The Stovebolt Site Forums The Shop Area Engine Shop babbit bearings

i have decided the knock in my 49 3600 216 requires some attention.
the shop manual explains how to 'adjust' the rod bearings by removing shims.
what if there are no shims to remove?
is this rocket science, or shadetree mechanic stuff?

No, it's not rocket science. If there are no shims to remove, your easiest option is to remove material from the rod caps, not recommended for the inexperienced. This can be done with a piece of plate glass and wet sandpaper. The other option is to rebuild the engine and replace the babbit rods with insert bearings. However, as long as you don't over-rev the engine, the 216 will run for a long time with a rod knocking.

Just a point to ponder.....If you remove material from the rod cap itself. It will be junk and you'll have to find another if you ever plan to rebuild the engine.

Are you saying that the babbitt can be replaced by bearings? Is this a straightforward operation?

Whizzer - Your 216 rods can be machined for the steel-backed bearings. You might check with your local parts store or some of the vendors, they used to sell them. Someone here had bought them from a parts store in the last year or two.

anyone used plastigauge when adjusting rod bearings?
shop manuals says 'remove a shim, torque cap, should not move sideways unless tapped with hammer... install .002 shim ...
seems plastigauge is more accurate?

Too bad Proffit's in Europe. He hates plastigage. It gets the job done, but is nowhere near as accurate as micrometers and snap gauges. Squeezing plastic is not an exact science, but for the rods on a 216 it will be good enough.

One another note, oil film will cause false readings. I assume you're adjusting the rods with the engine in your truck. I would use some carb or brake cleaner on the caps and crank. Get some thin rubber gloves so you don't leave any fingerprints on the crank. And after you are through adjusting, spray some oil on the crank and caps before re-assembling.

very good advice, i figured i'd worry about not introducing engine compartment dirt during the process, but fingerprints?

In my manual it recommends against using plastigauge when the engine is in the truck. (1954)

winchester ,, some people have very acidic sweat and it can damage a smoothly machined surface.
I had the surface table machined to true it up , then even though I oiled it , 2 days later it was a mass of gritty finger prints , because one of the workers had very acidic sweaty fingers . Real frustrating .

When I tore down my 235 I found one fingerprint on a main journal. I would guess over 30K miles on it, too. Polished, high carbon steel is prone to rusting, and the salt in your fingers will leach through a thin layer of oil and cause the rust.

i'm not sure why you recommend against using plastigauge? i'm thinking of loosening the rod caps, sliding it in, retorque, loosen and check
then see how the knocking one compares after i de-shim it. seems more accurate then 'tapping it sideways with a hammer, or sliding it sideways with one hand' per the shop manual?
also manual says to use new PAL nuts. do these really lock the rod cap nuts sufficiently?