1996 Corvette LT4 Bearing Replacement

[kosmaras]

I recently purchased a 1996 Corvette with the LT4 engine. Car has around 84k miles and seemed well maintained. I had the oil pan off for some other maintenance so popped some rod and main caps off to check the bearing and journal conditions. Bearings had more wear than I was expecting, so figured it was smart to drop new ones in. In the process, I cleaned up 2 Rod journals side by side with 2k grit sand paper doused with WD40. Before reassembly I rinsed everything off with good amounts of brake cleaner. Just finished the replacement of all the bearings - rods were straight forward, used standard size aluminum Clevite bearings (per the recommendation of Chad Golen), but the mains were a little more tricky. Had to mix and match oversized and std bearings to get my .0020-.0025 clearance.
Rods ended up at .0020” and mains 1-4 just over .0020” and main 5 at just under .0030”

Got the car started for the first time earlier in the week and got it up to operating temp. Oil pressure looks good and engine sounds good also.

My question is, with the work that was done what should I do as far as a clean out oil change. My plan was to drive 50 miles, then use the LiquiMoly engine flush before draining and filling with fresh oil and filter.

Should I consider a different process? - curious what you all think.

 

[PontiacHO]

Several short interval oil changes should do. Not fond of “flush” chemicals in engine. Did you change the oil pump?

 

[kosmaras]

Several short interval oil changes should do. Not fond of “flush” chemicals in engine. Did you change the oil pump?

Sounds good, I’ll do 2 changes maybe 1 at 50 miles and 1 at 150 then every 3k.

Oil pump is original, I considered a Melling standard pressure/volume shark tooth, but wanted to see what my clearances would give me with the stock pump. I’ve also read the M155 pumps casing is thinner than the original LT1/LT4 GM pump - so I stuck with it for now.

 

[PontiacHO]

I would be inclined to use a 5w40 or 10w40.

Edit: For what it’s worth….those engines were assembled tighter than what you now have. That’s the reason for the original bearing wear. You are right on the money with clearances on your new bearings.

 

[kosmaras]

I would be inclined to use a 5w40 or 10w40.

Edit: For what it’s worth….those engines were assembled tighter than what you now have. That’s the reason for the original bearing wear. You are right on the money with clearances on your new bearings.

Thanks for the words of affirmation! First time doing this, let alone in the car - so was a little concerned it would turn out bad. I was very detail oriented and tried to be as clean as I could. I had to go with the H and HX Clevite bearings for mains as that was the only Clevite bearing giving me "extra clearance" of .001".

I was thinking of going up in oil weight to increase oil pressure given the larger clearances. I was looking at Mobil1 0w40 as at the car is a summer only car here in Michigan. I think the newer GM engines use that oil and from what I've read it would be a good fit for the Gen 2 LTx engines.

 

[dfarr67]

I think she's due for a complete rebuild.......

 

[kosmaras]

It’ll eventually get a 383 short block. But for now this seems to be working!

 

[Mcbeem5]

I am not a motor rebuilder, but on the bearing wear chart I have it says-Oil starvation --APPEARANCE When a bearing has failed due to oil starvation, its surface is usually very shiny. In addition, there may be excessive wear of the bearing surface due to the wiping action of the journal. Not sure if its my computer screen but some of the wear areas look shiny! Need a engine rebuilder to chime in here!