[Kenny]

My mechanic has recommended that I use an oil additive, LW-16702, in my TIO-540 Lycoming. My engine has 1200 TTSN and I run straight weight Aeroshell and change oil/filter at 30 hours.

LW-16702 is an additive developed by Lycoming, but I have always thought that it was specifically for a series of four cylinder engines that had valve problems, back in the 1970’s.

Is there any reason for using this expensive additive? Are there any cautions about using it?

Thank you in advance for any comments.

[Les Flue]

I have considered CamGuard.  No final thoughts, yet.

[Kenny]

Les, have you observed symptoms that may indicate a need for an additive? if, not, why consider it? that is my question for my mechanic.

[CJN]

You probably know this, but AeroShell 15W-50 includes the Lycoming LW 16702 antiwear additive.

From the Shell website:
 
"Aeroshell Oil W15 - 50 is a premium semi-synthetic multigrade ashless dispersant oil specifically developed for aviation piston engines. AeroShell Oil W 15W-50 is a special blend of a high quality mineral oil and synthetic hydrocarbons with an advanced additive package that has been specifically formulated for multigrade applications. The combination of non-metallic anti-wear additives and selected high viscosity index mineral and synthetic base oils, give exceptional stability, dispersancy and anti-foaming performance. The advanced additive package in AeroShell W 15W-50 provides excellent protection to engines operating at extreme ambient temperatures. The ashless anti-wear additive package provides exceptional wear protection for camshafts and lifters and other wearing surfaces. AeroShell W 15W-50 has become very popular amongst engine manufacturers and operators alike. In order to cater for those Lycoming engines that need improved load carrying, the Lycoming LW 16702 antiwear additive has been incorporated into the formulation thus eliminating the need for supplemental additive addition."

Who can resist that sales spiel? 

(In the spirit of total disclosure, I use Aeroshell 15W50 and CamGuard)

[tonyrob]

Avblend in the oil, TCP in the gas. After two sticky valves I was told that if I used these additives, sticking valves would be history. And they are - can't guarantee thatit is because of the additives - but I'm not messing with the formulae!

Tony
C-GICE

[cgartly]

The 15W50 and the Aeroshell Plus straight weight oils have the additive already in the oil.  Lycoming recommends adding a bottle of the additive if you extend your oil change interval beyond 50 hours.

I have a 172 with the H model engine that requires the additive.  I don't think it is required in any of the other lycoming engines but it is recommended.

They call it an anti scuffing additive, supposed to help save the cam and lifters.

At least that is what all of my research has led me to believe!

[Klaus]

     Link to Airworthiness Directive;
      A.D. 80-04-03 R2 AVCO LYCOMING Applies to O-320-H series engines and O-360-E, LO-360-E, TO-360-E and LTO-360-E series engines; (all serial numbers and hydraulic lifter (tappet) configurations).

   The additive Lycoming LW 16702 is mostly to combat corrosion. The Camshaft is located in the upper half of the crankcase and the breather outlet is very near the camshaft. When the engine cools down and condensation forms it attaches to the forward end of the camshaft and front lifters more then normal. This is a problem with most Lycoming engines especially when they set for extended times.

   Both Aeroshell W100 Plus or W80 Plus and AeroShell Multigrade W15-W50 has the LW 16702 in its mix because it's a good for anti-wear and helps fight corrosion in all engines.

   Sticking valves needs additives like Marvel Mystery Oil / TCP. Until the 100LL goes away everyone needs to be vigilant and do whatever we can to prevent excessive leading problems.


      Klaus((100LL) Low Lead compared to what .....  A diving belt      )Marx

[faintfuzzy]

I don't get it, Lycoming put the cam under the crank in their first flat engine (currently propelling the Mighty Vagabond at modest velocities) where its bathed in oil, then went upstairs on the second rendition.  Makes you wonder about built in wear out factors.
Rodg (still perplexed) Petersen

[Frank]

In my IO-540 I use 15 50w.  I change oil and filter around the 25 hour mark.  I do not use any oil between changes. During the oil change I put in 6.5 qts.  My engine is happy  around 5.5 to 6 qts.

Frank   

[zekeaero]

Mike Busch swears by CamGuard.  I've been using it in oil changes since I've owned my plane.

Busch writes a lot of aviation maintenance articles in the trade mags.  He also runs the Savvy Maintenance program.  He's a very capable mechanic and, due to his Savvy program, he sees a lot of aircraft maintenance cycles.

[Domenick]

   Sticking valves needs additives like Marvel Mystery Oil / TCP. Until the 100LL goes away everyone needs to be vigilant and do whatever we can to prevent excessive leading problems.

From the MSDS MMO is ~75% naphthenic hydrocarbons, ~25% mineral spirits (Stoddard solvent, i.e., paint thinner), with a splash of wintergreen scent.

My take on the ingredients is that the naphthenic hydrocarbons are a thickener like paraffin, the paint thinner cuts the thickener for pouring.  The wintergreen is simply a pleasant scent. 

If put into engine oil the mineral spirits evaporate when the engine warms leaving behind the thickener.  Seems innocuous, though pointless.  If you want thicker oil, use a heavier weight.  It might be interesting for someone to put a measured amount of MMO in a container and let it sit for a few weeks then compare the volume and consistency with the original.

If put into the fuel tank both the paint thinner and the thickener are burned in the cylinder.  This seems innocuous and pointless as well.  Our engines are designed to burn some oil so a bit of thickener is unlikely to hurt anything.  The thing I worry about is the effect of the thickener on the carburetor.  I know pilots have been putting MMO in their gas for decades, but I'd never put it in my gas. 

[tonyrob]

   Sticking valves needs additives like Marvel Mystery Oil / TCP. Until the 100LL goes away everyone needs to be vigilant and do whatever we can to prevent excessive leading problems.

From the MSDS MMO is ~75% naphthenic hydrocarbons, ~25% mineral spirits (Stoddard solvent, i.e., paint thinner), with a splash of wintergreen scent.

My take on the ingredients is that the naphthenic hydrocarbons are a thickener like paraffin, the paint thinner cuts the thickener for pouring.  The wintergreen is simply a pleasant scent. 

If put into engine oil the mineral spirits evaporate when the engine warms leaving behind the thickener.  Seems innocuous, though pointless.  It might be interesting for someone to put a measured amount of MMO in a container and let it sit for a few weeks then compare the volume and consistency with the original.

If put into the fuel tank both the paint thinner and the thickener are burned in the cylinder.  This seems innocuous and pointless as well.  Our engines are designed to burn some oil so a bit of thickener is unlikely to hurt anything.  The thing I worry about is the effect of the thickener on the carburetor.  I know pilots have been putting MMO in their gas for decades, but I'd never put it in my gas. 

I know lots of people who swear by MMO. When you research it on the net there is lots of folklore about 50 gall barrels in WW2 airfields - but nobody can remember the spec.
I use TCP because it is approved for use in certified engines - insurance companies get picky about that type of thing -  As mentioned in an earlier post, I can't claim that it works - but I haven't had any problems since I started using it.

Tony
C-GICE

[Domenick]

Where does one get TCP in the Seattle area?

[tonyrob]

Where does one get TCP in the Seattle area?

I always buy mine at the Arlington Fly-In - usually from Aircraft Spruce.
It is made by Alcor - so they could probably point you at the closest supplier.
Here is their contact info -
http://www.alcorinc.com/contact.php

Tony
C-GICE

[Kenny]

Ladies and Gentlemen, the results are in LW16702 destroyed my cylinder barrels in 27.3 hours. Polished them to a mirror finish, which prevented oil from staying on them, which resulted overtemps on all six cylinders. The GEM temp probes are on the bottom of the cylinders and the cooking took place on top, thus, no indication of a problem until I pulled the cowl for a general look about.

The TIO-540-AJ1A has thin wall barrels, so there are no oversized pistons available. Lycoming had no cylinder assemblies in stock and it took five weeks to get them. We couldn't do anything with them, however because the connecting rods ordered at the same time were not delivered for three more weeks. Of course, one may not re-use connecting rod bolts a second time and, you guessed it; an additional two weeks. Push rods were a different story: We ordered 16 of them because some fitting is necessary for each cylinder to get the correct clearance regardless of what is stamped on the rod. Those dribbled in two or three at a time over a three week period. All of the cylinder assemblies were delivered at the maximum tolerance of two ounces weight difference between the lightest and heaviest. A good scale an some judicious machining got that down to two grams. Did I mention that I will never consider putting Lycoming's "recommended" oil additive in an engine ever again? Or, that in my next life I'll fly a turboprop

So, 107 days after the first parts order, we did a cowling off engine start. The next morning, the break-in run up sequence, which puts nearly an hour (in specific intervals) on the Hobbs. Then I flew over SZT for an hour, charting temps and performance. All was well there, so the next morning I re- positioned Big Bird to our new home at Twin Oaks (7S3). That flight was definitely IFR (I follow roads ) We'll load the last of the household this week and, after 33 years in Sandpoint, and 41 as Idahoans, we turn a new page in the adventure of life. If life wasn't so good, I comment on Lycomings abominable behavior in this affair. Instead, we're just moving on. Blue skies to all.