3 window

iTrader: (1)

Recently found out from a friend that a mutual friend of our that's a mechanic at a Chevy dealership has seen a few stockers spin the cam bearings as well. Seems to be a factory issue. Guess there's not much we can do unless it's a volume problem that Chevy has not fixed and we can bandaid it by over filling the pan.

gsxrred1000

iTrader: (3)

So I measured the last journal cam bearing in block and cam journal measurements. Block cam bearing measures 2.1450"

Stock cam and tick cam both measure 2.1640"

This is as accurate as I can get. Are these within specs ? Not sure what it should be.

gsxrred1000

iTrader: (3)

Does anyone's 5.3 turbo start harder after there is heat in it ? Car starts great when cold but as I drive it and go to restart after it gets heat in it it seems to crank harder? I have a dei starter heat shield and my dump pipe is wrapped below starter and battery is brand new. Just wanna see if it's common starting harder after its hot ?

69-chvl

iTrader: (11)

Cam is bigger than the bearing?

stevieturbo

The bearings and holes in blocks are 3 different sizes ?

Solution is easy if the block is part, pin the *******.

allmotordustin

iTrader: (1)

What/how did you do this with?

stevieturbo

Centre 3 are the easiest.

I drilled down through the valley, tapped it out M5 ( UK, we're metric here ) then screwed a grub screw into the hole.
I didnt tap right through the bearing, just partly so there would be some degree of interference fit and screwed grub screw in until it stopped cam from rotating, then back 1 full turn. So that leaves about 1mm clearance from the cam.
I loctited these into place

Front and rear are a little more awkward due to access.

I got a Desoutter 90deg drill ( aircraft industry tool, very compact for specific jobs ).

This allowed me to drill through the bearing and into a solid portion of block. Then I cut down a set of taps, welded a nut onto the top of the shortened tap so I can actually screw it in/out, and tapped the blind hole.

After this then again got some m5 grub screws and screwed on for same arrangement. ie approx 1mm below the surface of the cam bearing and loctited into place.

Whole process less than 2 hours.

Pic of grub screw in front bearing



And type of drill that allows access ( a friend got me mine second hand ). If you dont have one of these or access to one, then the job would be difficult. New these can be expensive.

gsxrred1000

iTrader: (3)

I'm sure I just measured wrong. Cheap micrometer too. Lol forget my measurements.

oscs

iTrader: (19)

That's a pretty clever idea but why go through all the trouble? Did you not mic out your cam and bearing ahead of time?

stevieturbo

First block it happened to was a shortblock built by A N Other, LS2 block

I wont name names, because I do believe it was a reputable build from a solid builder. I bought the shortblock from a Tech member though, new and unused, not directly from the builder.

I dont know whether the bearings were OEM fitted, or these were replaced, that's a good 5/6 years ago or so

I had no reason to mic the cam, as it resided happily in the previous LS6 blocked engine for a couple of years with no issues.

The LS2 ran for about 2 years before I took it apart to change some stuff and spotted the front bearing had almost walked right out, but as said, I took it apart for other reasons, it was just lucky I caught this at the same time.
Despite the huge hole in the oil system this would have left, oil pressure was still very good.

Next time it happened I've little doubt it was my fault for my DIY attempt at fitting bearings. This only lasted a few hundred miles, different cam though.

After that I decided **** this, got new bearings fitted properly and pinned them too. 2 years on and cam bearings were still perfect....couldnt say same for the mains though, but that's another issue.

Pic is from the more recent build with a brand new LS2 block, and I presume OEM bearings as they dont look aftermarket.

Whether it's needed or not I'm pinning it anyway. It's easy for me to do, costs almost nothing, and means the bearings will never walk. No brainer really.

allmotordustin

iTrader: (1)

Good *** idea. I will try this on one of the motors I have laying around.

oscs

iTrader: (19)

Ive never had issues with the cam bearing walking but interesting fix for those who have.

stevieturbo

Neither had I until it happened me. Then when you start searching for answers or reasons why....you find it does happen to others.

It shouldnt be a fix, it shouldnt be needed. But pinning cam bearings isnt new and others have done it long before me.

I still dont know what the cause was, or causes can be. I just know that pinning will certainly stop it from happening again

forcd ind

iTrader: (7)

Are you seeing the cam bearing problem more on alumn. blocks, or is it cast
and alumn.
I replace the cam bearing even if a SBE deal, always have regardless if SB, BB, etc

3 window

iTrader: (1)

I'm thinking it's both.

Torqueshaft

Interesting to see which bearings people are having trouble with.

All the ones I have seen or know about have been the second to last bearing.

6669camaro

iTrader: (1)

Mine was the front one pushed back and the second from the back was completely gone.

gsxrred1000

iTrader: (3)

Same here 2nd from back. Hmmmm

Torqueshaft

Well add two more second to last bearing failures to the list.

One I heard about and the other one I looked at.

The one I heard about was a gen3 that they had just put a crane n20 cam into...Spun less the 100 miles later.

Welded the bearing to the cam.

The one I seen, was a gen4 5.3 that they had just put a comp cam into.

It spun less than 30 miles later. Same thing as the other one, welded the bearing to the cam.

You can see were the block was discolored from the heat.

Both said that the cams went in with no problems and that they both had good oil pressure until the cam bearings spun.

I will say that I have not heard of any 6.0 that have spun them, only 4.8/5.3 and this was the first gen4 I have seen/heard about.

VintageCamaroChris

iTrader: (3)

I picked up an LQ9 6.0 today that has a bad cam bearing. It didnt spin it but it was close, it was stuck to the cam. No damage to the block. Engine is dead stock cam and all