Measuring piston clearance

SVcummins · Jan 17, 2021

Another method

BRSnKY · Jan 17, 2021

I don't think Hank done it this way...

SVcummins · Jan 17, 2021

That’s a good tune . I’ve never tried doing it this way might try it if I can find some ribbon though

Steve@Advance · Jan 17, 2021

Looks like it would be impossible not to influence the results by how the piston is held.

Why not use a telescope gauge and micrometer?

Better yet a dial bore gauge if you have one?

oldsarge · Jan 17, 2021

Look at the procedure in the FO-4 manual........ Farmers didn't have mikes and bore gauges in them days....................................gtm

SVcummins · Jan 18, 2021

I have bore gauges Just another way to do it

Steve@Advance · Jan 18, 2021

I have an ancient electricians hand book from probably the '20s.

Evidently test instruments were not yet available or unaffordaable.

It said to test a circuit and you knew the voltage was 220 or less, slap it!

If 120, touch it!

If 24 or less, stick it to your tongue!

Life was hard in the good ol' days!

bc · Jan 18, 2021

(quoted from post at 08:44:24 01/18/21) I have an ancient electricians hand book from probably the '20s.

Evidently test instruments were not yet available or unaffordaable.

It said to test a circuit and you knew the voltage was 220 or less, slap it!

If 120, touch it!

If 24 or less, stick it to your tongue!

Life was hard in the good ol' days!

That is how I learned by accident. 220 gives a jolt up to the wrist. 120 gives a buzz in the finger. 9 volt batteries use the tongue and a new one gives a buzz to the tongue.

bc · Jan 18, 2021

(quoted from post at 19:48:33 01/17/21) Look at the procedure in the FO-4 manual........ Farmers didn't have mikes and bore gauges in them days....................................gtm

What is that procedure? Thanks.

Gary Mitchell · Jan 18, 2021

Good post! gm

kencombs · Jan 18, 2021

Very similar to the published procedure for 216 chevy babbit engines with cast iron pistons.

also bearing clearance for the rods could be set by removing shims, oiling the crank and rod, then bolting it to the crank journal with the rod horizontal (no piston). If it didn't swing down to vertical, it was too tight so add a shim and try again. Trial and error. No measurement tools needed.

Thousands of those were done successfully, and probably some not so successful.

I even saw some back in the very late 50s that had all the shims gone and the rod caps filed to tighten up the fit.

Make do at its best.

Super H Mike · Jan 18, 2021

I took apart a Kohler 1 cylinder last winter that you could have measured the piston clearance with a ruler

SVcummins · Jan 18, 2021

I’ve seen that a time or two

DMartin9N-2N · Jan 19, 2021

Good morning, kencombs and others: The Chev. 216s gave trouble when too much needed to be filed off the rod cap mating surfaces. The area where excessive wear occurred was in the upper half of the babbitt bearing, meaning (of course) the upper half (the area in the rod, where the full force of combustion was felt) was worn to an unknown amount. Sooner or later, the upper babbitt would wear through to the steel of the actual rod, and shortly the crank surface was ruined. That filing of rods was always a quick-fix, but a poor one for the car's owner.

In the early 1980s I rebuilt a 216; at that time I was able to buy a set of re-babbitted rods at a local parts store. I drove the pickup with that engine for many years, my main problem was I re-used a piston that I should have replaced, so I listened to piston slap for years.

Dennis M. in W. Tenn.

Measuring piston clearance

SVcummins

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BRSnKY

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oldsarge

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bc

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