Pre-buy advise for a new member?

[TWinter]

Hello all,

I've been lurking around the forum for a short while and trying to get re-educated after a twenty year lay-off from flying.

I just got back into flying last December and it feels great being back in the air. I currently have a 69 Piper Cherokee that I have been playng with over the last six months. I recently struck a deal on a 74 Mooney M20E. It is waiting in the wings for a pre-buy and annual. All looks pretty good on the pre-buy/annual. I have some slight concern over the compression readings.

The plane has just under 3000 TT about 990 SMOH. The current compressions are 68,76,76,75.   Last years annual was 70 on the current 68 reading. No issues found so far. I've tried to research and see what a respectable variable is with regard to compression and pretty much get answers all over the place. I don't want it to be a deal breaker for me, but I'm usually seeing mid 70s on my aircraft. I know there are different factors as well and not all shops read the same.. This shop has done the annual on this particular aircraft for the last ten years plus. They say it's not a big deal. I have yet to fly the plane..or had my A/P look at it. I'm in TN and the aircraft is in Ohio.  It is being serviced by the seller's service center. They are a recognized Mooney service center (Akron, Ohio), for some of you that may know them. I have confidence, just concerned over the 68 on cylinder 1. Should I have any concerns? Any input is appreciated. Thanks and glad to be a part of the forum.

 

Thanks,

Tom

[Immelman]

Close scrutiny of an engine is called for with any pre-buy... I am not an engine expert but I would hope you're also looking at wear metals trends (was the prior owner using oil analysis), borescoping each jug to examine vavles, etc.

As far as the compression goes, let's say that maybe one cylinder is bad (I sort of doubt 68/80 is, but again I'm not the engine expert)... so is that a deal breaker? A cylinder is relatviely simple to replace...

[Becca]

Quote: TWinter

Hello all,

I've been lurking around the forum for a short while and trying to get re-educated after a twenty year lay-off from flying.

I just got back into flying last December and it feels great being back in the air. I currently have a 69 Piper Cherokee that I have been playng with over the last six months. I recently struck a deal on a 74 Mooney M20E. It is waiting in the wings for a pre-buy and annual. All looks pretty good on the pre-buy/annual. I have some slight concern over the compression readings.

The plane has just under 3000 TT about 990 SMOH. The current compressions are 68,76,76,75.   Last years annual was 70 on the current 68 reading. No issues found so far. I've tried to research and see what a respectable variable is with regard to compression and pretty much get answers all over the place. I don't want it to be a deal breaker for me, but I'm usually seeing mid 70s on my aircraft. I know there are different factors as well and not all shops read the same.. This shop has done the annual on this particular aircraft for the last ten years plus. They say it's not a big deal. I have yet to fly the plane..or had my A/P look at it. I'm in TN and the aircraft is in Ohio.  It is being serviced by the seller's service center. They are a recognized Mooney service center (Akron, Ohio), for some of you that may know them. I have confidence, just concerned over the 68 on cylinder 1. Should I have any concerns? Any input is appreciated. Thanks and glad to be a part of the forum.

 

Thanks,

Tom

[carusoam]

That defines the value of a pre-purchase inspection.  Pay a professional for advice in the areas you cannot interpret yourself.  Your risk in this case is installing a new cylinder....

Leaky valves and scratched cylinders, worn rings can cause leaks.  Only a mechanic can identify the details.

Search this site for PPIs and people experiences and costs to have a ppi done or not done....

Good luck, welcome to the world of Mooneys.

How did you manage twenty years without flying?

Best regards,

-a-

[Parker_Woodruff]

I know G-Force at CAK and they did good work for the previous owner of the M20J that I owned from February 2009 to December 2010.  They had serviced for probably 8 years before that.  I also had a good pre-purchase accomplished by them before flying it to Texas.  Maintenance then resumed under Maxwell Aviation (my preferred MSC).  Looking back at the invoices, I don't see any major skeltons that G-Force missed.

[fantom]

Good advise above....you need an independent inspection. 68 on one cylinder is probably nothing, but you need to make sure. Are the compression checks on a warm engine (better) or a cold one (usually lower readings).

After a Cherokee, you're gonna love a Mooney. Welcome to the club!

[KSMooniac]

68 probably isn't awful, but you need to check when the plane was overhauled and how often it has flown since the overhaul.  Oil analysis histories would be worth a lot.  At a minimum I would want pics of each exhaust valve (easy to do with cheap equipment after a compression check) to check wear/deposit patterns.  If only that cylinder ends up being "bad" in some fashion, you can remove and have it reworked for nominal money.

Has the -208 service bulletin been done?  

Good luck!  As Gary said, you'll love the upgrade over a Cherokee!

[TWinter]

Thanks for the great replies. They really just started the annual this past Monday and I've called pretty much daily (probably bugging the cra# out of them), but I'm pretty cautious and buying sight unseen is difficult. No other info regarding any findings just yet. The seller has sent me all the logs etc. I've looked them over pretty well, but will dig into them deeper tonight and look at all the compression readings over the past few years and see what that one has been showing. There is lots of info regarding compression on different sites. Most has been what was relayed here. 68 is not bad and it may just be a lower end reading for various reasons (lower engine temps or whatever as mentioned). The scope would give a more accurate indication. I'll bug them with that one now.

There was a mention independent inspection. The balance of the purchase  is not paid until my A/P takes a look. So I've got that covered. The seller is bringing the plane to me so our first stop is my A/Ps shop.

Why I  took a  twenty year lay-off?.Well it took me that long to build a business so I could fly these birds when I felt like flying and actually enjoy looking out the window and flying. Twenty years ago I think I was concerned about how much fuel I was burning and how many hours I had rented  for and what I owed for plane rental.  Back then $65 an hour wet for a Warrior was pretty tough. LOL.. We won't even get into how times have changed..and now with GPS..Life is good..Ha

Looks like a great forum..thanks again

 

[jetdriven]

Super deal killers:  rusty fuselage tubes, spar corrosion, camshaft or lifter problems. Pull off a cylinder and look at the cam and tappets, but we did this and 250 hours later a major overhaul.