Cam Bearings for a 3.4

[mongo]

So I am looking at Cam Bearings so I can finally get my 3.4 block out of the shop. It appears the bearings for a 96 Corvette LT1 5.7 liter will fit and provide an improved surface area when compared to the stock bearings. Can anyone confirm this before I purchase? I am trying to avoid purchasing each bearing separately.

Also, I have always used Clevelite77 bearings in the past but the set I have immediately and locally available are Sealed Power. Sealed Power has a great reputation for their pistons and rings but does anyone have an opinion on their bearings?

[3400-95-Modified]

I have a fully rebuilt engine using all sealed power stuff... its still running at 80k+ on the clock, and I can't remember how many times I hit that with a 100 shot of nitrous... Head gaskets had trouble hanging in there, but bearings were all fine. I just had it out not long ago due to engine swaps, and I did gaskets on it and inspected the bearings and rings and they were all still good.

And yeah its a GM 350 cam bearing set... Not sure if the year is that specific. Obviously that being a 5 bearing set, you throw away the individual largest bearing... keeping the pairs of the two other sizes.

[mongo]

Thanks! Thats what I needed to verify. To get the year I found the bearings listed individually on gmpartsdirect under the performance section for the 60 degree V6. It gave me individual part numbers which I took to the parts department at my local dealer. They wanted $58 PER BEARING. I asked them what models/years both bearings applied to and came up with 92-96 models with a 350. I just picked the Corvette at random. Went to Advance Auto and they had the set for $19 from Sealed Power. I'll be picking them up today and dropping them at the shop in the morning. Maybe I can get this project rolling again!

[3400-95-Modified]

you should buy a cam bearing install tool BUT if your shop is already doing work to the block, I doubt installing those will cost anything. I did mine separate of any work on the block... Bottom end stayed completely intact and I just changed out the bearings.

[mongo]

I dropped the set off with my machinist this morning. I compared the set to the stock set for my block and found that the 350 front bearing did NOT include an oiling slot for the timing chain. That will have to be ground in by hand. Also, the second oil hole in that bearing is off set by about 1/8 of an inch compared to the stock set. I am hoping that the block has a full groove in the journal rather than specific oil passages or my holes won't line up.

The bearings are difficult to measure accurately when they are not installed as it is the bore in the block that maintains their circular shape. My guess is that the center bearing is the one that gets tossed. Can anyone verify? If nothing else, I am guessing I can use the part numbers printed on them to work it out....

[3400-95-Modified]

Yeah I cant remember if its the front or the rear, but iirc, its the largest bearing. On a 350 I think journal 1 and 4 are the same, and 2 and 3 are the same... and 5 is large... although I could have this backwards. Either way last on that goes in is the largest one and thats the odd ball.

You are correct on the oil groove, that needs to be made, BUT there is a full groove in the journal for the oiling of the bearing itself, so no worries about it being slightly off.

[mongo]

Thanks! I'll inform my machinist.

[geoffinbc]

There is a oil galley that completely surrounds the cam bearing. The oil hole in each bearing should be at 4 o clock and aligned for and aft with the oil supply galley.

The groove only exists on newer engines and I believe they added it when the roller cam showed up. With a flat tappet cam it is not necessary because there is less thrust force on the block.

[mongo]

I was under the impression that the groove acts as a "weep hole" or "oil squirter" to drip/squirt oil on the timing chain for lubrication. Am I mistaken? if so, how would that affect thrust force on the block?

[3400-95-Modified]

Well to be quite honest, I'm not even sure if that oil groove even matters My stock bearings in my 05 didn't have it... Here are pics of my worn stock cam bearings from my 05 3400...

I had a Milzy Motorsports Stage 1 cam in there with LS6 springs and this is what that billet POS did to my stock bearings.

[mongo]

I think you may be right. The groove in the front bearing looked like it would clog pretty quickly anyway. It may have just been a case of "wishful thinking" by Sealed Power....

[ghrarhg]

It's the front bearing from the 350 set that is the largest, this is the one that gets tossed. For me, the front bearing was the only one with 2 holes in it. So I drilled a second oil hole in my

Labeling the 350 bearings from #1 being behind the timing chain to #5 being in front of the fly wheel, #1 is the largest, #2 and #5 are second largest, #3 and #4 are the smallest. #1 gets tossed, but is the only one with 2 oil holes in the 350 set. I drilled a second hole in #2 since in the v6 block it becomes #1.

I figured the bearing behind the timing set has 2 holes in every one I've seen, so I made it match. Your call on if you want to. I did not cut a groove in my bearing for oiling, but I have a gen 2, and it wasn't there from the factory.

[3400-95-Modified]

Drilling a second hole sounds fine if it only has one, no complaint there but as you can see my 05 3400 didn't have that oil groove from factory either... so maybe it was just some years that did, or just some aftermarket versions that they thought it was needed, or would help.

Thanks for the clarification on which bearings are which size. That will help me when I do mine eventually... I did Sealed power ones this last time around... I did not know about the 350 ones when I did it in early 08.

I guess if you do groove near one hole it makes sense to put in the second oil hole so there is another source of oil for the bearing that doesn't have an easy way out.

[mongo]

Now this is starting to make a little more sense! Every version I have seen has the second oil hole in the front bearing. I am beginning to believe the second hole's purpose is to cause enough oil weepage at the front bearing to oil the timing chain. Looks like Sealed Power took this one step further and added the oil groove/channel to direct the oil in a stream against the timing gear which distributes it to the chain....

I will drill the second hole but I am not sure I will cut the groove...

[CNCguy]

The front bearing uses two holes because that bearing has considerably more load on it since the timing chain is pulling downwards to rotate the cam. That's why the second hole is at the bottom.

The slot will get more oil to the cam locater and chain but you should be fine without it. If you decide to put a groove in, don't make it too big.