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I have an intercooler, but no wastegate. Manifold pressure was not controlled on takeoff and went to 50. The max is 37! If overboosting doesn't really exist because the relief valve opens, then how did the gauge even get to 50? It was at that level for 20-30 secs. The engine appears to run great afterwards.

Is there anything that should be inspected or done?

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    $\begingroup$ Did you happen to note the rate of climb??? Just curious. $\endgroup$
    – acpilot
    Mar 20, 2017 at 20:38

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This most likely warrants a call to Don Maxwell the veritable Mooney expert but I would for sure have the engine checked by a Mooney expert or someone that knows their way around the TSIO-360-GB. At the minimum a compression test and possible borescope check is in order.

If you have the early 231 in its original config you have a fixed waste gate that can be over boosted on takeoff.

The engine also had a fixed wastegate in the exhaust system, meaning careful pilot technique was required to keep from over boosting the engine on takeoff. If the pilot inadvertently added full throttle for takeoff or a go-around, the engine would over boost, with only a mechanical pop-off valve in the induction system to save the engine from literally coming apart on the runway. Fixed wastegates also mean high turbocharger speeds (RPM) at altitude, which reduces turbocharger life

I don't know much about the gauge itself but it may warrant checking it to make sure it is operating properly.

You can also reach out to continental and ask them what the over boost limit is. There is a chance they have some data on it or can let you know of a good course of action.

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The relief valve may have failed. It's advisable to have that engine inspected as that kind of overboost can cause severe detonation and damage the engine. This may mean a complete tear down of the engine. I'm not an A&P by any means but I think that's want they're going to advise.

Or you could simply have a bad manifold pressure gauge; have that inspected first; it could save you a lot of money.

Did you encounter additional symptoms i.e. Engine really running at a high pitch, possibly with knocking accompanying it?

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WHAT? 50" for 20 seconds??? That's nuts!

The first call should be to CMI.

The engine user manual directs a user to see Continental Service Bulletin M67-12 after operation in a sustained overboost condition. I would say this event qualifies!

Read the SB, call CMI, and then call an engine shop.

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  • $\begingroup$ Your document link just redirects to the main Continental site... $\endgroup$
    – Ron Beyer
    Mar 20, 2017 at 19:12
  • $\begingroup$ I'll deactivate the links but the message is the same. CMI has guidance on how to proceed. Either search online, email, or call the manufacturer for more information. $\endgroup$
    – acpilot
    Mar 20, 2017 at 19:45
  • $\begingroup$ Here's M67-12, but all it says is "call CMI". $\endgroup$ Mar 20, 2017 at 20:35
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I would say that you should definitely have the engine inspected. I had a P337 skymaster with two of those TSIO-360s, though mine had automatic manifold pressure control so overboosting was less common. The manual said an inspection was necessary for even a short overboost of 4 inches if I remember correctly.

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