The International Cessna^® 170 Association

Hey all,

I have this single laminated page that's been kept in my glove box since I bought the airplane:
I'm curious if someone could verify its authenticity, or its source if it is part of a larger document. I've got a copy of the "owner's manual" but it is also lacking some information, like instrument markings for maximum oil temperature and pressure.

Also, I'm working with EI to get a CGR-30P set up and would like to confirm the marking numbers off this sheet. The engine is a C-145-2H.

Oil Temperature - Maximum: 225 degrees (red line)
Oil Pressure - Normal range: 30-40 psi (green range)
Oil Pressure - Maximum: 50 psi (red line)

Thanks for the help!

Here's a nice pic from Sunday at Slate Creek, ID just because:

If you look at the original AFMs here, viewtopic.php?f=31&t=9024#p80111, you will see yours is not an original. Though it may have all the same words.

That’s one very pretty aircraft ,great surrounding country and being blue it must be faster than those red ones .

Looking at your airplane, it appears to be a B model. The B model AFM in our library dated 1950 would be a more appropriate AFM to be carrying in the aircraft.

As for your limits marks as they came from Cessna, you can see they are not listed anyplace. Actual limits are spread thru out various documents some approved such as the engine TC E-253 and others such as the Owners Manual, not.

Looking at your numbers questioned, oil temp gauges did come with a red line at 225° though according to the latest TCM Operators Manual if using straight 50w oil max temp is 240°. Oil pressure normal range is 30-40 and I recall this to be a green range. I do not recall 50 psi being a red line on the original gauge. We've had a discussion about this with input from members perhaps you could find that. Also study any instrument pictures you can find.

Thanks guys!

Bruce, I’ve noticed just that, seem to be spread out.

My current oil pressure gauge is only marked with the green range. There is no red line marked on either the pressure or temperature gauge.

When I get home from this work rotation, I think I’m going to print out the AFM at the link you sent, laminate it, and carry it with.

Thanks for the nice comments, I’m enjoying the airplane so far. It started life red, and somewhere along the line it was painted blue...someone must have been looking for some extra speed!!!!

The oil pressure gauge should have one red-line.... at the minimum 5 psi.

How I remember that (since I’ve never seen a gauge-so marked: The FSDO Inspector Mr Anderson was the guest speaker whom I had invited to speak at the Benton Harbor MI convention. By pre-arrangement, I had asked him to review all the 170 on the flight-line as a courtesy-without-penalty.... and as a private joke, pretending not to know it was the Parts and Mx Advisor to the Assocn’n, personal airplane.... he confiscated MY airplanes’ Airworthiness Certificate for having no 5 psi redline on my oil pressure gauge. Everyone got a good laugh at my supposed expense.

He was supposed to return it to me privately.... but as things should happen..... Mr. Anderson forgot to return it to me!

(It was located before the next flight however, stored inside the speakers podium.) Whew!

George, Rick Anderson bases his 182 on the same airport where I live. Now that I’ve gotten to know him a bit better, I think he may not have “forgotten” to return your airworthiness certificate.

Bruce Fenstermacher wrote:As for your limits marks as they came from Cessna, you can see they are not listed anyplace. Actual limits are spread thru out various documents some approved such as the engine TC E-253 and others such as the Owners Manual, not.

GAHorn wrote:The oil pressure gauge should have one red-line.... at the minimum 5 psi.

The oil pressure gauge in the 170/170A/170B, according to the IPC's is p/n 0411016-2. I'm quite certain this corresponds to Rochester p/n 2525-5-168. As you can see the original markings had two red lines, one at 5 psi and one at 50 psi. These numbers match the AFM. But Bruce is correct in that one can find a wide variety of limits sorting through various Cessna, FAA, and Continental publishings. The '69-'76 C-172 Service Manual lists the following for the O-300D engine:Here are some other places that list C-145/O-300 oil pressures:

My oil pressure at 200 hours TSOH ran at 55 psi. I first confirmed the accuracy of my gauge, then I contacted TCM and talked to their Field Rep in CO, a Mr. Thompson, who informed me the C-145/O-300 early lifters were risky above 45-50 therefore the early limitation, but that all engines built/ovhl’d since 1960 used lifters with upper limits of 55 therefor my indications were no problem. After 1000 hours TSOH fully warmed up my pressure runs at 50 psi hot, cruise RPM and 35 at hot idle RPM. (Here in hot, Texas summers, my oil temp commonly runs around 185-210 at cruise.)

We’ve seen this on the upper oil temp as well, with the Aircraft TCDS and gauges stipulating 225F, but the Engine Type Cert allowing 240F using straight SAE 50 wt oil as already mentioned. (Keep in-mind that early-on this engine was recommended to be operated on SAE 30 or SAE40.) The engine overhaul manual X30013, pg 35, specifies the Test Run Operating Limits oil pressure at 35-50 psi with normal oil temps 175-185F, and the min oil press 5 psi oil temps at 140-150F.
So.... the early limitations issued by Cessna do not match what the engine mfr’r specify, nor do the Cessna specified instrument markings.... inspectors need to see the Aircraft TCDS and AFM compliance on Inst. Markings.... but pilot knowledge of the allowable limit-differences should be applied to our operations. In every case, having calibrated instruments are important. Lot’s of unnecessary concerns, work, and expenses are avoided that way.

Although faded, you can see my oil pressure gage had red lines at 5 and 50 psi. Now they are a light pink.

Thanks for the continued discussion, all good points.

I think as George mentioned, probably best to plan instrument markings per the manufacturer of the airplane, and then have a knowledge of the the engine manufacturer limits also.

dstates wrote:Although faded, you can see my oil pressure gage had red lines at 5 and 50 psi. Now they are a light pink.

Doug, mine looks about like yours, and has since I bought the airplane in 1982. When I overhauled the engine in 2006, with a new spring for the oil pressure relief valve and new bearings, the pressure indicated 55psi in cruise, and till does at oil reps below 190 or so. I was a bit concerned with that being over the marked redline, but was assured that is what Continental intended with the current issue spring.

cessna170bdriver wrote:

dstates wrote:Although faded, you can see my oil pressure gage had red lines at 5 and 50 psi. Now they are a light pink.

Doug, mine looks about like yours, and has since I bought the airplane in 1982. When I overhauled the engine in 2006, with a new spring for the oil pressure relief valve and new bearings, the pressure indicated 55psi in cruise, and till does at oil reps below 190 or so. I was a bit concerned with that being over the marked redline, but was assured that is what Continental intended with the current issue spring.

Miles, same here. After overhaul I indicated 55psi, I was advised by the overhaul shop that the 55psi pressure relief spring was the only one available for these engines from Continental.