Airwolf Oil Chiller for 231

[M20Kid]

I know there are many knowledgable folks on this board and I'm interested in feedback or first hand information about the effectiveness of the Airwolf Oil Chiller.  It's a finned aluminum band placed around the oil filter to act as a heat sink and cool the oil temps.  The company says they get the best results when the oil filter is remotely mounted away from the engine and into the air stream in the engine compartment.

My issue is that (I believe) my oil filter is mounted on the accessory case behind the baffles and behind the majority of the airflow.  Without airflow I think this would be mostly a waste of money and time.  I'm new to the airplane and I've only had the cowl off a few times so please let me know if I'm wrong about the oil filter placement on this engine.

Has anyone put one of these on their 231?  If so, did you see any appreciable difference in oil temps?

Thanks in advance for your input!

[231flyer]

I have not used the Airwolf Oil Chiller in my 231 but experimented with a similar unit on my Lancair IV.  These units tend to be marginal at best.  Bottom-line even if you are able to duct cool airflow to the chiller fins, the limiting factor is the surface area of the oil exposed.  The Oil filter is a sealed can and cooling the outside is not an efficient method to cool the oil inside.  

Btw my 231 has never had any oil temp issues in the 19 years I have owned it and I live in TX.  The Oil Cooler is quite adequate but is very sensitive to airflow.  Check and make sure your baffles are tight and not leaking (I have replaced my original ones atleast twice) and also the fins on the oil cooler are clear and not mangled.  Bugs/debris tends to collect on top of the cooler (dead spot behind the oil filler tube).  

[M20Kid]

231flyer - very interesting about your oil temps!  In my airplane I cannot close the cowl flaps without the oil temp gauge heading for the red and the oil pressure gauge dropping to nearly the bottom.  Trailing the cowl flaps brings everything back to the center of the gauges but costs me 5kts.  I just installed an oil cooler and vernatherm so those should not be causing trouble.

Does your airplane have an intercooler?  Mine does not.  I posted on this forum before about my oil temp troubles but have yet to find a solution.  Maybe the baffles ... hmmm

[KSMooniac]

Baffles and seals are the logical place to start.  Any deficiencies with those will wreak havoc on the cooling airflow and thus should be fixed before spending money on other mods.  

An intercooler is a very, very good thing to have.  I'm not a turbo operator yet, but have been reading a lot lately and I wouldn't want a turbo without one.  This was posted here earlier and worth a read (along with the rest of Braly's posts): http://www.cirruspilots.org/blogs/braly/archive/2009/02/13/intercoolers-are-wonderful-devices.aspx

I've seen a product (Champion or Rapco or Airborne, I think) that is a little kit designed to divert some cooling air around a vacuum pump.  It requires a new hole in the back of the baffling, and a top hat-shaped piece of aluminum is riveted to the hole so a 1" duct can be connected to the outlet and directed to a fiberglass part that wraps around the pump and has a 1" intake flange for the duct.  I'm sure a similar thing could be done for a filter, but I agree with 231flyer that this is probably not the ultimate solution for your temps.

Depending on where you got your oil cooler and vernatherm, I wouldn't rule them out either.  A vernatherm can be tested I believe off the plane, and you could have a bad one, even if new or rebuilt.

[231flyer]

I have a stock TSIO360 LB engine with 950hrs (~300 since top). No intercooler and no Merlyn.  I do have to keep the cowl flaps open in the climb, but thats SOP.  Like I said, the baffles need to seal tightly to force air through the oil cooler.  The oil cooler location in the 231 seems to be sub-optimal.  The airstream has to make a 90 degree turn since its installed flat and behind the oil filler neck. Simple pressure gradient dictates the airflow will find the leak rather than make that obstructed 90 degree turn.  Since you are able to keep your temp in line with the cowl flaps open, I would suspect the issue is airflow rather than a plugged line or oil cooler.  I also assume your oil pressure is in the middle of the green range, else you will need to adjust the vernatherm.  Low oil pressure will cause inadeqate oil flow for cooling not lubrication. 

I am sure you have discovered the TSIO 360 is somewhat of a quirky but very efficient engine.  Power applications need to be very smooth and gradual.  Its easy to overboost on takeoff so you need to be careful and also abide by the 2" per 5 minute rule (no more than 2" of MP reduction per 5 minutes to avoid shock cooling).  I usually fly either FL110 or 120 (dont like sucking on straws).  All that said its hard to beat 170 knots on 11 gph!

[M20Kid]

Scott - thanks for the thoughts and for the link.  I found the article interesting enough that I'm again thinking of adding and intercooler; assuming I can find one on the market.

Oil cooler and vernatherm from Pacific Oil Coolers in CA.  I think the vernatherm can be put in boiling water to see if it opens - yes? no?

[231flyer]

Btw I remember seeing a SB about high rates of premature failure on vernatherms.  Apparently a bunch of bad vernatherms are in the supply stream. As Scott suggests not a bad idea to bench test the vernatherm since you recently replaced yours.  

[M20Kid]

231flyer - the reason I bought the 231 was for the higher flights possible.  In AZ many of the IFR routes start at 15,000 and above to avoid Cumulo-granite   However, I have the same oil temp issues when flying down low as up high.

As for operations, I have found this to be a great airplane!  I leave the cowl flaps full open during the climb but then close them to trail when leveling off.  If I close them completely the pucker factor is too great.

The baffles appear to be in good shape but that's perhaps not giving me the full story on their effectiveness.  Hmmm ... how to know?

[231flyer]

Tape a couple of paper tell-tails to the underside of the oil cooler (party crepe ribbons work well).  Now cowl up and get a source of air (leaf blower works) into the left nostril (block the right nostril). You should be able to see the tell tales moving by looking up from the cowl flap.  Close the cowl flap and repeat. To track the actual air leaks I used a party fog blower (cool smoke) and an inspection camera on my Lancair.  

[KSMooniac]

The party fog idea is great!  You can also stick a trouble light into the cowl flap cavity and look thru the inlets and oil door for light.  A borescope camera, mirror, etc. might be helpful for this.  

Also, what power/mixture settings are you using for climb and cruise?

[M20Kid]

Great suggestions!  I hadn't thought of the leaf blower with paper or the fogger.  I suspect I can get some mileage out of both those ideas.  Thanks!

For power setting, I use 38" for takeoff, reduce to about 35" for the climb to cruise, further reduce to 31" for cruise.  My plane needs the prop reset because it won't give more than 2500 RPM in any configuration.  However, for the cruise portion I do pull it back slightly to about 2450 RPM.  At cruise I usually only pull the fuel flow back to about 12.5 gph just to help keep things cooler.

On my last flight I did try a variety of power settings down to 60% right from book.  It reduced CHT and EGT by 10 degrees with no noticable reduction in oil temperatures.  But I did loose nearly 20 kts - not much of a trade off for me.

[KSMooniac]

I wonder if your fuel flow is setup correctly.  Do you have a fuel flow instrument/totalizer?  How about a full engine monitor?  Check out this link:  http://www.tcmlink.com/pdf2/SID97-3E.pdf and if you have any suspicions you should find a mechanic that is very familiar with the procedure.  You might be running too lean in takeoff and climb and that could be giving you high temps (CHT) that lead to higher oil temp.  You also should get that prop governor fixed for maximum climb rate too!

[M20Kid]

Good question, Scott - when I bought the airplane in March the fuel flow on takeoff was only about 16 gph.  I had a mechanic step that up to about 24 gph but he was not familiar with the engine and could not do anything else but increase the fuel flow.  I downloaded the document you linked and I'll have my mechanic try to get it dialed in better.

Thank you!

[jetdriven]

You need to set the proper takeoff RPM , then adjust the fuel flow to give you the number you need on takeoff.  RPM and FF are closely related.

[KSMooniac]

16 GPH!  Yikes!  That is less than our Lycoming IO-360s, and you should be much more than that.  I would not fly it again until you get the RPM and FF fixed properly.  Your mixture/low fuel flow is probably the reason behind the high temps.  Do you also have an engine monitor?  I bet your CHTs were very high too.

[jetdriven]

Now its no better, its at 24 GPH at 2500 RPM and 38", so when they adjust the governor its going to be 28 GPH. At 40" its going to be even more.  Its only a 210 HP engine!  That fuel flow will be higher than my buddy's 285 HP Bonanza. 

Seriously, that is a $40,000+ engine on that airplane, and if it will not run cool with the cowl flaps cool, take it to a real Mooney shop and get it fixed. Then go buy yourself a new Tahoe in cash with the money you saved. Start with baffle seals, but look at the whole thing.

[M20Kid]

I have passively looked for a good shop to get this set correctly but it's time to become more proactive and get the fuel flow/RPM settings right.  I live in Phoenix - does anyone have any suggestions of a place within a reasonable distance?  I know there's a Mooney service center in Chandler, AZ but I know of some horror stories from that shop and have not gone there yet.  Perhaps they're a place to start, though.

Any other thoughts on a great shop to get this set up?

[231flyer]

Rick, I just read your other post about the oil consumption issue too.  Given the oil temp/pressure, RPM/Fuel Flow, and the oil consumption issue I seriously suggest you self ground your airplane.  Something seems to be amiss that your mechanic is unable to diagnose correctly.  Your Mooney needs real expert service and not just from any MSC.  We have several in TX (Don Maxwell, Dugosh etc) and at a minimum your mechanic ought to have a long chat with Don and get some real ideas.  

We just lost a member here on this board and we all need to be a little extra careful.  Please don't fly this plane till you have a better idea of whats causing all these issues.  Clearly this is not normal.  Sorry if this sounds alarming/preachy but better safe than sorry.

[M20Kid]

231flyer - I'm beginning to feel the same way.  I think the next thing on the list is to get someone knowledgeable about this particular airplane who can find and fix the various engine issues.  The last thing I want is to damage the airplane or myself and family.

I have spoken in the past with Don Maxwell; it was before I bought my airplane but he seemed to know what he was talking about.

Any other suggestions for a more local shop?  Anyone??

[M20Kid]

OK - Since everyone convinced me I needed to take my airplane to the shop I thought I'd let you know what they found.

First, I just bought the airplane in March and the prebuy had descent, but not great, compressions; mostly 60s and a couple of 70s.  Now a mechanic that I trust has gotten a 28 and a 44 on two of them.  He got a 55 and 60 on two more and the front two are both in the 70s still.  The two that were below spec were pulled and there are two issues; apparently someone cooked the engine as the exhaust valves in both are torched and there's corrosion in the cylinders that is too deep to polish out.  Out they go.  But now if those valves are burnt, how are the rest?  We're pulling the other four off and having them checked, too, but I suspect they'll find the same issues.  Oh, and the turbo charger is missing about 1/3 inch off the ends of each blade - apparently it was cooked, too.  Sigh ...

It looks like 6 new cylinders and an overhaul or replacement for the turbo charger before I get my shiny new toy back.

Now to a question - I can get the cylinders locally as the overhaul shop has some in-stock and ready to pick up at a better price than I've seen online.  The turbo charger is another issue.  Does anyone have any suggestions for a good shop for that unit?  I've seen other postings here about Kelly and I don't think I want to go that route.

Of course, if anyone has a spare turbo charger sitting around for a 231 I may be able to help you out!

[KSMooniac]

Ugh.  Sorry to hear of that diagnosis.  Check Trade-A-Plane for turbo overhaul shops and call a few.  I'm not a turbo guy yet, but I think I read good things about Main Turbo or something like that over the years on the web.  If you end up with a Kelly unit, get your shop to inspect it thoroughly and make sure it gets installed correctly, pre-oiled, etc. before starting it.  Then be very wary of it for the first few hours of operations and check for leaks after every flight.

[kortopates]

Take your pick, both are good shops:

http://www.mainturbo.com/Home/tabid/116/Default.aspx

http://www.approvedturbo.com/

The importance of getting your fuel system set up per SID 97-3E can't be over emphasized and for this you'll need an A&P or shop that has invested in the equipment and past experience to do it right. This is likely why your cylinders deteriorated so quickly since the last test.  And as Byron pointed out, you can't even begin to get it set up properly with a max rpm of only 2500, but that could be your tach rather than governor. Both of these need to be addressed before breaking in those new cylinders.

Hope you're not down long!

[aviatoreb]

Quote: M20Kid

OK - Since everyone convinced me I needed to take my airplane to the shop I thought I'd let you know what they found.

First, I just bought the airplane in March and the prebuy had descent, but not great, compressions; mostly 60s and a couple of 70s.  Now a mechanic that I trust has gotten a 28 and a 44 on two of them.  He got a 55 and 60 on two more and the front two are both in the 70s still.  The two that were below spec were pulled and there are two issues; apparently someone cooked the engine as the exhaust valves in both are torched and there's corrosion in the cylinders that is too deep to polish out.  Out they go.  But now if those valves are burnt, how are the rest?  We're pulling the other four off and having them checked, too, but I suspect they'll find the same issues.  Oh, and the turbo charger is missing about 1/3 inch off the ends of each blade - apparently it was cooked, too.  Sigh ...

It looks like 6 new cylinders and an overhaul or replacement for the turbo charger before I get my shiny new toy back.

Now to a question - I can get the cylinders locally as the overhaul shop has some in-stock and ready to pick up at a better price than I've seen online.  The turbo charger is another issue.  Does anyone have any suggestions for a good shop for that unit?  I've seen other postings here about Kelly and I don't think I want to go that route.

Of course, if anyone has a spare turbo charger sitting around for a 231 I may be able to help you out!

[M20Kid]

I've checked both the turbo shops you listed here (they're also the only 2 shops listed in my most current Trade-a-Plane) and they both seem to run about the same price and similar turn times; it's really a push there.  The one thing I like with Main Turbo is they have a test chamber and pre-run the unit up to 50,000 rpm to check the balance of all the components before shipping back to me.  I think I like that and will likely go that route with this unit.

About all the other stuff, I took the airplane to this particular shop because I've used them for years on my Cherokee and I've always gotten good service.  They are equipped to get the rpm and fuel flow set after all this "other" work is done and then I can fly with confidence.

Erik - you're right about one thing, these are the issues I would rather find out about on the ground.  Sticker shop at the shop is better than sticker shock from the hospital

[jetdriven]

A 231 is a precision machine and demands exact care from a shop that knows exactly what they are doing. Enough reports from Chandler MSC suggests otherwise.   Last check, the TSIO-360-LB is a 40K overhaul.  Treat this engine with respect and care, because it can make you homeless.