cam bearing install issues
05-28-2013, 03:48 PM
#1
cam bearing install issues So, the saga of my 04 LS6 failure/rebuild continues. The engine developed a low oil pressure issue soon after a cam swap and the engine being swapped into a new chassis. I tore it down to find grooved main bearings and crank, but no major issues with any cam bearings and the cam still looked new.
I did find something curious after the old cam bearings were removed. The 1 and 5 cam bearing bores in the block had a deep scratch and some material removed.
I assumed this was something done wrong during the last rebuild, and lightly ground down the high spots.
I have the block completely stripped and am beginning a full rebuild including new cam bearings. I have the cam bearing install tool, which is a long metal rod, a centering cone to hold it straight in the bores, and a mandrel/holder for the cam bearing itself.
I have new durabond CHP-10 cam bearings. I am following the numbers for placement within the block.
So I started with #3, coated it with loctite 640 sleeve retainer, and it pressed in with about the same force as was required to remove the originals (which were numbered GM's). So everything seemed good.
Then I went to move on to #2 and found the bearing slid right through the bore with little more than hand force (one light tap of the hammer). So I removed it and checked it in the other bore it should fit, #4, and it did the same thing. Out of curiosity I grabbed a #1 and it slides right through the ! and 5 cam bore by hand, with a few thou clearance.
So then I dig out the old GM bearings and it turns out that they are all different sizes. The GM #3 was about 0.208, the #2's were about 0.235, and the #1's were about 0.250.
By comparison, the durabond #2's are about 0.227 and the #1's are about 0.335.
So WTF is going on here...are the durabond cam bearings sold for the LS1 not the correct size? What do I need to do, toss these and order new GM bearings instead?
I did find something curious after the old cam bearings were removed. The 1 and 5 cam bearing bores in the block had a deep scratch and some material removed.
I assumed this was something done wrong during the last rebuild, and lightly ground down the high spots.
I have the block completely stripped and am beginning a full rebuild including new cam bearings. I have the cam bearing install tool, which is a long metal rod, a centering cone to hold it straight in the bores, and a mandrel/holder for the cam bearing itself.
I have new durabond CHP-10 cam bearings. I am following the numbers for placement within the block.
So I started with #3, coated it with loctite 640 sleeve retainer, and it pressed in with about the same force as was required to remove the originals (which were numbered GM's). So everything seemed good.
Then I went to move on to #2 and found the bearing slid right through the bore with little more than hand force (one light tap of the hammer). So I removed it and checked it in the other bore it should fit, #4, and it did the same thing. Out of curiosity I grabbed a #1 and it slides right through the ! and 5 cam bore by hand, with a few thou clearance.
So then I dig out the old GM bearings and it turns out that they are all different sizes. The GM #3 was about 0.208, the #2's were about 0.235, and the #1's were about 0.250.
By comparison, the durabond #2's are about 0.227 and the #1's are about 0.335.
So WTF is going on here...are the durabond cam bearings sold for the LS1 not the correct size? What do I need to do, toss these and order new GM bearings instead?
05-28-2013, 04:14 PM
#3
I was told there are 55 and 59mm cam bearing bores depending on the year, and mine has the 59mm bores. The bearings are approx. the same size, we're just talking a difference of 10-15 thousandths of an inch. So are there actually 3 types of blocks? (55mm, 59mm small, 59mm large)?
