silverstone/healey/367 http://www.mustangworks.com/cgi-bin/moi-display.cgi?220 IP: Logged
Moneymaker Administrator Posts: 25883 From: Lyons, IL, USA Registered: May 99	posted 03-05-2005 02:40 PM FYI, All of my stuff is .030 or .040 under. ------------------ Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,'04 &'05 First SS/MA in the TENS! IHRA division 5 Superstock Champion Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked." Quote #2: "Make sure brain is in gear before engaging mouth!" Quote #3: "If you can't run with the big dogs, stay on the porch!" www.moneymakerracing.com IP: Logged
Buster Gearhead Posts: 1437 From: Hurricane alley Registered: May 2002	posted 03-05-2005 05:36 PM Mike, if it doesn't feel right....don't do it! If it didn't bug you, you wouldn't have made this post. Now is the time to fix it. I'm still kicking myself for not fly cutting a set of pistons. I knew it would come back to bite me if I wanted to change camshafts later on... and it did. btw, I've used king bearings for years and wouldn't use anything else unless I had to. good luck Mike IP: Logged

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