LS trunnion upgrades & longevity

[modok]

indeed it is tapered.
Although I think the K shape would work well for a rocker bushing also.
Rocker bushings could be tapered, since main load is one sided, but maybe that's another subject?

[Kevin Johnson]

indeed it is tapered.
Although I think the K shape would work well for a rocker bushing also.
Rocker bushings could be tapered, since main load is one sided, but maybe that's another subject?

I like "K" but then I am biased.

[turbo camino]

Is that an application with piston squirters? OEM stuff? Pretty impressive they can keep control of all the tolerances to the point where the bushings can be sized before install.

Kevin, why do you like the Y over a V shape? What does the straight leg do, why's it need to be there? Just curious.

There are inertial forces involved in a pin bushing that affect things that a rocker application doesn't have to deal with. In the conrod I guess it's possible to create a design that flings out as much oil as goes in.

[MadBill]

...Kevin, why do you like the Y over a V shape? What does the straight leg do, why's it need to be there? Just curious....

I believe it's the 'K' pattern that Kevin for unknown reasons prefers.

[modok]

Is that an application with piston squirters? OEM stuff? Pretty impressive they can keep control of all the tolerances to the point where the bushings can be sized before install.

Kevin, why do you like the Y over a V shape? What does the straight leg do, why's it need to be there? Just curious.

There are inertial forces involved in a pin bushing that affect things that a rocker application doesn't have to deal with. In the conrod I guess it's possible to create a design that flings out as much oil as goes in.

The bushings come about .030 short of size, bored to size after installation.
Pre-sized bushings are available for some engines, such as john deere, but they really don't work very well at all.

This engine does have piston coolers, but, I don't think that has much impact on the design of the pin bushing. Besides cooling.
There are several different sizes of piston coolers depending on the power level.

Other designs of pin bushing were used in the same engine family before this, holes, and/or a full groove, and they didn't work near as well.

While rockers and pin bushings are different, they are also very similar. For instance, I think it's really interesting that sometimes pressure oiled pin bushings and rockers sometimes wear FASTER than splash oiled. A lot of oil flow through the bushing does keep it cooled and oiled, but also brings with it more dirt.
Both are particularly susceptible to fine dirt in the oil because the oil film is much thinner than the main or rod bearings, much slower rotational speed compared to load.

[Kevin Johnson]

The insert is not regularly shaped (kinda like conic sections but obliquely through the cylindrical shape). It will only fit the small end in one way correctly and the notches are to control the insertion exactly.

(I say this because it appears that the small end is tapered.)

Just found a Mahle patent; see feature 112 (lubrication recess):

https://patents.google.com/patent/US20100300397A1/en

Another one: https://patents.google.com/patent/US8613137B2/en