Slow J

[Shadrach]

Just now, Llcrt said:

  The timing marks are very interesting, I'm not sure if the mechanics used a buzz box or not, I've only seen a box with lights, what the difference, I don't know.

That's likely a buzz box.

[INA201]

Im having similar speed issues in my 1978J.  Im in the 145+- range but I'm thinking the gear doors are the biggest problem.  You can check the thread on inner gear doors under the Modern Mooney discussion. http://mooneyspace.com/topic/4853-m20j-inner-gear-doors/  I also considered having my oil cooler serviced as it has been some 20 years since it was pulled.  The guys at Pacific Coast told me it would cost around $200.00 to service. May be worth a shot.  http://oilcoolers.com/  My timing was just done and now I have a high CHT in cylinder 3.  Hows your oil pressure? Can you call the previous owner?  Looking forward to hearing how it works out.

[Shadrach]

3 hours ago, cnoe said:

This may be too obvious but are you checking speed as measured by a GPS over an appropriate 3 or 4 leg course?

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Maybe, but with the piss poor climb, I think there's more to the story.  I'd be happy with 700fpm...climbing through a DA of 7000-8000' but not from 650'.

[cnoe]

Regarding oil temp, how high is "very high"? Over 210? 225?

I am not an A&P but I find a mis-timed cam more likely than a severely worn one on a 600 hour engine, particularly if the filter is clean.

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[M20F]

I would reccomend doing a 3 way ground speed test at your normal cruising altitude.  Report that, your power settings, and engine data (fuel flow, cht, egt, etc.).  Also note altimeter setting, temp, and IAS.

Could be a lot of things but without more information just a lot of guesses. 

[gsengle]

Def check the lifters, I had a similar problem in an arrow, with no other symptoms, I had an intake valve not opening far enough.

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[gsxrpilot]

I'd just book an appointment with the Dr at KGGG. You and a whole bunch of A&P's can try a million things and might get it by luck. Don can probably diagnose the problem walking across the ramp to shake hands as you arrive.

[Llcrt]

High oil temp is usually around 215 with cowl flaps open during the summer.  Half the time, I have to level off in my climb just to get more air speed and let the oil cool down once it hits 230, then resume my climb.  Oil pressure is between 65 and 73 depending on grade of oil and temperature.  I never thought of a mis timed cam, I will have to look into that.  I have chatted with Don and I am looking forward to pay him a visit for my next annual and see if we can't fix some of these issues.  I sent my oil cooler to Pacific Coolers, very nice people, fast turn around.  It helped a couple of degrees, but thats it.

[DonMuncy]

Do your JPI tracings give you any clue. Mike Busch might be able to give some insight.

[Llcrt]

Do the tracings give me a clue about what?  As long as I'm running rich of peak, all cylinders are pretty close to one another as far as temp goes.  Its when I start peaking out on

EGT is when they start seperating

[smccray]

17 hours ago, Llcrt said:

I own a 77 J model that will only true out at 160ish MPH or 140 knots.  It appears to be making good power, about 27" manifolf pressure on take off at 700 feet.  Typically in the Tesas summers, she only climbs at about 700 fpm, and the oil temp really starts to heat up.  I think my high oil temp is a result of my lower speeds.  The only 2 things I can think of to do now is to re-rig my flight controls because my right flap stays down ever so slightly and the ailerons are working to roll the plane back to the right.  Could be a little bit of drag.  The other thing that I was thinking was maybe a worn camshaft, but I have no oil in the filters when I cut them open and the engine appears to be running smooth.  Anybody have any ideas?

emphasis added...

What do you mean there's no oil in the filter?  I have an A3B6, not the A3B6D, but it's my understanding that the oil filter is in the same spot on the engine.  How much oil do you run in the engine?  If I change the oil, even if the plane is cold, I always end up spilling a little oil on the firewall.  The filter always has some residual oil left in it.

Really high oil temps are rare in my plane.  I can plan on 150 ktas on 8.5 mph LOP in cruise in my J, and my '87 is probably a lot heavier than your '77.

[Shadrach]

54 minutes ago, Llcrt said:

Do the tracings give me a clue about what?  As long as I'm running rich of peak, all cylinders are pretty close to one another as far as temp goes.  Its when I start peaking out on

EGT is when they start seperating

That's the opposite of mine. As soon as I get close to peak, my CHT spread starts to narrow quite a bit. By the time I'm 40LOP, the range from hottest to coldest is less than 25df. Also when I pass peak, my 2 hottest cyls #2 & #3 swap places and #2 become hottest by a very small margin

[KSMooniac]

I too vote for timing...either something internally wrong with the magneto or the cam gear as mentioned above.

Before I tore my engine down, I confirmed a worn cam lobe by measuring lift at the rocker arms and discovered the #1/#2 intake lobe was only opening the valves half as much as the others.  Easy to do.

I read a case from Maxwell years ago when the owner complained about low performance in his J.  Turns out the plane was a former Turbo Bullet conversion that used low-compression pistons and extra boost (>30" MAP).  At overhaul they removed the turbo system, but left in the low-compression pistons and of course it ran like a dog.  I'm not sure how you would verify the proper pistons were used at overhaul short of removing one, but that is another avenue to check if you have detailed records.

[aviatoreb]

19 minutes ago, KSMooniac said:

I too vote for timing...either something internally wrong with the magneto or the cam gear as mentioned above.

Before I tore my engine down, I confirmed a worn cam lobe by measuring lift at the rocker arms and discovered the #1/#2 intake lobe was only opening the valves half as much as the others.  Easy to do.

I read a case from Maxwell years ago when the owner complained about low performance in his J.  Turns out the plane was a former Turbo Bullet conversion that used low-compression pistons and extra boost (>30" MAP).  At overhaul they removed the turbo system, but left in the low-compression pistons and of course it ran like a dog.  I'm not sure how you would verify the proper pistons were used at overhaul short of removing one, but that is another avenue to check if you have detailed records.

Are people doing that often - and why?  Removing their turbo bullet conversions I mean.  I saw a Mooney recently at one of the paint shops I visited that was exactly that - a former turbo bullet.

[KSMooniac]

1 minute ago, aviatoreb said:

Are people doing that often - and why?  Removing their turbo bullet conversions I mean.  I saw a Mooney recently at one of the paint shops I visited that was exactly that - a former turbo bullet.

I don't believe it is supported at all any longer, but I could be mistaken.  I don't know how many were converted originally but am curious.  

[DonMuncy]

1 hour ago, Llcrt said:

Do the tracings give me a clue about what?  As long as I'm running rich of peak, all cylinders are pretty close to one another as far as temp goes.  Its when I start peaking out on

EGT is when they start seperating

I was only suggesting that If the CHTs and EGTs are all the same, it would likely eliminate all the possibilities that involve one cylinder. like a bad cam lobe.

[nels]

In a conventional engine, retarded timing does raise the engine temp.

[OR75]

 

it looks like you are based in the SAT area ....Plenty of good CFI in that area who are used to fly Js and know the settings well.... sooner or later you will need a bi-annual

 

[Guest]

I've flown an engine with a mis timed cam and crank gear, from your climb performance that's not the trouble.

Your engine is lacking balls or torque, I vote for a bad camshaft, but without knowing details it's my internet guess.  You should be able to remove the rocker covers and compare lift of the exhaust valve rockers and the intake valve rockers. Remember that the intake lobes of the cam do double duty, opening intake valves on opposite sides of the engine, hence double the wear of the exhaust lobes.

Clarence

[Bob_Belville]

31 minutes ago, OR75 said:

 

it looks like you are based in the SAT area ....Plenty of good CFI in that area who are used to fly Js and know the settings well.... sooner or later you will need a bi-annual

 

Biennial, now called simply Flight Review. (Bi-Annual would be twice each year.)

[Oldguy]

On 11/29/2015, 8:29:59, Llcrt said:

I own a 77 J model that will only true out at 160ish MPH or 140 knots.  It appears to be making good power, about 27" manifolf pressure on take off at 700 feet.  Typically in the Tesas summers, she only climbs at about 700 fpm, and the oil temp really starts to heat up.  I think my high oil temp is a result of my lower speeds.  The only 2 things I can think of to do now is to re-rig my flight controls because my right flap stays down ever so slightly and the ailerons are working to roll the plane back to the right.  Could be a little bit of drag.  The other thing that I was thinking was maybe a worn camshaft, but I have no oil in the filters when I cut them open and the engine appears to be running smooth.  Anybody have any ideas?

I see you listed two problems in your original post: low speed and poor performance. You mention the right flap droop and aileron roll to maintain attitude. Sounds like your comment about re-rigging is a good idea, but the question that comes to my mind is why the droop? Any damage history you know of or possibly a higher time air frame with some excessive wear? Anything outside of straight and level will eat away at airspeed.

On the performance side, looking at the POH should be able to tell you if the power generated by your lower MP and RPM are close to what the book says they should be for those settings. Your fuel flow on takeoff might be a little low - I've seen 19-20 gph given as the flow for a J on takeoff - but I'm not sure how that would affect oil temp as much as it appears it is.

It really sounds like there may be several minor issues (or not so minor if a camshaft is involved) adding up to present themselves as the effects you are seeing. But not being able to enjoy the speed and fun your Mooney should normally provide would lead me to agree with Paul an appointment with DMAX to get the symptoms diagnosed would be a good first step.

Best of luck and let us know how things go.

John

[Alhall]

Has anyone checked the muffler? It could be blocked some way.

[Loogie]

On November 29, 2015 at 10:35:35 PM, 201er said:

Are you sure you are comparing apples to apples? What RPM? What fuel flow? What EGT? What altitude and temp? What kind of mags and timing?

A good comparison test is to go to 7-8000ft, leave throttle full, leave RPM full, lean to 100ROP and calculate your TAS. This will be the best case scenario 75% cruise. I get about 160KTAS once a few hundred under gross.

I flew yesterday, and noted my cruise at 6500ft, 25RPM, 24", 120 ROP(keeps my cyl 368 degrees), RTB was at 5500ft.  The results in smooth air= 158kts both ways.  My J is average and my engine is @ 100hrs SMOH.

Something doesn't sound right in terms of power being produced, just wanted you to have another good data point like 201er mentioned. 

It could also be a fuel injection problem, where it gets leaned, not sure what it's called, but it could be affecting the fuel all the cylinders are getting.  Just a theory, not a A/P...to paraphrase Carusoam...:) good luck

 

 

[carusoam]

One way of checking the power being delivered that I really like, is to measure the T/O run, the  FF and Rate of climb.

1) T/O run can be measured using an app called CloudAhoy.  A few dollars for the app to get the details.  A WAAS supply for accurate data like my old SkyRadar.

2) Collect the data and compare to book values.

Being off by a measly 10% will show up measurably using these devices and technique.

Measuring speed at altitude is good, but also includes more aerodynamics into consideration compared to power being the concern....

I used these details to prove that 310hp is measurably different than the 280hp. Near 10% difference...

I am still not a mechanic.  Just a PP...

Best regards,

-a-

[slowflyin]

1 hour ago, Loogie said:

I flew yesterday, and noted my cruise at 6500ft, 25RPM, 24", 120 ROP(keeps my cyl 368 degrees), RTB was at 5500ft.  The results in smooth air= 158kts both ways.  My J is average and my engine is @ 100hrs SMOH.

Something doesn't sound right in terms of power being produced, just wanted you to have another good data point like 201er mentioned. 

It could also be a fuel injection problem, where it gets leaned, not sure what it's called, but it could be affecting the fuel all the cylinders are getting.  Just a theory, not a A/P...to paraphrase Carusoam...:) good luck

 

 

Loogie,

Do you recall what your ff was on this run?