Thrust bearing looks nasty

Performance mods and Advanced Stroker discussion.
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KarmaKannon1
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Stroker Displacement: 4.7
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Vehicle Model: Cherokee
Location: Utah

Thrust bearing looks nasty

Post by KarmaKannon1 »

So I only have maybe 500 miles on my stroker and I started to hear a noise and noticed my hot oil pressure was lower than the first 50-100 miles. I don't recall the number, but I believe it was on the low side of minimum at a hot idle. Maybe 20lbs on a mechanical gauge. Once again I don't recall and don't hold me to that. No transmission work was done since the engine came out to build, the trans seemed to function fine, and the thrust bearing from the previous engine (same block before my build) looked fine.

I thought the cam or cam bearings were toast and it turns out the cam/ lifters look fine and the bearings look alright considering the copper thrust bearing material in the oil. All bearings besides the thrust are worn into the shiny silver and not far enough that they are copper. Once again I'd expect this with the shape the thrust bearing was in and how that copper stuff was running in the oil.

The cylinders show some scoring. It's more than I had expected and I don't know if it's consistent with the lower oil pressure/contaminants in the oil or of it's worse. Either way I'm hoping I can have them honed and re-use the pistons.

My timing set shows some more wear than I'd expect too. I reused the factory style timing set from when the engine was rebuilt a few thousand miles ago by the previous owner and it developed piston slap in #5 if I recall. I don't know if there was enough wear to chip something into the thrust bearing and toast it, but since everything else looks much less toasted... I dunno.

Oil pump was a new standard melling if I recall.

Bearings were clevite for the rods and either clevite mains or sealed power.

4.7 stroker, .06 over, stock cam with new lifters, pistons and rods (bushed) are from Russ, crank was a new scat, it was assembled by me and all bearings looked good with plastigauge and I don't recall what the thrust clearance was, but it was within tolerance as I measured. It was a new crank with std bearings.

I'm trying to see if I can confidently put this thing back together knowing I won't have the same issue and if I can't do that... I'm likely looking at selling the jeep for parts or selling the engine for parts and putting a v8 in there. I really want the whole inline 6 thing to work, but I'm on the edge of pulling the plug and buying something else or putting in an engine that will make more horsepower without thousands more into the actual engine.
Thought
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KarmaKannon1
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Vehicle Model: Cherokee
Location: Utah

Re: Thrust bearing looks nasty

Post by KarmaKannon1 »

More pics
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Cheromaniac
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Re: Thrust bearing looks nasty

Post by Cheromaniac »

Was the torque converter installed correctly? This could be the root cause of the premature thrust bearing wear.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
KarmaKannon1
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Joined: May 21st, 2020, 10:13 am
Stroker Displacement: 4.7
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Vehicle Model: Cherokee
Location: Utah

Re: Thrust bearing looks nasty

Post by KarmaKannon1 »

Cheromaniac wrote: July 5th, 2021, 12:55 am Was the torque converter installed correctly? This could be the root cause of the premature thrust bearing wear.
I believe it was. I installed the converter to the transmission and then bolted the trans to the engine and the flex plate. I noticed no binding when I brought the engine to the transmission, there was no abnormal transmission noise, and the trans operated normally.

I still haven't removed the converter, so I would be able to tell if there's an issue now. Any ideas how I'd know if it isn't seated correctly?
KarmaKannon1
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Location: Utah

Re: Thrust bearing looks nasty

Post by KarmaKannon1 »

Anybody have any other thoughts? I could really use some help figuring this one out.

I'm dabbling with an aw4 to gm v8 bellhousing adapter and at very least I'd like to get this engine back together to pass emissions since it's up now and then sell my engine to someone after they can hear it run. Assuming it lasts more than 500 miles this time. I'm just having a hard time dumping more money into a jeep engine shaped question mark.

The other option is parting this engine out and losing more money that way. :doh:
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KarmaKannon1
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Joined: May 21st, 2020, 10:13 am
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Vehicle Model: Cherokee
Location: Utah

Re: Thrust bearing looks nasty

Post by KarmaKannon1 »

After some more inspection... The cylinders should hone out no problem and the piston wear almost rubs off. I also checked the cylinder bore and best I can tell they look good. The thrust surface looks to be within tolerance on crank too. With any luck I can get everything polished and get new bearings and be back to a new engine.
I just wish I knew why the thrust bearing went bad so I didn't waste more money instead of just parting out the engine as is. :deadhorse:
Russ Pottenger
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Re: Thrust bearing looks nasty

Post by Russ Pottenger »

Shoot me a email or call and I’d be happy to brainstorm with ya.

~Russ~
KarmaKannon1
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Location: Utah

Re: Thrust bearing looks nasty

Post by KarmaKannon1 »

Russ got back to me and talked me off the ledge, so to speak. The pistons cleaned up easily and after more inspection the thrust surface looks smooth and still has the machining marks on it. A little more cleaning, new bearings, a hone job, a new cam/ springs, and I'll be putting this engine back together.

Hopefully the block/head gets dropped off this week and I'll get the cam ordered within the next week. My buddy has a wrecked 2000 Chevy 1500 with a 140k 5.3 that's likely finding it's way to my house, so the stroker will be a fun direct comparison. It will still be a good bit before I can swap the 5.3 anyway. The stroker should run a good bit better with something besides the factory cam anyway.

I think some 0-60 and mpg comparisons between a mild stroker like mine vs a stock 5.3 with likely only a cam upgrade and maybe some head port cleaning, may be in order. :banana:
Bubby
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Re: Thrust bearing looks nasty

Post by Bubby »

I was wondering if you ever figured out what caused the thrust bearing to fail.
Iv got 4.6 fresh build, all new parts. Low oil pressure after break in and excessive thrust bearing ware at 100 miles.
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