Make your own cam shim removal tools for $1.99

Stooge tool award.

I LOVE IT!

 

I for see a problem. You get the car back together and you are ready for the first start.....and take a look at your home made shim tool....and realize that the heat shrink
safety coating.....is missing.

 

Damn Bo!
you are a box of surprises, on this timing/cam/tappet subject. Seems you embrace the same idiom I have inherited form my old man; 'if you need something and can't justify the cost, then make it from nothin'! I got 1/2 way through making something similar and decided to put the time into removing the cams after measuring the lash.
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Cheers
Pete K
Perth, WA

 

I like to take the cams-out and micro-polish the caps and the cams. Over the years the surfaces have become very smooth and glossy so the can't hold much oil.

 

The original Ferrari tools were steel.

The brass junk are reproductions.

 

So let me get this straight, the surface is too smooth so you want to micro polish the surfaces so they hold more oil?

If that is what your saying, you need some personal study on the subject of both friction and how oil works to separate metallic objects.

I suspect someone has fed you some malarkey.

 

Bravo!

 

Thank you for the expert explanation .

For what reason are cylinder bores honed (aside perfecting the shape)? Or, more modern, laser-structured? Instead of making a mirror finish?

Cheers, Bernhard

P.S.: laser structuring: "The process uses a laser to burn small pits into areas of the cylinder bore surface where ring loading and wear are highest. The pits improve oil retention and ring lubrication, and significantly reduces ring and bore wear." Or see here: http://onlinelibrary.wiley.com/doi/10.1002/latj.201290067/pdf

 

For what reason are cylinder bores honed (aside perfecting the shape)? Or, more modern, laser-structured? Instead of making a mirror finish?


Iron cylinders were honed to make them round and a Little rough to help the rings wear in and seal. The Nikasil liners on the later Ferrari's and other modern cars use a different tool to finish the cylinders, not conventional honing stones. What you mentioned above is the first I heard of this process.

 

Well, Opel (GM) launched laser honing in 2002 already.

 

When a mirror smooth surface rubs against another mirror smooth surface, under pressure, the oil is effectively "wiped-off". An example of this is with machinist gage blocks (or Joe Blocks) when they are rubbed together there is not even room for air. A finely lapped surface will not hold air, oil or anything. The micro polishing does not affect the dimension at all, but it does allow the surface to hold a few molecules of oil here and there. If there is no oil the surface can gall and pick-up a few molecules of each piece. This is why used valve shims have a few minor galling spots.
This galling shows-up too when putting a press fit pin, bushing... together. If the surface is mirror-smooth there is likely to be som galling however if you press in the same components, but you put a fine micro-polished finish and some oil the parts will press together with non or minimal galling. The micro finish should be fine like the finish on a new ball bearing race.
Attached are pictures of my cam caps when I took them out 5 yrs later they looked the same except for a few spots that were smoothed-out. 6 years ago I re-polished the shiny spots and I'm getting ready to do it again so in the next few months I should have some more pictures.
A shaft that has a seal rubbing on it should be micro-polished too or the seal should be shimmed-out so it does not rub in the same groove.
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Keith 360;
Yes the smooth surfaces do not hold oil very well. Along with what others have said, the hone marks in a cylinder should stay-in, if they wear-out there will be a lot of wear and heat.

 

bpu669, what looks like the oil wasn't changed/contaminated?

The black mark on the outside of the cam was corrosion from pressure washing the engine before I opened it up.

My car is a driver and it has over 7ok miles on it.

 

The cross hatch on the caps was put in to hold more oil on the cam & caps when the engine runs. They work like the cross hatch in a cylinder bore and they have mostly remained after the 1,000 or so miles between belt changes.

You are lucky you were not a machinist!!

 

It is highly relevant, how the surface structure is in detail. Just as an example look at the laser honing technology.

The laser makes tiny "pockets" into the surface. At the same time crater rims around the pockets are created. The latter is not desired and leads to excessive wear. Thus, the laser honed cylinder is afterwards subjected to a mechanical treatment, that removes the crater rims.

The laser technology results in very defined structures. Mechanical grinding/honing/micropolishing processes are far less defined and may result in a high number of tiny (undesired) protrusions, more or less sharp, together with the (desired) pockets for retaining oil. This depends very sensible on how and with what tools and materials the honing/grinding/micropolishing was done.