M20k engine questions

[Someguy]

I just bought an 83 M20K with a GB engine upgraded to an LB. Does anyone know the differences? I spoke with a rep at Continental and all he could tell me was the fuel system.  I also have the intercooler upgrade with the merlyn wastegate. Does anyone else have similar configurations? What charts are you using for power settings? I spoke with merlyn who is now Nord engineered products LLc and they gave me a chart but it is not “approved”. The same goes for the intercooler manufacturer found a chart on their website but it is not “approved” as well. I might be going overboard but I don’t not want to place undue stress on my engine. Also,has anyone had any oil samples prior to and after these mods on their aircraft. I’m sure I’ll have more questions in a bit. But these are the things of most concern for now

[carusoam]

Kinda late to ask now…

You already own it?

You can imagine how many M20K owners there are on MooneySpace right?

Many have upgraded up the scale to a 252 or Rocket…

You have a Continental TSIO360…

You have a Merlyn MP controller….

You have an intercooler…

Did you get the dual puck brakes with that?

Did you get the recommended transition training to go with all that technology?

Or are you just going to sneak around with…. I bought one of the greatest planes on and off the planet… but I don’t really know what I have…. 
 

Let’s see if we can get you up to speed a bit…

Better late than never…

Then we can discuss LOP vs. ROP….  Endlessly…

The coolest thing about transition training… you build a relationship with a great CFII that can answer some quirky questions that come up, and save the hard ones for the public forum…

This plane is too powerful to be shy… be sure to ask a bazillion questions… after learning the search function…

What part of the Mooney world are you located in?

PP thoughts only, not a CFII…

Best regards,

-a-

[hubcap]

Welcome!

I have exactly the same configuration that you described -

TSIO-360-LB with TurboPlus intercooler and Merlyn upper deck pressure controller.

Generally speaking with the intercooler your MP settings will be ~2” less than without. This is based on the TurboPlus conversion table.

Someone more knowledgeable than myself will come along and explain the differences between the GB and the LB….I just know the LB is better.

I believe @jlunseth is one of the more experienced with this setup.

 

[Someguy]

Thanks for being helpful hubcap. Is that other guy always like that?

[carusoam]

1 hour ago, Someguy said:

Thanks for being helpful hubcap. Is that other guy always like that?

He has difficulty writing…

But, he tries to be helpful…

See if you can get him to open up a bit, by answering a question that he brought up… then ask another…

Best regards,

-a-

[T. Peterson]

1 hour ago, Someguy said:

Thanks for being helpful hubcap. Is that other guy always like that?

No, he is not always like that. He is a very seasoned MS poster and long time Mooney owner. He is also very intelligent and posts buckets of useful information and is usually very gentle especially with new folks. I don’t know why he was a bit abrupt with you, but I encourage you to overlook it. That was out of character for him, but he genuinely means well and is a great asset to Mooneyspace. Stick around and you will learn the various personalities and our quirks! We all have our moments but 99 percent of the guys really want to help.

I too bought a 231 and enjoy it immensely even though I don’t have the intercooler. Someday I’ll get one and then my plane will also get 175 TAS on 10 gallons an hour!

Welcome!

[jlunseth]

Welcome to the forum. There were a lot of questions in that one post. What can we help with?

Here is just a little bit. I don’t know too much about the GB to LB conversion, most aircraft and engines were converted a long time ago so it does not happen much anymore. I believe there was a change to the throttle body, which was too restricted. The main thing is that the GB had a reputation for running very hot and the LB is less hot.

I have had a Merlin and intercooler on mine since I bought it. We did some oil analysis over the years. The Merlin and intercooler have no effect on oil analysis, if anything they make life easier on the engine so less likely to have oil problems. Don’t let anyone tell you that large oil loss is normal. I had oil problems early on, had the engine IRANd about 12-1300 hours ago. Since then it loses about one to two quarts between oil changes, small enough that I generally don’t have to add oil between changes if I make that change at around 25-30 hours. The engine is now closing in on 2400 which is 600 over TBO.

The Merlin is not a fully automatic wastegate despite the advertising. It mainly does two things. It limits bootstrapping and it allows the wastegate to fully close, which gives you a much higher critical altitude than the factory engine. The CA is the point where the engine can no longer make full power ( there are more technical definitions but that’s the simple one). It is 15,500 in the factory engine without the Merlin and most days I can make more than 22,000 with the Merlin. The wastegate is not automatic, the pilot is fully in charge of the MP. If you go up or down in altitude, for example, the wastegate will not hold your set MP. You have to push the knob in (or out if you are descending) in order to maintain a specific MP.

The intercooler is a real help. It cools the air that has been compressed by the turbo. The factory engine has a Compressor Discharge Temp and there is a redline limit. The redline limit is 280 dF. It is there to protect the engine from overly hot induction air which can cause detonation and damage to the engine. The intercooler pretty much eliminates CDT as an issue because the induction air temp will drop, at cruise, around 100 degrees and can be higher. The drop is variable depending on airspeed, OAT, flight regime, etc, but it is quite large. Helps the engine stay cool.

That’s it for starters. So like Anthony said, what other specific questions do you have? If you do some searches you will find that quite a bit has already been written on this board about the 231.

PS automatic wastegate and intercooler help the engine so much that they have been improved and incorporated in every turbocharged Mooney since the 231, which was the first turbocharged Mooney. All the models since then have a fully automatic wastegate that is “set and forget,” the pilot sets an MP and the wastegate maintains it with changes in altitude, etc. 

Edited April 12, 2023 by jlunseth

[LANCECASPER]

9 hours ago, Someguy said:

I just bought an 83 M20K with a GB engine upgraded to an LB. Does anyone know the differences? I spoke with a rep at Continental and all he could tell me was the fuel system.  I also have the intercooler upgrade with the merlyn wastegate. Does anyone else have similar configurations? What charts are you using for power settings? I spoke with merlyn who is now Nord engineered products LLc and they gave me a chart but it is not “approved”. The same goes for the intercooler manufacturer found a chart on their website but it is not “approved” as well. I might be going overboard but I don’t not want to place undue stress on my engine. Also,has anyone had any oil samples prior to and after these mods on their aircraft. I’m sure I’ll have more questions in a bit. But these are the things of most concern for now