Bruce,
I would go for the high oil pressure first. High oil pressure does funny things? Oil flooding is what you would be dealing with. The poor rings and vent system have a hard time coaping with a flooding situation. Be sure the pressure gague is correct before doing anything else. The oil pressure gague is a weak link in the system. Be careful when adjusting the oil pressure. A tight new engine can have high oil pressure when cold. Always correct the known problems first. Your venting is probably just a symptom.
Ralph
Losing oil out breather
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
When my engine was overhauled and returned to service I alsa had high oil pressure. Amoung the items returned to me with the engine was the original relief valve spring. We re installed it and that cured the problem. I still can get a little oil from the breather on shut down on cold days. But I have no problems maintaining a seven quart oil level. Bill K
Polished 48 170 Cat 22 JD 620 & Pug
I went through this high oil pressure thing when I purchased my 170 with a freshly overhauled engine. See the discussion on the subject here. http://www.cessna170.org/phpBB2/viewtop ... t=pressure
jc
jc
John
N2865C
"The only stupid question is one that wasn't asked"
N2865C
"The only stupid question is one that wasn't asked"
Don't be overly concerned about 60 psi oil pressure.
Several years ago I became concerned over a 55 psi indication on an O-300-C and visited with Cory Thompson, TCM field rep who informed me that up to 60 psi is now considered normal range on C145/O300 engines.
The oil pressure relief spring has a specification of length versus tension (compression actually) which may be checked if you're concerned. But my advice is to not worry about oil pressures up to 60. (Never heard of "oil flooding" and I am not convinced such is a problem, especially on a wet-sump engine such as this.)
Several years ago I became concerned over a 55 psi indication on an O-300-C and visited with Cory Thompson, TCM field rep who informed me that up to 60 psi is now considered normal range on C145/O300 engines.
The oil pressure relief spring has a specification of length versus tension (compression actually) which may be checked if you're concerned. But my advice is to not worry about oil pressures up to 60. (Never heard of "oil flooding" and I am not convinced such is a problem, especially on a wet-sump engine such as this.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
George,
I'd ask that Continental guy if he'd be willing to put in writing and sign such a declaration that its "normal" and or "okay" to run an engine with 20 pounds higher oil pressure than is approved in the TCDS. I'd bet he wouldn't.
If so, why not ignore a few other engine gauge indications?
I don't know if this is the problem or not, but in my opinion, its a very bad idea to start ignoring red radials on instruments, particularly engine instruments.
Again, I'm not familiar with these engines at all, but I'd be very careful, particularly with a new engine, running well over the specified oil pressure.
Now, it could be the gauge, and I'd sure check that first.
Just a thought, not a challenge
.
Mike Vivion
I'd ask that Continental guy if he'd be willing to put in writing and sign such a declaration that its "normal" and or "okay" to run an engine with 20 pounds higher oil pressure than is approved in the TCDS. I'd bet he wouldn't.
If so, why not ignore a few other engine gauge indications?
I don't know if this is the problem or not, but in my opinion, its a very bad idea to start ignoring red radials on instruments, particularly engine instruments.
Again, I'm not familiar with these engines at all, but I'd be very careful, particularly with a new engine, running well over the specified oil pressure.
Now, it could be the gauge, and I'd sure check that first.
Just a thought, not a challenge
. Mike Vivion
The Type Certificate for the O-300-D/E engines (which superceded the C145-2/O300-A engines) specifies normal oil pressure limits to be 30-60 psi. According to TCM, the C145/O300 overhaul manual (FAA Approved) authorizes the use of D/E parts and data on the earlier engines. I am in contact with TCM asking for further clarification, and I'll post any info as it becomes available. Hope this helps.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
As previously mentioned, I have followed up with TCM regarding oil pressure, and recieved an official reply fax from them in the form of Engine Model Specification, O-300-A, -B, -C, -D,-E, Dated 5-11-66. This is the document upon which the FAA Type Certificate is based, whether or not the FAA document is accurate. (In other words, even if the FAA has made an error transcribing to the TCDS* ... 
... THIS document is the real deal.)
It's a 6 page document. On pages 3/4, section F, the Oil Lubrication system is addressed. It states that normal oil pressure for all models of this engine is 30-60 psi. It also states that the minimum oil pressure for idling is 5 psi, and the maximum oil pressure (cold) is 100 psi.
I will be including the entire document in the upcoming Powerplant Section of the TIC170A Cessna 170 Service Manual.
* Over the years I have repeatedly attempted to get FAA to correct errors
in some of their TCDS. One example is their Revision 51 of the C-170 TC in which they pronounced that early versions of the B-model did not have the 20-degree flap setting.
FINALLY...after my third phone call to the aircraft certification branch they have issued Rev. 54 which correctly states the flap deflections allowable in the model. Moral: While the TCDS may be the law....it ain't necessarily the correct law.
... THIS document is the real deal.)It's a 6 page document. On pages 3/4, section F, the Oil Lubrication system is addressed. It states that normal oil pressure for all models of this engine is 30-60 psi. It also states that the minimum oil pressure for idling is 5 psi, and the maximum oil pressure (cold) is 100 psi.
I will be including the entire document in the upcoming Powerplant Section of the TIC170A Cessna 170 Service Manual.
* Over the years I have repeatedly attempted to get FAA to correct errors
in some of their TCDS. One example is their Revision 51 of the C-170 TC in which they pronounced that early versions of the B-model did not have the 20-degree flap setting.
FINALLY...after my third phone call to the aircraft certification branch they have issued Rev. 54 which correctly states the flap deflections allowable in the model. Moral: While the TCDS may be the law....it ain't necessarily the correct law. '53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
Not sure/not trying to explain what Mike Vivion might have meant...but only pointing out that TCM engines do typically pump about 2 gallons per minuteblueldr wrote:Re; Oil Systems.
What's this about "Continentals do volume and Lycomings do pressure"?
They both have gear pumps and relief valves. Where is the difference?
thru their engines at cruse rpms while LYC only runs about 2 quarts of volume at similar rpms. This is largely due to a much higher oil flow thru the lifter/pushrod/rocker arms design which TCM prefers. Keep in mind that in smaller displacement engines TCM was loathe to use external oil lines and therefore uses the pushrod housings as a form of oil cooler, while LYC uses oil coolers and external oil lines. This philosophical difference between the two mfr's has been used to explain the higher incidence of valve-train/cam problems in certain LYC engines. See: http://www.prime-mover.org/Engines/Marvel/tbo3.html
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
-
russfarris
- Posts: 476
- Joined: Wed May 15, 2002 2:25 am
It's not a 'wise-guy' question. It's a common one. Just keep in mind that the C145 is merely an earlier designation for the O-300. (While the original C145 engines/variants actually did have differences, time and subsequent overhauls have negated those differences. Several examples which come to mind are the updates to cam and lifter materials specifications. The first engines had steel cams with iron lifters, subsequently changed to iron cams with steel lifters. Getting the combination incorrect will lead to excessive wear and loss of power early in an engine's life. But since all overhaulers are supposed to use only the latest bulletins and manuals for overhauls (TCM Form X30013), then all engines are brought to the same standard in critical areas.)
The C145 shares the same oil pump/gallery system as the O300 and operates to the same limits. FYI, Form X30013 specifically states the oil pressure limits for the C145 to be the same as for the O300.
are supposed to use only the latest bulletins and manuals for overhauls (TCM Form X30013), then all engines are brought to the same standard in critical areas.)The C145 shares the same oil pump/gallery system as the O300 and operates to the same limits. FYI, Form X30013 specifically states the oil pressure limits for the C145 to be the same as for the O300.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
Bluldr,
The volume vs pressure point was simply that Lycoming moves oil under quite a bit more pressure than Continental engines do, while Continental moves larger volumes of oil, at lower pressures. Accomplishes the same net effect, in the long run, just different means to an end.
George listed data for the Continental O-145, which was a pressure of 30 to 60 psi.
The Lycoming O-360, on the other hand, calls for minimum oil pressure of 25, with a caution range from 25 to 60, normal range from 60 psi to 90, and a maximum oil pressure of 100 psi. I won't run a Lycoming, except at idle, below 60 psi. And I sure don't want to run one at 110 psi.
That was all I meant.
My point was that if an engine is operating outside its specified limits, I'd want to know why, and I'd want some answers from the factory.
I don't own a Continental O-300, and don't operate them much, so my point was general in nature. My understanding from the initial post was that his oil pressure was in excess of specified limits. If the limits have changed, then the gauges should also be re-marked, seems to me, so we don't worry about things like this.
The volume vs pressure point was simply that Lycoming moves oil under quite a bit more pressure than Continental engines do, while Continental moves larger volumes of oil, at lower pressures. Accomplishes the same net effect, in the long run, just different means to an end.
George listed data for the Continental O-145, which was a pressure of 30 to 60 psi.
The Lycoming O-360, on the other hand, calls for minimum oil pressure of 25, with a caution range from 25 to 60, normal range from 60 psi to 90, and a maximum oil pressure of 100 psi. I won't run a Lycoming, except at idle, below 60 psi. And I sure don't want to run one at 110 psi.
That was all I meant.
My point was that if an engine is operating outside its specified limits, I'd want to know why, and I'd want some answers from the factory.
I don't own a Continental O-300, and don't operate them much, so my point was general in nature. My understanding from the initial post was that his oil pressure was in excess of specified limits. If the limits have changed, then the gauges should also be re-marked, seems to me, so we don't worry about things like this.
In doing more research on crankcase ventilation for my overhaul, I found this link with good pictures showing the Continental O-200 Aerobatic breather elbow. Scroll to to the bottom of this link where they show pictures of a standard vs. aerobatic elbow as installed in a crankcase. Makes a lot of sense to me. Would this elbow be legal to install on an O-300? I think I will try to track down a price for these. George, did you ever find the Service Bulletin for this too?gahorn wrote:The crankshaft slings oil all over the upper inside surfaces of the crankcase and the oil then runs down to the brass elbow where crankcase pressures encourage it to exit via the breather system. Some O-200 engines are especially bad about this and there is a modification to that elbow which silver-solder's a short extension tube inside the threaded end of the elbow. (Careful, don't make it so long it hits the crankshaft.) Or TCM will happily sell you one already modified for a small fortune.
The purpose of the extension is that it places the elbow's "inlet" well inside the open spaces of the crankcase so that oil running down the inner walls go around the elbow and down into the sump rather than draining directly into the elbow. The slight upward "kick" to the exit end of the elbow like you've described is intended to assist in preventing so much oil entering the breather system.
Not that any of this info helps you, but thought it might contribute to understanding part of the problem. I'll try to locate the Service Bulletin that addresses this issue.
http://150cessna.tripod.com/c150o200ainsp.html
Bruce Christie