Tempest fine vs massive w long electrode

[bonal]

Still having occasional plug fouling even with very aggressive leaning on startup and taxi.  Looking to replace with either fine wire or possibly long electrode massive.  Would naturally  prefer to spend the much lower cost for the massive any experience with these would be appreciated.  Also looking at the application table there is a few options for the o360 a1d not sure which is correct part number.

Suggestions and advice would be appreciated 

[bgpilot1]

Fine wire spark plugs are a good idea.  You could try replacing just the bottom plugs with fine wires.

Also, you could buy TCP Alcor and add to the fuel.  (Not recommended for turbos.)

https://www.aircraftspruce.com/catalog/appages/alcortcp.php

Barry

[Ragsf15e]

1 hour ago, bonal said:

Still having occasional plug fouling even with very aggressive leaning on startup and taxi.  Looking to replace with either fine wire or possibly long electrode massive.  Would naturally  prefer to spend the much lower cost for the massive any experience with these would be appreciated.  Also looking at the application table there is a few options for the o360 a1d not sure which is correct part number.

Suggestions and advice would be appreciated 

One thing to consider before throwing parts at it... what are the plugs fouling with?  Is it clearly lead deposits?  If so, are you really leaned aggressively?  Do you have abnormally long time at low power?

Or are they possibly wet with oil in the cylinders?  
 

Is it all the bottom plugs or only one or two?

 

Just trying to help fully understand the problem before throwing $$ at it.

[Ragsf15e]

My thought is that fine wires are great and will probably help cover whatever is actually causing the problem... for now.

[EricJ]

Fine wires in the bottom plugs solved most of my fouling problems, until I started cruising LOP fairly regularly.    I'll still cruise LOP once in a while, but not nearly as much as I used to.  Gotta keep those head temps up.

But, yeah, for idle/shut down fouling putting fine wires in the bottom plugs should do the trick.

[MB65E]

REM37BY in the tempest or champion variety work really great! They don’t last as long as the fine wires but burn clean and are cheap. 
double check your spark plug lead size prior to ordering. 
I had all BY plugs in my engine for awhile. Switched to all fine wire to see what the rage was about. Bottom plugs started to fowl. Switched bottom plugs back to BY plugs. Problem solved. 
-Matt

[RLCarter]

Can you run a protruded electrode? Would hate to smack the top of the pistons 

[Seanhoya]

I had good luck with the fine wire, aggressive leaning, and I also changed out the carburetor. For me, it was worth the extra expense.

[toto]

2 hours ago, bonal said:

Still having occasional plug fouling even with very aggressive leaning on startup and taxi.  Looking to replace with either fine wire or possibly long electrode massive.  Would naturally  prefer to spend the much lower cost for the massive any experience with these would be appreciated.  Also looking at the application table there is a few options for the o360 a1d not sure which is correct part number.

Suggestions and advice would be appreciated 

I'm in exactly the same boat, and I'm just over it. I'm at a point where it's worth the fine wire money to me not to have to tell passengers we're scrubbing the flight while sitting in the run up area because a plug is fouled. 

It doesn't happen *often*, but often enough to be incredibly annoying.

My biggest concern is about mx personnel dropping a C-note on the floor. 

Anyhoo.. the best price I found on Tempest plugs was at QAA. Spruce had a competitive price during the Oshkosh promo, but that ended yesterday. Now there's no one close to QAA. (If you've found something better, please do tell :))

[bonal]

Looking at this can anyone tell if I have 5/8 24  or 3/4  20. Trying to determine which will be correct replacement.  Will also pull lower plugs to look for possible oil fouling but when checking at annual their was no sign of any oil residue.  Thanks for the help.

 

[MB65E]

If a 3/4 wrench fits on the lead it’s a REM type plug. If it’s a 7/8“ it’s and RHB plug. 
 

However, It does look like you have 3/4” REM type plugs. 
Tempest and Champion have slightly different Part numbers respectively.

 
-Matt

[bonal]

Thank you Matt

[yvesg]

Here is a nice older thread about the plugs:

 

Yves

[Prior owner]

I switched to the tempest massive extended electrode plugs and although I only have about 35 hours on them, it ended my plug fouling problems.

[bonal]

11 hours ago, PilotCoyote said:

I switched to the tempest massive extended electrode plugs and although I only have about 35 hours on them, it ended my plug fouling problems.

Do you recall the part number 

[Prior owner]

35 minutes ago, bonal said:

Do you recall the part number 

I believe mine were UREM37BY. Not sure which ignition harness fittings you have. Check your engine logbook for prior entries regarding which plugs were installed. I think Tempest website has a cross reference chart you can use, once you have the part number of the plugs you have installed in there now

Edited July 28, 2020 by PilotCoyote

[Prior owner]

20 hours ago, RLCarter said:

Can you run a protruded electrode? Would hate to smack the top of the pistons 

Yes, at least in my A2D I can. You also get the benefit of having your compression ratio raised by 0.002.

Edited July 28, 2020 by PilotCoyote

[Fry]

I own and fly an M20J with a fairly old Lycosaurus IO-360-A3B6D (8000h total, 1700h SMOH) and I am leaning agressively LOP whenever higher than 4000ft MSL. My average fuel burn is 9.2 gallons per FLIGHT hour, i.e. ALL fuel purchased in the nominator, divided by only the hours airborne in the denominator. So any taxi fuel is included in the nominator but the corresponding time is missing from the denominator.

And I have no issues whatsoever. The engine runs fine with any mixture setting until it quits. CHT is typically 300-330°F, in climb 360-380°F.

Spark plugs are Tempest URHM38S Fine Wire. They were already in when I bought the airplane.

[bonal]

I intend to remove and inspect the plugs at which time will determine if a 3/4 or 7/8 wrench is required.  Looking at tempest application info I don't see indications for short vs extended electrodes on the massive plugs.  Will likely go with the FW but can't for the life of me understand why such a huge price difference.

[bonal]

30 minutes ago, PilotCoyote said:

Yes, at least in my A2D I can. You also get the benefit of having your compression ratio raised by 0.002.

Not sure if my A1D would be the same. 

[Skates97]

22 hours ago, bonal said:

Still having occasional plug fouling even with very aggressive leaning on startup and taxi.  Looking to replace with either fine wire or possibly long electrode massive.  Would naturally  prefer to spend the much lower cost for the massive any experience with these would be appreciated.  Also looking at the application table there is a few options for the o360 a1d not sure which is correct part number.

Suggestions and advice would be appreciated 

 

1 hour ago, bonal said:

Do you recall the part number 

I have the same engine in mine. The Tempests with the long electrode are the UREM37BY plugs. I put them in just after I got the plane and ran them for around 250 hours without any issues. I replaced them in June 2019 with a new set and ran them for about 50 hours before replacing them with fine wires while doing some other work on the plane. I saved them (no sense tossing out plugs with 50 hours on them) and keep a couple in the tool box in the baggage compartment. I figure if I have a problem with a plug away from home one of the 50 hour plugs will get my back.

If you want to try the ones with the long electrode in the bottoms I'll send you four of the 50 hour plugs I pulled out, just PM me an address.

[bonal]

That's very thoughtful Skates,. Did you notice any difference/improvement when you went to the fine wire?

[jwarren2]

31 minutes ago, bonal said:

  Will likely go with the FW but can't for the life of me understand why such a huge price difference.

It's always been my understanding that the Iridian that fine wires are made of is a first cousin of gold, that's the reason for the extra expense. 

[bonal]

Well at least there is some logic in that

[Skates97]

14 minutes ago, bonal said:

That's very thoughtful Skates,. Did you notice any difference/improvement when you went to the fine wire?

I'm honestly not sure if I noticed much of a difference. Maybe if I had old/tired plugs in then I would have noticed a big difference, but then there would be a difference regardless of putting in new plugs. In the 350+ hours I've had the plane I've only had a plug foul out twice, both times it was a short from the side electrode to the center.