Hobbsy

My Feedback: (102)

They are closing the exhaust valve a few degrees sooner to prevent air from flowing in through the exhaust and diluting the intake stroke. Not related to when combustion occurs, that is determined by compression pressure and mixture ratio. Leaner fires sooner and richer fires later.

Darklotus

My Feedback: (4)

Dead on Hobbsy... Hence valve overlap.

krop

My Feedback: (19)

Jim,
Wind and wind and rain is the forcast for a while.
So, I'll let you know when get the Trurboheader with both mufflers going probable the first of next week.
At least I hope!
krop

scratchonly

Mounted new 91 on my test stand today. Compression was next to zero. Checked the vave adjustment and the clearance was was so close I couldn't feel any at all; adjusted clearance, still no compression. Squirted some fogging oil into plug hole, still no compression. Spun engine with electic starter for a few seconds, compression is awesome. Anyone know what happens here?

freeonthree

My Feedback: (1)

Cylinder was dry, ring was stuck, just needed a little oil... valves maybe needed to be slammed shut a few times before they sealed good... Thats my guess...

R.C. ROB

hello club saito. I just got my first saito and i am having a blast with this thing. 220 in a h9 28% extra 260 whatamotor lol.

RC Specialties

Thanks Krop,

I'm looking forward to your results. Keep us informed.

Jim

Darklotus

My Feedback: (4)

Heres a good read on cams. Watch the animation, then switch to the performance cam.

http://auto.howstuffworks.com/camshaft.htm

James

blw

My Feedback: (3)

There's a new Saito .50 for $159.99 at Southeast RC.

RVM

Has anyone tried Sea Foam as an ARO? I think it is almost exactly like Corrosion X.

RC Specialties

RVM,

I have not heard of Sea Foam. Who makes it?

Jim

RVM

Anyone want to buy or trade for a problematic, unable to idle, underpowered and generally troublesome Saito .82 GK?

I didn't think so.

Since that is the case, I'm going to throw it in a saltwater bath so I can watch it slowly corrode away. I hope it has a soul and central nervous system, so that it can suffer over the time that this takes. I think I'll keep the velocity stack and o-ring that came with it, as those items actually work properly. If the rest of the engine melts away in a vat of sulphuric acid I would be just as happy (and that would be much more destructive than saltwater anyway).

*sigh*

RVM

I dunno. I saw it at AutoZone and read the label and description. Seems to be the same thing as Corrosion X.

Pit-Viper 1

My Feedback: (12)

[link]http://www.seafoamsales.com/[/link]

RVM

There we have it!

N1EDM

My Feedback: (2)

RVM, if it hasn't seen any physical damage, send me a PM....

Pit-Viper 1

My Feedback: (12)

Sounds like pretty good stuff..


Shane

NM2K

My Feedback: (14)

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Send it back to Horizon for a look-see. What have you got to lose except postage and a little time?

It could be something simple that you are over looking. <G>

Seriously, let them take a look at it.


Ed Cregger

Hobbsy

My Feedback: (102)

Robert, there has to be something wrong with your plane set up, it ran perfectly on my test stand and idled like a Swiss watch. Maybe you have lousy fuel or something.

RVM

Yeah that is what I am going to do. I was just pissed and frustrated so thought I'd throw that out there. It's the same .82 I've been *****ing about for the last 5 months or so.

RVM

I have no doubt it ran fine for you. Lately, I've had the worst luck known to man. I'm 99.99% sure the RC gods decided, whie it was en route to me, that I was not deserving of a good engine.

I couldn't even get it started this evening for awhile because it didn't have enough compression. Once I did get it started, it would warm up and the leak from the intake and exhaust valves wasn't as bad, but you could still turn it all the way through compression by grabbing the drive collet with your thumb and forefinger. If it quit, and you tried priming it, the engine would lose almost all compression. Literally, you could twist the prop and it would freewheel around like it didn't have a glow plug installed. Once you got it running, it would warm up and the compression would improve somewhat. Then, when it quit again, you repeat the whole cycle.

I tried 2 different fuels, one of which was from a brand-new, unopened container. I used some homebrew 20% nitro, 15% oil and some Omega 25% (this was the new fuel).

The engine runs alright above about 3000 RPM. It will die if I bring it lower than about 2800 RPM. I reset the needles three times. The lowest reliable idle I got was around 2900, and after a few seconds of that the engine quickly lost RPM and died. I was able to barely keep it at a decent idle around 2200 RPM but I had to leave the glow driver attached. Take it off, engine dies within a second. Top end was short about 600 RPM. Peak on an APC 14x6 was 8800 RPM, maybe 9000 depending on how hard it would surge (lots of surging, especially at full throttle). I checked on two different tachs. I didn't bother trying another prop. There should not be that much variance.

No, neither the low speed nor the high speed needle were too rich or too lean. I am very proficient at tuning Saitos. The intake pipe is properly sealed. There are no leaks in the fuel system.

Valve clearances are good.

I don't think any of this matters relative to the fact it has practically no compression.

freeonthree

My Feedback: (1)

Don't do that ! Saito's are easy to diagnose and repair. I'll be glad to look at it for you if you like, but no salt water please. It would anger the model airplane gods if ya made it swim with the fishies. lol It's probably something simple, cam timing, leaky valve, vacume leak at intake, or something silly. I love working on Saito's, and won't run anything else. Im spoiled !
Are you sure it's an 82 ? I never heard of an 82, just an 80. Is this a brand new engine they came out with ? Hmmm... is it a 72 ? They do have a tendancy to idle a little funny, but they will idle dependably at 2200 to 2300 rpm, they just have a little lope to them. They like to idle on the rich side a bit. I love mine ! 82 ? Hmmm...

freeonthree

My Feedback: (1)

I see they do make an 82, I'll be darn ! Must be a relatively new engine then. I went to horizon support and looked it up in the parts explosions. I learn something new every day. lol\
Can you tell me how this problem occured, or has it been like that since it was new ?

RVM

It just developed over a couple of gallons.

rajul

My Feedback: (58)

Sounds like your valves are sticking