Warming up engines

This forum has been developed to discuss maintenance topics in Canada.

Moderators: ahramin, sky's the limit, sepia, Sulako, North Shore

Post Reply
Message
Author
User avatar
Bede
Rank 10
Rank 10
Posts: 2770
Joined: Tue Mar 09, 2004 5:52 am
Contact:

Warming up engines

#1 Post by Bede » Mon Oct 16, 2017 9:30 am

How long do you AME's recommend warming up an engine prior to flight?

If I reference the C172 POH, it says, "If the engine accelerate smoothly, the airplane is ready for take-off." Later it says, "...long periods of idling may cause fouled spark plugs."

I understand that there is trade off between adequate lubrication and plug fouling.If the first sentence is correct, than only a minute or two is required, but this doesn't seem adequate at all. I have always waited until the oil pressure indicates a temperature.
---------- ADS -----------

crazyaviator
Rank 7
Rank 7
Posts: 671
Joined: Sun Oct 21, 2007 7:52 pm
Location: Ontario

Re: Warming up engines

#2 Post by crazyaviator » Mon Oct 16, 2017 10:45 am

With todays multi-grade oils, if it is room temp it will flow just fine, and therefore it is more of an issue of getting the cyl. temps up (1-3 min)
If the oil is cold, then I would suggest waiting till it shows on the gauge as you mentioned !
---------- ADS -----------

PostmasterGeneral
Rank 4
Rank 4
Posts: 246
Joined: Mon Feb 16, 2009 3:50 pm

Re: Warming up engines

#3 Post by PostmasterGeneral » Mon Oct 16, 2017 10:57 am

I’ve always followed the practice of letting the engine warm up FULLY before I pour the coals to ‘er. Lean it out on the ground to prevent plug fouling, do a good run up if it’s cold out, and once the oil temp is in the green, give’er.
---------- ADS -----------

trey kule
Rank 11
Rank 11
Posts: 4222
Joined: Fri Aug 19, 2005 7:09 pm

Re: Warming up engines

#4 Post by trey kule » Mon Oct 16, 2017 2:17 pm

Depends.

I am assuming you are referring to typical horizontally opposed lycoming/continental type engines.

The radials require a different procedure.

Personally with the O engines, I like to see CHT and oil temp at the bottom of the green, and the oil pressure enough below red line to allow for it to remain bellow red line on the runup.

As an aside, some of the preheat systems are good enough that everything is in the green 30 secs after start.
---------- ADS -----------
Last edited by trey kule on Mon Oct 16, 2017 4:36 pm, edited 1 time in total.

crazyaviator
Rank 7
Rank 7
Posts: 671
Joined: Sun Oct 21, 2007 7:52 pm
Location: Ontario

Re: Warming up engines

#5 Post by crazyaviator » Mon Oct 16, 2017 4:16 pm

Radials LOVE long, slow caresses! They bitch and belch and complain and will not follow your lead UNTIL you have been patient with her idiosyncrasies Hmm, Am I talkin about engines or women? :wink:
---------- ADS -----------

photofly
Top Poster
Top Poster
Posts: 5982
Joined: Tue Jan 18, 2011 4:47 pm
Location: Part of the "me, me, me" crowd, and loving every second of it.

Re: Warming up engines

#6 Post by photofly » Mon Oct 16, 2017 5:57 pm

Bede wrote:I have always waited until the oil pressure indicates a temperature.
If the pressure gauge is indicating temperature, it's probably wired up wrongly :-O
---------- ADS -----------
Control the horizon, control the airplane

ahramin
Rank Moderator
Rank Moderator
Posts: 5344
Joined: Tue Feb 17, 2004 5:21 pm
Location: Vancouver

Re: Warming up engines

#7 Post by ahramin » Mon Oct 16, 2017 6:47 pm

I follow the POH and don't wait for oil temperature indication before departing. If I operated in cold temperatures or wasn't sure that the oil was the proper grade for the temperature then that's a different story.

Having said that, one of the RV-10s I fly has an IO-540 that the owner blew the prop seal out after taking off with cold oil. He now will not takeoff with an oil temperature below 70°F. I downloaded the engine data from the event and the oil pressure was indeed way above redline. I would think this indicates a problem with the pressure relief valve but that's how the owner has decided to deal with it.
---------- ADS -----------

lhalliday
Rank 3
Rank 3
Posts: 129
Joined: Sun Dec 06, 2015 5:30 pm

Re: Warming up engines

#8 Post by lhalliday » Tue Oct 17, 2017 8:19 am

My personal SOP is to wait until I have at least one CHT at 200F (courtesy the Insight engine monitor) before I taxi. Pre-taxi preparations are usually enough for this, except on the very coldest days.

I look for the oil temperature to be in the green range (starting at 120F) before takeoff. Taxiing and runup will usually accomplish this, except, again, on the very coldest days.

...laura
---------- ADS -----------

goingnowherefast
Rank 8
Rank 8
Posts: 827
Joined: Wed Mar 13, 2013 9:24 am

Re: Warming up engines

#9 Post by goingnowherefast » Wed Oct 18, 2017 3:56 pm

20W50 oil in a cold engine will exceed the upper oil pressure limit when the engine RPMs get higher. That's even at 1200-1500 rpm if the engine is too cold. The injected Lycomings will accept a lot of throttle when they're still very cold.

Oil pressure should be running in the middle to lower end of the normal operating range in cruise. You just have to make sure the oil is warm enough that the pressure won't exceed the limits at take-off (or run-up or any rpm with a cold engine).

Back when I was routinely operating piston engine'd aircraft, there was one particular engine that I warmed up by oil pressure. After starting, I'd set about 700-800rpm and note the oil pressure. As the oil warmed and the pressure decreased from the red line, I would increase the rpm gradually, keeping the oil pressure slightly below redline, until around 1200 rpm or so. We leaned quite aggressively on the ground as it takes a while to warm up an engine from 5*c
---------- ADS -----------

User avatar
Cat Driver
Top Poster
Top Poster
Posts: 18847
Joined: Sun Feb 15, 2004 8:31 pm

Re: Warming up engines

#10 Post by Cat Driver » Wed Oct 18, 2017 3:59 pm

I found the best way to warm an engine in very cold temperatures was with engine covers and a herman nelson.
---------- ADS -----------
The hardest thing about flying is knowing when to say no


After over a half a century of flying no one ever died because of my decision not to fly.

crazyaviator
Rank 7
Rank 7
Posts: 671
Joined: Sun Oct 21, 2007 7:52 pm
Location: Ontario

Re: Warming up engines

#11 Post by crazyaviator » Wed Oct 18, 2017 6:03 pm

herman nelson.
Another one of those names that cannot be related to anything material, unless you burnt your pant leg off with one ! :wink: Might as well call it a Canadian Quickie or a spuzzmodit !!!
---------- ADS -----------

Heliian
Rank (9)
Rank (9)
Posts: 1093
Joined: Wed Apr 29, 2009 2:14 pm

Re: Warming up engines

#12 Post by Heliian » Thu Oct 19, 2017 4:38 am

crazyaviator wrote:
herman nelson.
Another one of those names that cannot be related to anything material, unless you burnt your pant leg off with one ! :wink: Might as well call it a Canadian Quickie or a spuzzmodit !!!
H.w. nelson co. inc. was the creator.
---------- ADS -----------

User avatar
JasonE
Rank 5
Rank 5
Posts: 357
Joined: Sat Sep 06, 2014 8:26 pm

Re: Warming up engines

#13 Post by JasonE » Thu Oct 19, 2017 2:56 pm

At the cost of fuel these days, I preheat as much as possible before firing up below 0!
---------- ADS -----------

tazin river
Rank 3
Rank 3
Posts: 164
Joined: Sun Dec 11, 2005 7:24 pm
Location: Way up north

Re: Warming up engines

#14 Post by tazin river » Sat Oct 21, 2017 5:21 pm

...was told to always wait until temp shows 75F before taking off
..that was 20 years ago and stayed with it since...

Cheers
---------- ADS -----------

gwagen
Rank 3
Rank 3
Posts: 103
Joined: Tue Dec 01, 2015 7:30 am

Re: Warming up engines

#15 Post by gwagen » Sat Oct 21, 2017 6:58 pm

I find the heated hangar works quite well!

Only downside, when you leave your heated hangar and stop for awhile in the winter somewhere and despite the engine blanket you come to find your old battery was only hanging on because of the warm hangar.
---------- ADS -----------

Post Reply

Return to “Maintenance”