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Bob Grimstead
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Posted Thursday, January 13, 2011 @ 11:49 PM  

Hi Folks,

You may be interested to see a problem Dave Bland has been having with the Rectimo in his RF4D.

As you can see, a couple of camshaft lobes and their cam followers are very worn.

He doesn’t know the precise reason in this case, but a common cause is a long period of inactivity (one month or more) between flights. Another cause can be leaving old oil in the engine (going more than three months between changes).

In the first scenario, after a couple of weeks the oil drains off all the metal surfaces, down into the sump, leaving the bare metal to rust. In this case it will be that part of the cam shaft and followers that are not submerged in oil that rust.

In a Lycoming, with its camshaft running along the top of the engine, the camshaft and followers are particularly prone to rusting like this. That’s why both Lycoming and Continental (TCM) say you should inhibit (pickle) your engine if you are going to leave it inactive for more than ONE WEEK!

When your oil gets old, it accumulates acids from the by-products of combustion combined with the water that it holds in suspension. Ensuring your oil temperature increases above 80°C helps to boil off these acids in fresh oil, but after three months you need to change your oil to get rid of them. That’s why both engine manufacturers and lubricant suppliers specify a three-month oil change interval, as well as one based on hours flown or miles/km driven.

Either that rust or the acids in your oil will etch into the very thin layer of case-hardening on your camshaft and its cam followers (‘valve lifters’). This hard layer is usually only ten to fifteen thousandths of an inch thick, so it doesn’t take much rust pitting or acid etching to get through and under that hard layer. Once this happens, the hardened layer peels off in small pieces (‘spalling/galling’) and the whole lot quickly flakes away, as you see on the cam followers here.

Underneath that hard layer, the steel is much softer, so then it wears away very quickly, giving you flattened cam lobes like these.

To prevent this: fly weekly, ensure your oil temperature exceeds 80°C and change your oil every three months.

To see if this is happening in your engine, when you drain your oil, strain it though a fine filter in your funnel (I use my chamois fuel filter). If you see tiny specs of glittery metal, remove your engine and strip it to replace your camshaft & lifters.

Francis Donaldson (Chief Engineer of Britain’s certifying authority, the LAA) says you can see when this camshaft wear has taken place, by popping off your rocker-box covers and turning over your propeller (backwards, of course, and with the magneto and fuel turned off). He reckons you can easily spot when one or more valves are not opening as much as the others. In his case (Evans VP2) apparently one valve was hardly opening at all!

Somewhere on this site, Collin (and others) states the correct valve lift, so it should be easy enough to measure this if you are unsure. Might be a good idea to do this after your first flight following a prolonged period of inactivity?

Yours, Bob

Jorgen
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Posted Friday, January 14, 2011 @ 05:06 PM  

Hi Bob and Happy New FournYear and all that,
very good heads up. I have heard about Dave's persisting oil loss, was that related to this problem?

We had another good thread on this topic earlier:
http://sbeaver.com/cgi-bin/fournier/cutecast.pl?session=gueQdLgVeBq9gbkjqpMnAxhg4t&forum=13&thread=280
It's as you point out one main problem we have: we don't fly often enough. I always use the engine dryer during winter hangarage as I describe in the above thread and I think it makes sense to do so. I also try to prop 15 blades every week and like to think that helps too.

Keep your faith, Fournieteers, spring won't be long now!

May the 4's be with you/ Jörgen

Bob Grimstead
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Posted Monday, January 17, 2011 @ 09:29 AM  

Hi again Jorgen,

Thanks, I had quite forgotten about that thread.

One of our problems is the lack of electricity in our hangar, so we have to just seal up the engines in winter and hope for the best.

I don't think Dave's oil loss would have been associated with this, but I'm not sure.
He also had a badly damaged thrust bearing, but again I'm not sure if it was associated.
He now says that his 300-hour cylinders are worn well out of limits.
I think he suspects that all the new parts he paid for in that engine when it was rebuilt (fairly inexpensively) may not have been new after all!

On another topic, if you keep looking at Flygrevyn, you may notice your name appear soon.
Since I got unexpectedly stranded in the snow in England for a couple of weeks, I got stuck into some typing and I've sent Christina a long, rambling account of my journey up to Dala-Jarna & back.
Of course, since you were so helpful you get a mention.

As you say, spring will come soon.

I am now back where I should be, in Perth, and trying to discover why there is so much internal friction in my new 1750 engine. I hope it's just the end-float adjustment. Eugenio suggested this, and there certainly seems to be absolutely no end-play in the crankshaft at all.
The engine should be out by tomorrow, and then I should know more.

As usual, I will copy in everybody on my findings.

Roll on Spring!!!!

Yours, Bob

Jorgen
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Posted Tuesday, January 18, 2011 @ 06:47 PM  

Hi Bob,
sorr to hear about Dave's predicament, he deserves a turn for the better. Thanks for the heads up on "Flygrevyn", I'll follow your story there and I did tell you that I heard a lot of positive remarks about your display there from the Swedish Aerobafficionados, didn't I? Glad to hear you're back in Perth, forecast tells about another coldspell over Europe next week so Fournier springsoaring still looks distant. On the other hand ice on the lakes are 15 cm thick so some fun to be had during commutes on the lake along the way back home.

May the 4's be with you/ Jörgen

Collin
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Posted Tuesday, January 18, 2011 @ 06:59 PM  

Notes from Great Plains on Extended storage.

Extended Storage?
If you have a brand new engine that’s never been run
or one on your aircraft that just sits for the winter,
you may consider prepping your engine for
storage. Here are several easy things you can do
that will keep your engine healthy.
1. For an installed, running engine, consider
fogging it. Simply, use a spray bottle of
lightweight oil and spray the carburetor with the
engine running at about 1200 rpm and choke the engine down so it
quits. Yes, the engine should be at operating temps and if needed, remove the prop to do this.
2. For an non-installed, non-running engine - remove the top plugs and using a syringe, put an ounce or
2 of oil in the cylinder. I use a small tube on the end so I can move it around a little when pushing the
oil out of the syringe. Do this to each cylinder and re-install the plugs. Do not turn the engine over
again!
3. Remove the valve covers and take the rocker arms off. This closes any valves that may be open and
keeps the moisture out of the cylinder. Stops our good friend “Rusty” from working. Keeps him on
unemployment!
4. Cover the carburetor inlet up so air cannot enter.
5. Cover the exhaust outlet up so air cannot enter.
6. If you cylinders are not painted, spray a light coat of WD-40 on them to prevent winter rust. But
don’t get carried away.
7. Change the oil! Don’t let used oil sit in you engine all winter long. You may consider adding the 4th
quart so oil is up over the camshaft and lifter. If you have a tail dragger, raising the tail so the
aircraft/engine are level for the winter. This covers more internal engine parts.
8. If allowed by your Airport Authority, you may install a 40W light bulb or two in the cowling.

http://www.greatplainsas.com/beetle2010a.pdf

Collin
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Posted Tuesday, January 18, 2011 @ 07:37 PM  

Hello,

It is rare that VW's have cam troubles.

It helps to use oils that still have a lot of zinc added. Newer automotive oils have less zinc added because of having catalytic converters and most newer automotive engines now have roller rockers arms or lifters.

In the USA the Racing Oils (Valvoline Race 30w) and truck oils (Shell Rotella or Chevron Delo (not LE version)) still have a fair amount of zinc added.

http://www.valvoline.com/faqs/motor-oil/racing-oil/

Mike-RM
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Posted Saturday, January 22, 2011 @ 01:44 PM  

In the UK I use Bradd-Penn 20W-50 from Stateside Tuning www.statesidetuning.co.uk/ where James Calvert builds VW racing engines. He also recommended using a high zinc content racing oil to reduce cam wear. He mails it to me. What he said seemed like a good idea, and Collin's post bears this out. It's not cheap, but not much more than synthetic oil and seems worth using. No doubt Valvoline is available in the UK too but I haven't looked.

Mike

Bob Grimstead
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Posted Tuesday, February 1, 2011 @ 06:34 AM  

Hi Guys,
With all my Aussie engine troubles, I've been pointed to some YouTube clips, and I've been watching them all day.

Here's one that could well explain this problem.

Apparently, if you don't keep your rpm above 1500 to 2000 for the first 20 minutes of running a new engine, you can wear off the camshaft's case-hardening (as happened to LZ) because of lack of splash lubrication from the crankshaft sploshing around in the sump's oil below 1500 rpm.

John Maher made a big thing of 'breaking in the camshaft' on WGN's new engine for hallf an hour before he did anything else, but then I didn't know why. I do now.

http://www.youtube.com/watch?v=23sYBHH9fUA&NR=1

Yours, Bob

Carl G
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Posted Saturday, October 22, 2016 @ 06:58 PM  

Interestingly, in reading up on this, I discovered a statement at http://www.machinerylubrication.com/Read/28576/comparing-gasoline-diesel-engine-oils-

"Diesel engine oil has more additives per volume. The most prevalent are overbase detergent additives. This additive has several jobs, but the main ones are to neutralize acids and clean. Diesel engines create a great deal more soot and combustion byproducts. Through blow-by, these find their way into the crankcase, forcing the oil to deal with them. When you put this extra additive load in a gasoline engine, the effects can be devastating to performance. The detergent will work as it is designed and try to clean the cylinder walls. This can have an adverse effect on the seal between the rings and liner, resulting in lost compression and efficiency."

Maybe a loss of compression isn't such a bad thing from the standpoint of cooling, but I'm wondering just how "devastating" the performance drop could be...

Carl

Quote:
Originally posted by Collin

Hello,

It is rare that VW's have cam troubles.

It helps to use oils that still have a lot of zinc added. Newer automotive oils have less zinc added because of having catalytic converters and most newer automotive engines now have roller rockers arms or lifters.

In the USA the Racing Oils (Valvoline Race 30w) and truck oils (Shell Rotella or Chevron Delo (not LE version)) still have a fair amount of zinc added.

http://www.valvoline.com/faqs/motor-oil/racing-oil/


Bob Grimstead
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Posted Friday, February 10, 2017 @ 10:02 AM  

Of course all of this information carries across to cars.
Three of ours are quite old (although not as ancient as my Fournier's 1968 Rectimo!) — a 1988 BMW 325i, a 1983 Mitsubishi Colt, and a 1995 V-12 Jaguar Sovreign. All of these have flat (non-roller) cam followers, so clearly all of them need ZDDP in their oils. It has been a struggle enough to compensate for the lack of TEL in modern auto fuels!
While trying to find local oils with the correct formulation, I have added molybdenum disulphide to their sumps, in the hopes that it will provide some additional cam-follower lubrication over and above that of the existing ordinary mineral oil.
I do enjoy keeping these older vehicles serviceable and running, and it is becoming increasingly rare to see similar examples on the road — indeed, I don't think I have seen another 'square' Colt like mine in the six years I have owned it.

I am becoming increasingly convinced that this is because other owners of similar cars do not use the correct fuels and oils.

--------------------
Flying and displaying Fournier RF4Ds VH-HDO and G-AWGN, building replica RF6B G-RFGB and custodian of RF6B prototype F-BPXV

Bob Grimstead
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Posted Sunday, February 26, 2017 @ 02:24 AM  

Regarding this oil business, we're very fortunate here in Australia, because our home-grown oil company Penrite not only understands our flat tappet problem, but produces a lubricant specifically designed for air-cooled VWs.

Not only that, but their customer service is excellent, in that they print a comprehensive catalogue with full details of the additives and their proportions in all their oils.

Also there is an in-store electronic gadget, kinda like an iPad on the wall, into which you can type your car model to find which of their lubricants suits it best. To my amazement it knew and accepted all three of our eighties cars plus my Rectimo (as a late sixties Vee Dub of course). Each selection came up with a 'best oil' — Classic Light for the Colt, Classic Heavy for the Jag & Beemer, Classic V-DUB for the Rectimo — but they all gave a 'next best'. In every case this was their HPR 30, a 20-60 multigrade (summer temperatures up to +42°C or 110°F remember) with 0.16% of ZDDP plus a special 'sticky' additive for vehicles that spend a lot of time laid up.

Needles to say, I bought five litres of HPR 30 to use in any or all of our engines.

So a) research pays off and

b) we can keep our engines going for ever.

Happy Fournicating, Bob

--------------------
Flying and displaying Fournier RF4Ds VH-HDO and G-AWGN, building replica RF6B G-RFGB and custodian of RF6B prototype F-BPXV

Bob Grimstead
Captain

Gender: Male
Location: Perth, Western Australia or West Sussex, England
Registered: Dec 2006
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Posted Friday, March 17, 2017 @ 07:54 AM  

In the unlikely event that anybody from Britain is reading this, I've been using Comma Classic Motor Oil in my British RF4D for the past couple of years. The tech specs say it has 8% zinc and 7% phosphorous, so presumably (mad randon assumption) that means 15% of ZDDP, which is pretty much what Martin said we need.

https://s3-eu-west-1.amazonaws.com/storage.commaoil.com/files/products_masters/11759.pdf?response-content-disposition=attachment%3B%20filename%3D%2211759.pdf%22&AWSAccessKeyId=AKIAJXQ2YUDI5JWFP3IQ&Expires=1489754882&Signature=NuYSq9CQtCp1f9veRwy26o4ZS74%3D

--------------------
Flying and displaying Fournier RF4Ds VH-HDO and G-AWGN, building replica RF6B G-RFGB and custodian of RF6B prototype F-BPXV

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