Freezing cam bearings before installation?

[CNC BLOCKS]

Can I ask people's reasoning behind installing cam bearings dry? I install my cam bearings with lube on both the bearing and housing bore and have never had a problem. My reason for doing this is I believe lubing both parts will help the bearing knock in with less force/friction, and to help prevent the bearing/housing bore from galling or peeling some of the back of the bearing off. Same thing if I have to drive/press a sleeve, guide, valve seat etc. I also lube one piece rear mains (except when I have the rear cap off, eg late model Windsor), cam, front crank seals and the like whilst installing them.

Now, when I shrink fit something with liquid nitrogen sure it's dry. But that's because the part being inserted will have clearance whilst it's cold and will slip in under gravity. Also I fit conventional big end and main bearings dry (as would most people I presume) but I think we can all agree that is a completely different application given the bearing is in two halves and installs in a different manor.

I have bought brand new OEM replacement blocks from GM and they all have come with cam bearings installed and look like they were installed dry and how many cam bearings has GM installed over the years?

[Cubic_Cleveland]

Can I ask people's reasoning behind installing cam bearings dry? I install my cam bearings with lube on both the bearing and housing bore and have never had a problem. My reason for doing this is I believe lubing both parts will help the bearing knock in with less force/friction, and to help prevent the bearing/housing bore from galling or peeling some of the back of the bearing off. Same thing if I have to drive/press a sleeve, guide, valve seat etc. I also lube one piece rear mains (except when I have the rear cap off, eg late model Windsor), cam, front crank seals and the like whilst installing them.

Now, when I shrink fit something with liquid nitrogen sure it's dry. But that's because the part being inserted will have clearance whilst it's cold and will slip in under gravity. Also I fit conventional big end and main bearings dry (as would most people I presume) but I think we can all agree that is a completely different application given the bearing is in two halves and installs in a different manor.

I have bought brand new OEM replacement blocks from GM and they all have come with cam bearings installed and look like they were installed dry and how many cam bearings has GM installed over the years?

Please don't think I am saying my way is right, and installing them dry is wrong. It obviously works for a lot of people. I'm more interested in the reasoning behind it, maybe I can learn something.

[racear2865]

Barry said:

But if you are purchasing Clevite, F-M, or Durabod bearings you are getting the same parts.

Do you know who makes King's?

TIA
Dave

Dave
I think their headquarters is based in Kiryat Gat, Israel. Their manufacturing plant is also located there. It is listed as King LTD. Unless thet have started farming out, all engine bearings are produced there.The United States is listed as the North American Headquarters and Distribution Center and it is known as King Engine Bearings Inc based out of Cedar Grove, NJ. I think this was true in the beginning and they were looking at bringing some operations to here. Dont feel this is the gospel but I think it is so.

Look at page 2
http://www.cartek.com.mx/files/catalogo ... 711558.pdf
reed

[fastvette]

My thoughts on installing dry are if there are any shavings after installing them you can blow out with compressed air. The first thing I do with a clean dry block is install the cam bearings and then blow through the cam bearing oil holes and all the oil passages before the oil galley plugs go in. Just my way of doing it.

Randy

[dave brode]

Thanks, Reed.

Dave

[smeg]

I am not saying you are wrong in oiling the cam bearing before you fit it. It is probably what we all should be doing but, I am chamfering the tunnel before I
fit the bearing and have had no problems ever. After we fit the bearings we blow it out and final wash the block.
What we have found, but it is another topic, is heaps of undersize cam tunnels. That is another problem all together.

[Cubic_Cleveland]

I agree with chamfering/de-burring the block and I too re-wash the block after installing cam bearings and then install gallery plugs. I'd hate for one of those little slivers to jam the pressure relief valve open or something like that...

[Kevin Johnson]

Please don't think I am saying my way is right, and installing them dry is wrong. It obviously works for a lot of people. I'm more interested in the reasoning behind it, maybe I can learn something.

The following is an opinion.

I think the reason they are installed dry is because that method has been successfully used for so long and when you change a process, even in seemingly insignificant ways, it can have unintended consequences (see silicone lubricants in paint shops). Often, step manufacturing processes will involve a drift by individual workers in technique and, like tolerance stacking, this can be a problem. If a chemical product vendor changes a formulation or even the sourcing of raw materials it can definitely be an issue. Revisit the threads on fastener assembly lubes, for example. Outside of the automotive industry, people with severe allergies can die simply from trace cross contamination of cooking/handling surfaces. Why do chemists triple-wash glassware?

If you look in the old Chevrolet factory service manuals, the installation of press fit rocker studs specifically calls out using a lubricant. The cam bearings do not have this called out but in other areas of the manual it is advised to coat all exposed machined surfaces with a light oil. Temperature changes in the Detroit area (for example) at various times of the year would certainly allow humidity to condense and flash rust. If an operation could not be carried out immediately, it would probably be coated. This does not take into account the trace amounts of (then - oil based) cutting fluids which would normally be present.

Moreover, it is an unknown in this discussion whether cam bearings come pre-coated with a thin layer of lubricant/preservative. The Timken catalog mentions using such coatings on bearings and heating up bearings in baths of oil and using lubricants on interference fits to reduce force.

As an aside, and because I just appear to think about everything as zebras rather than horses, it would be wise to review the history of vacuum welding in the space programs and specific incidents (capsule hatch door and another with the Galileo that was traced to truck transport vibration that went unconsidered (and then go back even further in years to unanticipated vibration/galling issues that arose when first shipping automobiles by rail)).

The important thing is for people to always keep thinking and asking.

As a younger man starting out in the world, I was admiring a carpenter friend's skill with a hammer. When I asked about the hand eye motor skill involved he paused and said
"You just have to be smarter than the hammer."
That simple statement was kind of an eye opener to many things.

I have since found this to be true for all machines that we use and the metal we try to move.
Outsmarting the quirks of a machine to arrive at the desired result is what makes a good machinist.
Some get it, some never do.

[SchmidtMotorWorks]

I am in the habit of using dry ice to freeze just about everything with a press fit except hard dowel pins.
When you can just put the part in place with no effort there isn't any reason to use oil, in fact the oil gets syrup like, wastes time (seconds count on thin parts), and becomes an annoyance.
Dry ice can be bought in the meat section of many grocery stores.

It can also be useful to disassemble things. I just used liquid nitrogen to remove some class abec-7 bearings off a spindle shaft, it changed it from a difficult press job that I would never consider reusing the $1,200 bearings to something that could be tapped apart with a plastic hammer.

[BrazilianZ28Camaro]

I read about some SBC Durabond cam bearings distorting on istallation creating "high spots" due the hammering of the installation tool.

This may be caused by excessive crush also, assuming a correct sized cam bore.

IMO, the lubrication or freezing of the bearings would reduce drastically these problems, BUT they seem to be rare and I agree, no need to fix what isn't broke.


Have anyone seem cam bearings distorting on assembly making the cam clearance tight or negative at some areas?

How much crush you like to see on the cam bearings?


Thanks for the good replies!

[rfoll]

The distortion I have seen was due to problems with the cam tunnel itself. It's pretty easy to bang thins up driving the old bearings out. I have been doing few spins with a small brake cylinder hone in each bore to show the high spots if any exist.