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Oil cooler relocation with dog house


vik

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I have 67 M20E which still has the dog house. I would like to relocate the oil cooler from the lower cowling. What are my options? The only available STC I found is for the open baffling.

I do not mind getting rid of the dog house if that is the only way to relocate the oil cooler to the rear wall of the baffle, right behind the cylinder #4. That location looks best for me: minimal number of parts, shortest hoses etc. However, I could not find any info how to get rid of the dog house. 

My understanding is that Mooney got rid of the dog house the same year, but my airplane still has it.

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37 minutes ago, Yetti said:

Have not figured out why people relocate the oil cooler.   From my experience flying in the hot Texas Summers, there are not cooling issues with it located where AL Intended for it to be.

The oil cooler in its original position is known to have the airflow flow backward through it in certain regimens of flight..  The original cowlings and pressure cowlings on our old birds are -quite- inefficient.  I've always wished I could move it on my C, but the battery box is in the way.

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Oil cooler modification is particularly appealing for the C models, which have cylinder cooling problems at baseline.  The oil cooler blowing air into the bottom left cowl and decreases the pressure gradient from the doghouse - not surprisingly my #2 and particularly #4 cool the worst. 

I've wondered if there could be a shroud engineered over the back of the oil cooler to dump the air passing through overboard somehow and not into the bottom cowl.  That would be preferable to tacking it on the back of the doghouse, which would also be predicted adversely affect cylinder cooling by forcing less air down over the fins.

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5 hours ago, takair said:

What is the piece that is riveted to the top of the foot well?

Don't know why it was there, no need for it now.  Looks like several rivnuts so something could be fastened on top.

P1010722.thumb.JPG.4b188da71598d8498a6a15d199736f85.JPG

 

Don't think the relocation works well as temps get near 215 on a summer climb.  A second funnel at the bottom and dumping out near the cowl flap opening would improve that.  Wait...this is not experimental.  Oh well.

Next annual, those hoses and some others are being replaced.  Also, some general wiring cleanup there are a complete extra set of wires for CHT, EGT and carb temp not being used.  Ah, 45 year old airplanes.  You should have seen under the panel before a wiring cleanup.  Better but not pretty now.

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10 hours ago, cctsurf said:

The oil cooler in its original position is known to have the airflow flow backward through it in certain regimens of flight..  The original cowlings and pressure cowlings on our old birds are -quite- inefficient.  I've always wished I could move it on my C, but the battery box is in the way.

Why not move the battery to the tail cone? I did.  Its all in 43.13 on how to do it as  minor alteration. 

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On 9/18/2021 at 1:32 AM, vik said:

I have 67 M20E which still has the dog house. I would like to relocate the oil cooler from the lower cowling. What are my options? The only available STC I found is for the open baffling.

I do not mind getting rid of the dog house if that is the only way to relocate the oil cooler to the rear wall of the baffle, right behind the cylinder #4. That location looks best for me: minimal number of parts, shortest hoses etc. However, I could not find any info how to get rid of the dog house. 

My understanding is that Mooney got rid of the dog house the same year, but my airplane still has it.

I’ve got a complete set of late model baffles for sale.

Clarence

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4 hours ago, M20Doc said:

I’ve got a complete set of late model baffles for sale.

How I wish I could use these on my plane...  I really want Sabremech's cowl, but I haven't seen much from that recently.  At the same time, I've got a replacement set that would fit mine, but I'm missing a couple of components...  Need to either source them or build them.

 

22 hours ago, cliffy said:

Why not move the battery to the tail cone? I did.  Its all in 43.13 on how to do it as  minor alteration. 

I really don't love the long battery cables.  I've got them in my Cherokee.  I also think I would have weight and balance problems...but I haven't studied that carefully.

As of right now, I'm happy with where I am.  It's flying and annualed for the first time in 3 years after an extensive list of repairs and upgrades.

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On 9/18/2021 at 8:36 PM, cliffy said:

Why not move the battery to the tail cone? I did.  Its all in 43.13 on how to do it as  minor alteration. 

My battery is already in the tail, so I do not have it in the way. What I want to do is to relocate the oil cooler to the baffling wall just behind cyl #4. I saw STC for that, but only for open style baffling. My plane still have the dog house. Upgrading it would probably involve another STC + $$$$ for new baffling. So, I am not sure I wanna go that route.

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The problem is that the 3in hose on the oil cooler still doesn’t have enough enough volume. Could be more efficient than air flowing backwards through the cooler at the front of the cowl. I installed an air dam on mine like the C model has. I thought making the oil cooler have its own exit air out the left cheek would be the best.  
-Matt 

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3 hours ago, vik said:

Do you have a picture of the air dam? Is it considered a minor mod?

I believe it is in the Mooney service bulletins on their website, way back in the early to mid 60s...  I'm sure I read about it.  With that pedigree, it's definitely something an A&P can do.

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