360 Teardown.. Bearing Opinions (dialup beware)

dbesade

Okay,

Hows these bearings look :mrgreen:

#1 Main:

#2 Main:

#3 Main:

#4 Main:

#5 Main:

#3 looks pretty groovy.. I wasn't told the milage on the 360 when I got it, however it came from an 80's J truck but what is weird is the casting numbers on the block are from a 76.. which means this engine was probably swapped in. Opinions are welcomed.. I'm good at this tearing down part.. its the putting back together than makes me nervous :mrgreen:

-Dave

Blown7

Yep they look like old bearings, don't worry about them at this point. It's what the crankshaft looks like and measures out that counts. Is there any fretting on the main caps? Jeff

82Waggy

Interesting that #3 is worn into the copper so evenly and none of the others are. It was probably too tight when installed but I would also check for blockage in the main bearing oil feed path to #3. Looks like the engine had its' share of dirt in the oil. Even wear pattern suggests the crank bore is straight enough - no align hone will likely be necessary. Like Blown7 said, mic the crank and have it turned as necessary to clean it up - install the correct size new bearings.

dbesade

Blown7 wrote
Yep they look like old bearings, don't worry about them at this point. It's what the crankshaft looks like and measures out that counts. Is there any fretting on the main caps?

Jeff

Jeff,

Sorry if I sound n00bish (which is fine because I am :mrgreen🙂 But what is fretting?

82waggy,

I was wondering about #3 myself.. bearings appear stock.. at least the pistons were stock (had AM script logos on them).. but got all the pistons out of the bores and I'll probably pull the crank out today or tomorrow and finish the tear down. So I can get started on the machine work.

-Dave

Blown7

dbesade wrote
Blown7 wrote
Yep they look like old bearings, don't worry about them at this point. It's what the crankshaft looks like and measures out that counts. Is there any fretting on the main caps?

Jeff

Jeff,

Sorry if I sound n00bish (which is fine because I am :mrgreen🙂 But what is fretting?

-Dave

Dave,
Fretting is the minute movement of the cap rubbing on the block.It can be identified by a disappearing of the original machining marks. The surface material has a non directional sometimes shiny area. It can be caused by the cap to block mating surfaces not being flat, parallel and square to each other even when the cap is fully torqued. Sometimes if allowed to proceed long enough you'll have the kind of wear pattern you have on the number three thrust bearing. Also if the number three main journal is out of round you'll see that kind of wear pattern. The important part is to have the crankshaft inspected and inspect the block cap area, if all is well, everything else is just the previous history. You'll be writing a new history when it's all overhauled.

Jeff

AMX69PHATTY

Might there be an AM logo on the backs of the bearings if stock ? :-|

dbesade

AMX69PHATTY wrote
Might there be an AM logo on the backs of the bearings if stock ? :-|

There is a script AM Logo like on the pistons on the Main bearings and the Rod Bearings.. followed by "AT-20"

-Dave

dbesade

Blown7 wrote
dbesade wrote
Blown7 wrote
Yep they look like old bearings, don't worry about them at this point. It's what the crankshaft looks like and measures out that counts. Is there any fretting on the main caps?

Jeff

Jeff,

Sorry if I sound n00bish (which is fine because I am :mrgreen🙂 But what is fretting?

-Dave

Dave,
Fretting is the minute movement of the cap rubbing on the block.It can be identified by a disappearing of the original machining marks. The surface material has a non directional sometimes shiny area. It can be caused by the cap to block mating surfaces not being flat, parallel and square to each other even when the cap is fully torqued. Sometimes if allowed to proceed long enough you'll have the kind of wear pattern you have on the number three thrust bearing. Also if the number three main journal is out of round you'll see that kind of wear pattern. The important part is to have the crankshaft inspected and inspect the block cap area, if all is well, everything else is just the previous history. You'll be writing a new history when it's all overhauled.

Jeff

Jeff,

I didn't see what you are describing on any of the bearings... Looks to be a fairly even wear pattern. But I'm by no means educated on what exactly I'm looking at 😉 but its surely a nice site to see some progress on the teardown.. damn thing has been sitting in my living room for too long.

-Dave

rollen dean montoya

dave, make sure you hot tank the block, heads, and the caps. let them soak for at least 3 days just to make sure that all oil passages are clean.get the crank checked.

jeepsr4ever

Other than dirt inclusion it doesnt look like the crank is twisted or you have oblong mains. That last pic almost looks like you lost chunks of coating.

82Waggy

Nothing there that won't get fixed with std machine work. I assume you are going to have the crank mic'd and turned if necessary? Be sure to clean everything well before re-assembly - they are never clean enough.

rollen dean montoya

when you re-assemble the engine mix up some STP and 20/50 castrol to coat everything.my dad taught me this trick and we never have had any problems with 1st startup. it might smoke alittle but that goes away in minutes.

dbesade

Thanks all for the information on the crank and bearings.. I will be having a shop have some fun with the crank sometime soon and will post the results. Thanks again guys.. I really appreciate it :!:

Mudrat

I looked at his crank this weekend (no snide comments Bob, I know how you think 8) ). The bearings you can see, the crank journals had some normal wear. Not bad but will need some deep polish or possibly even turned 2-3 thou. Still not significant, but enough I would have it mic'ed with a minimum grind / polish. don't know if they make oversize in less than .010??? :idea: The strange thing is the cross drilled oiling holes in the crank. Front and rear didn't have any, just the one oiling hole but, #2, 3 and 4 were at different offsets of 50*-60*, I think it was #3 that was 180 :-| Correct me here Dave if I've got the numbers wrong, lack of sleep and the f)&&^% traffic out of St. Augustine on Sunday .... And a question I have .... we tried to losen the harmonic balancer bolt to get the front end appart, and it was not EVEN thinking of moving :(: I was holding the block and Dave was on a 1/2" breaker bar and we broke a hickory hammer handle on the un-torquing. Needless to say, it's still there - the bolt I mean, the hammer handle turned into a dog chew toy 111!!! Suggestions?? I didn't want to use a metal bar on the crank journal after that. 'Rat

Blown7

Mudrat wrote
And a question I have .... we tried to losen the harmonic balancer bolt to get the front end appart, and it was not EVEN thinking of moving 🙁: I was holding the block and Dave was on a 1/2" breaker bar and we broke a hickory hammer handle on the un-torquing. Needless to say, it's still there - the bolt I mean, the hammer handle turned into a dog chew toy 111!!! Suggestions?? I didn't want to use a metal bar on the crank journal after that.

'Rat

1/2" drive air impact wrench.

Jeff

dbesade

Blown7 wrote
Mudrat wrote
And a question I have .... we tried to losen the harmonic balancer bolt to get the front end appart, and it was not EVEN thinking of moving 🙁: I was holding the block and Dave was on a 1/2" breaker bar and we broke a hickory hammer handle on the un-torquing. Needless to say, it's still there - the bolt I mean, the hammer handle turned into a dog chew toy 111!!! Suggestions?? I didn't want to use a metal bar on the crank journal after that.

'Rat

1/2" drive air impact wrench.

Jeff

I needed an excuse to run air fittings in the living room :mrgreen:

Mudrat

I'm thinking of bringing down the 175PSI air-machine and 600ft/lb wrench on the next trip home. Just can't justify a 1400 mile trip just for Dave's crank :razz: 8) :-| :?: It was kinda funny watching Dave bounce up and down on the breaker bar - especially when the hammer gave way :?: But, Dave's dog (a black Lab) took to the hickory handle pretty quickly though :mrgreen:

dbesade

Mudrat wrote
I'm thinking of bringing down the 175PSI air-machine and 600ft/lb wrench on the next trip home. Just can't justify a 1400 mile trip just for Dave's crank :razz: 8) :-| :?:

It was kinda funny watching Dave bounce up and down on the breaker bar - especially when the hammer gave way :?:

But, Dave's dog (a black Lab) took to the hickory handle pretty quickly though :mrgreen:

I'll crank up my small compressor here and see if it doesn't do it.. Its only 125PSI though.
Damn dog did take the handle pretty quick didn't he... 111!!! better than my new shoes... again.. :mrgreen:

Rat, don't you have to go home to fix erin's jeeps registration? anyway? :-|

-Dave

Mudrat

dbesade wrote
Rat, don't you have to go home to fix erin's jeeps registration? anyway? :-|

-Dave

It's both Erin's and the wife's 'Burbon (and doing taxes), but because of the timing, I'm fly'n this trip (get to meet some Congressional staff 'on-tour' the day I leave).
I'll make a weekend Bonzi run later, but the trailer w/CJ is a wee bit heaver than flat towing a YJ. Plus whatever I need to work on your Heep :wink:

dbesade

Mudrat wrote
dbesade wrote
Rat, don't you have to go home to fix erin's jeeps registration? anyway? :-|

-Dave

It's both Erin's and the wife's 'Burbon (and doing taxes), but because of the timing, I'm fly'n this trip (get to meet some Congressional staff 'on-tour' the day I leave).
I'll make a weekend Bonzi run later, but the trailer w/CJ is a wee bit heaver than flat towing a YJ. Plus whatever I need to work on your Heep :wink:

I hear ya.. must of forgot when you mentioned you were flyin.. I hadn't slept in 2 days the day you came over.. :razz:.

-Dave