w8ye

My Feedback: (16)

Just run it with your fuel and it should clear up

clytle374

I pulled the rocker covers and found the exhaust pushrod had jumped out of its screw and was against the rocker arm. The intake had no detectable lash.

I then pulled the rear cover and found that the crank and bearings are a bit rusty and the rod has made contact with the case.

Cory

w8ye

My Feedback: (16)

It may need bearings then?

clytle374

I feel almost no play in the bearings, but I can see movement in the big end of the rod. To be safe I'd need to replace both. I'm going to try and return the motor first. If not I'll tear it all the way down and see how the rest of it looks. What little of the cylinder I can see looks good. Win some, loose some.

Thanks
Cory

Edit: i should clarify that I work on machinery for a living and can feel a couple thou. Don't have the tools here to get real numbers.

clytle374

So I looked through the sellers history on rcgroups and found this.

The motor I bought was listed as being on his sons edge... well now I know its been dropped too. wonderful

Rudolph Hart

The guy sounds like he does'nt have a clue,still..it's better than having one you just dived in at full throttle

clytle374

I gave $165 for it shipped. What do you guys think? Rebuild it, or dispute it.

Cory

SrTelemaster150

If the big end of the rod had enough slop to hit the case, I would suspect crank damage too. Perhaps the original owner/seller just replaced the rod on a worn crank. You could end up W/as much or more in itas a new engine after parts are added to the purchase price.

I would dispute the purchase.

rexracer

Well, for anyone that's interrested, I tested a bunch of props on my .40a today. I wanted to test some of the MA S2 props (formerly scimitar) since they seem to perform well. I haven't run this engine since I broke it in in '08. I tested some props back then, and the ones that I tested both then and now confirm that the engine is running about the same. The 3 that I ran both times were all about 150 to 200 rpm down today, but it was 25 degrees warmer today so I'll attribute it to that,
Here we go;
Saito .40a
70 degrees ambient, 25% humidity
New Fox miricle plug

PROP SIZE PEAK RPM IDLE THRUST

MA-GF3 11X6 10,200 2200 4LBS 6OZ
MA-K 12X4 10,050 1800 4LBS 10OZ
MA-K 12X5 9150 2200 4LBS 1OZ
MA-S2 12X5 9500 2200 4LBS 6OZ
MA-S2 12X6 9050 2200 4LBS 1OZ
MA-S2 11X7 9500 2400 3LBS 11OZ
MA-S2 10X8 10,400 2600 3LBS 9OZ
MA 3BLADE 10X7 9600 2300 3LBS 10OZ
MA-GF3 11X7 9100 2300 3LBS 9OZ
APC 12.25X3.75 9400 1800 4LBS 6OZ

I think that MA-S2 in 12x5 is going to be a great flier for the Beaver, and it should pull it out of the water well. The numbers don't tell the whole story. Not only did the 12x5 S2 pull more revs and better thrust than the K series, it spun up way faster. The S2 12x6 spun up faster than the K series 12x4. I like these props.

clytle374

Is it common for the crank pin to wear? Just thinking aluminum against steel.
Cory

Mustangman40

My Feedback: (1)

Thanks for all the tips guys, the V stack sure did clean up the mess that I was getting.. My buddy had one on a GK82 he had sitting on the shelf, so I got his in till mine comes in at my LHS...

added a velocity stack and changed the "O" ring in the carb that seats the intake manifold and tweaked the low end.. Got her purring like a kitten, spinning a 13x4W at 10,500 backed it off to 10,000 and idle was at 1,950. I let her idle for a solid 10 minutes and the transition was perfect, no hesitation and a little smoke trail... Thanks again!

Jimbo

w8ye

My Feedback: (16)

I've never experienced a worn crank pin on a Saito. Not even ones with bad rust. The rod always went in sloppy situations.

clytle374

Ever put a micrometer on one to know what it should be?
Cory

w8ye

My Feedback: (16)

I never bothered to mike one

I always visually inspect them for streaks and signs of wear but have never seen any.

The crank is pretty hard. Probably 44 Rc?

I have seen cranks that were bent on the outer end where the threads are though.

Rudolph Hart

So have i..bloody expensive.

SrTelemaster150

Not particularly common, but dirt/carbon/metal from other worn parts can imbed in the soft metal part (rod) causing wear on the hard part (crankpin)

If the bearing got so bad that the rod contacted the case there could have very well have been (fine) hard metal particles in the case.


I have a crank in my (very used) FA 150 that has no noticable signs of wear, but it is marginal (just a bit loose) even when a brand new rod is placed on the journal.

Since the valves, seats are also marginal & the valvesprings, lifters, bearings are shot, I'm converting it to a high compression 180 to run on spark ignition W/alcohol based (either methanol or ethanol) fuels on spark ignition.

It will only cost a little more to up the displacement & CR over just rebuilding it as a 150.

SrTelemaster150

If you have a new conrod you can check for excess play on an existing crank pin, but I never realized how much play I had until I dismantled a just broken in engine & compared. Problem is, you would have to invest in a new conrod just to see.

Not sure what the specs are for the crank pins or where you could find them.

spaceworm

I have a never-flown FA 180 that I had to replace the bearings in because the previous owner did not store it right after bench testing. I plan to convert it to RCEXL spark ignition, to increase the fuel efficiency, but run it on standard 18-20 percent oil glow fuel.

You say "high compression 180" how did/do you raise the compression of the FA 180? Are you raising the CR so that you can run it on low or no-nitro fuel? How does CR affect the glow fuel nitro content when on spark ignition?

Thank you.

Sincerely, Richard/Club Saito #635

SrTelemaster150

The crankcase deck on a 150 is .052" shorter than on a 180. That will raise the CR to 15.1:1, a bit too high I'm afraid. I plan to experiment W/stroker plates to lower the CR. .010" will drop CR to just under 14:1.

Higher CR makes more TQ across the RPM band & promotes better effeciency & fuel economy. W/spark ignition it should not promote detonation when used W/alcohol based fuels.

The 180 crank fits right into the 150 case. I have relieved the case for rod clearance W/careful dremel tool work & there will need to be some minor machining to allow thw 180 jug to fit down all the way into the case. After that I will need to take a half round file to relieve the case some more for piston skirt clearance.

You could accomplish the similar results by machining about 1mm from the case deck of a 180 case. If my experiment proves practical I will most likely do the same to my FA 180.

I am waiting for a check to clear before ordering the parts necessary to get to the next stage which is checking VTP clearances. Even @ the full .052" deck reduction, piston to head deck clearance will be in the .020" range.

Ernie Misner

Don't know how much it will help the carbonized exhaust valve but Clarence Lee runs fuel injection cleaner through a dirty 2-stroke. Either mix it will a tank of fuel or dribble it down the carb while running. I would never have thought of that...... and haven't tried it either!

Mustangman 40, did they have any high temp Viton O-rings at the hardware store? Just curious, thanks, and let us know the dimensions of the new one you might pick up.

Thanks,

Ernie Misner

mike early

I wonder if SEAFOAM would be of any benefit?

FNQFLYER

Gee a guy is away for a couple of weeks and there is heaps to catch up on.  Just been to the SAM 1788 Champs in NSW, good to see the country side so green, even had a lake on our comp site this year.  A few observations from the previous posts.  At the champs Saitos were the preferred 4 stroke for both Texaco and Duration.  I ran a 65 with a 12.5 x 5.5 Bolly special on 30% Nitro in an 85% Bomber for a mid field finish, and ran the same beast in Texaco with a 15 x 8 (and a 16 x6) and 20% nitro again for a mid field finish.
From other events I would not recommend running a Saito 56 through the sides (yes opposite walls) of a shearing shed at full throttle you won't get much back except bits (very small) of metal and covering.  Anothe observation was that most 56s that crashed broke the engine mount lugs, any thoughts guys
On removing crankshafts from crankcases I use a 2 ton arbor press (cost me the same as the prefered 1 ton version) and I also now use same for the reverse process.  One can feel resistence and it is very easy.  For Old Farts sake I bought it from "The Mans Toy Shop" in Townsville.  The only place my wife won't let me takeany form of plastic money card. 

Rudolph Hart

You still got that big hammer?

earlwb

To remove the crankshafts, I use a short scrap piece of 4x4 hardwood as a anvil. I heat up the crankcase using a Hakko heat shrink tubing gun, and with a, big brass hammer, I tap the crank on out of the engine. Sometimes the bearings pop out sometimes not. I tnen use a 1/4 brass rod with a lip on one end to tap the bearings out (after reheating the crankcase up good again). I need to wear leather gloves for the hot engine too. Putting a nut on the tip of the crankshaft to help protect the threads is a good idea.

FNQFLYER

Old Fart, yes I have the big hammer and itstill does good service.  As an aside I purchased a JR 9X 11 2 years ago with a 2.4 gig conversion (spectrum) used it at the comp and I won't go back to the others I have been using (A Spectrum DSX7 and a JR 2720) not that they are bad just that the 9x is good with the best of both worlds 36mhz and 2.4 gig.
The Saitos worked well at the comp and by far were the most popular and now if the "idiots" stop leaning them out to excess we might see some real performance and maybe not so many broken ones
IC forever