Technical Sbc undersized cam journal/thanks

That rear bearing with two holes in still has me concerned or am I overthinking this??

 

You need to knock that rear bearing out and check how the block is machined. That's the wrong bearing for any 350 SBC, and should have a single hole centered. The 2 hoes wont align with the oil passages and can cause major issues.

 

Exactly. Get that bearing and the others out of there and put in a standard set for a 350. As for the oil hole location, 350's have the cam bores in the block grooved in the center all the way around. You'll get oil anywhere you clock the bearing BUT it works very well to put the oil holes at about 2 o'clock as viewed from the top front of the block. Just make sure the holes line up in the grooves.

 

^^^^^ Never place oiling hole at 6 o’clock!

 

I’m digging in!!! Thanks for all the help and support!!!

 

My guess is that Johnny Gee and Chicken have the correct answer. Be sure to tag the removed cam so it doesn't end up in a set of standard bearings in some other engine.

 

I’m breaking that sucker in half!!! Lol

 

I was always told to put it at the 4 o'clock position to introduce a better cushion of oil to the journals. Any truth to this? It makes sense to me, in a strange way...

 

Interesting. Most of the SBC’s I’ve seen over the years had the oil feed holes around the 100* mark.
I wonder if the rebuilder was one of those who tried to reuse everything possible, and it was cheaper to turn down the cam and install oversized bearings than to buy new cams and standard bearings? Maybe it is their way to insure no flat tappet cam failures, as the lobes are already broken in?
You never know all the cost cutting measures the bean counters stick in…

 

*shrugs* what do you do? You could always call atk and ask them since they built it... or replace the cam bearings with non .010 under ones...

 

Pretty sure that’s the case.

 

Replacing cam bearings this weekend.

 

Thanks for all the input and support!!! Changed the cam bearings out and the new cam slides in nicely. I don’t know what I would do without you guys!!!

 

Swell!

 

Make sure you got that rear cam bearing correctly installed....the location of the one with 2 holes, as pictured, is not driven in far enough by nearly 1/4" to 3/8"....you can see part of the annular feed groove machined in the block showing broad daylight right behind that bearing!

ATK didn't even install the wrong bearing correctly, it would have a huge internal oil leak out the back edge of that bearing.

Always take a wire or hooked pick to feel and be certain the oil hole is aligned over the feed groove correctly.

 

Thanks, I used a small Allen wrench to make sure I was in the groove on each bearing.