[tom s]

JMHO,I love the Butlers,buy quite of bit from them.BUT from the email from them they knew there could be a issue and for sure there should of been something put in with the receipt to call attention to the issue.And I still have not found a narrow main bearing?H are for HiPo and X is for 1 thou more clearance but find nothing with a N like a narrow rod bearing?Tom

[PontiacJim1959]

Originally Posted by tom s

JMHO,I love the Butlers,buy quite of bit from them.BUT from the email from them they knew there could be a issue and for sure there should of been something put in with the receipt to call attention to the issue.And I still have not found a narrow main bearing?H are for HiPo and X is for 1 thou more clearance but find nothing with a N like a narrow rod bearing?Tom

As stated, I am not an expert on engine building and am sure you have more experience than myself, but I found a few interesting things in an article on the web. I realize that rod bearings come in narrow widths - which is more of what I was leaning to. The chamfers on the main bearings I did find available for a small block. I also know that you can purchase a tool to chamfer bearings, but of course the average guy with an electric drill and vice isn't going to be doing this.

Clevite & King sell a .001 narrowed main bearing set (also .002 for Clevite) and King main bearings do advertise the chamfers for large radius cranks.

Here is what I read: "Taken as a generalized statement, stock replacement rod bearings are often slightly wider than their high performance bearing cousins. To illustrate this point, we measured the width of a set of stock replacement aluminum Federal-Mogul connecting rod bearings for a big-block Chevy compared to a set of Federal-Mogul (Speed-Pro) performance tri-metal bearings. The stock aluminum versions measured 0.885-inch while the performance bearings were 0.020-inch narrower at 0.865-inch. Using the wider bearings on a performance forged steel crankshaft could cause the outer edges of the bearing to bind on the larger fillet radius of the crankshaft. This could cause immediate bearing failure, and at the minimum will cause bearing debris to be released into the oil."

Now I found this interesting and thinking out of the box, is it possible the bearing halves were mixed up at the factory? I realize you align the oil hole in the bearing half with the oil hole in the block, but what if the wrong half got drilled at the factory? Why I ask is that this same article mentions the register tang position having an upper & lower position to the bearing half - this is again in regards to a rod bearing, but could this apply to a main?

"Narrowed bearings also brings up the issue of rod bearing chamfers. Most performance rod bearings are designed with a chamfer on one side of the bearing to accommodate the large radius on the edge of the journal. Since the inboard side of the bearing avoids this fillet radius, there is no need for a chamfer on both side of the bearing. But with both upper and lower bearings, this demands that the bearing be placed in their proper orientation. Because the bearing is located by its tang, a chamfered bearing must be installed either as an upper or lower bearings since the chamfer will be on the opposite side for a lower compared to an upper bearing half.

This requires performance rod bearings with these chamfers to be marked “upper” and “lower”. Some bearing companies abbreviate this by using “U” and “L” as stamped on the back side of the rod. If these bearing halves are incorrectly installed, the bearing’s flat edge will face the fillet radius and create immediate bearing wear in this location–often the rod will even bind once the cap is torqued. "

I read that the bearing tang was slightly off. Is it possible the factory.manufacturing source had the bearings flipped and drilled the oiling hole in the wrong bearing half thus positioning the tang in the wrong place and pushing the bearing in the direction of the crank radius rather than away from it? Just thinking here knowing how quality control can be - especially if outsourced from overseas.

[wbnapier]

I read that the bearing tang was slightly off. Is it possible the factory.manufacturing source had the bearings flipped and drilled the oiling hole in the wrong bearing half thus positioning the tang in the wrong place and pushing the bearing in the direction of the crank radius rather than away from it? Just thinking here knowing how quality control can be - especially if outsourced from overseas.[/QUOTE]

I am hoping that the Clevite rep takes an interest and answers these questions.

For the record, I have no illusion of financial relief at this point. Just intellectual curiosity.

[Sirrotica]

I'm kind of surprised of the content of that E Mail. Although I've never done any business with the Butlers, I have shared an adjoining spot on the manufacturers midway at Norwalk for 7 years, and have had occasion to talk to them during the event in the course of selling my Pontiac themed T shirts.

One year there was someone displaying a crank that was pretty much destroyed in the swap meet, that was from an engine that had problems, alluding to the crank was bought from the Butlers, and was alleged to have been defective when bought, causing the engine to fail. The situation got back to the Butlers and they went and discussed the situation, and came to some type of understanding that the aggrieved party was going to get some type of compensation for their trouble.

From the story I was told, it didn't sound to me that the crank was the fault of the vendor, but in a leap of good faith they were willing to do something to help out the customer.

I've heard that some of the employees in the past have been abrupt on the phone with customers, and that the owners would have been less than happy with the responses from their employees. In my speaking with them over the years they're nice, fair, people. I'm wondering if the E Mail was from an employee, rather than one of the Butler family.....

The core shift response sounds like a far fetched reach in trying to explain away what happened with the rotating assembly. Just kind of surprised at that response.

I'm in agreement that core shift happens during the casting process when the block is made. It has little to do with how main bearings sit in the block decades after the fact. IMO, If anything, the factory machining initially would make a problem, not core shift. FWIW.

I have a friend that builds his own SBC oval track engines, when he stepped up to using aftermarket cranks over factory pieces, he also ran into the radius problem on rod throws. He caught the interference problem and had to order the relieved rod bearings to solve his problem. The Pontiac community doesn't have anywhere near the choices of bearings that SBC builders do, we sometimes have to modify the bearings themselves rather than buy a bearing that fits our applications. Just a fact due to the supply, and demand in our small circle..............

[wbnapier]

I spoke to my machinist yesterday, and the long block will be ready for me to pick up the week after Thanksgiving... So, I should have it installed and running by Christmas.

He will be using FM bearings this time around!

Some other interesting points from the machinist.

The camshaft woodruff key didn't sit well in the groove and I broke one cam gear on install, and another on disassembly. The machinist uses a non-Pontiac one that has a flat bottom and nests better, solving this issue.

Also, he doesn't like the composite dizzy gears. I had a BOP one I was going to put on, but he thinks a gear that matches the camshaft alloy is best.

Anyway, I'm excited to get this project moving forward. I'll post photos when the time comes.