New 4.6L stroker build

[SilverXJ]

What would i be using something that can spark for?

[lafrad]

"Put a small groove" in things that are metal often comes with high RPM spinn-y devices... thats all

[SilverXJ]

Ahh crap. Having looked at the block from upside down for the past month or so I forgot where the stock oil hole is on the cam bearings when the block is in the correct orientation. Its already at about the 2:15 position. Its recommended that the oil hole be placed at the 2 to 3 position with the load coming at the 12 position. So.. I'm not sure if these bearings will help any.. just so I can rotate the bearings just slightly. I suppose I can still use them.. maybe put another oil hole someplace in them.. but where then?

I'll have to get a good head on picture of the actual block to illustrate.

[SilverXJ]

"Put a small groove" in things that are metal often comes with high RPM spinn-y devices... thats all

Ahh... I understand.... it would be a dremel... haven't decided on a bit yet... and i don't think the bearing material will spark.

[dwg86]

Did you check to see if ACL makes an aluminum cam bearing for the Jeep 6, or one from another engine that will work? They make make aluminum race cam bearings for some engines.

[lafrad]

I'm pretty sure the 'backing" on most rebuild cam bearings are steel. I wouldn't do anything with fast sanding devices. Keep it to a manual file or a REALLY SLOW spinning burr tool.

I ran into this problem through experiance. Went through 3 sets of main bearings trying to find a proper setup to 360*-oil them (in turn, to 360* oil the rods... the thought here is that 360 of oiling to the rods would sling more oil at the cam, at the expense of some main bearing surface area, which, on a 7 main I6, is at a HUGE excess....)

[SilverXJ]

Did you check to see if ACL makes an aluminum cam bearing for the Jeep 6, or one from another engine that will work? They make make aluminum race cam bearings for some engines.

Yeah, I already checked. They only make the standard babbit, as do all the others.

I'm pretty sure the 'backing" on most rebuild cam bearings are steel. I wouldn't do anything with fast sanding devices. Keep it to a manual file or a REALLY SLOW spinning burr tool.

I wasn't planning on using any abrasive bit as I don't want abrasives becoming embedded in the babbit.

I ran into this problem through experiance. Went through 3 sets of main bearings trying to find a proper setup to 360*-oil them (in turn, to 360* oil the rods... the thought here is that 360 of oiling to the rods would sling more oil at the cam, at the expense of some main bearing surface area, which, on a 7 main I6, is at a HUGE excess....)

How deep and wide of a groove did you go with? I've heard of people removing the locating tang on another set of top bearings and putting those in the bottom for 360* oiling.

[lafrad]

My final (and current) solution was to use another set of top shells. i ground the locator on the main cap wider (so the tang still properly located the shell), and then got a little risky and smudged a touch of JB weld in the "Old" tang area, basically putting the filler in to still have the shell positively located in the horizontal direction. After the JB weld hardened, I pulled the bearing out and sanded the JB down a bit, so any thermal expansion differences would not interfere with bearing shell roundness.

after 14K miles I have no issues to speak of, and the HV pump has no problem keeping up with the new oiling demands... 20+ psi at Hot idle with 5W40 Synthetic oil.

[SilverXJ]

Here is the issue I am talking about:



Here is the full image of the bearing alignment, taken from http://www.dura-bondbearing.com/Portals ... lletin.pdf:


That is pretty much were the stock oil hole goes. I am not sure the benefit of the bearings with the OD grove unless I position the hole more clock wise, but I don't know if that is of benefit. Is it? Or if I drill another oil hole in the cam bearing. I'm not even sure why Durabond offers these bearings in this case. But it does explain why they are the only ones that offer them.

[Exos]

This is getting pretty complicated. Maybe I'm just lucky, but I've had no issue whatsoever yet, after 15000 km. In fact, the engine is giving me more than I expected. I've done no modifications to anything to get it to fit. I don't understand why you're having so much trouble.

[I6FAN]

Looking at the hole for cam bearing lube, it looks like if there wasn't enough back pressure further down stream in the line feeding the main and rod, I could see the oil going straight past the cam bearing without being forced down into it. You ground a port in the side of the rod bearings for cam lobe oiling, and I thought I heard someone report that their bearings also came without the oiler holes in the bearings. Do you think there could be too much oil liberation at this point due to the ARP rod bolt having a different architecture and size than the stockers; maybe they don't relieve them depending on the hardware used?

P1200309.jpg

P1200654.jpg

[SilverXJ]

The stock bearings had the notch, the Clevite bearings did not, but the King bearings I have now do. It is a fairly small hole that the oil passes through and I thing that if that was draining off that much oil pressure there would be main and rod bearing damage. Remember that the oil has to pas through the rod bearing to get to that hole in the first place. Plus I also had 40 PSI hot at idle at the rear of the block.

[SilverXJ]

Here is a pic of where the journals were rubbing the bearings near the oil hole.

[I6FAN]

It looks like the rubbing is kind of biased towards one side of the bearing. I wonder if that was the first half or last half that was inserted into the journal? I'm curious about the clearance at the rubbing point and offset to it. I would think this limits the amount of lubricant for that "wedge" effect if used as is.

[SilverXJ]

#1 and #2 it would be the second half, #3 and #4 would be the first half. I'm wondering about the clearance there too.. possibly rubbing up against the oil hole and blocking it. One person on speedtalk said it looks like possible distortion when the oil hole was punched in the bearing.