M20K 252 TSIO 360 - SB (Road to make it run LOP)

[Will.iam]

On 8/27/2025 at 4:19 PM, Fix said:

Put back my newly inspected 500h Slick Mag.
Engine runs more smoothly in general, but didn't solve my LOP issue.

I can get it running 29" 2300 10.1 but it's not 100% smooth as I would like.


Good news is that my GAMI Injectors will be sent out this week.

Another good news is I had an little oil leak that been hard to find over the last 12 months.
If my detective work is correct, then it was leaking from the Oil Stick rubber hose.
Fitted 2x new clamps and a new rubber hose and made sure that the metal tubes got connected as they should.
Last flight over an hour it appear that it stopped leaking... 
It was not leaking much, but it flying around everywhere making a mess.


 

What are you using for fuel flow readings?

my stock fuel flow meter is .8 gallons more than actual. When i got my jpi to read fuel flow also i used it as changibg the “K” factor is software where as the original would need me to flip some dip switches. I calibrated the jpi by running one tank dry in flight, land add 5 gallons to that tank. Reset the totalizer, start up and fly on the 5 gallons. When engine runs out note what the totalizer shows and adjust accordingly. I have mine down to .1 accuracy now on my jpi but my original show .8 per hour over so i use the original for flight planning purposes but use the jpi for leaning purposes. 

[Fix]

On 9/6/2025 at 8:59 AM, Will.iam said:

What are you using for fuel flow readings?

my stock fuel flow meter is .8 gallons more than actual. When i got my jpi to read fuel flow also i used it as changibg the “K” factor is software where as the original would need me to flip some dip switches. I calibrated the jpi by running one tank dry in flight, land add 5 gallons to that tank. Reset the totalizer, start up and fly on the 5 gallons. When engine runs out note what the totalizer shows and adjust accordingly. I have mine down to .1 accuracy now on my jpi but my original show .8 per hour over so i use the original for flight planning purposes but use the jpi for leaning purposes. 

Will check it next time.

[Fix]

My road to getting my -SB engine to run smoothly at LOP continues...

I now got my Maggie Harness (Thanks Paul for assisting) and also my Gami Injectors arrived.

I've suspected lots of things, but made the decision to change ignition harness to be 100% that there wasn't any issues.
They looked fine when we looked at it, but since left mag even when I changed it and also did an 500h inspection didn't solve rough LOP I decided to buy one anyway.

What can you say, I'm glad that I did order a new harness, since there was damage to the old one on several wires.
One of the wires were actually really bad, and was in direct contact with metal.
This was 5B on Left Mag... rest of chaffed wires were on bottom plugs too.
This was only on ~550h since new!

All damage was in clamp. (You needed to remove wire to see it) 
Wire with most chaffing was forced against an rivet due to wrong installation and wrong clamp.
Also impossible to see without removing wire.

Even if this don't solve my LOP issues, I now have a fresh and correctly installed ignition harness.

Started to install new harness yesterday.

Gami injectors will be next up.

Cylinder 5B.
Severe chaffing, through outer rubber and braid shield...

 

 

Some more chaffing, due to JPI probe wire in same clamp.

 

Some more chaffing, due to JPI probe wire in same clamp.
 

When the installed new engine, they used old/wrong clamps that put lots of force on wires.
On several wires when clamped together.

 

 

After some hours of careful wire planning it slowly looks much better.
Now all Ignition wires will be in own clamps, and all JPI probe wires in separate clamps.

 

 

Edited September 11 by Fix

[Fly Boomer]

25 minutes ago, Fix said:

Severe chaffing, through outer rubber and braid shield...

I am sorry you have to go through this on a low-time engine, but I have to admit to a little relief to know that the engine was not installed by the factory.

[kortopates]

Do your best to route those EDM wires away from the ignition wires; allowing them to be in close proximity to ignition wires will cause unnecessary noise in the readings.


Sent from my iPhone using Tapatalk

[Pinecone]

I just flew 5 hours yesterday after new SureFly settings.

The shop retarded the Surefly by 1.5 degrees to 1.8 total retard.  With the previous setting, I had to go way LOP to keep CHTs under control, bit TIT was very cool (1520 or so).  I was at 31.5 inches to keep CHTs under control with 10.1 GPH.

With the new setup, 30.6 inches, 2300, 10.1 GPH yielded about 15 degrees LOP, and CHTs fine with the cowl flaps just slightly cracked open.  With them closed, most times they were fine, but occasionally one would drift over 380 (my personal limit).  TIT ran 1605 - 1610.  

Very smooth operation.  When I did the sweep to see the actual peaks, with stock injectors, I was about 0.3 GPH GAMI spread.

[Ragsf15e]

6 minutes ago, Pinecone said:

I just flew 5 hours yesterday after new SureFly settings.

The shop retarded the Surefly by 1.5 degrees to 1.8 total retard.  With the previous setting, I had to go way LOP to keep CHTs under control, bit TIT was very cool (1520 or so).  I was at 31.5 inches to keep CHTs under control with 10.1 GPH.

With the new setup, 30.6 inches, 2300, 10.1 GPH yielded about 15 degrees LOP, and CHTs fine with the cowl flaps just slightly cracked open.  With them closed, most times they were fine, but occasionally one would drift over 380 (my personal limit).  TIT ran 1605 - 1610.  

Very smooth operation.  When I did the sweep to see the actual peaks, with stock injectors, I was about 0.3 GPH GAMI spread.

Wow, your TIT runs warmer than mine at similar settings.  Last weekend I ran 29.5/2350/10.4 with chts at 350 and below, tit 1510.  Then i pushed it to 31/2300/11.0 and saw 370 and lower with 1550tit.  I don’t think my OAT was that cool? Maybe -4c? At 13,000’

[Pinecone]

How old is your TIT probe?   When I got the plane, I had a JPI 830 installed.  The JPI and stock TIT were running a significant difference.  Like 50 degrees or so, IIRC.   I had the shop replace the stock probe and all of sudden, they were almost exactly the same.

As the TIT probes age, they read lower and lower.

[Ragsf15e]

1 hour ago, Pinecone said:

How old is your TIT probe?   When I got the plane, I had a JPI 830 installed.  The JPI and stock TIT were running a significant difference.  Like 50 degrees or so, IIRC.   I had the shop replace the stock probe and all of sudden, they were almost exactly the same.

As the TIT probes age, they read lower and lower.

It’s pretty new.  Less than 200 hours on it, maybe 3 years?

[Ragsf15e]

On 9/12/2025 at 8:50 AM, Pinecone said:

How old is your TIT probe?   When I got the plane, I had a JPI 830 installed.  The JPI and stock TIT were running a significant difference.  Like 50 degrees or so, IIRC.   I had the shop replace the stock probe and all of sudden, they were almost exactly the same.

As the TIT probes age, they read lower and lower.

The tit seems pretty reasonable compared to all my egt readings as well.  What do your egts read at this power setting?

[Pinecone]

On 9/13/2025 at 3:23 PM, Ragsf15e said:

What do your egts read at this power setting?

 

I have NO idea.  I know that I am 15 degrees LOP on the richest cylinder.

I will check on my next trip

[Fix]

Update:

New Maggie Harness, Gami Injectors and new Tempest Fine wire Spark plugs...

Engine runs runs smoother, more even RPM drop at Engine run up. 
Also idle is stable after a flight when taxi, before I had some issues were I needed to add some rpm to have it running and not quit.
Guess the harness fixed that.

Did some Gami spread test and most likely in average I have 0.7 with Gami. Cyl 1 & 3 is to lean.
Hopefully Gami will send replacement, they are not the fastest to respond.

LOP, is not perfect but now I can at least fly LOP 29.5" 2300 10.1 (LOP 5-15 degree).
After some fiddling I can get engine to run OK, but I expect improvement when I get replacement injectors.

On my from ESSB to ESML I got a new speed record at FL160.  
29" 2300rpm 10.1g/h, Cowl flap closed, All CHT under 369f, TIT ~1590-1600f

Tail winds are nice :-)
 

 

[Pinecone]

Nice.

TIT is a bit high.  Have you checked your mag timing?

[Ragsf15e]

On 10/4/2025 at 2:50 PM, Fix said:

Update:

New Maggie Harness, Gami Injectors and new Tempest Fine wire Spark plugs...

Engine runs runs smoother, more even RPM drop at Engine run up. 
Also idle is stable after a flight when taxi, before I had some issues were I needed to add some rpm to have it running and not quit.
Guess the harness fixed that.

Did some Gami spread test and most likely in average I have 0.7 with Gami. Cyl 1 & 3 is to lean.
Hopefully Gami will send replacement, they are not the fastest to respond.

LOP, is not perfect but now I can at least fly LOP 29.5" 2300 10.1 (LOP 5-15 degree).
After some fiddling I can get engine to run OK, but I expect improvement when I get replacement injectors.

On my from ESSB to ESML I got a new speed record at FL160.  
29" 2300rpm 10.1g/h, Cowl flap closed, All CHT under 369f, TIT ~1590-1600f

Tail winds are nice :-)
 

 

I agree with @Pinecone, mine would have a TIT ~1500 at that power setting.  What are the egts?

[Fix]

23 minutes ago, Ragsf15e said:

I agree with @Pinecone, mine would have a TIT ~1500 at that power setting.  What are the egts?

I replaced my Stock TIT prove around 60h ago, so I expect it should be OK.

I've noticed that if I calibrate my JPI TIT after the stock TIT, they will differ depending on what altitude I fly on.
If I calibrate it for at 4000ft at some power setting, JPI TIT will under read if I then fly higher, and vice versa.

Right now I think it's calibrated so it's not showing "too low" values on the JPI, where I think it's better to be safe than sorry.

Used flower pot, digital meter and spark plug pin.
If I didn't mess up, my mags should be timed within 0.5degress.

At FL 160 where the turbo have to work harder I have:

25" 2500 12.6g/h (65% ROP) 
EGT: Highest 1418f - Lowest 1353f - TIT: 1499f
CHT: 359f - 330f

- - 

29.5" 2300 10.1 (65% LOP)
EGT: Highest 1493f - Lowest 1406f - TIT: 1599f
CHT: 353f - 316f

My Cyl 6 EGT is lowest by ~40f from the others.


***

I've checked some other flights at FL140.
There my TIT was ~1500F at 25" 2500 12.6g/h 

 

Edited October 6 by Fix

[Ragsf15e]

Interesting how we all have different TIT values at similar power settings, but TIT is relatively important for turbo health.  Im starting to think our tit readings aren’t that consistent or something differs from engine to engine that’s causing it.

Based on your EGTs, the TIT seems reasonable, yet how can my egts and tit be 75-100 lower at the same power setting?

[Fix]

8 hours ago, Ragsf15e said:

Interesting how we all have different TIT values at similar power settings, but TIT is relatively important for turbo health.  Im starting to think our tit readings aren’t that consistent or something differs from engine to engine that’s causing it.

Based on your EGTs, the TIT seems reasonable, yet how can my egts and tit be 75-100 lower at the same power setting?

Would be interesting to gather some more information here...

I assume regarding EGT is where the probes are mounted/drilled in the exhaust.
Or are they "factory drilled" at exactly the same position?

Also with TIT Probe, is that location always the same on all -MB / -SB

 

[Pinecone]

17 hours ago, Fix said:

I replaced my Stock TIT prove around 60h ago, so I expect it should be OK.

I've noticed that if I calibrate my JPI TIT after the stock TIT, they will differ depending on what altitude I fly on.
If I calibrate it for at 4000ft at some power setting, JPI TIT will under read if I then fly higher, and vice versa.

Right now I think it's calibrated so it's not showing "too low" values on the JPI, where I think it's better to be safe than sorry.

Used flower pot, digital meter and spark plug pin.
If I didn't mess up, my mags should be timed within 0.5degress.

29.5" 2300 10.1 (65% LOP)
EGT: Highest 1493f - Lowest 1406f - TIT: 1599f
CHT: 353f - 316f
 

Those numbers look good.

There is a relationship between timing and CHT/TIT.  High CHT with low TIT you should retard the timing slightly.  

@jetdriven installed a SureFly last annual.  I had higher CHTs and lower TIT, so the retarded the timing about 1 degree.  That brought CHTs down and TIT up.

[Fix]

Had another trip last friday at FL100.
This flight my engine behaved as it should :-)

FL100
29.5" 2300rpm @ 9.9-10.0g/h
TAS: ~163KT
TIT: ~1575F
 
Will install my replacement Gami Injectors next week for Cyl 1 + 3 and it will be interesting to see how engine behaves then and if I get below 0.5g.

[Ragsf15e]

On 11/9/2025 at 8:48 AM, Fix said:

Had another trip last friday at FL100.
This flight my engine behaved as it should :-)

FL100
29.5" 2300rpm @ 9.9-10.0g/h
TAS: ~163KT
TIT: ~1575F
 
Will install my replacement Gami Injectors next week for Cyl 1 + 3 and it will be interesting to see how engine behaves then and if I get below 0.5g.

Im still surprised that your tit ends up that high, but maybe Im further lean of peak?  Here’s an example from today…

[Pinecone]

That could be a mag timing issue.  

[Ragsf15e]

2 hours ago, Pinecone said:

That could be a mag timing issue.  

I think that’s possible too.  While I was flying, I messed around with the MP just a little bit while keeping the ff at 10.4 for 65% power.  By increasing MP (and thus being further lop), I was able to lower tit by about ~25 degrees.  Obviously, you eventually start running rough as you get to the limits of your gami spread or ignition.  I was a little surprised that I could manipulate the tit that much while maintaining the same 65% power (and TAS).  I didn’t mess with the rpm, but I think lower rpm would also reduce tit.

[Fix]

On 11/12/2025 at 12:24 AM, Pinecone said:

That could be a mag timing issue.  

I've timed my mags several times with flower pot and digital meter and piston pin.
Maybe I messed up, I've double checked it.
At least both mags are even, maybe could try to adjust both mags 1 degree.

At 29" 2300 RPM at 10.1g/h LOP I my TIT show just above 1550f on the analog gauge, most likley 1510-1560f range.
Maybe it's higher than "normal", but on the other side it's still well below 1650f and also if the reading is "higher" even if the real TIT should be lower I have a margin to ~1600-1610f were my personal limit is. 

If I had a very low TIT with a functional TIT probe, then I might get above 1650f with out knowing it?


On the Garmin G500, do you calibrate the TIT against the analog gauge or how does it work?
I can also see that your EGT is lower than mine, what would be normal EGT temp?

Is there any difference between JPI probes and Garmin Probes and the original Probes with read out?
 

Edited 2 hours ago by Fix

[Fix]

Updated my Gami Injectors and did a quick flight today.
Now I have a Gami spread of 0.3 - 0.4g/h instead of 0.6-0.7g/h.

Will do a proper test flight soon as the weather is favorable here again.