The International Cessna^® 170 Association

Who's been best for our O-300 Crancase Overhaul Inspections

Hi fella's

Just wondering who has been the best for overhaul and inspection of our O-300' Crankcases.

I am on deployment right now but need to get my case sent out for inspection.

This crankcase was overhauled a long time ago by Columbia Aircraft Services Bloomsburg Pa and sat on the shelf.

Actually I have two crank cases its just this one I have someone to ship it and the other one no one there to ship.

Over the years I have become vary wary of people throwing aircraft parts on the assembly line and doing every service
available whether it needs it or not.

Not looking forward to someone saying they want to face the split line faces of the case where the halves mate so
they can charge me for a line bore that is not needed and end up in a situation where the case is worse off then it was
if I had just thrown it back together with possibilities of the accessory case misalignment, journals not being properly
bored and oversize or undersize, cracks from welding, and journal pins that hold bearing journal becoming loose by being removed.

I have an IO-540 narrow deck crank case I want inspected to but I imagine those of us here with our O-300's would know who is best on our O-300 engines.

Heard lots of horror stories.

Mike Robinson

Ney enterprises at Tulsa OK , explain what you want done.

he is the inventor of the Ney nozzle that cures the 0-320 H 2 AD problems.

It's been 8 years now, but I was very happy with the work Nickson's Machine Shop in Santa Maria, CA did on my case, as well as the internals of my O-300A. Ask for Klaus.

Thanks fellas,

Turns out I found a case that was overhauled many years ago to send in instead for inspection.

It is a O-300-D case by serial number, and since I am deployed right now I am not where I have info to see if I can use it.

There is also no one at home to send my A case in for overhaul but this D case that was originally overhauled is in a place where it can
be shipped.

But;

I know I can use a large flange A crank with a D case,

but I'm unsure if the D case will accept the A accessory housing, gears, and oil pump, and the B&C starter that I had bought for the A case.

I do know that there is an oil gallery in the D case that needs to be plugged that went to the D starter.

But the above is all I know at the moment.

A cases never had a hole for a pump on the right side of the forward nose case did they?

All my notes are at home.

Aryana wrote:The A case does have the hole on the right side of the forward nose.

Funny thing,, the 48 - 170 came from the factory with a C-145-A with a fuel pump on the nose of the case.

huh.... I didn't know that. Being so far away from home without pictures of my A case and no illustrations or books I didn't remember there being a hole there on the right side nose of the case.

an8pilot wrote:huh.... I didn't know that. Being so far away from home without pictures of my A case and no illustrations or books I didn't remember there being a hole there on the right side nose of the case.

The left and right cases are the same from the C-125 thru the 0-300-D, there are 3 different accessory cases, two versions of the sump.

Actually the cases got beefed up over the years with the D model being the heaviest.

T. C. Downey wrote:...The left and right cases are the same from the C-125 thru the 0-300-D, there are 3 different accessory cases, two versions of the sump.

Not exactly. There were at least three different cases produced. The earliest(C125/145 cases) had no nuts on the thru bolts at the front/right. The latest (so-called "heavy" case) was produced and used on the O300-C, D, and E engines and had 7/16" nuts on the thru bolts. There were other minor differences such as early studs were "wet" and later ones were blind at the cyl bases, etc. (You probably know that and were just simplifying matters, but I wanted to complicate things.)

you talk hardware, I was speaking of the castings.

T. C. Downey wrote:you talk hardware, I was speaking of the castings.

The castings are also different. How else would you turn open-ended "wet" studs into blind studs?
How else would you provide for nuts on thru bolts? What about the thru bolts at the bottom-center of the case, etc etc ?
A simple check of the Parts Manual will also demonstrate 3 different part numbers for crankcases applicable to different "dash" number engines to accommodate these differences.

gahorn wrote:

T. C. Downey wrote:you talk hardware, I was speaking of the castings.

The castings are also different. How else would you turn open-ended "wet" studs into blind studs?
By "studs" you mean the "thru bolt" the "O" ring type will fit the same thru cast bore as the non "O" Ring type, and vise versa.
How else would you provide for nuts on thru bolts?

simple, you up grade to the "O" ring type

What about the thru bolts at the bottom-center of the case, etc etc ?

Those are stopped at the case center seam by sealant

A simple check of the Parts Manual will also demonstrate 3 different part numbers for crankcases applicable to different "dash" number engines to accommodate these differences.

All the P/Ns from the old Parts catalog have been updated to after market suppliers numbers that all interchange..

I up grade all the engines I build to "O" Rings on the thru case bolts that hold the cylinders to the case and seal the case at the lower case thru bolts.

Well, now you're talking technique... not crankcase casting differences.
The studs I was referring are those which are open-ended (so-called "wet" because they eventually leak) in the crankcase vs those which are "blind" such as cyl base studs, etc. There are so many differences in castings that I only mentioned the most obvious.

Getting back to subject, tell me which P/N has no hole for the fuel pump.

The case halves can't be ordered new by any part number, we must get them from used part sources , So the 3 different numbers issue is a moot point.

Any two cases can be be made a match set, as long as there material to lap and line bore and still meet the deck height tolerances.

T. C. Downey wrote:

Aryana wrote:The A case does have the hole on the right side of the forward nose.

Funny thing,, the 48 - 170 came from the factory with a C-145-A with a fuel pump on the nose of the case.

I don't know who thought that they don't have a mount-pad for a pump. (But I never heard of a C-145-A before either )....