To Do Rocker Bearing Modifications?

[Chopchop]

Here is a multi-part question for the experts. My 49 Pan heads are at the machinist; had a stuck intake valve; he said I need new valves and guides due to metal transfer & excessive guide clearance, damn! FYI, the heads do not have intake oilers or felt pads; also, they have all (4) different types of upper rocker bearings as described in the Palmer book (p 184).

1. There was quite a bit a black-tar like deposits in the inlet ports, valves & guides. Was this due to over oiling since it didn't have the oilers as decribed in the Palmer book (p 185)?

2. I bought a set of repop oilers from Vulcan Engineering, does anyone have knowledge of this brand? They seem robust. The "Spare Parts" book shows an odd-shaped washer between the oiler and the rocker bearing; is this required? the oiler body has a shape to allow the oil to run from the stud hole, and down a groove into the oiler tube.

3. I have "read" there is a modification to drill a hole on the top of the rocker bearing to aid oiling. Is this recommended & on both inlet and outlet rockers? It appeared there was plenty of oil in there when I took them appart. Also, doesn't adding this hole reduce the oil pressure to send oil to the inlet oilers? Can someone post a sketch showing the dimensions & hole size of this added hole modification?

4. Since I have the (4) different type of upper rocker bearings, one with no oil groove, one with double grooves and the inlets with single grooves. Should I modify 3 of them so they have double grooves?

Sorry for the excess verbage & questions, I am probably over analyzing the subject.

I appreciate any help offered on this subject.

Thanks, Jeff

[mule]

I am NO expert, but I think the holes drilled in the top half of the rocker arm bearing was to allow trapped Bearing debri to escape. Panheads are Famous for sticking intake valves, thats why the oilers, it is a factory fix to a problem. Marvel Mystery oil in the oil and a small amount in the fuel helps with sticking valves, I have heard it was developed for our war planes in WWII that had sticking valve problems. Mule...

[Cotten]

A true expert told me to save Clymer manuals for the outhouse, only.

The holes in the caps with holes are for the intakes, although it is probable that no harm would occur on an exhaust. It allows oil in from the felts for start-up, as there will always be a lag before the top end recieves oil from the pump.
It seems there was a "Shop Dope" that eliminated the oilers, but the felts are still manditory. (Felts for rocker oiling was not uncommon on other machinery prior to the Pan era: '38-'39 Indian Fours, and perhaps others that I have had no experience with... used pads inside their covers.)

The "odd-shaped washer" was upon '48s only, apparently.

"Tar-like substances" are indeed burnt oil, but are a result and not a cause. Oil can come from many sources, not only past the valves with excessive clearances, but from the combustion chamber when other things are amiss. One very bad scenario is when previous guides have been carelessly removed and their bores in the head casting are scored, leaving canals direct to the ports.

For any oil to burn to tar, the temperatures must be elevated.
Which brings us to the statement: "Panheads are Famous for sticking intake valves". This is a misleading excuse, as properly maintained Pans are equally famous for their durability and longevity.
After all, it took many decades of use and abuse, and a tragic decline in fuel quality, before both Pans and Chubbleheads everywhere suffered valve sticking as a common occurance, in the late Seventies and early Eighties. (Ya had to be there....)

Heat sticks valves.

Cure the excessive heat, and motors can run phenomenally.

The most common source of excessive heat, although there are many, is the evil manifold leak.
The fuse is never lit where the bomb goes off.


....Cotten

[NightShift]

A true expert told me to save Clymer manuals for the outhouse, only.

What I said was that Clymer books ain't even good for the outhouse.

[mule]

Yes cotten is right about the heat, The only time I stuck an intake valve on one of my Pans was due to the machinist who did my heads did not cut one intake seat after he installed new guides. The combustion gases blew past the valve and overheated it and it stuck in the guide at 58 miles. I have that bent valve sitting here as a reminder. The intakes get less oil on a panhead ,being located at the top of the head, less oil more heat, if something is not right... I guess Pans are a little more Famous for sticking valves out here in the Central Valley of California as the temp today is 108 Deg. NO expert ,Mule....

[Chopchop]

Thanks for the input regarding my questions!

I am not sold on the theory that the pads provide any oiling to the rocker bearings especially if there isn't a hole; the pads may help oil the springs and valve stems... I think that any oil the "migrates" from the pads into the hole in the top intake rocker bearing will be very nominal??? Any oil that is in the rocker bearings when the engine is shut down should still be there for start-up, I don't think it will leak down...

It seems that the hole in the top of the intake rocker bearing will be more effective in providing oil to the intake valve.

Was the "hole" installed to replace the "oilers" or can the both be used at the same time?

If so, can someone provide a sketch of the location, angle & diameter of the intake rocker bearing hole.

Thanks!

Jeff