Author Topic: My 427/452 autopsy results are in  (Read 5729 times)

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AlanCasida

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My 427/452 autopsy results are in
« on: September 19, 2020, 08:52:49 PM »
I pulled the 427 apart today to see how bad it was but before I did I ran a compression check and all the cylinders checked 195-200 except #8 and it was 175. I figured that was probably where the problem was and that is where I thought I heard it knocking. Next I cut the oil filter apart and found a bunch of metal in it. When I pulled the heads you could see where the knocking was coming from, the top of the piston had a couple of good shiny spots where it had been hitting the head. When I got it out and the pan off I could see #8 rod had gotten pretty hot and when I pulled the cap off my suspicions were confirmed, I had spun the rod bearing. They had gotten thin enough that one half was laying on top of the other. It scratched it up pretty good. Hopefully it will be salvageable, we'll see. The good news is it looks like the cylinder is ok. It has some scratches but I think they'll hone out...I hope! I guess I should have went with my gut at the motel in Norman when I was running the valves. It was turning over really hard by hand and I thought something was up but I couldn't put my finger on it. It still had good oil pressure. Anyway, I have all winter to decide what I want to do.         

cjshaker

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Re: My 427/452 autopsy results are in
« Reply #1 on: September 20, 2020, 02:05:52 AM »
How does the crank and other bearings look? I've had that happen before and never could come up with a good reason why one rod bearing failed and the others looked good.

At least the problem isn't fatal to the block, and everything except the one rod should be reusable, assuming the crank is ok.
Doug Smith


'69 R-code Mach 1, 427 MR, 2x4, Jerico, 4.30 Locker
'70 F-350 390
'55 Ford Customline 2dr
'37 Ford Coupe

Stangman

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Re: My 427/452 autopsy results are in
« Reply #2 on: September 20, 2020, 08:35:49 AM »
Glad it’s not worse Alan. Do the bearings have the bevel on the edge on one side maybe that one was riding on the crank were it bevel up on the journal?. Not really liking the piston it looks like it was beat down a little. Does the ring feel ok in the ring land. Also not sure how it works but with that one rod seeing so much heat does that hurt it’s strength?. I think I would be more comfortable getting a new rod and piston but I would see what some of the builders think. I’m glad it’s only this stuff though. Good luck I’m sure you will keep us informed.

jayb

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Re: My 427/452 autopsy results are in
« Reply #3 on: September 20, 2020, 08:42:07 AM »
Looks fixable Alan, I'm sure you can get it back together with fairly minimal fuss.  Check the oil hole in the crank and make sure it is good between the #5 main and the #8 rod, and mag the crank too to be safe.  How does the #5 main look?
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
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My427stang

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Re: My 427/452 autopsy results are in
« Reply #4 on: September 20, 2020, 09:17:53 AM »
If there is enough journal to turn, have it magged, just in case a crack was dumping the oil

What were your bearing clearances and what were you running for a pan? Also what was total timing on that one?
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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

AlanCasida

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Re: My 427/452 autopsy results are in
« Reply #5 on: September 20, 2020, 10:58:04 AM »
Thanks for all the replies. I haven't dug into it deeper as of yet. It was late last night when I got to the rod.  This is the new Scat crank I put in last year after torque converter issue ruined my OEM crank. I had it all rebalanced at Gessford Machine and I am pretty sure they magged it while it was there. They are pretty thorough. As far as clearances I don't remember for sure but I think it was .002" or maybe .0015". I am thinking it might have been on the tight side but my memory isn't what it used to be. I really need to take notes when I do stuff like this. I am running a Canton rear sump pan that only holds 6 quarts and that has been a concern of mine for awhile. I had even been considering adding a "T" to the sump to give it more capacity. I was running 32 deg total timing. I got to thinking this may have started even before I left. On one of my shake down drives I noticed the oil pressure gauge fluctuating a bunch +- 20 psi and I had to drive it maybe 15-20 before I could get to a place that had oil. I think it was sucking the sump low enough to make the pump cavitate.   

wowens

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Re: My 427/452 autopsy results are in
« Reply #6 on: September 20, 2020, 03:46:31 PM »
My 2 cents. The piston to the left looks awfully clean on the quench area. It's down in the hole and it's dark in the hole so hard to tell. You may not have enough quench clearance. A light touch may have crushed the bearing resuting in the final damage.
I would look very closely at piston to head clearance on all the pistons. Especially on that corner of the block.
Woody

AlanCasida

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Re: My 427/452 autopsy results are in
« Reply #7 on: September 20, 2020, 04:20:35 PM »
My 2 cents. The piston to the left looks awfully clean on the quench area. It's down in the hole and it's dark in the hole so hard to tell. You may not have enough quench clearance. A light touch may have crushed the bearing resuting in the final damage.
I would look very closely at piston to head clearance on all the pistons. Especially on that corner of the block.
Well when I saw that I got to thinking I did go with some .027" head gaskets to gain a little compression. That may not have been a good move on my part.

frnkeore

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Re: My 427/452 autopsy results are in
« Reply #8 on: September 20, 2020, 04:48:30 PM »
Had you measured the deck clearance, before ordering the .027 gaskets? If so, what was it?
Frank

AlanCasida

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Re: My 427/452 autopsy results are in
« Reply #9 on: September 20, 2020, 05:15:05 PM »
Had you measured the deck clearance, before ordering the .027 gaskets? If so, what was it?
I did a quick measurement with my dial calipers and it looks like .010" in the hole.

frnkeore

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Re: My 427/452 autopsy results are in
« Reply #10 on: September 20, 2020, 05:49:34 PM »
If accurate, that's .037 and that's right on the raged edge.

I would remeasure the other holes for deck clearance, with a depth mic and see what you get.
Frank

My427stang

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Re: My 427/452 autopsy results are in
« Reply #11 on: September 20, 2020, 07:37:04 PM »
Good to check, but that kissed one is likely due to the bearing.  .037 should live but it starts getting tight and you don’t want to be guessing
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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

Hemi Joel

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Re: My 427/452 autopsy results are in
« Reply #12 on: September 20, 2020, 08:42:26 PM »
The rule of thumb for FE's with stock style pans is to always fill it, then add an extra quart before making any drag strip passes. You could have run the pan dry, I know of a few instances where that has happened.
If your bearing clearance is on the loose side, only you will know it. If your clearance is on the tight side, everybody will know it. I usually shoot for 003 to .0035 on the rods and use h series bearings that give more clearance at the parting lines.
Good luck finding the cause and getting it all fixed, Alan

My427stang

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Re: My 427/452 autopsy results are in
« Reply #13 on: September 21, 2020, 09:25:01 AM »
Thanks for all the replies. I haven't dug into it deeper as of yet. It was late last night when I got to the rod. This is the new Scat crank I put in last year after torque converter issue ruined my OEM crank. I had it all rebalanced at Gessford Machine and I am pretty sure they magged it while it was there. They are pretty thorough. As far as clearances I don't remember for sure but I think it was .002" or maybe .0015". I am thinking it might have been on the tight side but my memory isn't what it used to be. I really need to take notes when I do stuff like this. I am running a Canton rear sump pan that only holds 6 quarts and that has been a concern of mine for awhile. I had even been considering adding a "T" to the sump to give it more capacity. I was running 32 deg total timing. I got to thinking this may have started even before I left. On one of my shake down drives I noticed the oil pressure gauge fluctuating a bunch +- 20 psi and I had to drive it maybe 15-20 before I could get to a place that had oil. I think it was sucking the sump low enough to make the pump cavitate.   

I doubt anyone magged a new crank if you didn't ask.  However, you can't assume anything now, even though I suspect that crank is junk

I'd be very leery to run an FE journal at .0035, pretty loose for anything but maybe race only, cold start can hammer the top bearing a little over time if too loose. if that applies to you,  but the oil supply is certainly good advice.   I like .001 X rod journal, round up, especially for something on the street.  So in this case,  .0025 is what I'd be shooting for up to .003 if the parts forced me there.  FWIW I haven't seen a tight SCAT FE crank yet either, on the 2.20 stuff I generally need .001 or a mix, haven't run a SCAT FE journal though. 

Of course restricting helps keep a little more oil in the pan too

My gut says, still tranny/converter problem combined with maybe kissing the heads based on the marks on the adjacent cylinder, but who knows, could have taken out a second bearing, just not spun yet.

Sounds like you have a strong running combo, just needs some careful measuring on the next version to get it to stay together

Where are you from Alan that you use Gessford?  They aren't close to me in Omaha, but closer than most others, I use a single local guy that holds numbers better than anyone I know, but you pay for it.  If he drops from overwork, I am hurting LOL
« Last Edit: September 21, 2020, 11:27:43 AM by My427stang »
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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

67xr7cat

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Re: My 427/452 autopsy results are in
« Reply #14 on: September 21, 2020, 10:46:55 AM »
Sorry for your bad luck.

From your two threads I see three issues that likely caused the failures:

1. Ran low on oil. No. 8 last in line so makes sense. I'd get a better pan on there and make sure mark the dipstick once you figure out the right level.

2. Rod clearance is too tight. .0025 - .0028 be a good clearance.

3. Get rid of that converter. Pull and check the front pump and input makes sure all is good.

If you are still running the oil relief at the back of the engine I'd check make sure it is working right. Pumpbuilder sells a new spring and valve.

Good luck, Steve
« Last Edit: September 21, 2020, 10:48:52 AM by 67xr7cat »

blykins

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Re: My 427/452 autopsy results are in
« Reply #15 on: September 21, 2020, 11:12:38 AM »
I've never needed to add oil to the rear sump pans in an actual vehicle.  On the dyno, I'll add another quart just to help with the oil that won't find its way back from the front sump.

I'd also check bearing clearances again and adjust as needed.  .0015" is definitely too tight and I don't like .0020" either on a factory, narrow, FE bearing.  I'm usually at around the .0030" mark for non-BBC journal FE stuff. 

My guess, however, is that your converter took the crank out and probably pushed the crank so far forward that it began to take the rod side clearance out. 
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cjshaker

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Re: My 427/452 autopsy results are in
« Reply #16 on: September 21, 2020, 02:15:17 PM »
My guess, however, is that your converter took the crank out and probably pushed the crank so far forward that it began to take the rod side clearance out.

If that is the case, I wonder if the other rods would show signs of wear on the rearward face (big end), where the clearances closed up? Maybe on the crank throw rear radius' also?  Although the crank may have moved far enough forward from the thrust wear that they may have come into contact post-damage. Just trying to think of tell-tale signs for Alan to look for.

Alan, I'm sure you checked crank end play, and given the amount of damage on the crank thrust, I wouldn't think that it was from racing only (since you've only made a few passes), so that would seem to point to something creating a constant forward thrust. The only thing that comes to mind is the transmission. Any chance the rear of the block had been faced before, which would close up distances? I've heard of guys in racing circles doing that, just to verify the trans mounting is perpendicular to the crank centerline. Not sure how you'd measure that though.
Doug Smith


'69 R-code Mach 1, 427 MR, 2x4, Jerico, 4.30 Locker
'70 F-350 390
'55 Ford Customline 2dr
'37 Ford Coupe

AlanCasida

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Re: My 427/452 autopsy results are in
« Reply #17 on: September 21, 2020, 04:42:55 PM »
My guess, however, is that your converter took the crank out and probably pushed the crank so far forward that it began to take the rod side clearance out.

If that is the case, I wonder if the other rods would show signs of wear on the rearward face (big end), where the clearances closed up? Maybe on the crank throw rear radius' also?  Although the crank may have moved far enough forward from the thrust wear that they may have come into contact post-damage. Just trying to think of tell-tale signs for Alan to look for.

Alan, I'm sure you checked crank end play, and given the amount of damage on the crank thrust, I wouldn't think that it was from racing only (since you've only made a few passes), so that would seem to point to something creating a constant forward thrust. The only thing that comes to mind is the transmission. Any chance the rear of the block had been faced before, which would close up distances? I've heard of guys in racing circles doing that, just to verify the trans mounting is perpendicular to the crank centerline. Not sure how you'd measure that though.
I have started wondering if the dimension on the rear of the block is correct. This is an agricultural block that at some point was not deemed worthy of getting crossbolt main caps so I thought maybe that dimension could be off but it would not make any difference on an irrigation pump. I had my 428 in the car for a couple hundred miles and the thrust bearing is ok on it. When I put the engine back in the car I am sure I measured the clearance between the converter and the flexplate at .125" before I bolted them together but maybe I got it wrong. I'll dummy the transmission up to my 428 and check the clearance but I am definitely getting another converter.

frnkeore

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Re: My 427/452 autopsy results are in
« Reply #18 on: September 21, 2020, 04:44:59 PM »
The rods can follow the crank, for as much clearance the small end, has inside the piston bosses. I'd look inside the pistons for signs of that.

But, if the limit of axial travel was exceeded, I think all the rods would show it and be discolored, at the big end.

If the rod clearance was in spec, for the load range, I'd follow that crank passage back to the main bearing.

Could it be that that the crank pushed far enough forward, that it covered up most of the feed hole to the pin?

No matter what, the end play issue, has to be fixed before it's put back together. I'd suggest mounting the face of the block to a eng stand, put in a good used thrust bearing, crank and FW on, then put the trans on a table at the same height and push them together to find, when and where they bind. Start with 1/8" thick washers and reduce the space, until ii binds.

My guess is it the shank that drives the pump having no end play. Nothing can give between the converter mounting pads and the end of the pump drive.

You can also put a indicator on the flex plate as you tighten the bell housing bolts, to know when it starts pushing the crank.
Frank

frnkeore

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Re: My 427/452 autopsy results are in
« Reply #19 on: September 21, 2020, 04:49:35 PM »
One other thing, when you bolt a trans to the block, after it's bolted, there should be enough clearance between the flex plate and the converter to be able to turn the converter, to line up the holes.

Are you using a block plate, between the bell housing and the block?
Frank

AlanCasida

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Re: My 427/452 autopsy results are in
« Reply #20 on: September 21, 2020, 05:33:13 PM »
One other thing, when you bolt a trans to the block, after it's bolted, there should be enough clearance between the flex plate and the converter to be able to turn the converter, to line up the holes.

Are you using a block plate, between the bell housing and the block?
Yes I am using the OEM block plate. When I put it motor in the car I checked and thought I had .125" clearance. This same thing happened to me last year causing me to have to get a new crankshaft. I found the tail end of the pump snout had not been beveled on the converter causing it to be too close and pushing the crankshaft forward...or so I thought. I put the bevel in the converter and reused it. In hind sight I probably should have gotten a new converter.     

frnkeore

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Re: My 427/452 autopsy results are in
« Reply #21 on: September 21, 2020, 06:51:59 PM »
So, if there was clearance between the flex plate and the converter, when they were installed, then, maybe the converter ballooned and pushed the crank forward?
Frank

AlanCasida

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Re: My 427/452 autopsy results are in
« Reply #22 on: September 21, 2020, 07:11:00 PM »
So, if there was clearance between the flex plate and the converter, when they were installed, then, maybe the converter ballooned and pushed the crank forward?
That's a possibility. I haven't gotten that far in my investigation.

runthatjunk

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Re: My 427/452 autopsy results are in
« Reply #23 on: September 21, 2020, 08:18:15 PM »
One other thing, when you bolt a trans to the block, after it's bolted, there should be enough clearance between the flex plate and the converter to be able to turn the converter, to line up the holes.

Are you using a block plate, between the bell housing and the block?

Don't think I've had any trannys that you could turn converter with block bolted together,  I think I would be worried about enough pump engagement at that point
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AlanCasida

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Re: My 427/452 autopsy results are in
« Reply #24 on: September 21, 2020, 09:57:22 PM »
One other thing, when you bolt a trans to the block, after it's bolted, there should be enough clearance between the flex plate and the converter to be able to turn the converter, to line up the holes.

Are you using a block plate, between the bell housing and the block?

Don't think I've had any trannys that you could turn converter with block bolted together,  I think I would be worried about enough pump engagement at that point
The converter I am using does not have studs. It has threaded holes and uses bolts to mount it to the flexplate so you can spin it around.

RJP

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Re: My 427/452 autopsy results are in
« Reply #25 on: September 22, 2020, 09:57:31 AM »
Alan, Did you check the crank pilot bore for clearance including depth of the bore? I've heard of aftermarket cranks that the bore diameter could be correct but the depth is too shallow and/or have a secondary bore for the 385 series converter pilot [1.375"?] Just another thought.

My427stang

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Re: My 427/452 autopsy results are in
« Reply #26 on: September 22, 2020, 10:20:50 AM »
If it could spin with bolts out during assembly, you had clearance, could it spin when you pulled the engine this time? If not could have ballooned

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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

jayb

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Re: My 427/452 autopsy results are in
« Reply #27 on: September 22, 2020, 11:13:10 AM »
To check for proper clearance you should be able to spin the converter, but also push it forward so that the mounting pads are in contact with the flexplate.  If you can't do that, then you are bending the flexplate to conform to the converter location when you bolt them together, and that will put pressure on the crank.  There have been many cases where I've had to put spacers between the converter mounting points and the flexplate in order to ensure correct installation.
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
- 1969 Shelby Clone, Drag Week 2015 Winner Modified NA (Average 8.98 @ 149), 585" SOHC

   

AlanCasida

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Re: My 427/452 autopsy results are in
« Reply #28 on: September 22, 2020, 12:26:20 PM »
To check for proper clearance you should be able to spin the converter, but also push it forward so that the mounting pads are in contact with the flexplate.  If you can't do that, then you are bending the flexplate to conform to the converter location when you bolt them together, and that will put pressure on the crank.  There have been many cases where I've had to put spacers between the converter mounting points and the flexplate in order to ensure correct installation.
Now that I finally have everything out on the floor that is something I am going to check.  I did notice my flexplate when laying on the concrete floor was not flat so there may have been something like what you mentioned going on. At some point I am going to mock it all up to my 428 and see what it looks like.

AlanCasida

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Re: My 427/452 autopsy results are in
« Reply #29 on: September 22, 2020, 09:06:51 PM »
I took another look at the thrust bearing and it looks like the front side of the bearing has not been touching at all...it looks brand new. So, I bolted the transmission to the block/crankshaft with the crankshaft pushed back as far as it would go. Since the front side of the bearing looked new I felt this would be accurate. I put a dial indicator on the front of the crank to check for movement. I took a measurement from the flexplate to the converter with the converter pushed all the way back and then another with it pushed up against the flexplate then subtracted one from the other and I got 0.125". Then I put one bolt in the converter and tightened it down and checked for movement on  the dial indicator...there was none. So either something is causing the converter to push forward or something in the motor is causing it. I didn't put anymore bolts in the converter as I didn't see it was necessary for what I was doing. I sure wish I had found something obvious.
« Last Edit: September 22, 2020, 09:09:02 PM by AlanCasida »

My427stang

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Re: My 427/452 autopsy results are in
« Reply #30 on: September 22, 2020, 10:36:35 PM »
What are you putting for thrust clearance when you assemble? Do you check it before and after cap install?

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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

FERoadster

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Re: My 427/452 autopsy results are in
« Reply #31 on: September 22, 2020, 10:37:04 PM »
I know nothing about your issue but do/did you need the reinforcing ring on the flex plate? That's the only X factor I do not see but it could be a non Issue to the convertor?  Think I forgot the ring on my sons 59 T=Bird so we are pulling the engine.

Richard >>> FERoadster

AlanCasida

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Re: My 427/452 autopsy results are in
« Reply #32 on: September 22, 2020, 10:47:57 PM »
What are you putting for thrust clearance when you assemble? Do you check it before and after cap install?
I don't know off the top of my head but it was within spec. The thing is, it has worn about an .080" groove in the thrust area of the crankshaft. If it had been that tight when I got it all together I would have known it right off. I watched a video of a transmssion that had too much line pressure and you could see the converter being pushed forward when they revved the motor up. It was a GM transmission but it may still be applicable to a C6. My next move is to pull the valve bod and see if the pressure spool valve is stuck. 

Rory428

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Re: My 427/452 autopsy results are in
« Reply #33 on: September 23, 2020, 02:43:35 AM »
Alan, I mentioned your situation to a buddy who does a ot of transmission work, and he told me that he has seen a similar case, where the transmission cooler was clogged, which caused the transmission line pressure to climb, which caused the torque convertor to move forward. He recommends checking the transmission line pressures at both the cooler lines. They should be equal, if not , you have a restriction , like a clogged cooler, pinched hose or kinked cooler line, that can cause such a condition. Something to look at.
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Falcon67

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Re: My 427/452 autopsy results are in
« Reply #34 on: September 23, 2020, 02:52:26 PM »
I don;t know about a C6, but even with a manual valve body in a C4 the pressure to the cooler only runs about 30 lbs, not anywhere near the internal pressure to the clutches and servos. 

I have personally run a motor with .100 endplay and the only thing that cause a problem was the counterweights rubbing the internal bulkheads, slowing the motor.  All the bearings looked great except for the thrust.  And the crank got a nice machined groove about .250~.300 x .100 deep or so.  The converter was a built unit that did not ballon, that same unit is in the car now with another 1000 passes on it and works fine.  I attributed the crank problem to some debris or issue with the crank thrust face as nothing else stood out.  That's the only thrust issue I've ever had with a motor.  The dragster engine is apart after splitting a cylinder.  It runs a Powerglide built for a lower end alcohol funny car so you can imagine the internal pressures.  Three years before the mast, end play was .008 going in, .009 coming out. 

I'd agree that if the crank didn't move with the converter bolted up then there is a mechanical issue somewhere.  The engine I referenced above, you could see the belt misalignment up front.  A push on the crank pulley moved the entire assembly - talk about a weird feeling to see your crank pulley move backwards about 1/10 of an inch.  "Well...heh, that's a problem."