Shell 15W-50 to 100W +Cam Guard Switch?

[Ray B]

At the Lancaster TX CPPP training I learned from Zach that the additive in shell 15W-50 is not cam guard as I had thought. Also the oil starts out as a thin viscosity and has additives to thicken it as it warms up, the opposite of what I thought was taking place. Since I have read great things about Cam Guard and the price is aprox the same per oil change I decided to switch.( Shell 15W-50 has been used since OH). I change oil and filter every 25 to 30hrs and the oil is usually to about the 18 -20 hour mark when it starts turning dark. ( PA24-250 engine SMOH 1220hrs.) After the change to 100W and a pint of Cam Guard the oil is already starting to turn color at 4-5 hours. (also switched to Champion CH48111-1 Filter). Is this due to the Cam Guard cleaning sludge out where the 15W-50 didn't? Will it clean up after an oil change or two? Is changing oil Wt. not a good idea mid stream? What do you think? Has anyone had this same experience?--- I should note that the engine was completely cleaned when down for a prop strike 400 hours ago. Ray B

[N3322G]

Ray,

I'll be very interested in what's happening. Ken saw a clip on Blackstone oil analysis company a while back and we've been using it ever since because they actually give you words on what is 'going on' in the engine - like after one change ... 'this will probably clean up in the next change because of the circumstances you cited' and it did.

They send free sampler kits and then bill when you use them. http://www.blackstone-labs.com/ if you want to try them.

While I'd like to be able to answer your question, we haven't had this experience, so I hope this is of help to you.

[Ray B]

Thanks Pat, I ordered a test kit. Ray B

[John Wedge]

Hi Ray,
I guess I was asleep as I don't remember or did not catch the discussion about the oil. We use the shell 15w-50 because we thought it had the best additives BUT have read about the Cam Guard. My question is - was it a recommendation or general consensus among Comanche people that using the 100w with Cam Guard would be better for the engine? I too have ordered the Blackstone kit. Enjoyed meeting you and talking about the old war planes etc.
John

[Jay]

There was a long discussion over on the AOPA board about this, including a rep from CamGuard.

After my engines were overhauled last year, and after consulting with a couple of IAs and two engine shops, the consensus opinion favored break in on straight mineral oil then after 50 hours going to Phillips 20W-50 plus CamGuard, which is what we've done. According to CamGuard there is no aviation oil out there with the same additive package.

Jay

[Zach Grant L1011jock]

Ray,
You may be cleaning a bit of stuff out of the engine, or you could be seeing the difference in the oil formulation, or it could be something else entirely. Using the proper oil for the temperature range is the key to all oil servicing. I do have to say I am not quite on board with the Philips XC 20-50 as it is a non ashless dispersant oil (multigrade, but straight mineral oil) and Lycoming specifically states that only Ashless Dispersant (AD) oil should be used after break in (and on the factory turbo engines, it says to use AD from first start). I am not an oil expert, but I believe that the Camguard additive does give some of the detergent qualities, but how well it suspends the impurities, I really don't know. I have seen several things from oil. Castrol Aviator is like the stuff they give you before a colonoscopy. If there is something in the engine, it will break it free, and pretty scarry at that. Aeroshell, is not the greatest at keeping things cleen, but seems to be consistant in not breaking up anything bad either. Camguard works great, but is an additive, it does not change all of the properties of a given type of oil. Exxon Elite is somewhere inbetween Aeroshell and Castrol, and I would not use it midstream. Start it in a new engine and you will be fine. As for running non AD oils in Lycomings. I wouldn't run them much more than 15-20 hrs between changes if it were up to me, and I wouldn't let it sit for more than a month or so. Too much stuff can settle out and plug up important nooks and crannys. Everyone has an oppinion on all of this. These are mine.

-Zach

[Ray B]

Thanks Zach, I may have "cried wolf" too soon. I've put another couple of hours on the oil since I posted the question and the oil has remained the same, no further darkening. I stayed with 100W for the winter because I rarely see very low temps here in southern OK. plus my oil sump preheater makes for easy starting even when it freezes. I'll post what happens with the oil as it gets 18 to 20 hours on it and what the filter looks like at oil change. Ray B

[Jim Worley]

Zach,
I just switched to phillips X/C in my 250 (from Castrol AD120, no longer produced). Here is a quote from the X/C sales blurb

"Phillips 66 X/C® Aviation Oil is an ashless dispersant, multigrade engine oil specifically formulated for year-round use in aircraft piston engines."

Am I completely out to lunch on the AD thing. If so, I am switching to something else next oil change!

Thanks
Jim

[9089P]

Hi Jim, Zach,

You are both right! Phillips makes 2 types of 20-50, The type A is AD and the Type M is not. In the 3 lycomings I have broken in I used the type M for the first 25 hrs then went to the type A in the first one and to aeroshell in the last 2. Truth be told I liked the Phillips better (can't explain why) but I'm following the expert advice.

Good luck, Don

[Jay]

Phillips XC 20W50 is a mineral based ashless dispersant. http://oilstore.stores.yahoo.net/phxcavoil20c.html

Jay

[Richard Andrews]

If I recall correctly Lycoming engines require an anti-scuff additive to help protect the cams. I think I recall that AeroShell is the only one with the specific cam scuff compound the Lycoming requires. Does CamGuard meet this requirement?

[Ray B]

Well, I didn't cry wolf too soon. Oil is definitely darker and turning that way fast with only 10hrs time on it. This after switching from shell 15W-50 to shell 100W plus cam guard. (I also switched to the longer oil filter) I think the oil will be completely black by the 15 hour mark so I'll change it then (or sooner) and cut the filter open to check for more than normal sludge and carbon deposits. I'll report what I find. Ray B

[Zach Grant L1011jock]

Only the O-320-H2AD as installed in the late '70s 172s are covered under the AD to require the anti scuff additive. Camguard is not an approved replacement for the LW...xxx snake oil. Other approved sources are the aeroshell 15w50, and "plus" single grade oils. The additive package in the camguard is more anticorrosion in content, but does have some antiwear properties.
-Zach

[Zach Grant L1011jock]

Ray,
Check the oil suction screen on the sump as well. It probably will show more obstructions than the filter does if there has been crud cleaned out of the engine. You might also want to do a quick compression check to see if you might have a ring issue causing excessive blowby. I can't say I have seen the switch you made in oil make the oil this dark this soon without something else happening coincedently.

Zach

PS- Merry Christmas, and happy new year to all. Also, thanks for the cracked bungee arm.

[Ray B]

Thanks Zach, I'll check the screen and do a comp. ck.------I have a matching cracked bungee arm if you need another one. Ray B