old-pilot

W8YE, will you or Hobbsy point me to the thread concerning Bill's fire? thanks.

P47 Jug - Al

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[link]http://www.rcuniverse.com/forum/fb.asp?m=5417994[/link]

av8rdavid

compression is BACK!!!!!! Turns out the cam adjustment allen screw was turned correctly to adjust gap in the cam, but i must have tightened the nut and turned the screw enough to open the exhaust valve thus loosing compression.....The engine is back together and with the new piston ring and re-polished piston/ valves and combustion chamber, it feels like it did the day it was born! I'll have it fired up this weekend!
Thanks everyone...

Dave

johnS555

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[quote]ORIGINAL: P47 Jug - Al


[quote]ORIGINAL: old-pilot

W8YE, will you or Hobbsy point me to the thread concerning Bill's fire? thanks.

http://www.rcuniverse.com/forum/fb.asp?m=5417994[/link]

Thanks P47 Jug-Al, I am aware of the off line Posts that show up occasionally, but this, I think is the time for an off line Post to go out on the Saito Forum, if I`m wrong, I appologize, but this needs to get on this Forum for more exposure, The wealth of knowledge and assistance that Bill Robison has contributed to this Forum is unmeasurable, let alone the time and money he has spent to send out information to us that were less informed on the Saito engine and others, you may say he kept it going and brought it up to the level it is today, tops in RCU Forums, you can`t tell me that you have not got at least 20 dollars (and probably more) worth of information from his experience, so now is the time to notify Flyboy Dave for an email address for pay pal or an address for a letter, lets get Bill back in the air with some Saitos, we can`t do much for the feeling of loosing everything but can surely do something to help him get started over......LETS DO IT..........JohnS555 #118 (I think)

freeonthree

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You won't get a flow into the crankcase from the rocker ends of the push rod tubes. There's little lifters in the cam cover, and you would have to suck pretty hard to suck thru the clearance between the lifters and the bores they run in.

freeonthree

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I have an even easier way to check for valve leakage. Simply turn the engine counter clockwise (normal rotation), and as the engine is going thru the compression stroke, listen carefully at the exhaust tip for a compression leak. Do the same while listening to the carb with the throttle open. My 72 has a very obvious exhaust valve leakage. My 56 and my 65 come up clean using the same test, no detected leaks whatsoever. I'll be lapping the 72's valves in the near future, and I think it has always had that leak too because it has never idled quite right, while the other 2 Saito's idle like Briggs & Stratton's.

w8ye

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You cannot lap the valves in a 72. They have just a hard chrome seat on aluminum. If you scratch through the hard chrome, you are history with the 72. You will need a new jug. This may have happened already because someone lapped the valves.

freeonthree

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Nah, I bought the engine new. I hear if you use toothpaste, it won't hurt the valve or the seat. Of course, I will just clean and inspect first. May be just cruded up. There sure is alot of crap in the exhaust port area. I shot some carb cleaner in there to wash it out, and lost all compression for a while. lol Pulling the cylinder and a good cleaning may be all it needs I hope.

w8ye

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Sounds good.

The valve is probably partially stuck from the black stuff around the stem. The black junk is usually just on the exhaust valve.

The valves are usually hard to get out of a used jug. Where the clip is that holds the valve retainer usually has a burr on it and the valve retainer doesn't want to come off? Then when you get that done, the valve will not go down through the guide because there is a flange beat on top of the valve by the rocker arm. These will need to be removed before you can get the valve out to clean the burned carbon from the back side of the valve.

freeonthree

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Sounds good to me, and I have a set of little jewlers files to beburr the stem, so that shouldn't be a problem.

freeonthree

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It can't be 180 off. Every other turn, it's 180 off.

av8rdavid

I checked the valves for compression by removing the cylinder, leaving the valves on and with the springs closing both then blowing through the cylinder....No hiss noise means a solid leakproof setup...
Now setting the cam gear back to the original position is a task in a half i noticed....The piston (i understand) should be in the full compression poition and the cam gear dot straight down...
I'll be firing the engine up tonight...I'll keep you all posted.

Dave

Pit-Viper 1

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Hello guys/gals,

I have a questoin reguarding the .62. I have a Great Planes Ultrasport+ 40 and was considering this as the power plant, size is very restricted due to the size of the engine compartment. I am looking to be able to hang it on the prop and was wondering if this would be enough to do this with. Weight should be around 5-5 1/2 lbs.



Thanks

Shane

freeonthree

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With the engine facing you, set the cam gear for dot position, and use a razor blade to hold the gear from moving. The razor blade should be on your right side. We have found the right side teeth work better than the teeth on the left for having the gear dot perfectly positioned. I like to stick the gasket to the bottom of the cam cover with oil, then administer the blade, and set er down.

blw

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Shane,

I don't have a .62, but it probably isn't going to be enough for that. Maybe. But you will be really close to either it being enough or not enough. I had that kit but sold it to a friend. I remember the cowl, etc. I think you could put an .82 on it with no problems. Might look good mounted sideways.

khodges

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At 5-1/2 pounds you'll have a great power-to-weight ratio. You might not have unlimited vertical, but it ought to go like stink. My Cub weighs 11 pounds and flies very well on the old .65 at half throttle. The .62 is lighter and makes more power than the .65, probably revs faster and higher too. It has the same stroke as the .56; basically, it's a bored-out .56, cases are the same also.

NM2K

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----------------


Yes, the .62 will fly the Ultrasport 40, but if you want performance similar to that of a .46 two-stroke, you will need at least an .72 to .82. No, I'm not an overpower the model freak. I'm talking about parity with the .46 two-stroke. I am surprised that Saito is still making the .72 after the introduction of the .82. Go figure...

The .72 and .82 are made in crankcases that possess the same beamwidth as the .62, so fitting the model will not be a problem.


Ed Cregger

w8ye

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The 72/82 do not exactly have the same beam width as the 56/62. The bigger engines are 1/8" (3mm) wider in between the beams but the bolt pattern for the mounting bolts is the same.

mstcitabria

Hobbsy,
I see that Jim from rcspecialties is offering the TurboHeader at 10% off to all registered Club Saito members till his current add has expired, good deal....mstcitabria

http://www.yourfilehost.com/media.ph...e=WS_10005.WMA

Birman

w8ye & Hobbsy, now tha Bill cannot get on line for awhile, will someone else be taking over assigning numbers for membership? I would like to be able to take advantage of 10% off on the TurboHeader. See my post #5886.

mstcitabria, I went to the link you posted but I didn't see anything about the 10% off. Just an audio file of the engine running with the TurboHeader.

Larry

mstcitabria

Birman,
Jim had placed it in an add that appeared in a banner at the top of these post earlier, here's the market add in RCU...................... http://www.rcuniverse.com/market/item.cfm?itemId=260395 . Very nice, well worth the money, works as advertised..........mstcitabria

s_moorman

Hey gang,

I have a saito 72 with a stock muffler that I modified like Don at www.rcdon.com I'm using a sullivan skywriter to pump the oil into the copper tubing that is wrapped around the bolt in the muffler. Unfortunately it creates too much pressure in the muffler which kills my RPM's most likely do to the pressure in pushing the exhaust as well as the increase in tank pressure enrichening the mixuture. I'm wondering if switching to a larger muffler will help the problem. I know I can put the muffler from a 100 on it with no modification but can't find the difference between the 100 and the 100 revised which everyone seems to be sold out of. Additionally I was wondering (given the lack of saito explanation) if I could go with an even larger muffler and use muffler adapter nuts to put maybe a 120 muffler on it. Any help will be appreciated.

Thanks

SM

RC Specialties

mstcitabria,

Because many club members are contributing to Bill Robison's aid, I will continue offering the discount to the club members when the Ad is renewed.

Jim

mstcitabria

Jim,
Thats great! Hope many of the members contribute to help out with Bill's situation, this thread would not be the same without him. He has helped out many of us and it's time for a little payback. Lets support Bill in what he loves most, Saito engines.......................mstcitabria

Pit-Viper 1

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Thanks guys, the plane should come in under 5lbs from the looks of it. So far it is sitting at 2.5 with all harware and motor as it sits now. Not using epoxy on everything like instructed, only on critical areas like firewall, wing joint, etc. heres a few pics of it now. We have a .72 in a cub that I might be able to try if it needs a little more.


Still breaking the motor in now, it does seem like it will transition very quickly. 1 more question, while running the first tank at 3 turns out it is only reaching temps around 60*F, should it be a little higher for break in? I know from the racing days offroad that the motors needed to be at normal operating temps to allow the metals to expand and contract properly during breakin. Just doing as the book says but it sure seems cool. I know the .72, 1.00, and 1.25 we have don't run much over 120*F at any givin time so it mayt not be abnormal, just cautious I guess.

Thanks again

Shane