So in looking at a block I had assembled locally,...the cam bearing feed hole on the passenger bank is aligned with the oil feed hole in the block,..so the holes are at 8 and 4 o'clock,.....now in TAs catalog it shows and describes the bearing holes sitting at 7 and 3 o'clock ,..these are the dual groove bearings I'm pretty certain they are Teflon coated and I generally always order the dual groove,....and it appears to have small opening visible on the driver bank ,....wonder what kind of situation I'm in?
No clue but I'd be interesting in hearing what others say and what you do to resolve it. My gut is telling me it being hardened will be better than stock but you aren't gaining near as much benefit by having the oil coming out at the optimal TA spec'd locations.
I know the point is to have the oil enter the correct "clocking" and exit the correct "clocking" to optimize the wedge and provide both proper oiling of the cam journal as well as flowing the oil around the back shell and block to get the most volume and pressure. I let my machinist install my bearings as it seemed prudent at the time, but he clocked them "wrong" and I ordered another set and did them myself. (what happens when you are doing two cars and "outsource" in spite of your mind telling you to do it yourself...) TA Performance folks looked at this issue a long time and took the input and experiance of a lot of folks over the years to get it right. $100 bucks in bearings and doing it yourself, is worth the cost of motor pull, tear down and doing it again. (I have many years of such experience when other's chose to go the "fast/cheap" route...) email me if you want to know details.
With the TA back grooved bearings, the oiling hole in the bearing should be at the 3 to 4 o’clock position
I had a machine shop do this to me on a Buick 350 a few years ago. I specifically told them not to align the oiling holes and to follow the instructions from TA that were included with the bearings. So of course they lined up every single one of the bearings. I had to order another set and I made sure they knew I would be taking the difference out of the balance due.
That’s an issue these days, people assume they’re doing it right because that’s how it’s done ALL the time. I’d be in a world of hurt if I didn’t stop and read directions doing paint work
Had a shop do it wrong and they wanted to pull them out and put back in. I said NO get a new set. Before that a shop had put stock ones in wrong and I had them re-installed correctly...only problem, then the cam was tight...wouldn't spin. One of the reasons I try to run my motors as long as possible if doing OK. Had a shop convince me to put new bearings in over a winter....even came to my house. 40 passes later it chewed up the new bearings. Both good shops I used to use are closed/retired......
My machinist called me the day he was installing them. I stressed how important it was to follow the TA instructions. He ended up calling them before putting the bearings in just to make sure. After 50 plus years of doing machine work, he learned something new that day.
They call that mentality following norms. In aviation it is part of a "dirty dozen" list of accident causing human factors. Doing things the way they have always been done certainly doesn't make it right.
I would not be concerned about the bearing being in at 4 o'clock instead of 3... When these bearings were in development, there were more than a few failures. Because of this, for years, I actually turned that bearing around, and the holes were in at 9 and 1 o'clock. I wanted at least one hole exposing the factory oil passage. There are literally dozens of HP BBB's out there with the TA cam bearings in like this, that have had no issues. Anything I built before about 2013... The wider, hardened bearing solves the real issue we had, oil placement is just a nice upgrade, needed really for only the most sever applications. Still plenty of HP Buicks out there with stock cam bearings in them.. I see them all the time, when they come in for other issues. I still use the stock cam bearing, (well, the durabond HP) in the number 2-5 positions at times.. Like now, when you can't buy TA bearings. JW
