hy flyr

My Feedback: (27)

Hey guys,
I'd like to hear your thoughts on this..
Flying my Hangar 9 Mustang this morning. 35deg. weather. 14x8 master airscrew prop, 9800 rpm, 15% nitro, needle out about 11/4 turns, running a tad rich. I have probably15- 20 hrs on this engine.
The plane was flying fine for 8 min. then it just died! fast! no warning! Got it in without any problems. Now when I turn the prop the engine turns very hard. Like it is almost seized or something? No grinding noise, just turns over very hard. Do you have any ideas?

w8ye

My Feedback: (16)

I sent you a PM

hy flyr

My Feedback: (27)

Got it and thanks!

w8ye

My Feedback: (16)

For others reading this . . . .

Flying in colder weather - the engine tends to get leaner (on you) up in the air in cold weather. So you have to set your HS needle a little richer on the ground.

If you are running fuel with only 17% oil the Saitos get to feeling mighty dry inside if run lean. Yet if you can remove the back plate there is still some residual oil inside the engine.

Fuels like Cool Power and even Wildcat premium will leave your engine feeling at the prop like it has a lack of oil if run lean (and the Saito still ran without backfiring). I have been using Wildcat Premium Extra lately and it has more castor oil. Prior to that I ran Rich's Brew for several years and before that was Morgan's Omega. These all ran fine.

After some detected problem as noted by the original poster, it becomes a matter of isolating the problem. . . . .
Remove the engine
Begin disassembly by first removing the carb and back plate and looking inside. Note the oil, how much oil, how the oil looks, is there metal in it, etc
The next step is to remove the cylinder with the piston to see if the problem is in the crankcase or the cylinder?

I had one like this and I couldn't get the rod off the crankshaft as the rod had seized on the crankpin.

The usual problem is main bearings

reyn3545

I didn't know that cold temps would have that much of an effect. I guess with colder, dense and dry air, you need more fuel to keep the mixture right.

Another good reason to live in the South!

Sorry to hear about your motor, I know how much we come to depend on something that works like a Saito does.

Ken6PPC

Don't turn it over any more!

I'd open it up, and take a look. You might have lost a bearing, and now have debris inside. If so, turning it over will only make things worse!

Take the carb off, remove the back plate, and peek inside. You may need to go further to really find out what happened.

Rudolph Hart

Many thanks for the thoughtful explanation,it answers a problem and raises one,does the same rational apply in the converse as it gets hotter??(weather) i don't want to lean off that cool fuel supply on a stinking hot day.In average conditions and a minute of fuel left in the tank i climb vertical and watch the smoke trail,if i can just see it all is fine.
ps ju8st managed to get some sheilded rear bearings for my 115 rare as rocking horse do do they say.

w8ye

My Feedback: (16)

In the very hot summer you have to lean them out if they get to sounding rich

wyo69cowboy

My Feedback: (2)

Hello fellas, I picked up a new Saito 1.00 and plane at an R/C auction recently. Motor appears almost new; no residue on the muffler or anywhere on the exterior of the engine. However, it had no compression. Spun it over with the electric starter after attempting a prime; nothing. Pulled the valve covers and the valves were all the way compressed. I then pulled the cylinder, and noted both valves stuck open, and they were interfering with one another(overlapped faces). I tapped the exhaust valve in with a 1/4" extension (all I had on hand), and then the intake. After pushing the exhaust valve in & out a few times with my finger, it seems freed up and working correctly. The intake valve still sticks; I can get it to go in & out, but not freely.

Couple questions: I searched and found a little info earlier in this thread about using ATF or a similar oil to soak them and free them up. I also thought about using carb cleaner to shoot around the valve. Suggestions?

I would take valves out, but have never done so. I made a quick attempt to remove the rocker arm pivot screw (straight blade head), but they were tight and I didn't want to mess them up. What, if any, special tool might work here? Heat help? If I get those out, what holds the retainers/keepers on? Is the retainer a snap fit, like an e-ring? My main concern with pulling the valve is to see if one or the other is bent, because of the way they were overlapping/stuck. Thanks for any advice.

w8ye

My Feedback: (16)

It is difficult to get valves out of a four stroke head.

The top edges of the keeper grooves get a burr on them and the tops of the valves get peened over by the rocker arm.

You cannot get the spring retainer up off the valve or the valve down through the guide.

You have to file or stone the burrs of the the stems.

On a bad head that is going to be scrapped, you get the retainers off the valves and drive them down through the guides but on a goood head you don't want to be doing this.

You want to dress the stem grooves with a whet stone before sticking old valves in a new head.

You best bet is to warm up the head with a Monokote gun and see if the intake loosens up?

Put some fuel around the stems and let them soak

When valves stick, the pushrods fall out of the sockets and jam the valves partially open. The push rods will have to be replaced into the sockets on the rocker arms.

wyo69cowboy

My Feedback: (2)

Thanks W8YE, that was the first thing I saw when the valve covers came off: the pushrods just dangling there. Glad I didn't bend the pushrods by spinning it over (or the valves, they fortunately aren't an interference fit where the piston could hit the valves, apparently); I checked the pushrods by rolling them on the table and they are straight.

This engine appears to be barely run at all; it was mounted in an inverted installation, and there was oil in the rocker boxes. The piston top shows no discoloration or deposits whatsoever; I'm guessing it was started once or twice and that was it. Would the oil from the fuel sit in the guides and gum them up? I think that's what may have happened...

w8ye

My Feedback: (16)

It is all gummed up

The heat gun and some oil may fee it up?

w8ye

My Feedback: (16)

It is all gummed up

The heat gun and some oil may fee it up?

wyo69cowboy

My Feedback: (2)

Thanks, I'll try the heat gun and maybe some carb cleaner and/or Marvel Mystery Oil. Do you think the valves could be bent? They were basically pushed all the way down, and the larger face of the intake was overlapping the exhaust.

BTW, does anyone make a small, hardened tip screwdriver to take the rocker pivot shaft bolts out? I have a Duratrax set for my RC cars, and it started to bend the tip on the small screwdriver that would fit...

w8ye

My Feedback: (16)

I got one at the hardware store

Usually the guides in the head get bent before anything happens to the valves themselves.

wyo69cowboy

My Feedback: (2)

Well, took some pics and worked some brake cleaner thru the valves over the lunch hour. Intake valve now also feels like it is opening and closing smoothly. You can see some surface corrosion on the valve faces. Pulled the backplate and the crankcase is largely dry, though the bearing race faces show similar surface corrosion. Hope the bearings aren't shot; turning it over with the cylinder off, the bearings feel a bit gritty, but it also feels like that could be the cam gear drive. Not sure. Will assemble it tonite and hopefully try firing it up this week.

w8ye

My Feedback: (16)

The Saito 100's that age were bad about the front bearing suddenly being a pile of rust.

So keep and eye on your bearings

wyo69cowboy

My Feedback: (2)

Well, went ahead and pulled the cam; spun the crank over after that, and boy, the bearings feel gritty! Guess I'll order up some bearings from Boca. When I re-install the cam, manual says timing mark on cam goes @ 6 o'clock, with crank at 12 o'clock. I did it a couple times, and it seems that the cam gear will put it either slightly before or slightly after 6 (just a degree or so either way)when I place it back onto the crank splines. Any way to be certain which gear tooth position to use?

blw

My Feedback: (3)

An exacto knife blade stuck into the gears will pin the gears right where you need them. Also, reversing the push rod where the pointed end goes into the cam cover, and into the gear does the same thing.

greybeardaviation

My Feedback: (2)

My first post to CS, however I have read ALL of Mr. R notes on SAITO's. Im still amazed at all the folks who have problems with these gems. I've never had a problem from my first 56 to my 125 now and quite a few in between ( other than operator error).

I've replaced many sets of bearings and never had a problem so I went and ordered a cermaic set for an 80 I'm rebuilding. Then I saw all the problems folks have been having. Should I return them for a SS set or just be extra special careful on the installation?

Oh, and I guess I should request a number to make me official.

Love the club guys, keep posting!

greybeardaviation

w8ye

My Feedback: (16)

I use the regular bearings

Tarasdad

I have a Saito FA-80 that I received as a birthday present in either 1988 or 1989. It made many flights in the nose of a Carl Goldberg Anniversary Cub (just a teensy bit overkill), and was slated for my Goldberg Super Chipmunk. Unfortunately it never made the move, as I had to stop flying due to financial constraints when the plane was 90% completed. Since then it's been in storage at my dad's house near Houston, Texas. I was finally able to retrieve it last July, and am now in the process of rebuilding it - 10 years in the humidity and heat of SE Texas did it no favors, that's for sure!

Rudolph Hart

GBA there's no way in the world you are getting in,one ignorant ******* is enough and these so called "gems" can defy logic at times,just like the handbrake does.Simulaters are great for learning how to fly but how much different does it feel at the field when you rock up with your pride and joy and need to fly it in the real world,sheesh,makes you think.Like cam timing did for me and it took ages good luck pard

greybeardaviation

My Feedback: (2)

Sorry Old Fart, but cam timing is easy...........it's removing those drive washers that kills me!
Maybe living on the other side of the equator makes things backwards from here. Sounds logical........up is down, down is up, left is right, rich is lean.................I need a beer!

Fly slowcrash slower

Hobbsy

My Feedback: (102)

Jim et al, I ordered a couple of the Saito velocity stacks the other day while they are in stock and put them on my Saito .56GK and .62. Took some pictures in case anyone asks for a how to. Easy 1-2-3 peazy.