---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Sat 09/16/06: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:05 AM - Re: Rotax 9XX: TCP, Dip stick, Hydraulic Lock (PWilson) 2. 04:23 PM - 582 Water pump housing ? (Rob Stapleton) 3. 06:39 PM - R-582 Water pump housing (Rob Stapleton) 4. 06:49 PM - Re: 582 Water pump housing ? (Malcolmbru@aol.com) 5. 07:00 PM - Re: 582 Water pump housing ? (Dave) 6. 08:41 PM - Re: 582 Water pump housing ? (Guy Buchanan) ________________________________ Message 1 _____________________________________ Time: 07:05:30 AM PST US From: PWilson Subject: RotaxEngines-List: Re: Rotax 9XX: TCP, Dip stick, Hydraulic Lock --> RotaxEngines-List message posted by: PWilson Hi Eric, Lots of subjects. Long discussion. Syn oil: The purpose of TCP (a fuel additive, not an oil additive) is to keep the lead deposits from clinging to the valve stems. When this happens the friction becomes greater than the spring force and the valve hangs open causing the valve to burn and requiring a top overhaul to correct. The TCP also helps prevent deposits in the piston rings. Thus it is very desirable if using leaded fuel. I suppose there might be some benefit in reducing sludge in the sump but I have never read of that benefit. The stuff is commonly used in the lyc/cont engines for the purpose stated. The kind of oil used in the engine is not relevant to the above discussion I forget what the oil additive is that Lyc specified for my C172 but it was not TCP. Sorry. Maybe someone can fill in that detail. I must say that all the engine issues I had with my Lyc had to do with the valve sticking other than that Lyc said that for them to warrantee the engine I had to reduce the oil change intervals and use the oil additive. They just replaced the jugs to correct the sticking valves and did not require me to use TCP. Comments: IMO, to be safe change the oil at short intervals and use semi syn. But, is there a real benefit over a high quality petro oil? These days the petro oil used in cars does not prevent the 200k mile engine life. If one is using syn to protect against high temps it would be more logical to get a proper oil cooler. If one likes the easier starting benefit on syn then use petro with a lower viscosity and/or a stronger RG battery. If one is using syn to get lower friction I believe the benefit is very small. If one is using syn to extend the oil change interval then the user is mistaken as the change interval actually needs to be shorter. The arguments for syn/semi syn are very weak when using leaded fuel. Rotax does not REQUIRE syn with unleaded fuel. It is just one of the options. Rotax strongly recommends using the motorcycle oil that has the gear lube. This is applicable with petro, Syn, & semi syn. Not many oils available in the US have been tested. To bad for us. I wonder if the latest oil formulation has reduced the sludge formation. There have been many recalls of autos due to sludge formation caused by the use of petro oils in engines with high oil temps. I noticed that Rotax now Requires the use of service grade "SG" or higher Dip Stick: Another change that evolved from the US EPA wherein the oil chemistry reduced the anti-foam additive because it was contaminating the cat converters. However, this oil resulted in an improvement in fuel economy due to additives that reduced friction. This change applies to all oils including Syn. Rotax has identified some oils that did not change as they were motorcycle specific and you will find them on the approved list. Rotax raised the oil level in the dry sump tank to account for the additional aeration due to foam and they wanted to avoid any compromise in the lube system. Make me wonder how such a small change could make a difference? There are oils available that should not require the new dipstick due to old formulation, but how long will they be available? Rotax published a new list this week. Hydraulic lock: This is caused by non-optimal location of the dry sump tank and the use of very low viscosity oil. The higher the tank is then gravity overcomes the ability of the oil pump and other system flow resistance prevent leakage/drainback into the sump. This is exacerbated by using very thin oil, especially after a hot shutdown when using an oil like like 5Wxx (or full syn?). On older engines wear in the pump creates less resistance to oil draining. I suppose that one could increase the resistance in the oil line from tank to pump to lessen this issue. Or add a flapper check valve for the increased resistance. Beware, any change from the Rotax design requires testing of oil flow rate and pressure at the pump inlet to avoid engine failure. BTW this is a generic issue with all dry sump engines but seems to be more of an issue with the Rotax. Just be sure to check the oil level before every flight. And if it is lower than it was when you parked the plane after a flight then take corrective action. The auto racers do not have this issue very often due to their use of very high viscosity oil like SAE 50 and their use of scavenge oil pumps with high back flow resistance instead of using crankcase pressure like Rotax does. A 10Wxx or 20Wxx oil would be a recommendation of an action to take to prevent drain back. Comments anyone? Please cross post to both lists using the "reply to All" button. I hope this helps, Paul ============================= At 03:49 AM 9/16/2006, you wrote: >How about this angle to the thread? > >We know that Rotax states that the 912 motor requires synthetic >(with no 100 LL) or semi synthetic (for when 100 LL) is being used, >for reason of lubing the reduction drive. > >But how about if you purchase the TCP lead scavenger fuel additive >from John at Sport Plane LLC / Kitfox. ( side note: John, why don't >you have your S.P.llc catalogue on your Kitfox site ?) >The way I am thinking of this is; If I use the TCP to remove the >lead, then there is no issue with the oil I use and we could use >full synthetic. > >Any thoughts on this? > >Another question. (New topic, KITFOX 912 OIL TANK DIP STICK) >For us who have the 912 with the oil tank behind and above the motor. >Why are we using the new replacement dip stick? >I know that there was a Rotax service memo about this. >This will only load the system more than full and you get a dirty >belly or you get hydraulic lock after the plane sits for a while and >gravity drained the oil to the lowest places. >This happened to me. It is a good thing that I always hand prop a >couple of times with power off. I would hate to think of what would >happen if I used the starter! Could have bent something. > >Has anyone had the hydraulic lock problem? > >Eric, Atlanta. > > >Mark, > >All I know about this subject is from the Rotax bulletin on preferred oils >and the Rotax seminars. > >Synthetics are recommended by them for unleaded fuels only. When using >occasional leaded fuels they recommend a synthetic blend or full mineral if >using 100 LL. > >If you would like to read their bulletin on this, follow the links below to >the numbered bulletin. When I change oil, I wipe down the oil tank with a >papertowl and without fail, if I have been using 100LL as in a long cross >country, I get a pasty residue from the tank. It is light gray colored. >With the exception of the gear additive recommended by Rotax because the > >engine oil also lubricates the gear box, I am comfortable with their general >recommendations for all four stroke engine types. > >It would be good of course to have other data from other engine types to >eliminate the need to extrapolate. > > >http://www.rotax-owner.com/ > >SERVICE DOCUMENT RETRIEVAL SYSTEM > > >SI-18-1997 (2004) > >SI-912-016 (2006) > >Lowell > > >----- Original Message ----- >From: "Mark Thompson" >To: >Sent: Friday, September 15, 2006 3:45 AM >Subject: Re: Kitfox-List: Question on oil > > > > --> Kitfox-List message posted by: "Mark Thompson" > > > > Lowel what do you think about running fully synthetic oil in an air cooled > > VW engine using 100LL,........I hope this is ok because I am fly this > > morning to fuel up again with 100LL,This will be the first flight using > > synthetic oil.............. > > > > > >> [Original Message] > >> From: Lowell Fitt > >> To: > >> Date: 9/10/2006 12:08:14 PM > >> Subject: Re: Kitfox-List: Question on oil > >> > >> --> Kitfox-List message posted by: "Lowell Fitt" > >> > >> Dee, > >> > >> The value in a full synthetic is the higher temps they can tolerate, the > > hit > >> is their inability to keep the lead residues in suspension. If you fly > >> strictly with car gas, the synthetic should be fine. If you occasionally > >> use 100LL then you might want to avoid synthetics. This from the Rotax > > oil > >> recommendation bulletin. The Rotax 912 series engines use the same oil > > in > >> the engine as well as the gear box so they recommend a motorcycle engine > > oil > >> with the gear additive. If your engine is similar, you might want to > > check > >> the Rotax owners association website for info. > >> > >> Lowell > ________________________________ Message 2 _____________________________________ Time: 04:23:31 PM PST US From: "Rob Stapleton" Subject: RotaxEngines-List: 582 Water pump housing ? Does anyone have experience with a leaking gasket under the water pump housing on a Model 99 DCDI 582 (Blue head) ? I have a leaking gasket that was replaced with a new one, (the old one started leaking after I switched to DexCool from Prestone) and is torque to specs 70 ip and it is still leaking. Nothing anywhere said to use gasket sealer or any silicon so the gasket was replaced without any. The leak is under the front lower bolt and the rear lower bolt (the engine is sitting with the head upright) and is leaking only in drops-at-a-time. The water temp is also high (and always has been) around 180-185F. Should I use a gasket or silicon material on the gasket and replace it? Any other ideas or experiences. Baffled in Anchorage! Rob Stapleton They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." - Benjamin Franklin ________________________________ Message 3 _____________________________________ Time: 06:39:20 PM PST US From: "Rob Stapleton" Subject: RotaxEngines-List: R-582 Water pump housing Does anyone have information on whether or not one is to use gasket sealer on the water pump housing gasket, and if so what type is acceptable to Rotax standards? Rob Stapleton ________________________________ Message 4 _____________________________________ Time: 06:49:32 PM PST US From: Malcolmbru@aol.com Subject: Re: RotaxEngines-List: 582 Water pump housing ? Rob there was a posting a little while ago on the same topic was that you? first 180 on the temp is at the higher end. properly cleaned gasket surface is a must. then is the pump housing warped? set it on a piece of glass and some very fine wet sand paper and smoothie it off in a figure 8 motion checking for warpage if you find any markes on eather surfice from a raser blade or anything used to clean the old gasket off you could try a lock tight product to fill the gap and seal the gaskit .but do not try to sand or grind out any gouges on the housing or motor block good luck mal michigan kit foxer ________________________________ Message 5 _____________________________________ Time: 07:00:02 PM PST US From: "Dave" Subject: Re: RotaxEngines-List: 582 Water pump housing ? Hi Guys , A few things -- what is leaking antifreeze or oil ? On the 582 one of those lower bolt holes goes into crankcase and I fixed mine by using blue loctite on threads after cleaning hole with thinnners. And Temps for 582 I have found that mine runs 175 to 185 all the time and have no issues as per my gauge. I have a 7 pound rad cap and never had an issue except bugs in rad blocking some airflow. I have been told by Rotax experts that 180 to 200 is the caution zone but not the end of the world like some think. Hope this helps. Dave ----- Original Message ----- From: Malcolmbru@aol.com To: rotaxengines-list@matronics.com Sent: Saturday, September 16, 2006 9:49 PM Subject: Re: RotaxEngines-List: 582 Water pump housing ? Rob there was a posting a little while ago on the same topic was that you? first 180 on the temp is at the higher end. properly cleaned gasket surface is a must. then is the pump housing warped? set it on a piece of glass and some very fine wet sand paper and smoothie it off in a figure 8 motion checking for warpage if you find any markes on eather surfice from a raser blade or anything used to clean the old gasket off you could try a lock tight product to fill the gap and seal the gaskit .but do not try to sand or grind out any gouges on the housing or motor block good luck mal michigan kit foxer ________________________________ Message 6 _____________________________________ Time: 08:41:19 PM PST US From: Guy Buchanan Subject: Re: RotaxEngines-List: 582 Water pump housing ? --> RotaxEngines-List message posted by: Guy Buchanan At 04:22 PM 9/16/2006, you wrote: >Should I use a gasket or silicon material on the gasket and replace it? >Any other ideas or experiences. In the interests of science I fired up my HomebuiltHELP 582 tear down DVD to see what I could learn about the water pump housing. Now unfortunately this DVD only covers tear-down and inspection, and not re-assembly. (Of COURSE it does, otherwise we wouldn't need to pay good money to have someone do it for us!) Anyway, it was clear during disassembly that there was no sealant on the water pump gasket. The Rotax manual does call for something called Loctite 221 on the threads. I remember a thread on the Kitfox list where the latter was deemed to be very important, else water can leak past the bolts into the crankcase, thereby leaning the mixture and raising EGT's. You will have to beg borrow or steal a straight edge, (and I mean a REAL straight edge,) and check your mating surfaces. If uneven you will have to true them. One trick, if you are fastidious enough, is to put valve lapping compound between the mating surfaces, (with no gasket,) and gently rub them together. You MUST, however, get all the compound out of the wetted area lest you get it into the coolant, with the resulting deleterious effect on your water pump seals. Guy Buchanan K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.