Overhaul time?

[2jetman]

I just wanted to put this out there and see if anyone had any ideas on how to fix the problem. I have 1700 hrs on the original new engine in my bravo and I just done a top overhaul about 200 hrs ago. I had the top spine on the case starting to seep oil towards the font of the engine and I had a mechanic shoot some silicone under high pressure in the case bolt holes to temporary fix the problem. It worked, and that was about 150 hrs ago. Now I have the same problem on the bottom of the engine and and the top is starting to ooze again. A different mechanic is telling me that the silicone is not a good fix and I should just do a major overhaul. Anyone else had this problem on a higher time engine, and if so how did you handle it? 

 

Tommy

[jetdriven]

Oil leaks are annyoing but not critical. If it is not making metal and the oil analysis looks good, clean the case well and put epoxy or equivalent on the case halves to stop the leaking. Note, this may also be a symptom of excess crankcase pressure so be sure your breather is not obstructed.  Fly on and monitor carefully.

[gwcolwell]

M20F owner here.  Had a consistent oil leak between the case halves @ the lower seam between the starter & alternator. Leak had been addressed a couple of times by various methods, epoxy, case bolts, etc.  Fuel tanks were leaking @ annual time so I elected to seal the tanks & pull the engine. Sent to overhauler. Upon disassembly & inspection the overhauler found the front main bearing locating tang had rotated up into the case thus rendering the crankcase ng.

[2jetman]

Just and update, I'm in the process of fixing the problem by hanging on a factory rebuilt. During the removal of the old engine they found a few hoses that were chafing on one of the engine mounts that had worn the mount well beyond limits. It was in such a position that the only way to have found it was buy removal of the engine. 

[chrisk]

I've been thinking about getting a Bravo, but am concerned about the cost of an overhaul.  --So, what does an overhaul cost?  Is it closer to $40K or $80K?  I wasn't able to tell with a quick google search.

[jetdriven]

It's about 60K for an overhaul on a Bravo. More if things are bad like the crank or case.

[chrisk]

Thanks for the info!

[carusoam]

A break down of Byron's number might go something like this...

OH engine $40k

OH turbo system $10k

R&R the whole lot $10k

The Acclaim factory reman is in the $60k bracket, R&R not included. And it comes with a pair of snails (TNs)...

I had a dream, that one day, my children earned a scholarship, or two...

Best regards,

-a-

[AndyFromCB]

A break down of Byron's number might go something like this...

OH engine $40k

OH turbo system $10k

R&R the whole lot $10k

The Acclaim factory reman is in the $60k bracket, R&R not included. And it comes with a pair of snails (TNs)...

I had a dream, that one day, my children earned a scholarship, or two...

Best regards,

-a-

 

50K to 60K is pretty much dead on if your case and crank are fine:

 

$32K to overhaul the engine if your cylinders are fine, so $1K per cylinder for new pistons, valves, honing, etc, etc. Add $9K if overhauled with new cylinder assemblies.

 

$4K to overhaul turbo, controllers and wastegate (actually less, since most of the time, everything but the waste gate butterfly valve will be just fine, to overhaul the controllers in the field is like $10 worth of o-rings)

 

$2K to overhaul the exhaust if transition is fine

 

$5K for new transition (yes, $5K for a hunk of metal that would cost $200 in a car, retail is actually $9K), certain shops will "overhaul" that part for about $1K (build a new one from scratch, keep one atom of the old one, call it overhaul)

 

$2K to overhaul the engine mount

 

$2K for new engine mount pucks

 

$4K to R&R (10K is a bit high there, it's about a 4 day job for one guy or a 2 day job for 2)

[AndyFromCB]

Just and update, I'm in the process of fixing the problem by hanging on a factory rebuilt. During the removal of the old engine they found a few hoses that were chafing on one of the engine mounts that had worn the mount well beyond limits. It was in such a position that the only way to have found it was buy removal of the engine. 

 

Same thing happened to me. Two tubes were replaced. It really makes sense to pay attention at oils changes to all the moving parts in the engine compartment.

[AndyFromCB]

Just and update, I'm in the process of fixing the problem by hanging on a factory rebuilt. During the removal of the old engine they found a few hoses that were chafing on one of the engine mounts that had worn the mount well beyond limits. It was in such a position that the only way to have found it was buy removal of the engine. 

 

One critical part to pay attention to is the turbo to exhaust v band clamp. It will set you back a grand, yes a grand for a clamp. You only get 2 more removals and reinstalls after that before having to have to buy a new one. This part is critical as so far it killed 3 Bravo drivers.

[carusoam]

That is an eye opener!

Flying a TC'd engine in the flight levels is a pretty serious business.

Not time to save an AMU here and there.

-———-

Would the TN engine of the Acclaim have been any better for those lost souls?

Or is that too apples to oranges to compare?

One TC vs two TN, compression ratios that are significantly different, different clamps,.....etc...

Best regards,

-a-

[AndyFromCB]

That is an eye opener!

Flying a TC'd engine in the flight levels is a pretty serious business.

Not time to save an AMU here and there.

-———-

Would the TN engine of the Acclaim have been any better for those lost souls?

Or is that too apples to oranges to compare?

One TC vs two TN, compression ratios that are significantly different, different clamps,.....etc...

Best regards,

-a-

 

The problem was that the v band clamp was a two piece design where the two pieces were welded together. The weld failed and turbo would spew gases directly into the engine compartment. NTSB found two cause: weld failure and inadequate firewall design by Mooney. Nothing was done about the firewall but the clamp design was changed to where after welding, three or four rivets are driven thru the parts essentially preventing a total instant failure. 

 

However, if the welds to fail, and fail they will eventually things will start moving and slowly leaking exhaust into the engine compartment. This is why grabbing the exhaust pipe and giving it a tug should be on every turbo owners list. 

 

Also, like I mentioned, the part now has a 3 RR cycle limit. I track mine in a logbook and was lucky enough to purchase 2 of them on ebay from a closed maintenance shop for less than 180 bucks each. 

[jetdriven]

The firewall is stainless still but the exhaust tunnels are simply aluminum. Any fire simply melts out the tunnels and then kills the occupants. Something about the design of the exhaust is the coupler breaks and the exhaust then points at the firewall which burns through pretty quickly with 1600F exhaust torching it.

[carqwik]

There is a shield required to be installed on the firewall right behind the exhaust as part of the AD with replacement of the old clamp.  1 AMU for a new clamp...ouch!

[Piloto]

I found that silicon seal  does not last too long for oil leaks. I use fuel tank sealant PRC-1422-A2. Clean the surface very well with MEK and brush in the PRC into the crevices. It blends very nicely and really stop the leaks.

 

José