Nearly as good as an oil thread: diode boards

[Chuey]

ADV it got huge by making a playground for asshats and it can afford to alienate an aweful lot of people and still be big. The owners bottom line is they would rather be big than good.

I'm not so sure that's true. They didn't try very hard to help me when I couldn't register. I just love a good playground!

Chuey

[ME 109]

No, when you rebuild a top end only you do NOT prime the circuit.

I should have been specific. Prime the oil filter cavity and galleries.

After a bottom end rebuild.
Even with assembly lube, why wouldn't one prime the circuit?
It isn't difficult and gets oil everywhere sooner.
Not everyone has/uses ass. Lube.

[kutter]

And you get to check that the oil feed to
the rockers along the two upper head studs
have not been blocked by over generous use
of crankcase sealant !

[Major Softie]

And you get to check that the oil feed to
the rockers along the two upper head studs
have not been blocked by over generous use
of crankcase sealant !

And THAT is the most important reason of all.

[ME 109]

And you get to check that the oil feed to
the rockers along the two upper head studs
have not been blocked by over generous use
of crankcase sealant !

And THAT is the most important reason of all.

Oil flow to the rockers can be checked primed or not tho'
Just leave the covers off and start it.

[PITAPan]

And you get to check that the oil feed to
the rockers along the two upper head studs
have not been blocked by over generous use
of crankcase sealant !

You do not use sealant on the later engines. On the earlier ones with base gaskets (Rather than o-rings) you do not get overgenerous with the sealant. You don't have to check for a bad thing it because you don't do the bad thing. If you know enough to check, you know enough not to do it in the first place.

If you repaired an upper thread stud you check---with the top end off. You may do a flush for chips after drilling and tapping if you are worried, then clean up and glue in your insert.

[bbelk]

When one comes and goes from these threads, it is really hard to figure out how prime a circuit when we are in a discussion of diode boards. It is probably like putting smoke back into a Lucus system. I am sure there is a punch line somewhere. Oh look - its FunHoliday again. Now I am really lost. Maybe more wine would help.

[ME 109]

O ring system gets sealant. My 81 does.

Depends if one likes oil leaks.

[bbelk]

if one likes oil leaks.

I think the diode board is the only thing on my bikes that doesn't leak oil.

[PITAPan]

No, when you rebuild a top end only you do NOT prime the circuit.

I should have been specific. Prime the oil filter cavity and galleries.

After a bottom end rebuild.
Even with assembly lube, why wouldn't one prime the circuit?
It isn't difficult and gets oil everywhere sooner.
Not everyone has/uses ass. Lube.

The galleries are tiny and you have to do a major re-build to get them dry. The oil pressure relief cylinder at the timing chain has some volume but again doesn't drain. The filter canister and oil cooler get dry. I have noticed when changing oil that the pressure comes up in 1-2 revolutions, measuring mid-gallery. The relief isn't draining any oil yet and the pump has a lot of capacity. I've got full pressure++ before the engine catches.

"Even with assembly lube, why wouldn't one prime the circuit?"

Because you have assembly lube taking care of the lubrication.

If you do not have assembly lube, you get some. it's basic. if you don't know what you are doing, don't monkey with it. Take it to a pro. They will have, and use, an assembly lube.

The valve springs exert pressure on the followers/cam all the time. The only way to beat it is to remove the followers. They must have at least enough pressure on them to keep them in contact with the cam. Back the adjusters way off and they can float, and get hammered, even at starter cranking speeds. pulling the plugs and spinning the motor eliminates compression and thus pressure on the conrod and crank bearings. but the cam/follower is still under full pressure from the valve springs. Compress those valve springs by hand to get a feel for it.

The bottom end bearings (and the ones at the conrod small end) are all babbit bearings. They retain oil from the last run and can be spun under lighter pressure without damage. They aren't getting hot. With the engine firing the pressure against them is high, they get hot and need oil flow for lubrication and cooling. The cam interface at the follower is a different deal. Steel on steel and the polish means it holds oil poorly.