Spark Plug Doghouse Interferance?

[cctsurf]

Has anyone had trouble getting tempest spark plugs to fit under the doghouse on the early mooneys?

Having recently installed a Surefly SIM in place of my left magneto.  As in many other things, my plane is playing "If you give a mouse a cookie."  My sim was misfiring and it seems I need new spark plugs.  This was not terribly surprising, but I am anticipating replacing the champions with urem38e Tempest plugs.  I keep reading that the spark plug socket for the tempests needs to be quite long. I'm concerned especially on cylinder 1, where the doghouse on my '62 is shortest that I might be -very- tight against it.

I'm hoping I am making a big deal about nothing, but I thought I would ask on here.

Thanks!

 

Edited November 12, 2020 by cctsurf
This doesn't just apply to Tempest plugs

[J0nathan225]

'64 E here no issue, I switched to fine wires. I was destroying missives with the surefly installed. 

[carusoam]

cct,

I highly recommend posting a couple of pics...

Oddly, there were a couple of doghouse and cowling changes over the years...

Just for a few parts of an inch here and there...

Then again... lots of Surefly installs... none reporting a space issue that I recall...

Supply some pics, then we can call the doc.... 

PP thoughts only, not a mechanic..

 

Best regards,

-a-

[cctsurf]

3 minutes ago, carusoam said:

Supply some pics, then we can call the doc.... 

I'll have to get out to the airport to take some pictures...probably tomorrow.

[DXB]

FWIW I have a '68C with Tempest UREM37BY with no issues.  I need an extender on the spark plug socket to pull the top plugs but that's all.  I think the doghouse may have changed a bit between 62 and 68 but don't know the specifics

[Bolter]

The need for socket depth is not the overall height of the plug versus the champions, but having a relief in the right place so the socket will reach down to the hex part of the plug.  I had to get a different socket when I went to Tempest.  Some fit, some don't.  However I think if it fits the Tempest, it fits them both.  

[cctsurf]

 

That picture helps a lot.  I kept reading about the need for a deeper deep socket and began to wonder if the tempest plugs were longer than their champion counterparts.  I see that the hex for the wrench to address is lower on the plug and that makes the difference for the socket.   I picked up a special socket, so I should be OK on that.

I just dislike how tight the plug wires must turn to miss the doghouse and I was concerned that the tempests might be a bit longer and make that corner even tighter.

10 hours ago, DXB said:

I think the doghouse may have changed a bit between 62 and 68 but don't know the specifics

The early Mooneys had an interior pressure cowl inside of their exterior cowl.  It goes all of the way around the top of the engine.  This is what makes me concerned especially about the length of the top plugs.  If you notice the front right corner of the doghouse in this is angled down and it gets quite near the spark plugs (notice the bump here, mine doesn't have that).

[smwash02]

I moved to all UREM38S plugs in my '66C, never had an issue with fitment.

I've attached a few photos that might help you see the sizing and such.

[cctsurf]

Finally got out to the airport to take some pictures...  No, the rem38e plugs will not fit under the doghouse there.  I wish I had ordered the -BY version..   Hmm.  Thankfully, that old plug  (a -BY one...I was wondering what was going on there), was the only one that tested good... And that plug is still fired by the magneto...so back it goes until I can get a replacement.

 

[carusoam]

Let’s see if @M20Doc has seen solutions to this tight area at the plugs and dog house... (older dog house vs. newer doghouse)

Best regards,

-a-

[mike20papa]

The solution involves a piece of annealed alum. hammered to accept the plug wire bend.  I also added a piece of 1/4" wool felt to improve the clearance & seal.  Joe 

[carusoam]

M20P is on fire with the pics tonight!

Best regards,

-a-

[jwarren2]

Wished my doghouse looked that good. 

[Pasturepilot]

I ran into similar problems... and started thinking I was crazy. My 7/8 spark plug socket I’ve used since I was a teenager wouldn’t fit. And the newfangled tempest plugs were missing the top of the doghouse. 
 

So I installed the tempest plugs on the bottom and stuck with champions up top. 

[cctsurf]

6 hours ago, Pasturepilot said:

tempest plugs were missing the top of the doghouse.

placing the old Champions level next to the new Tempest plugs they are the same length.  My problem would be just as true of champion plugs in the #1, top hole...  The more I think about it, I should have gone with the UREM37BY plugs instead of the UREM38E's...  Too bad that's another week wait for shipping.   I either have to make a dome like mike20papa showed above or get a REM37BY for that position...I'd really like to have the same plugs all around...  Honestly, I like the REM37BY design better...  Anybody want a set of UREM38Es with a couple hours on them?

[cctsurf]

REM37BY

REM38E

UREM38E

[Pasturepilot]

4 hours ago, cctsurf said:

placing the old Champions level next to the new Tempest plugs they are the same length.  My problem would be just as true of champion plugs in the #1, top hole...  The more I think about it, I should have gone with the UREM37BY plugs instead of the UREM38E's...  Too bad that's another week wait for shipping.   I either have to make a dome like mike20papa showed above or get a REM37BY for that position...I'd really like to have the same plugs all around...  Honestly, I like the REM37BY design better...  Anybody want a set of UREM38Es with a couple hours on them?

Something caused me to put the champions up top. Maybe the new spark plug socket was hitting the doghouse walls? 
 

it’s been months and I’m not certain I remember what was for breakfast today!