New 4.6L stroker build

[SilverXJ]

I6FAN wrote:
Not if it the leak was after the M and R bearings; like the feed line that intersects the main feed and leads to the cam bearings. (How do they drill those anyway, unless they are "cast in"?).

The oil path on the 4.0L is different from the V8s. I'll try to describe it here. The oil pump goes to the filter, which then goes to the lifter gallery. The lifter gallery also feed everything else. From the lifter gallery the oil goes to the main and rod gallery, which the cam bearings intersect. The cam bearings get their oil directly from the same line that feeds the main and rods, so there is no cam bearing gallery of its own. The oil system is different from the various V8s that have a separate feed for the lifters and cam bearings.

Yes it was 40psi, but was it 40psi everywhere it needed to be?

I moved the oil pressure sender from directly off the filter to the end of the block, which is at the end of the lifter gallery, before it goes to the mains, rods, and cam. If there was a leak between the lifter gallery and cam bearings then the main and rod bearings should be showing it as well. And that was at the very end of the gallery, and the #3 cam bearing showed the worse wear all times.

That's right. And these were two big changes that I would think each one, independently, should have yielded results. You would think both remedies together would push you over the top. Unless there is some serious leak somewhere?

If there is a serious leak it would have to be at the cam bearings themselves.

But if there is a leak at the cam bearings.... did the leak come first, or did something else cause the bearing wear which in turn caused the leak?

[I6FAN]

The oil path on the 4.0L is different from the V8s. I'll try to describe it here. The oil pump goes to the filter, which then goes to the lifter gallery. The lifter gallery also feed everything else. From the lifter gallery the oil goes to the main and rod gallery, which the cam bearings intersect. The cam bearings get their oil directly from the same line that feeds the main and rods, so there is no cam bearing gallery of its own. The oil system is different from the various V8s that have a separate feed for the lifters and cam bearings.

I got it. I envisioned the cam feed to "tee" into the line from Lifter Gallery-to-Main, but the Main feed on 1,3,5,& 7 actually intersects cam journals at a point tangent-like-to the cam journal diameter; there is no "line" to the cam journal.

Yes it was 40psi, but was it 40psi everywhere it needed to be? I moved the oil pressure sender from directly off the filter to the end of the block, which is at the end of the lifter gallery, before it goes to the mains, rods, and cam. If there was a leak between the lifter gallery and cam bearings then the main and rod bearings should be showing it as well. And that was at the very end of the gallery, and the #3 cam bearing showed the worse wear all times.

I see what your saying if there is a leak along that "line" anywhere, all bearings in that circuit should show it. But would they? They kind of see different kinds of stresses at different speeds. It might take more miles for there to be signs. Could there be something about Main #5 that is affecting Cam #3? Do all of the Mains feed Rod pins, or does Main 1, 3, 5, & 7 feed cam 1, 2, 3, & 4, and Mains 2, 4, 6 feed Rods pins 1 & 2, 3 & 4, and 5 & 6 (repectively)? Or in other words, does each Rod pin interdict with each Main journal on either sides of it? Kind of difficult to see that in schematic.

That's right. And these were two big changes that I would think each one, independently, should have yielded results. You would think both remedies together would push you over the top. Unless there is some serious leak somewhere?If there is a serious leak it would have to be at the cam bearings themselves.

But if there is a leak at the cam bearings.... did the leak come first, or did something else cause the bearing wear which in turn caused the leak?

This is a stitch, but how about between the bearing liner and the cam journal?

[SilverXJ]

I see what your saying if there is a leak along that "line" anywhere, all bearings in that circuit should show it. But would they? They kind of see different kinds of stresses at different speeds. It might take more miles for there to be signs.

But the mains and rods are under a lot more stress than the cam bearings. The cam bearings shouldn't be under a heavy load.

Could there be something about Main #5 that is affecting Cam #3?

like what?

Do all of the Mains feed Rod pins, or does Main 1, 3, 5, & 7 feed cam 1, 2, 3, & 4, and Mains 2, 4, 6 feed Rods pins 1 & 2, 3 & 4, and 5 & 6 (repectively)?

Main gallery #1 feeds main #1 and cam #1
Main gallery #2 feeds main #2
Main gallery #3 feeds main #3 and cam #2
Main gallery #4 feeds main #4
Main gallery #5 feeds main #5 and cam #3
Main gallery #6 feeds main #6
Main gallery #7 feeds main #7 and cam #4

This is a stitch, but how about between the bearing liner and the cam journal?

Hopefully measuring at several different points and using machinist blue on the bearings will show something.

[dwg86]

[/quote] But the mains and rods are under a lot more stress than the cam bearings. The cam bearings shouldn't be under a heavy load.

Are the rods and mains under more load? The cam bearings are under a pretty good load with 12 valve springs pushing down from anywhere from 100psi to 250psi (or what ever your valve spring values are on the seat and full open). But then again are the bearings on a load or is it the oil film on the bearings? I didn't think the bearings were to contact metal during engine operation. If it did, wouldn't the bearings wear out fast. I don't think engines would last 100,000-200,000 miles or more with metal to bearing contact

[SilverXJ]

The cam is under a very small load from the lifter while the lifter is on the base circle. When the valve starts to open that is where the pressure comes from. Still, its not a lot compared with the downward forces seem from the piston on the crank and rods. Also, the rod and main bearings are under a lot more violent motion than the cam bearings see. The cam gradually lifts the lifter, where the combustion event isn't that gradual or gentle. Compare the cam bearings to the rod and main bearings on a well worn but otherwise sound engine and there will be very little wear on the cam bearings compared to the rod and mains.

While there is an oil layer between the bearing and the journal, the oil is still incompressible and the force has to go someplace. While it can push oil out the sides of the bearings, some force is still transmitted to the bearings.

[I6FAN]

Do all of the Mains feed Rod pins, or does Main 1, 3, 5, & 7 feed cam 1, 2, 3, & 4, and Mains 2, 4, 6 feed Rods pins 1 & 2, 3 & 4, and 5 & 6 (repectively)?
Main gallery #1 feeds main #1 and cam #1
Main gallery #2 feeds main #2
Main gallery #3 feeds main #3 and cam #2
Main gallery #4 feeds main #4
Main gallery #5 feeds main #5 and cam #3
Main gallery #6 feeds main #6
Main gallery #7 feeds main #7 and cam #4

Think about Rod bearing oiling in your map above. What I'm getting at here is: If Main #5 and Cam #3 are not getting any flow could adjacent Rod bearings 4 & 5 force some pressurized oil back down to Main #5. if so that may be how those bearings survive and cam #3 doesn't.

Could there be something about Main #5 that is affecting Cam #3? like what?

Something that would allow too much bleed off i.e. clearences or cracks. I've heard that when these engines suffer a crank failure I believe it's # 5 that goes. If so, #5 gets stressed more?

Hopefully measuring at several different points and using machinist blue on the bearings will show something.

x2

[SilverXJ]

Think about Rod bearing oiling in your map above. What I'm getting at here is: If Main #5 and Cam #3 are not getting any flow could adjacent Rod bearings 4 & 5 force some pressurized oil back down to Main #5. if so that may be how those bearings survive and cam #3 doesn't.

Not possible. The only way the mains are connected is through the lifter gallery. There isn't another gallery that runs adjacent to the lifter gallery.

Something that would allow too much bleed off i.e. clearences or cracks. I've heard that when these engines suffer a crank failure I believe it's # 5 that goes. If so, #5 gets stressed more?

I haven't heard of an actual crank failure during normal operation. I've heard of the piston failing though.

[I6FAN]

Not possible. The only way the mains are connected is through the lifter gallery. There isn't another gallery that runs adjacent to the lifter gallery.

Okay, I couldn't make out the schematic for the rod pin oiling. I was thinking every main journal was drilled through to each rod journals on both sides. I think this is correct (added what was in blue):
Main gallery #1 feeds main #1 and cam #1 and rod #1
Main gallery #2 feeds main #2 and rod #2
Main gallery #3 feeds main #3 and cam #2 and rod #3
Main gallery #4 feeds main #4 nothing else
Main gallery #5 feeds main #5 and cam #3 and rod #4
Main gallery #6 feeds main #6 and rod #5
Main gallery #7 feeds main #7 and cam #4 and rod #6

Main gallery #4 only feeds main #4 is it a smaller diameter than the others? Seems like it should be, or run tighter clearence on #4 to boost the others. There is something about main bearing bore to crank main bearing insert matching that is different for #1 and 7 and 2 thru 6 are all the same per (FSM)? I know you said something about an oil leak? Also, there was some question as to the tightness of the oil tube pickup before, and the FSM shows a special tool for installing this. I'm thinking that it is more of a serious press-to-crush fitment to require a special tool.

[SilverXJ]

Main gallery #4 only feeds main #4 is it a smaller diameter than the others? Seems like it should be, or run tighter clearence on #4 to boost the others. There is something about main bearing bore to crank main bearing insert matching that is different for #1 and 7 and 2 thru 6 are all the same per (FSM)?

All the main bearings are the same except #3 which is the thrust bearing. No oil galleries are different.

I know you said something about an oil leak?

External or internal? I had a small external one at the back of the block. At one point the oil pump pickup wasn't seated correctly, and the oil pump wasn't flush with the block. All have been fixed.

Also, there was some question as to the tightness of the oil tube pickup before, and the FSM shows a special tool for installing this. I'm thinking that it is more of a serious press-to-crush fitment to require a special tool.

Its a press fit. You don't need a tool, but I made a tool that worked well. Its tight now.

[I6FAN]

I was thinking about the external leak. I remember theoil pump wasn't seating properly, but you rectified that... Did you find out what was leaking or causing it?

[SilverXJ]

Leak at the oil pan at the rear.

[SilverXJ]

Won't be using the telescoping gages. They aren't working out the way they should. Its hard enough to get a consistent measurement when I have direct access to the bearing, like at the front, but the bearings inside of the block aren't working out at all.

On inspecting the latest batch of bearings I noticed that there was a little bit of rubbing on the bearing on the sides of the oil hole, parallel to the cam shaft. I wonder if it was possible for the oil flow to be partially blocked by a high spot in the bearing.

I got the N-7B bearings with teh OD groove. The OD grove measures .018"x .256". The hole through the bearing is slightly smaller than stock and I am wondering if I should open it up or not. The hole will be installed at the 2-3 o'clock position. I will chamfer the holes on both sides, and put a small grove on part the ID of the bearing to coax the oil in. I'll also check for high spots using the engineering blue, then check only with engine oil for binding. I'm also going to make an attempt to check the clearance my self. Snap gages didn't work very well though in the confined space in the engine, so I won't be using those.

I did measure the cam journals and they are right in the middle of the specs.

[dwg86]

I know this is not practical or needed on a street engine, but it's COOL and would take care of the babbit bearing problem.
http://www.holbrookracingengines.com/ma ... llerb.html

[lafrad]

Be sure NOT to use anything that can spark... the hot sparks from grinding or shaving will melt themselves into the bearing face and cause all sorts of problems.

[SilverXJ]

err.. yeah... that would get costly. The cam journals are 4 different sizes as are the bores. Resizing the bores to a standard size wouldn't be a problem. The cam journals would also have to be turned down to a standard size. The cam journals would also have to be induction hardened to handle the roller bearings. Not sure one could even do that to a cast cam. One could possibly have the cam journals machined to accept a hardened sleeve though. Hesco does have a full roller cam, but its race only as it uses a different ignition/computer to get the cam sensor signal from a different place. Major bucks for either option.