Cold weather Engine starting techniques

Any of the snow bound operators out there care to share their cold engine starting/stopping rituals or tips?

Prestart actions

During start actions

After Start actions until power check

Pre-shutdown actions

Post shutdown actions

We are just into freezing temperatures over here in the UK and the machine is kept in an unheated hangar, so I don't envisage having to build a tent round the nose and light a barrel of tar under the cowling to thaw the machine out, I anticipate -10C (14F) to be about the lowest sea level temp we get in this part of the world in mid winter disregarding wind chill.

Engine is a 0290-D2

Thanks in advance

UKCN

I'm really anxious to see the posts on this thread.

There are those with and a very few of us without electricity. I'm without.

I really don't like to use the red dragon, but I do. Hauling it to the cub and preheating makes me figure that things are getting to warm too fast in places and not at all in others. I set the heat on low and stick the hose under the engine cover. I usually watch for the snow or ice on the cover to start to melt to indicate that everything is warm. Then while removing the engine cover and preflighting the engine compartment I stick the hose in the cockpit to warm the instruments too. I usually blow some hot air on the windscreen to make it easier to scrape off the ice and on the tiedown knots too.t

I'd really like to use one of the old white gas catalitic converters and hang it under the cowling the night before. Everything will be nice and warm the next morning everything is nice and warm. If you use one you better fly because they seem to make a lot of water that you want to boil out of the oil. I figure that a good white cas catalitic heater and a can of blazo will heat you your airplane and cook a meal in the bush. this year I moved to the ones powered by little green propane cans. Not a versatile, but the old one has had it.

The catalitic conver combined with a red dragon can really get you ready.

Still on wheels? Forget the habit of tapping the brakes in the air to stop the wheels from spinning. Bouncing on landings to free a frozen brake - especially one frozen brake will "break" the habit. Put the tailwheel and main gear on sticks to keep it from freezing into the snow or mud when you are tieing down.

On skis? Put the skis on round sticks and put a few in front to get you moving. Even if you are not frozen on, it is hard to start moving an cold skis without a wing shaker. A little roling on the sticks usually does the trick.

I use those teabag sized chemical hand warmers in my gloves. That way my hands stay warm after touching all that cold metal and my gloves can be thin enough to let my hands function. I have gone to the toe warmer packs since there are two to a pack and are smaller.

When I was concerned about ice in the cold on floats, Mike Vivion suggested using the RV antifreeze. I still carry a spray bottle just in case

Watch the weather. In the cold things seem to change faster about Cook Inlet and the big lakes.

Still on wheels? When you land make sure you roll to a stop. Remember the frozen brakes. Keep that engine cover in the back seat. It makes a nice robe for the heat starved back there in the air and you have to have 'em if you spend any time on the ground. Keep your GPS warm too. The LCD screens seem to begin to freeze just below 0 Deg F and take a while to warm up. Mine comes in every evening when it is cold.

Make sure you have a carbon monoxide monitor that works before pulll that heat lever.

There were several good threads on survival gear that you should search.

Now lets see what advice the real experienced winter flyers can give us.

GR

Thanks Gary........for those of us that don't have the severe cold and have the luxury of hangars it's still nice to get advice and tips for those times we stray from the nest.

Buy a generator and a space heater. hundred other uses for them when you arent trying to preaheat your airplane. Plus you can use it to work on your airplane on those cold nights. farmers around here have been doing that for years, if their hangar is too far from electricity.

I'd agree with the previous post. If the temp is below freezing (0 Celcius for the UK types), I would pre-heat. If you don't, you'll put a LOT of wear on your engine in very short order.

Once you've adequately pre-heated, and start the engine, I try not to spend too much time on the ground, though I don't rush it. I just see no point in sitting around with the engine at idle for a half hour prior to launch.

Depending upon what the outside air temp is, sitting around at idle is actually cooling the engine off, not warming it up.

Once you takeoff, the engine temps will actually stabilize, which is what your're looking for.

MTV

My sequence of events.
With the engine blanket on, I preheat as thoroughly as the situation will permit. I prefer my generator and about 4 hours with the oilpan heater, but I have my ammo box heater, or a Red Dragon as the last resort. Prime according to the amount of preheat. More gas for less preheat. Once it starts, I use minimum throttle to keep it running, and idle it slow until oil pressure comes up. Then I idle up to 1200. I don't leave the parking spot until the CHT is comfortably in the warm, and if I did my preheat, some oil temp is showing. Of course during this time the windshield ices-up, so you get to wait for the defroster to do it's thing, anyway. In the reverse, I don't do much at shutdown that is different from summer, except I get the engine cover on as soon as possible, even before I drag the plane back into it's spot.

Otherwise, I never fly in winter without my survival gear, and engine cover, warm clothes, and a cell phone. Anchorage can get fogged in, and I've had to park the plane in Palmer for a few days and call for a ride home. Usually the fog rolls in about three hours after you start to preheat. Sometimes it gets you on the way home. I hate big boots, so I usually wear a lighter pair and carry a warmer pair. My biggest hassle is cleaning the windshield in the cold. It always seems to have ice, or worse yet, the damage from dust under the windshield cover. Also be careful of sumping your wings. Ice only seems to come out enough to block the quick-drain from reseating. I don't sump the wings in the winter. I had one freeze wide-open once. The lessons we learn.
SB

Cold Weather

I defer to those with more experience, but here's what I do: Sump heater because power available, >2 hours or more, with 'cowl cozy' on. Leisurly preflight. Go back inside, restroom break....In an unheated metal hangar, usually palpably warm on top of case, off the peg on oil temp, if >10F. Sorry you guys up in the frozen great white north....If it's REALLY cold you folks know about draining the oil, putting it inside next to the stove, THEN preheating....

Gloves on, chocks, 2-3 shots of prime. Pull through prop=number of cylinders. Works best if primer lines=number of cylinders. Chocks off, and strap on. She usually starts right up, first or second blade. Count seconds out loud. Continentals take ~20 seconds longer for oil pressure, as they're measuring oil pressure at the discharge side rather than pressure side on Lycomings...) If > 30 seconds shut down, more preheat. If really cold, carbheat seems to help run smoothly.

Multiweight oil helps a lot in colder weather (I'm, running Aeroshell 15W50, on most of the fleet, but some have better ideas), but same basics prevail. If you're running a Consant Speed Prop, multiple SHORT prop cycles at runup seems to work better than the nominal one-or two to mix cold/warm oil in the prop dome.

The 'hot air' preheats don't necessarily do anything for the CSP dome, and the front bearing; there are lots of stories (thankfully none mine, tho lots'a others...) of blown seals and turned front bearings, owing to cold conditions.

I guess it depends on what "cold" really means in your real-world situation.

Thanks for listening to my screed.

Cubscout.

Some excellent information here many thanks for the posts. I think I don?t know what real cold is by the sound of it!

For Cold starts over here I have the following ritual. As I say I live in a temperate (some say temperamental) climate so I think the use of a heater is not a prerequisite.

Wheels chocked, usual check for mag switches to off etc.
Fuel on,
Mixture Rich,
Throttle closed,
Pull engine though 4 or 5 blades
Strap in.
Throttle set
Prime with 4 to five shots and keep primer charged at the full extent of its stroke
Start engine on L mag then on to both as soon as it catches.

Then I find I need to ride the primer with gentle pressures if the engine falters to keep it firing this is probably only for about the first 30 seconds to a minute from stone cold then stow and lock it as the engine settles down.
I have found this a much better routine than playing the throttle to encourage the engine to keep running when stone cold. I also put the carb heat on for the warm up.


Seasons greetings and best wishes to all and if you are flying tomorrow on the centenary like I intend to, have a fun, safe flight!

Get a quick-drain installed on the oil pan. Then, whenever you go flying, carry two empty (clean) 1 gallon metal containers (the kind used for solvents), a funnel, and a drain hose. Then every night, drain your oil into the cans, and remove your battery. They'll be your mistresses for the night, so be prepared to sleep with them in your tent. In the morning, warm up the oil (next to the bacon and eggs) until the can is just too hot to touch but the agony is bearable with gloves on (Loosen the cap while heating the oil, and don't overheat it!). When you're ready to go flying, install the battery, do all your preflight up to engine start. Now poor in the hot oil, prime 4 times and start. It's not pretty, but it's cheep, fast, and effective. It worked for me in the Arctic for years.

Merry Christmas to all !

S.F.
Nick

Anonymous said:

Get a quick...Nick

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Oops! Forgot to log-in. Anyway, I'm the culprit for this post.



S.F.
Nick

Cub Bloke,

A number of years ago, the engine manufacturers, Lycoming in particular, started suggesting sorta strongly that you NOT rotate your engine through a few blades prior to a cold start, or any start, for that matter.

This habit of pulling an engine through prior to start is a leftover from the days that radial engines were the norm. The purpose of this drill was to ensure that no oil had leaked past a ring into a bottom cylinder, which would cause a hydraulic lock (commonly known as a hydraulic). If you had a hydraulic, and punched the starter, the piston would come up on compression, hit the oil in the top (bottom of engine) of the cylinder, and promptly bend a connecting rod. End of flight for the day.

Horizontally opposed engines do not have any risk of hydraulic lock in normal operations, so this practice is irrelevant.

Now, the reason Lycoming suggests you NOT pull your engine through by hand prior to start is that you are simply scraping all the oil off the cylinder walls, cam journals, etc, by rotating the engine by hand. Now you punch the starter and rotate everything some more without any lubrication, before the rotation of the engine finally gets the oil pump working, and oil moving to all parts of the engine. You do far more damage by pulling the engine through by hand than good.

As to rpm after start, Lycoming recommends that you run the engine at approximately 1000 rpm right after start, to get as much oil moving as possible throughout the engine. At lower rpm, the oil pump just isn't moving much oil. Granted, a slightly higher rpm may wear cold steel a bit more, but the oil pump at 1000 rpm will get oil throughout the engine VERY quickly at this rpm, which is the point.

If you are having to use the primer to keep the engine running after start, I would propose that you are starting cold enough that I'd sure recommend some sort of engine pre-heat. At 0 C, a bit of engine pre-heat will do wonders for reducing engine wear.

There was also a great article in the Anchorage paper last week about a fellow who went flying up to Eklutna Lake in a 172, wearing no survival gear and light clothing. He lost it on the strip at the Lake, and woulnd up in the lake, then spent the night and walked 8 miles before gettting picked up.

Moral of that story is this: your survival gear is that which you carry on your person, the stuff in the baggage compartment isn't survival gear, it's camping gear. Sink it in a lake, and you won't get your camping gear out.

MTV

MTV

Mike,
You should mention that the best survival gear is the ability to make good decisions. Taking a 172 into a strip with 8" of crusty snow with a glacial lake at the end is questionable. Perhaps scuba gear would be appropriate in that case.
SB

mvivion said:

Cub Bloke,

A number of years ago, the engine manufacturers, Lycoming in particular, started suggesting sorta strongly that you NOT rotate your engine through a few blades prior to a cold start, or any start, for that matter.



Now, the reason Lycoming suggests you NOT pull your engine through by hand prior to start is that you are simply scraping all the oil off the cylinder walls, cam journals, etc, by rotating the engine by hand. Now you punch the starter and rotate everything some more without any lubrication, before the rotation of the engine finally gets the oil pump working, and oil moving to all parts of the engine. You do far more damage by pulling the engine through by hand than good.


MTV

MTV

Click to expand...

Hmmmm- thats why I always pull a cold engine thru a few times. Scrape off all that thick sludge so when I do hit the starter, it would actually turn over at a higher speed that might start. I always do seem to think backwards!!!

Using A/S 15W50 really helps on those cold starts.

S2D said:

Hmmmm- thats why I always pull a cold engine thru a few times. Scrape off all that thick sludge so when I do hit the starter, it would actually turn over at a higher speed that might start. I always do seem to think backwards!!!

Using A/S 15W50 really helps on those cold starts.

Click to expand...

I'm with you S2D, I've always pulled a cold engine through and you can feel the difference... I'm also a proponent of 15W50 in cold country... When I built engines, I always found a film of oil on the internal parts even after rotating, disassembly and handling... I suppose if an engine sits for a long time in a moist atmosphere, it might lose some of the oil film, but by then it won't matter whether you pull it through or not... Just my opinion, obviously not Lycomings...

Agree with you, MTV, and others... to a point. However, pulling the engine through is not--nor was it ever--just to check for hydrolocking: the pull-through also serves to detect stuck valves, mainly exhaust valves (also internal ice buildup, internal damage, swallowed valves, or other resistance, plus low compression, loose cowling, etc.). Unless you're sure your TDC piston clears a valve struck open, and that your engine is in good shape, hitting the starter after your bird has been sitting around for a while can really make you cry. And O-320 valves do sometimes stick. This reality is recognized even by the Lyc people. They even have a fix for it without without removing the jug (Nylon rope through the spark plug hole and work through the exhaust port).

So my take on the subject is, pull the engine through 2 revolutions if it's been sitting around for a long time; especially an older engine. Better yet, pull it through on every cold start. Yes, it will scrape the oil off the jug walls. But you won't have to pay for that overhaul right away. This isn't monkey see-monkey do (as suggested in this thread, earlier): Its common sense learned from expensive experience.

Yes, the Lyc people are right, provided your engine and its installation are sound. But is that always a relistic assumption?

S.F.
Nick

Nick,

Sorry, but in my opinion, you're repeating old wives tales. I really can't tell how many thousands of hours I've got starting little Lycomings in cool temps, variable to cold temps. I've never experienced any of the sorts of events that you describe.

Lycoming publishes a very good publication, called "Key Reprints". It contains all sorts of wisdom on operating your engine.

And, again, don't mean to be contrary, but hydraulic lock is precisely why we always pulled engines through prior to start, in the radial engine days.

Having flown Beavers for a number of years, I can tell you that a hydraulic is something you don't want to encounter with a starter, as opposed to your hand.

I've never heard of any of the ails that you describe, frankly, but I sure don't know everything, though I have had valves stick, but the symptom would not have been revealed by pulling the prop through.

I do like Lycoming's advice, which is to pre-heat when appropriate, run the appropriate grade of oil, and just punch the starter button, but please don't pull the prop through prior to start.

Do what makes you happy, though. Cylinders are cheap, eh?

MTV

Pull it

I have found that priming the cold engine and pulling through all the cylinders, then leaving the cold engine right at the top of the compression and before the mag fires often gets me a faster and more reliable cold start, ALL OTHER THINGS BEING EQUAL.

of course, heat is good when the cold is deep.

Mike, where do you buy them cylinders cheap? I made TBO last run with my techniques, but they say "past performance is no guarantee of future results."

that's 2 cents with a money back guarantee....

All I've ever seen written about the problems with turning the prop addressed doing it between flights to prevent corrosion. If you're about to hit the starter and rotate the engine, how can manually turning it be a problem? I too have manually turned the prop when my battery was weak, to loosen things up, and it seemed to help. Granted, I don't always do it. In fact, I only did it once. A new battery solved the problem.

I think turning the prop after shut-down is much worse, and I see guys do it all the time. Of course, I see guys start and idle their planes, warm them, shut them off, and go home. Bad juju. But, it's their money.
SB

P.S. Am I the only one that checks my prop before start-up? I usually have to move the prop to do so, especially with the big three blade. I like to see what new chunks are missing, and address them if need be.

Stewart,

Certainly turning a prop, then leaving it for a long time is worse than turning it then starting it right away.

It's all relative, I suppose, but why do you suppose they sell those pre-oiler gizmos?

As I noted earlier, the wisdom I got from a Lycoming rep was that turning your prop through by hand doesn't "loosen" anything up, it just wipes all the oil off the bearing surfaces.

That may not make a nickel's worth of difference in many engines, but I'm paranoid about introducing any wear that isn't necessary.

Biggest thing is pre-heating when it's cool, though. And all the things that you refer to as bad ju-ju are indeed, in my opinion.

Best thing you can do is fly the hey out of it. Unfortunately, most of us don't have that luxury.

MTV

I've always wondered about those preoilers. Anybody ever have one? Is there any evidence, outside of the manufacturer's claims, that they extend engine life? I've never even seen one.
SB

stewartb said:

I've always wondered about those preoilers. Anybody ever have one? Is there any evidence, outside of the manufacturer's claims, that they extend engine life? I've never even seen one.
SB

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Put one on a Mustang... The Merlin has overhead cam racks and the racks are brittle... We used the preoiler when the engine hadn't been run in awhile, not for everyday use... The V12 engine builders claim it stops chipped cam lobes...

stewartb said:

I've always wondered about those preoilers. Anybody ever have one? Is there any evidence, outside of the manufacturer's claims, that they extend engine life? I've never even seen one.
SB

Click to expand...

Probably work good on an engine that does a lot of sitting between flights, but I'd bet they'd suck if you tried to use it on a real cold day without preheating.

My first Engine went 3200 hrs before i took it out. It never had one speck of metal in the screen. And I did every thing I could to abuse it. even starting it below zero a few times. Instant oil pressure with the A/S 15W50. two I have now have about 1500 each without any metal and I don't treat them much better. Not necessarily because I think I know what I'm doing, but usually from poor preplanning or plumb laziness.

I think the key was the right oil and frequent use.

One piece Venturis seem to have eliminated the ability for me to start my airplanes cold anymore.

I've waited to see what you others would mention before adding my two cents.

Seems like most everything got covered, though I'm surprised no one has nailed UK Cub Nut for cold starting at 14F. Probably most of us have cold started at lower temps than we ought to, but regular cold starts at 14F are probably going to prematurely wear Cub Nut's engine.

Also, you guys that are priming and then turning the engine through are doing about the most effective job of cleaning the oil off your cylinder walls as is possible without removing the cylinders and actually wiping them with a solvent rag. This is bad. Think about it........squirt gasoline into the cylinder head and then scrape yor pistons up and down several times......will it prematurely wear your engine? Probably. Does hand-turning alone, to "loosen" her up hurt? I'm not sure, but the manufacturer cares enough to recommend not doing it. And they ARE interested in your engine staying together. I used-to "loosen-her" up. I haven't pulled it through by hand for a few years now. I think when I got that new lightweight starter I quit thinking I had to loosen her up. Those new starters are strong.

Some of you guys have mentioned waiting for the oil pressure to come up on your cold engine. That's interesting. The highest oil pressure that engine will ever see is following start-up with cold oil. That's right, start-up with cold oil is the highest oil pressure you'll ever see. It's because of the thick oil not running so easily out of the nozzles and passages. One could possibly over-oil-pressure ones engine with cold start-ups. If you're waiting for pressure to come up, it may be due to your not having flown as often as you do in the warm temps, and the oil has seeped away out of your passages and pump pick-up tube. Probably one of the reasons that these engines will sometimes push out the nose seal is the high oil pressure on cold starts.

I preheat if it's less than freezing. If I have to use an extra shot of prime after start-up to keep her running......I probably should have heated, or heated better.

I throw the engine cover on while I'm stopped someplace if it's for more than 30 minutes.

I use a windshield cover, but cringe at the thought of what it does to the plastic. It does less damage than a scraper, though.

Frozen brakes are a problem. Be ready to power and rudder-through any problems on landing touchdown. Think about those brakes, not how pretty your alighting is supposed to be.

I've been using a small generator to preheat with the Reiff system, or the generator with a ceramic heater placed inside the cowling on birds without a dedicated system. It's only slightly less crude, and a bit heavier (56lbs) than the camp stove with ducting trick. Also, you can leave it to go have breakfast and not worry about burning the a/c. I guess Gyrene Nick has the right idea of draining his oil and warming it next to his bacon.

A caution, though. One of the reasons we preheat is to warm the oil. Another is to warm the engine. Among the reasons for warming the engine is the fact that the coefficients of expansion of steel and aluminum are vastly different. Starting from a low temperature, a rapidly expanding aluminum piston can seize itself inside a relatively slower expanding steel cylinder as the engine runs and begins to warm. Even if it doesn't seize, it can scuff, and that will mess up the seal of your piston rings.

All of this has been learned over time. None of it is very scientific. One of you will likely come along and shoot me down with some new, better, more correct idea. Please do.

DAVE

mvivion said:

Nick,

Sorry,...

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Don't be sorry, mate, that's what this site it all about. It would be boring if everybody just kept parroting the same rhetoric. I'd like to think we can respect and learn from each other's opinions without necessarily sharing them.

I think I did agree with hydraulic lock as one of the reasons so I don't see any point beating that dead horse. As for the rest, what more can I say? We all have our unique baggage: first-hand and witnessed experiences, exposure to documented events, etc., but I don't want to bore everyone here to death with mine. As long as you flow manufacturers' guidelines, you'll always have a good excuse no matter what happens after you hit the starter. So if a forgotten pair of sidecutters jammed behind the flywheel makes a mess of things; or a seized generator burns your belt to a crisp; or worse, a piece of the disintegrated starter (solenoid froze in the engaged position after that last failed start attempt by another crew) maims a loved one for life, you'll find comfort knowing that you only did what the manufacturer told you to do.

The suggested point to ponder is that, the pilot, not the engine maker, is responsible for the operation of the aircraft. Yes, we all take a lot for granted. We have to. That's how the system works. But that same system relies (sometimes heavily) on the last safety net: the pilot. In simple terms, shit happens; and the pilot is expected to catch it. That's why some of us pull the prop through.

S.F.
Nick

.....And the wing covers don't go back on after flying if it's windy or expected to be. If I'm leaving it for a week. I'll not cover it.

I DO have the luxury of going in the hangar if I get caught with the covers off in the above instance. I realize others not near a hangar, or out on a hunt, etc. must keep it covered up and babysit it if the wind is expected to abate followed by snow or frosty conditions.

Also, Nick, just because a guy doesn't pull 'er through a few blades as you do doesn't necessarily mean that he ain't pre-flighting.

Also, the whole pull-through thing is kind of a moot point. Several rotations of the crank by hand are not likely to damage any more than the first several moments of the starters rotation. The important part is that oil needs to get to our parts to alleviate wear......and that it will get there in it's own sweet time. We're splitting house-fly wing-hairs on this topic, in my opinion.

David M. Calkins said:

Some of you guys have mentioned waiting for the oil pressure to come up on your cold engine. That's interesting. The highest oil pressure that engine will ever see is following start-up with cold oil. That's right, start-up with cold oil is the highest oil pressure you'll ever see. It's because of the thick oil not running so easily out of the nozzles and passages. One could possibly over-oil-pressure ones engine with cold start-ups. If you're waiting for pressure to come up, it may be due to your not having flown as often as you do in the warm temps, and the oil has seeped away out of your passages and pump pick-up tube. Probably one of the reasons that these engines will sometimes push out the nose seal is the high oil pressure on cold starts.
Dave

Click to expand...

I sorta agree with you here Dave, but I think what we are referring to is the oil pressure registering on the guage. Might not be what is actually happening at the engine. I know the thicker the oil,the longer it takes for the "guage" to come up, and the farther the guage is from the engine(like in spray planes). Youre right when it comes to Super Cubs and especially Radials, they really over redline till they warm up a bit. However the Cont 520's are just the opposite, maybe its just where they take the oil pressure reading from but I've got in a hurry to leave a few times and noticed the oil pressure go way below the bottom of the green on takeoff.

You may not be taking into consideration the engines pickup ability with real thick oil either. This could cause it to have lower oil pressure initially, especially if the pump is not 100%.

Iv'e flown cubs that initially start out with a lower oil pressure and build up as they get warmer and ones that start out high and get lower and ones that go from one end of the green to the other and then back again.

The one I'm flying right now will start out just below green if it is not thoroughly warmed up then go up to top of green after it is warmed up.

With the oil this cold, it is high-pressure bypassing anyway. Possibly lots of pressure at the gage, but no flow where it's needed.

I hear what you guys are saying.

On the other hand, Ron, could thick oil have a tough time bypassing at the relief?? Yes.

Some superb bits of information here, I would like to see the Lycoming document referred to in the earlier post, any chance of a link or a copy? .

Pulling a prop through on an engine prior to start for whatever reason be it to check for hydraulic lock (and that goes for any engine with inverted cylinders not just radials), to check the compressions are even, or even to prime the engine can?t be THAT bad for an engine, surely? , that?s part of the Armstrong starting technique anyway ?switches off , throttle closed, Suck in?. The cylinder bores don?t know whether they are being scraped by hand effort or electrical starter action!

I totally agree that its bad practise pulling the engine through after the flight or if the engine is not going to be run immediately afterwards.

The thing that has caused debate in my flying group has been the issue of using the primer to prevent the engine faltering and stopping during the first 30 seconds or so. As I said in my earlier post a gentle squeeze of primer gives a much more satisfactory means of coercing the engine into steady running than trying to catch it by pumping the throttle wildly.

I stress this is only required when the ambient temperatures are around freezing, it is not required in warmer temperatures.

The prime has to be right or the engine would not fire up in the first place, it?s just that once the prime charge has run through without a choke the cold carb isn?t getting the fuel into the engine in the right mixture to see it through the first few seconds of running, after it?s through this phase it runs as sweet as a nut at 1000RPM.

Does this engine need attention? I hasten to add it passes every power check, runs smoothly and does not foul it?s plugs. I contend that it is perfectly serviceable and that is one of the reasons it has a primer fitted in the first place.

Had a great flight yesterday , the weather played ball and the whole of our field got airborne!

Seasons greetings

UKCN

I would reiterate my previous comment that if you have to use primer to keep an engine running, you need to pre-heat the engine.

Not saying I haven't used that procedure myself, or won't in future, but I wouldn't do so as a regular matter of course. I doubt there's anything wrong with the engine that a little heat wouldn't fix.

It's worthy of note that Continental and Lycoming take their oil pressure pickups off different ends of the engine, so you will see different behaviours on those engines.

As to oil pressure on start up, remember that the line to the oil pressure guage is a tiny little thing. If the temperature is cold enough, it takes a while for the oil in the line to move a bit, to give any indication at all.

At -40 or so, you'll likely never get any indication for oil pressure, due to the above. At those temps, if you've decided to go flying in the first place, you may have to decide to ignore the oil pressure indication for the moment, hoping that it'll come up when it warms up.

It's a long thin line, and the oil can coagulate in it. This doesn't necessarily reflect what's going on inside the engine, particularly if you have properly PRE-HEATED.

You own the engine, you decide whether you want to pull it through prior to start. Just don't do so to an engine I have to pay the bills on, okay?

You can find the Key Reprints reference on the Lycoming web site.

MTV