Warming your engine?
CB,
It may be worth your , and the clubs while , changing to a thinner grade of oil during the winter season, even if ground temps remain somewhat lower than normal.
I also concur with the others that a gauge temp check should be carried out, and maybe a small blanking plate over part of the oil cooler may help to keep temps. up. If the oil pressure is normal
then it is probably ok, but I`d get an engineer to check it out.
It may be worth your , and the clubs while , changing to a thinner grade of oil during the winter season, even if ground temps remain somewhat lower than normal.
I also concur with the others that a gauge temp check should be carried out, and maybe a small blanking plate over part of the oil cooler may help to keep temps. up. If the oil pressure is normal
then it is probably ok, but I`d get an engineer to check it out.
Avoid imitations
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A couple of things to consider before giving full throttle to a cool engine.
1. Application of full throttle causes rapid heat exansion of the pistons. If the CHT isn't up, the cylinder bores haven't yet reached their full working diameter. This results in a reduction of clearance between piston / bore and might result in bore scuffing or piston ring area damage.
2. If the oil is too cold, the oil pressure is likely to go high enough to force the oil filter bypass off its seat so you are running cold, unfiltered oil around your engine at full power.
Neither of the above is likely to result in good engine longevity.
1. Application of full throttle causes rapid heat exansion of the pistons. If the CHT isn't up, the cylinder bores haven't yet reached their full working diameter. This results in a reduction of clearance between piston / bore and might result in bore scuffing or piston ring area damage.
2. If the oil is too cold, the oil pressure is likely to go high enough to force the oil filter bypass off its seat so you are running cold, unfiltered oil around your engine at full power.
Neither of the above is likely to result in good engine longevity.
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I have been running a cherokee-6 with an IO-540, 300 HP lycoming for about a year. I sought out the advice of a very helpful guy who had run the same type of a/c as a parachute jump plane and had achieved TBO and beyond with it.
His recommendations seem to work well and my engineer agrees that my engine is in great condition, certainly I haven't - yet - had any nasty surprises (fingers crossed).
Immediately after startup, lean aggressively at no more than 1000RPM. This warms the engine as rapidly as possible, still taking several minutes, giving me time to check out all four tanks and run through the checklist, tune radios, etc.
Never exceed 1000RPM until the CHT is well off the stop.
If you are parked on grass, for a tarmac runway, pull the a/c off the grass by hand so that you don't have to over-rev to get moving.
If you've got the runway length available, open the throttle progressively rather than just firewalling it, this also stops stones, etc, being sucked into the the prop - don't forget to richen the mixture.
Although its off subject, after landing I also do a scavenge run on the engine for a couple of minutes at 1200 RPM with the mixture leaned back until the RPM just starts to droop.
The last endoscopic check showed the cylinders in good condition and the plugs just seem to go on and on...
His recommendations seem to work well and my engineer agrees that my engine is in great condition, certainly I haven't - yet - had any nasty surprises (fingers crossed).
Immediately after startup, lean aggressively at no more than 1000RPM. This warms the engine as rapidly as possible, still taking several minutes, giving me time to check out all four tanks and run through the checklist, tune radios, etc.
Never exceed 1000RPM until the CHT is well off the stop.
If you are parked on grass, for a tarmac runway, pull the a/c off the grass by hand so that you don't have to over-rev to get moving.
If you've got the runway length available, open the throttle progressively rather than just firewalling it, this also stops stones, etc, being sucked into the the prop - don't forget to richen the mixture.
Although its off subject, after landing I also do a scavenge run on the engine for a couple of minutes at 1200 RPM with the mixture leaned back until the RPM just starts to droop.
The last endoscopic check showed the cylinders in good condition and the plugs just seem to go on and on...
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The POH for my 182 (Continental O470) recommends 2 to 5 mins running at 1000rpm after start in cold weather, and a check on oil pressure to ensure it remains normal during run ups. The big problem, apart from insufficient lubrication is, I understand, that if the oil is very cold and viscous the pressure relief valve may not be able to "dump" sufficient oil, the pressure rises to a level which burst pipes or joints leading to total loss of oil pressure - not good!
I generally ensure the oil temp is in the green before take off, on cold mornings starting the engine first and running for 5 mins very lean before I do the airframe checks (engine stopped!) generally means the heat soak from the engine has nicely warmed the oil on restart.
I generally ensure the oil temp is in the green before take off, on cold mornings starting the engine first and running for 5 mins very lean before I do the airframe checks (engine stopped!) generally means the heat soak from the engine has nicely warmed the oil on restart.
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To put this into some sort of perspective.
The group aircraft's engine holds 8 quarts of oil, thats 2 gallons. Last weekend the temperature was 2deg C. So imagine a domestic bucket full of oil just above freezing point - I certainly wouldn't want to put my hand in it. It would be painfully cold and stiff like treacle.
The POH recommends keeping the revs below 1400 until the temperature reaches 40deg C, which is the maximum temperature recorded in the UK last summer.
So what we are asking the engine to do is to take a bucket of treacle from just above freezing to midsummer temperature - its not surprising that it can take 10 minutes.
But its definately worth taking the time to do it.
The group aircraft's engine holds 8 quarts of oil, thats 2 gallons. Last weekend the temperature was 2deg C. So imagine a domestic bucket full of oil just above freezing point - I certainly wouldn't want to put my hand in it. It would be painfully cold and stiff like treacle.
The POH recommends keeping the revs below 1400 until the temperature reaches 40deg C, which is the maximum temperature recorded in the UK last summer.
So what we are asking the engine to do is to take a bucket of treacle from just above freezing to midsummer temperature - its not surprising that it can take 10 minutes.
But its definately worth taking the time to do it.
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Pre-heating a must
To each his own, but I wouldn't start (let alone fly) an airplane in the winter without first pre-heating. In my view, this is advisable whenever the temperature is below freezing, and an absolute requirement whenever the temperature is minus 7 C. Pre-flight idling is insufficient, and may itself damage the engine.
See further:
(1) AvWeb;
(2) F.E. Potts' advice (note this comment: "Mike Busch, the Cessna Pilots Association's engine specialist, claims that one cold start at the lower temperature extremes can cause as much wear as 500 hours of normal cruise operation. This takes into consideration the metal-to-metal contact between the piston and cylinder walls caused by the uneven expansion of the aluminum pistons and steel cylinders as the engine goes rapidly from very cold to very hot");
(3) Peter Tanis' SAE paper.
On the other hand, see also this contrary view.
See further:
(1) AvWeb;
(2) F.E. Potts' advice (note this comment: "Mike Busch, the Cessna Pilots Association's engine specialist, claims that one cold start at the lower temperature extremes can cause as much wear as 500 hours of normal cruise operation. This takes into consideration the metal-to-metal contact between the piston and cylinder walls caused by the uneven expansion of the aluminum pistons and steel cylinders as the engine goes rapidly from very cold to very hot");
(3) Peter Tanis' SAE paper.
On the other hand, see also this contrary view.
Last edited by MLS-12D; 13th Jan 2004 at 05:49.
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Well I just read through all those 40-odd posts and was wondering when someone would recommend a pre-heater - MLS-12D just beat me to it! Tanis is the way to go for sure, heats the entire engine. You can even get a system to switch it on by cellphone, so you don't even need to stop by the hangar to turn it on a few hours beforehand.
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I know its not all that relevant on this thread...but for what it is worth here is what we do with the PBY.
Each engine oil tank holds 55 imperial gallons of oil. 100 weight in winter and 120 weight in summer. ( That is 990 pounds total for the oil. )
We cannot use more than high idle RPM until oil temp shows 40 degrees C.
We must pre heat if the ambient temperature is plus 2 degrees C or lower.
Note:
There is an oil thremostat that ensures no oil will be taken from the oil tank until the temp of the engine oil reaches the proper temp....otherwise it would take forever to heat all the oil.
Chuck
Each engine oil tank holds 55 imperial gallons of oil. 100 weight in winter and 120 weight in summer. ( That is 990 pounds total for the oil. )
We cannot use more than high idle RPM until oil temp shows 40 degrees C.
We must pre heat if the ambient temperature is plus 2 degrees C or lower.
Note:
There is an oil thremostat that ensures no oil will be taken from the oil tank until the temp of the engine oil reaches the proper temp....otherwise it would take forever to heat all the oil.
Chuck
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I fly a Yak-52 and echo everything already said about the M14-P, but once when sitting in the AC on a very cold day waiting for the temps to come up, I had the owner of my maintenance org and supplier of the plane in the back and he suggested pulling the prop back. His words went along the lines of it would make the engine work harder and warm up quicker.
Has anyone come across this technique before, either for radials or other types? Though the actual RPM is going to be low the engine will be under a relatively increased load before it's warmed up. I must admit I don't do this, preferring to do it the hard way - waiting!
Has anyone come across this technique before, either for radials or other types? Though the actual RPM is going to be low the engine will be under a relatively increased load before it's warmed up. I must admit I don't do this, preferring to do it the hard way - waiting!
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660, I would have thought increasing the load on the cold engine would simply result in increasing the wear on the engine. After all, increasing the rpm really just increases the load on the engine too. Kind of defeats the purpose, doesn't it?
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IO540 - sorry it's taken a week to post, but you were right!! From an email sent to club members last Weds:
So I was blaming the ambient temperature, when it appears that all the time, there was a gauge problem!!
Moral of The Story: Never Assume, CHECK!!
Thanks, guys!!
Sorry folks but I have today grounded the aircraft following an afternoon at Perth trying to produce a fix for a problem xxx encountered yesterday. The oil temperature guage has ceased to function and there is no way of monitoring engine temp. I have managed to source one which we can borrow until ours is fixed - the new one is yes you have guessed a Fuji part and as readily available as rocking horse jobbies. It is a borden tube type so they apparently are repairable and recalibrated- more on this as it unfolds.
Moral of The Story: Never Assume, CHECK!!
Thanks, guys!!
