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Oct 15, 2021, 01:19 AM
Still gassin' it.
Oh, well... Saito 180, my way...

Startgedrag (1 min 50 sec)
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Oct 15, 2021, 07:56 AM
Registered User
Gary Cee's Avatar
Quote:
Originally Posted by BernardW
I use a welding glove, a real doozy, and that's pretty good protection. But don't use anything less, like a gardening glove or even most workshop gloves, they're nowhere near enough. The main issue I had isn't getting whacked on the knuckles by the prop but slicing them open on the prop trailing edge, they're surprisingly efficient for cutting. I had mine slide along that edge once and it opened my glove and my hand inside it right open no problem. So I learned how to hold the prop for a start, with the fingertips on the top side of the prop between LE and TE,at about half span, and push down, don't slide. Works for me... I find doing it that way I don't really need a glove, because your hand naturally falls out of the way, though I'm such a klutz I'm probably going to do it wrong or grab the muffler or something anyway so I use my welding glove
Exactly; For any one of many reasons. A stout glove won't hurt the man nor the machine and provides a huge measure of protection. Like I said Cheap insurance
Conversely, I would neveruse a stick. Yes, trailing edges can slice like razors.

Use whatever works for you is the bottom line, I am all set

The big Saitos on methanol remain a very, very easy engine to hand start, especially if you master the simple reverse flip method.


Bert, Nothing unusual about that. They start just as easily on glow ignition.
Last edited by Gary Cee; Oct 15, 2021 at 08:02 AM.
Oct 15, 2021, 10:50 AM
Registered User
Is there a fourm like this for Saito gas engines?
Oct 15, 2021, 11:34 AM
CC (Certified Curmudgeon)
flyerinokc's Avatar
I haven't seen one. This one and the one over on RCU seem to cater to both glow and gas.
Oct 15, 2021, 12:42 PM
Registered User
Notme2's Avatar
Quote:
Originally Posted by smking0656
Is there a fourm like this for Saito gas engines?
You're in the right place, fire away. Watcha got?
Last edited by Notme2; Oct 15, 2021 at 01:07 PM.
Oct 15, 2021, 12:53 PM
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Notme2's Avatar

Collapsed valve spring culprit


Been giving some thought to Dave's FA120 with ONLY the top half of the valve spring collapsed. Anyone who has worked on a well used Saito 4 stroke knows how tough it can be to depress the valve spring retainer, broken more than a few thumbnails attempting that myself. The answer is of course to heat things up a bit to soften the cooked on oils. Heating with a torch, even a butane pencil torch, is bad news. Just a couple of seconds of misdirected flame will overheat the spring and take the temper out ie anneal it. A heat gun, with its diffused heat, is the right tool for the job.

I suspect the person who overheated the top half of the spring didn't even know the damage they caused until the engine was run again.

The Culprit
Last edited by Notme2; Oct 15, 2021 at 01:06 PM.
Oct 15, 2021, 01:17 PM
Registered User
Notme2's Avatar
While on the subject of heating, disassembly of any of our model engines becomes a much easier task when heated up. I heat them evenly with a heat gun to a temp just a little hotter than can be held with bare hands, take the heat away, wait 5 minutes and begin disassembly. It's amazing how easy the screws come loose, even those little rocker pin/screws. No more rounded off allen wrenches and oftentimes the gaskets release and can be reused.
Oct 15, 2021, 01:53 PM
Registered User
Quote:
Originally Posted by Notme2
You're in the right place, fire away. Watcha got?
I picked up a used FG30 and plan to use it in my H9 1/4 scale J3 cub. I started it this morning and it ran good. Is there anything I should check over? What size gas tank should I use? What about prop sizes? Anything else I should know?

Steve
Oct 15, 2021, 02:34 PM
Still gassin' it.
Quote:
Originally Posted by smking0656
I picked up a used FG30 and plan to use it in my H9 1/4 scale J3 cub. I started it this morning and it ran good. Is there anything I should check over? What size gas tank should I use? What about prop sizes? Anything else I should know?

Steve
Check what plug cap you have. If it has a hex shape, be aware that you have to push it down (hard) and twist it clockwise 30 degrees to lock it, CCW to unlock it. It has to enclose the entire hex part of the plug or it is not on properly. The plugcap with the round steel ring at the base is a simple pop-on cap, but also should enclose the entire hex part of the plug. Important.

Also: use Saito plugs, the generic RcExl plugs are a fraction (about 0,06" or so) shorter, and might not make proper contact in the cap.

Tanksize, 8 oz should be enough, I'd say that would suffice for something like 15 minutes WOT.
A felt clunk in the tank, 3-line set-up and no additional filters, and do NOT place the tank in CoG, because the Saito pumpcarburettors do not have a really strong pumping action like the Walbro's.
Propsize probably around 17 x 8 or 18 x 6 or so to begin with. That should bring it into the mid 8K range IIRC.
Oct 15, 2021, 03:05 PM
Registered User
Notme2's Avatar
Well said Bert. Both Saito and Rcxel plugs work fine on my Saito ignition units, whether twist on, press on or clip on plug caps. So far anyway.

SMking0656, check your valve clearances before running again. Should be set to .0015"-.0020" at room temp. Readjust when they open up to .0040", or sooner.

Be aware that gas engines have a very narrow range of adjustability as compared to glow. Once close to optimal running changes to the needles should be in very small increments with a 5 minute waiting period between adjustments.

No need to set your high speed needle much below peak rpm as the pumped carb helps with changes in fuel levels. 100-200 below peak (with full tank) is generally rich enough. Lean the low speed needle as lean as possible while still getting good transition off idle. If it burbles at high idle to midrange lean the low speed needle even more and slow down your throttle servo with your TX setting for good transition.

As for fuel tank size, I use 14 oz or larger tanks, typically the ones the plane came with and position the vent line so the tank holds the amount of fuel I want. I do this so the Tygon fuel feed line is longer and flops easier within the tank without buying more expensive super flexible fuel line. For an FG30 I would use a 14-16 oz tank and position the vent so the tank holds 8-10 oz.
Last edited by Notme2; Oct 15, 2021 at 03:47 PM.
Oct 15, 2021, 05:21 PM
Registered User
Gary Cee's Avatar
Not yet found a one type does it all heat source for engine work.

I try to fit the source to the purpose.

For gummed up carb bodies on in-plane engines, a soldering gun or iron usually turns the trick cleanly, locally without risk of adjacent collateral damage.

Same iron trick can work well at freeing up sticky rocker pivots, unfortunate Loctite treated fasteners etc.

The heat gun works for moving bearings out of their housings and just as well for putting them back in place.
Some folks make good use of a boiling water bath, hard to beat as an evenly spread heat source.


Big stuff uses similar methods on a larger scale. Of course the stakes are greater as well, but proper methods pay off in either case.

The bronze bearing pair in this press connection get packed in dry ice. The connector bore is pre-heated for 8 hours with a large, gas fired multi jet ring burner. The rim bushings are then positioned over the bore below an overhead crane. Once centered it is lowered and driven home by a crew of four to six workers using maple blocks and rawhide hammers.

You usually get but one chance to get it right
Latest blog entry: Responsible fliers.
Oct 15, 2021, 05:48 PM
CC (Certified Curmudgeon)
flyerinokc's Avatar
Wow! That's the biggest Saito piston rod I have ever seen!!
Oct 15, 2021, 11:03 PM
No more wasted spark 😉
ClubFlyer's Avatar
Quote:
Originally Posted by paulinfrance
Sorry but no way would I use a glove on a 4 stroke, with the kick backs I still use a stick,,,

just look at the notches in my wooden spoon !
With glow ignition 4 strokes, you don't even need to flip it through compression to start it. Just bounce it off the compression stroke 180 with a back flip. Of course with spark ignition, you'll have to pull it through compression, but CDi rarely kicks back.


Backflip start- Engine ASP FS.61-AR (1 min 51 sec)
Oct 15, 2021, 11:34 PM
What could possibly go wrong?
Good illustration of "big stuff" Gary
Oct 16, 2021, 08:12 AM
A man with too many toys

Compression Ratio


Does anyone know the compression ratio if the typical FA and FG series large engines.

Just wondering if I convert a FA to gas will it have the same compression ratio as a factory FG engine? No engine in particular, just a general question.

.


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