Hey.. everyone loves an engine failure mystery - Brand X
#3061538
07/21/22 11:57 PM
07/21/22 11:57 PM
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Joined: Jan 2003
Posts: 8,182 Detroit, MI
CokeBottleKid
OP
master
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OP
master
Joined: Jan 2003
Posts: 8,182
Detroit, MI
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Sooo this one has me a bit puzzled... Foxbody 302 build, has maybe 5-7k miles on it. Re-ring frankenstein build, block I got out of the junkyard and rotating assembly I got from another fox motor. Everything was cleaned properly, crank polished by hand and on lathe, block dingle ball honed, all clearances checked (bout 1.5-2 thou on mains and rods). Had a vibration develop at 4k plus RPM recently so stopped driving it and took it out. #5 main is toast, all the rods are fine though, none of the bearings look great but #5 is definitely the culprit. Usually with oil starvation a rod dies first so not sure what to think about this one, it clearly is a 50z crank and I had 50 oz weights on the flywheel and balancer... (SB fords have a 28oz and 50 oz external balance depending on year etc) 2 things that stick in my head: 1 - The starter bendix sticks for a couple seconds after starting then retracts... This actually started with the last motor (which blew up) I actually had drilled the starter holes out when I first put this motor together to get the bendix to return properly, just firing the bendix manually with a "lone wolf 3000" it would pop back immediately but when the motors rolling it takes a couple seconds... But perhaaaps it has been shoving the crank into the main during cranking... 2 - I had raced some audi looking mercedes a couple nights before the vibration developed... it was a deep freeway pull soooo it's possible the pan was sucked dry... that said it was full on oil, and I'm only spinning it to 6k on with a stock oil pump and pan... surely stock SBFs can handle 6k with a stock pan/pump right? It's always been my experience though that rod bearings die before mains sooo *shrug*
Last edited by CokeBottleKid; 07/22/22 12:00 AM.
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Re: Hey.. everyone loves an engine failure mystery - Brand X
[Re: CokeBottleKid]
#3061568
07/22/22 09:07 AM
07/22/22 09:07 AM
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Joined: Jan 2003
Posts: 1,768 Windsor, ON, Canada
Diplomat360
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,768
Windsor, ON, Canada
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I know nothing about Fords...but did you check the bearing clearance on EACH journal? Crank is straight, yes? So runout was checked and in-spec?
Beyond this, perhaps looking at restrictions in the oil feed is the next place to go? What does that routing look like on the 302? Where in that feed sequence is #5: start or end?
Last, visually it just looks to me like #5 was simply too tight, or there was a pile of dirt that got dumped into that somehow??? (maybe stuff was trapped in the oil feed passage and when things came up to pressure it all went straight out)
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Re: Hey.. everyone loves an engine failure mystery - Brand X
[Re: CokeBottleKid]
#3061616
07/22/22 12:16 PM
07/22/22 12:16 PM
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Joined: Mar 2010
Posts: 1,061 Atlanta, GA
mgoblue9798
super stock
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super stock
Joined: Mar 2010
Posts: 1,061
Atlanta, GA
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Sooo this one has me a bit puzzled... Foxbody 302 build, has maybe 5-7k miles on it. Re-ring frankenstein build, block I got out of the junkyard and rotating assembly I got from another fox motor. Everything was cleaned properly, crank polished by hand and on lathe, block dingle ball honed, all clearances checked (bout 1.5-2 thou on mains and rods). Had a vibration develop at 4k plus RPM recently so stopped driving it and took it out. #5 main is toast, all the rods are fine though, none of the bearings look great but #5 is definitely the culprit. Usually with oil starvation a rod dies first so not sure what to think about this one, it clearly is a 50z crank and I had 50 oz weights on the flywheel and balancer... (SB fords have a 28oz and 50 oz external balance depending on year etc) 2 things that stick in my head: 1 - The starter bendix sticks for a couple seconds after starting then retracts... This actually started with the last motor (which blew up) I actually had drilled the starter holes out when I first put this motor together to get the bendix to return properly, just firing the bendix manually with a "lone wolf 3000" it would pop back immediately but when the motors rolling it takes a couple seconds... But perhaaaps it has been shoving the crank into the main during cranking... 2 - I had raced some audi looking mercedes a couple nights before the vibration developed... it was a deep freeway pull soooo it's possible the pan was sucked dry... that said it was full on oil, and I'm only spinning it to 6k on with a stock oil pump and pan... surely stock SBFs can handle 6k with a stock pan/pump right? It's always been my experience though that rod bearings die before mains sooo *shrug* Did you take the new oil pump apart and clean it out prior to the build?
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Re: Hey.. everyone loves an engine failure mystery - Brand X
[Re: justinp61]
#3061649
07/22/22 03:06 PM
07/22/22 03:06 PM
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Joined: Mar 2005
Posts: 3,024 NY
B1duster
master
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master
Joined: Mar 2005
Posts: 3,024
NY
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[u][/u] The .0015-.002” on the mains would concern me, I run more than that on my rods. Remember what Monte Smith always said, “build a loose engine, only you’ll know, build it tight and everyone will know”. I like that ! Not sure who coined it but there’s also “ Loose is Fast “
Last edited by B1duster; 07/22/22 03:08 PM.
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Re: Hey.. everyone loves an engine failure mystery - Brand X
[Re: Cab_Burge]
#3061683
07/22/22 06:10 PM
07/22/22 06:10 PM
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Joined: Jan 2003
Posts: 8,182 Detroit, MI
CokeBottleKid
OP
master
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OP
master
Joined: Jan 2003
Posts: 8,182
Detroit, MI
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I know nothing about Fords...but did you check the bearing clearance on EACH journal? Crank is straight, yes? So runout was checked and in-spec?
Beyond this, perhaps looking at restrictions in the oil feed is the next place to go? What does that routing look like on the 302? Where in that feed sequence is #5: start or end?
Last, visually it just looks to me like #5 was simply too tight, or there was a pile of dirt that got dumped into that somehow??? (maybe stuff was trapped in the oil feed passage and when things came up to pressure it all went straight out) Yes all clearances checked, crank straight? dunno but the motor it came out of had bearings that were like new. #5 is at the end... so ya oil starvation is a possibility. Block was cleaned pretty thoroughly so kinda doubt the dirt theory The .0015-.002” on the mains would concern me, I run more than that on my rods. Remember what Monte Smith always said, “build a loose engine, only you’ll know, build it tight and everyone will know”. I mean it was that after polishing to b00t *shrug* that looks like crank to bearing rubbing, not enough clearances or not enough oil flow on start up Well clearly it rubbed at some point, 0.00175 shouldn't be toooo tight tho, was primed before start-up and also had plenty assembly lube.
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Re: Hey.. everyone loves an engine failure mystery - Brand X
[Re: topside]
#3061690
07/22/22 07:13 PM
07/22/22 07:13 PM
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Joined: Aug 2019
Posts: 9,574 Super Spudsville
Mr PotatoHead
Half Baked
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Half Baked
Joined: Aug 2019
Posts: 9,574
Super Spudsville
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I agree with topside, they were done well before 6k, more like nose over just under 5500 and go figure ford replaced my 86 5.0 Capri motor twice for bearing related issues and 3 T5 transmissions as well. Fun cars but the stock parts pushed always seemed to catch up sooner then later. A cat delete, 3.70 rear gear and comp ta tires and things would start to break soon after.
STOP POTATO HATE!
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Re: Hey.. everyone loves an engine failure mystery - Brand X
[Re: topside]
#3065058
08/04/22 02:12 AM
08/04/22 02:12 AM
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Joined: Jan 2003
Posts: 8,182 Detroit, MI
CokeBottleKid
OP
master
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OP
master
Joined: Jan 2003
Posts: 8,182
Detroit, MI
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I think there are 2 or 3 different external balance specs on the SBF, aren't there ? Never had my stock '89 5.0 to 6,000 - ran out of pull long before that. .0015 sounds too tight to me, regardless of make & size. There is, 28 and 50, this is a 50 and it had the right ones
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Re: Hey.. everyone loves an engine failure mystery - Brand X
[Re: CokeBottleKid]
#3065060
08/04/22 02:47 AM
08/04/22 02:47 AM
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Joined: Aug 2003
Posts: 43,309 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,309
Bend,OR USA
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You guys are crazy, .003" crank bearing clearance? This isn't the titanic How big is the O.D. on those mains? The standard race clearance standard is .0010 per one inch of journal diameter, rods, mains or cam journals There are way to many internet and forum racing experts that have only raced on their keyboards, most of their "knowledge" is based on reading or hearsay, no real world at the track or dyno testing and racing I was told years ago by a Ford SS drag racer, Ted Wells(he race 1967 a 410 HP 427 C.I. side oiler motor that he shifted at or above 8800 RPM ), to run a little more clearances than the recommended minimum if i wanted my NHRA Street 426 Hemi stock class race motor to live, he was correct . I've used 0033+ on the mains and .0030+ clearance on the rods long before you bought that Daeco race drum from me with no bad results on hundreds of street and strip and drag race only motors,Hemi, RB.B and lots of SB Mopars Yuu will never spin a bearing with those oil clearances, you may with less than .0010+ per 1 inch of bearing I.D. diameter on the clearances
Last edited by Cab_Burge; 08/04/22 02:51 AM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Hey.. everyone loves an engine failure mystery - Brand X
[Re: CokeBottleKid]
#3065288
08/04/22 07:09 PM
08/04/22 07:09 PM
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Joined: Jan 2003
Posts: 19,384 Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,384
Las Vegas
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Looks pretty clear to me it was an oiling issue....No way no how I would run the clearances that tight for sure. Not 100% familiar with windsor oiling but if you really think it wasnt a bearing clearance isseu(which is hard to believe)then I woudl start looking there as to where oil travels in the engine. Hard to tell from pics but looks like it had plenty of "stuff" going through it too, but could just be the pics and lighting.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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