Hobbsy

My Feedback: (102)

Yeah Pete, when my generation is all dead and gone I think most of the smart people are going to be elsewhere. The little Saito .30 is like a 302 Ford, they run big for their size. By the way, that 11,675 rpm reading on the .30 was using 16% lube, I don't know how much effect that has, it must have some effect.

SrTelemaster150

Less lube equals more power as well as better fuel economy.

FNQFLYER

Ok a couple of things to comment on. Reduced oil content in our glo type engines will result in increased power but also increased wear. You don't get improvements without payback. It is all a trade off. Now under the heading that things aren't always the same or not what they seem. I have 2 x 63 YS engines. Both have been playing up not revving over 8500 rpm, and not at all responsive to HSN adjustment. 1 is a series 1 and 1 is a series 2 (different positions for the pressure regulator). It appeared if both were flooding, they were. I had worked out that the timing was off, fixed that, found my "special" fuel was crap. Now with the last in mind I pulled doen the series one regulator and found that there was carbon crap under the valve, cleaned it out now for the bench run. The series 2 was to be given the same treatment and as I was pulling it down I found the exhaust tappet wound right off, the valve was hardly opening, fixed that bit I decided to check the timing and found that the exhaust cam follower was stuck and when I removed it to clear it it had a slight bur on the cam to follower interface. That will be fixed. So I goofed and didn't follow ALL the investigative procedures result 3 weeks (most recent) of frustration and 2 litres of good fuel burnt wasted). Remember all is not what it seems.

blw

My Feedback: (3)

The Z-1 for me.

Hobbsy

My Feedback: (102)

Thanks Dan, some worry about excess wear when using less oil but I don't think there is anything to worry about when using 16%. As I mentioned the same amount of residual oil is in the crankcase after 30 minute run.

Charley

My Feedback: (2)

[QUOTE=FNQFLYER;12101687 So I goofed and didn't follow ALL the investigative procedures result 3 weeks (most recent) of frustration and 2 litres of good fuel burnt wasted). Remember all is not what it seems.[/QUOTE]

Your real goof was in not doing your preventive maintenance.

CR

Rudolph Hart

Trev i've long run 15% oil and no problems yet.I do a bearing set once a year on the 82's in the decathlon but it's flown a lot and mostly aerobatics.

The original z1 or z900 was also known as the 'super four' my favourite was the first yoshimura z1r as raced by graeme crosby.Okc i've painted the odd vincent or two over the years,you might look up brough superiors (ss100) too,te lawrence (lawrence of arabia) used to ride them at huge speeds back in the thirties on bad roads.

Dave thanks for the info.A few weeks ago i ran into a guy who had imported a cafe racer from belguim and guess what it used for an engine? 2x490 maico barrels and heads on a common crankcase squeezed into a yamaha 250 lc frame,you should have heard it!

acdii

Some fuels, like cool power are 16% oil content, and are 4 cycle fuels, Wildcat is 20%, and since all my engines state 20% oil, thats what I use. I see quite a few flyers using cool power, so guess 16% is ok in the long run.

Hobbsy

My Feedback: (102)

I don't use the Wildcat 20% YS fuel, I use to run the Premium Extra 18% and the Premium 16%, now I use the 2/4 at 18% full synthetic. I had the 16% when I had two RCV engines which recommended 16% Wildcat.

SrTelemaster150

This may shed some light on the feasibility of running REDUCED OIL CONTENT in 4-stroke glow engines.

I have found a reasonable price for straight methanol by the 4 gallon case ($20 for a case) as well as straight nitro & lube. I will have the local club pick it up on their annual fuel run in the spring.

I am retiring my FA-91S from flight duty as every plane I have mounted it on has met with an untimely demise. An FA-115 will take over it's slotted place in my 1/5 scale J-3 Cub. The FA-91S will be relegated to fuel testing to gage the affects of reduced lube on power output, fuel economy & most importantly, engine wear & reliability. The tests will be done W/CDI of course.

I am particularly interested in running straight methanol/lube & running minimal lube to see if reduced lube will make up for the loss in power from the elimination of the nitro. I'm going to start with 11% lube, (8:1 mix) running @ WOT for extended periods & reduce the lube content by 2% increments until I get to around 5%.

I think assuring that the case is filled with oil at the outset will assure adequate residual lube in the case. I believe the weak point will be the rod journal interface & I will check that as the tests progress.

I would be hesitant to do this W/glow ignition due to the volatile ignition timing factor. Bear in mind that the Laser tests were done by a factory research technician under controlled conditions. Turning the general public loose with such low lube percentages& GI would, I'm sure, result in some catastrophic failures.

blw

My Feedback: (3)

Dan, that will be interesting when you keep us updated.

I'm not sure why I would reduce oil content too much if not competing and pushing things to the limit though.

Hobbsy

My Feedback: (102)

Thanks Dan, maybe you could be careful a couple of times to keep the engine nearly level while dismounting it and removing the backplate and shoot us a picture or two of the residual oil.

SrTelemaster150

If I were running GI, I don't think I would reduce oil content significantly, especially on the smaller displacement engines. I read somewhere about the boire determining the amount of oil that is necessary.

Interesting that Saito spec's a much smaller ring end gap on the big muti-cylnder engine based on the FA-150 than it does for the FA-150 itself. The ring gap spec'ed for the 300T ring which is also used in the FA-450 radial is much smaller than the FA-150 counterpart.

My guess is that there will be more oil blow-by to lube the bottom end when more than 1 cylinder is present.

acdii

An FA-100 in the 1/5th is way over power, with a 115 you can hand launch that bugger! If you look at the Evolution Radials, they recommend 5-7% oil content, and low, 5-10% nitro, so oil content in the fuel is something I always wondered about. Do they really need that much oil in the fuel?

acdii

Um maybe twice, to three times as much depending on twin or triplet? Still kicking myself for not grabbing that 300T for $300 last spring.

SrTelemaster150

Yes, I think that high oil content is critical for the initial running to get enough oil into the crankcase to lube the rod journal. After the case is filled to what doesn't blow out of the breather tube, much less oil is necessary. The ball bearing are much less critical I think. The front bearing gets little oil from blow-by as it is shielded. The usual reason for failure of the ball bearings is more related to corrosion IMO. Injecting oil into the case through the breather & several drops down each push rod tube will serve the same purpose.

Since my FA-91 is the least expensive to repair, I feel less apprehensive in testing to failure. That engine seems to be a jinx anyway.

I won't be getting the fuel delivery until early spring so it will be a while before I can do any testing.

SrTelemaster150

Since the FA-115 is physically smaller than the FA-100 & it fits nicely inside the cowl with only the rocker covers sticking out slightly why not have enough power to hover if I get the urge? I have already mounted the FA-91S & made the necessary (minimal) cut outs in the cowl. The only difference in dimensions between the FA-91S & the FA-115 is 1mm further to the rear for the carburetor & 2mm taller why not have the extra power? The extra 2 1/2 oz of weight in the short nose will probably come in handy for proper CG too.

How was the CG W/the FA-100? The 115 is just a bit more than 1 oz heavier than the FA-100.

SrTelemaster150

That's my take on it too. Larger bores would also deliver more lube to the bottom end.

Yeah it was a dual carb version too wasn't it? Nobody seems to understand how to set those up, but when they are set-up properly, they idle better than the single carb versions. The "pump" can just be left at the factory setting, but if you know what you are doing, it can be used to fine tune the fuel delivery. Especially if the tank location is less than optimal.

acdii

My Cub required no additional weight to it with the 100. Had I used a smaller engine I would most likely have needed some lead in the nose. I used a 5 cell NiMH under the fuel tank for proper balance, I was going to use a 2200 Life, but it would have needed to be moved a bit aft of CG and out in the open, so I used the NiMH instead. On yours, you may have to move the pack to under the servo tray to balance it out, but I doubt you will need any dead weight in it. Other than my Something Extra, and 4*120, none of my SIG planes required additional weight. The SSE needed 2 ounces in the tail to compensate for the OS 70, and the 4* was tail heavy due to moving the elevator servo to the tail, but I balanced it on that goofy rig that you sit the plane one, so i doubt it is properly balanced, after I replace the hinges in the wing with pin hinges, I plan to rebalance it on the vanessa rig like I have done on my last few builds, and every one has come out spot on during the maiden flights.

Speaking of the SSE, Off to the field to remaiden it after the unfortunate dead stick that landed wrong. Hopefully raising the tank like I did will prevent any more inverted dead sticks.

FNQFLYER

Charley, Proper maintenance has always been my mantra. This problem (apart from the loose valve adjuster) was the result of crap fuel. I found 500mls of water in the fuel I was using during this current problem (using the freezing fuel technique). Don't know how the valve adjuster came loose but a point to keep an eye on in the future. On the reduced oil content thing. I always run factory spec never had a problem however there was an exception I was involved with. One of our O/T number was experimenting with 8% oil in a racing OS 61 (4s) which achieved and increase of nearly 1,000rpm. He did this by prcharging the crankcase with a measured amount of oil prior to starting to ensure a "wet/lubed" start and then he relied on the dry sumping unit he had in place for lubrication. He used 2 x 2oz Dubro tanks (1 fuel, 1 oil) and the pump of a OS pumped 2 stroke to deliver the oil. I worked, very "Heath Robinson" but it worked. He even took it to the SAM international champs (way back when?) and left it there for either John Pond or some other person.

Charley

My Feedback: (2)

The loose valve adjuster was what I was referring to. Those of us who run 4-cycle engines have to keep in mind that the valve lash needs to be checked periodically. Back when our OHV car engines had solid lifters we were more aware of this as a maintenance item.

CR

FNQFLYER

My only comment to that Charley is that the engine was set up for the round of comps I was entering and as usual I checked all the valve clearances on all the 4 strokes. Don't know how it happened BUT it was down to me and no one else and since the find I have been through all of my competition engines and except for the other YS in the narrative all are operating ok. Dammed if know but back to the triple check system.

Rudolph Hart

Trev is it true that the 91 is the only saito with a chrome to aluminium barrel and all the rest have chrome plated brass liners,would that make a 91 a poor selection for lubrication tests? i still favour 3 to 5% castor you can read the plug tip ring on temp so you don't run it to lean for long periods.

SrTelemaster150

I think that are all AAC (aluminum/aluminum/chrome) I am not aware of any that are still ABC. (aluminum/brass/chrome)

The only thing castor does is coat the inside of the engine with varnish. It is not beneficial, especially with CDI. The higher EGTs will coke up the exhaust port.

FlyerInOKC

My Feedback: (6)

I wouldn't say that it does provide low cost used engines to guys who know what they are doing and buy supposedly "locked up" engines at swap meets because the previous owner never bothered with running them dry and adding after engine run oil.