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Saito 115 cam lubrication
My Saito 115 took a dump today. I opened it up and the camshaft supports had both broken. The cam jamed up and really screwed up the crankshaft, crankcase and of course the cam. The cam and surrounding area seemed quite dry of oil, not completely dry, but not wet with oil either. This engine was only 5 months old and has used about 2 gallons of Coolpower 15% fuel. It appears that the failure was due to a lack of lubrication in the cam bearings, even though the crankcase was literally dripping oil when I removed the back plate. I'm wondering if anyone else has seen this type of failure on this engine. I talked to Horizon Hobby and they said to send it in and they'd look at it. I'm hopeing that this isn't some kind of a design problem as I just got another 115 that hasn't even been started yet. So has anyone seen this before, or do you think it was just a fluke happening?
Paul |
RE: Saito 115 cam lubrication
What prop were you running when this happenned, is it possible it over revved and jammed a valve. I seriously doubt that lack of lube would be the problem, I have about 20 Saitos both rear vent and front vent and no problems ever. Thanks, Dave
PS, also what fuel? |
RE: Saito 115 cam lubrication
I keep telling people that you should pre-lube the cambox area of those Saitos with a backplate-mounted crankcase breather nipple.
There's simply nothing to push the oil past the rear bearing and into the cambox area beacuse all the excess oil just vents out the back of the engine. I've outlined the process I use at the start of each flying season before and I've never had an issue but I've heard of quite a few other folks who've ended up with dry camshaft bushes because they perform no manual lubrication or think that oil dripped down the pushrod tubes will make its way into the cambox (which it wont). |
RE: Saito 115 cam lubrication
XJet, what is the process that you're speaking of? I know that dripping oil down the pushrod tubes won't make it to the cam, but on the other hand one shouldn't have to perform a lubrication ritual to keep the cam lubed. The engine should do that through it's design.
Hobbsy, The prop was a 14x8 which tachs at 9900 at my altitude (4300 ft), so I know it didn't over rev. Besides, this is the same prop I've always used on it. Fuel was Coolpower 15%. I'm quite sure the failure was due to lack of lubrication as the cam housing was quite dry of oil. We'll see what Horizon Hobby has to say. Paul |
RE: Saito 115 cam lubrication
Most new Saitos come from the factory with black Molybdenum grease in the cam and rocker arm areas
However I just took an older 100T twin apart that had never been run and there was nothing but just some light machine oil in it. |
RE: Saito 115 cam lubrication
ORIGINAL: 42etus XJet, what is the process that you're speaking of? This allows the oil to trickle past the rear bearing and pool in the cambox. Put a rag under the front of the engine because much of the oil will seep out the front bearing. I leave my engines/models like this overnight to be absolutely sure that the cambox is bathed in oil. As soon as you start the engine up, any excess will be blown out the breather but this "dose" of lubrication seems to last the whole season long if you use the engine regularly. I have a feeling it also helps prevent rust. |
RE: Saito 115 cam lubrication
Xjet, I have been consternating over the question of how four cycles get adequate lubrication to the cam lobes and big end con rod bearing. Ring blow by? I'm conjuring up a cotrivance in my little brain where I employ a Perry Pump injecting ATF oil into the cam drive box powered by muffler pressure to insure adequate lubrication and venting crankcase pressure/blowby directly into the intake manifold. I haven't acted upon this for fear I will be escorted to a padded room somewhere.
Bill |
RE: Saito 115 cam lubrication
Paul,
Even if this only happened in *your* engine, this is what the warranty is for. The damage you describe seems to be quite extensive; justifying a replacement, rather than a repair of the engine... With labor and parts, it will cost more to repair... Send your engine back to Horizon Hobbies, without wasting any time. If you ran it according to the instructions, they will replace it. Just make sure you ask them to send you a replacement engine from a different production run, just to make sure... |
RE: Saito 115 cam lubrication
Dar, my thinking is that if the failure was due to lack of lube the damage would only be stripped teeth on the cam, the catastrophic breaking of the cam supports had to come from severe down force from the cam pushing against a jammed valve or other.
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RE: Saito 115 cam lubrication
Hmmm, I submitted this post last night and it seems to have disappeared.
Get a pump oiler. Fill it with ARO. Attach it to the breather and pump the crankcase FULL of oil. Clamp off the breather. Turn the motor over by hand several times. This will pump the oil past the rear bearing. Unclamp the breather and turn the motor over until the breather quits spitting oil. DONE. |
RE: Saito 115 cam lubrication
Cris,
I cannot see that your post was ever on here. If it was deleted, I would have a notation of it |
RE: Saito 115 cam lubrication
I may have killed the session too quickly?
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RE: Saito 115 cam lubrication
I agree, I think Horizon should replace the engine rather than just repair it, but I suppose it's their call in the end. I sent it to them yesterday afternoon USPS and insured. I should be hearing from them next week some time. I'll post back when I do.
Paul |
RE: Saito 115 cam lubrication
Follow up:
Horizon called me today. They had no explanation for the failure, but said that it shouldn't have happened. They agreed to repair the engine under warranty and return it to me. Fair enough. In my first post I mentioned that I had a 2nd new, never run 115. Well I took the cam cover off and was shocked. There appeared to be no lube of any kind in there. No grease and no oil, absolutely bone dry. Needless to say, I pre-lubed the thing with Xjet's method. In the future, I'm going to store all my Saito equipped planes in a nose down attitude, the idea being that any residual oil in the engine will drain down to the cam. Any comments? Paul |
RE: Saito 115 cam lubrication
Sounds like a winner. I guess they quit putting the moly grease in the new ones
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RE: Saito 115 cam lubrication
ORIGINAL: XJet I keep telling people that you should pre-lube the cambox area of those Saitos with a backplate-mounted crankcase breather nipple. There's simply nothing to push the oil past the rear bearing and into the cambox area beacuse all the excess oil just vents out the back of the engine. I've outlined the process I use at the start of each flying season before and I've never had an issue but I've heard of quite a few other folks who've ended up with dry camshaft bushes because they perform no manual lubrication or think that oil dripped down the pushrod tubes will make its way into the cambox (which it wont). As for fuel, I'm using home brew of 5% castor, 15% red Klotz, 10% nitro & the balance methanol. As you can see, there is ample oil in the fuel. I think I need to switch back to my other cam box cover with the breather mounted on the cover itself, the vent on the backplate being plugged. I also like X-Jet's idea about pre-lubing the engine as earlier described in these posts [8D] |
RE: Saito 115 cam lubrication
>>>I've heard of quite a few other folks who've ended up with dry camshaft bushes because they perform no manual lubrication or think that oil dripped down the pushrod tubes will make its way into the cambox (which it wont). >>>
If the pushrod tubes go down to the lifters, how could the oil not reach the cam? There must be a tiny bit of clearance around the lifters ... ? granted it wouldn't get there too fast though, but overnight? Thanks, Ernie |
RE: Saito 115 cam lubrication
The lifter/cambox seal is a very good one. On all my Saitos it's gas-tight and won't allow oil to get past.
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RE: Saito 115 cam lubrication
Thanks XJet. What kind of trouble could I get into by pulling the cambox cover off (Saito 82) to take a peek in there? Wreck the gasket.... or?
Also, I am blanking at the moment. How does oil get up to the top end (rockers) if not past the lifters? Thank you, Ernie |
RE: Saito 115 cam lubrication
Making the cam box seal unsealed would attract oil mist into the cambox, thus lubricating the cam, cam bushings and lifter bottoms. Of course, the whiners complaining about oil leaks would drive the folks at Saito USA nuts. Gaskets are for sissies, unless you absolutely need a pressurized crankcase. [&o]
Ed Cregger |
RE: Saito 115 cam lubrication
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Ed, here is the 18 year old cam out of my 1.50, I thought it was worn out but low and behold the new one is identical. I thought it was worn because the exhust cam is kinda pointy, so is the new one. apparently the exhaust valve opens very quickly, the intake is more rounded.
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RE: Saito 115 cam lubrication
I recently rebuilt a crash damaged Saito 72 with reportedly less than 5 hours running time total. Both cam followers had the outer edges worn on opposing sides giving the appearance of a slightly peaked roof, with the worn areas having a scuffed appearance. The cam lobes showed no appreciable wear. This is obviously a lubrication failure problem. I suspect that the engine had never been treated to an after run oil. This engine has the breather nipple at the bottom of the front case which should ensure proper lubrication to the cam box area. The cam followers in this engine are significantly smaller diameter than those used in OS engines and are therefore more highly loaded.
I have never seen this type of wear before in rebuilding many 4 stroke engines. |
RE: Saito 115 cam lubrication
Almost any tear down of a Saito medium engine actually requires refacing/replacement of the cam followers
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RE: Saito 115 cam lubrication
It seems like nearly all manufacturers of model four-stroke engine, either think that all modelers are suckers... Or that none of the manufacturers ever studied mechanical engineering...:(
The camshaft and lifter lubrication, in most four-stroke engine, can at best be considered rudimentary/borderline. I am surprised they even last as long as they do... And some manufacturers even do worse, by making mistakes; such as the one OS made, but using a fully sealed rear bearing in the now defunct .70FL, which made the availability of fresh oil to the camshaft/cam-gear/lifters, even less copious than none at all...[sm=disappointed.gif] Also; if you look at the cams and at the lifters/tappets/cam-followers, you will see another moot design consideration... The lifters in a full-size engine had a rather large diameter (or are 'mushroomed') and a have convex bottom, so they only contact the cam-lobe with their bottom and are actually rotated, as the rotating cam-lobe slides against it. This rule does not appear to be followed by model four-stroke engine manufacturers... It appears the cam lobes could ride on the edges of the rather small diameter lifter; which can damage both the lobe and the lifter. ...It appears engine longevity was never paramount, on their requirements list... For a long time I was quite reluctant to purchase any four-stroke engine; because of these, among the reasons. I own just one such engine, which I traded for a used one with another prominent member of this forum. Despite any fear I had, this Saito .72 has so far given me no trouble at all. But from all I have read here, I think perhaps I am lucky... |
RE: Saito 115 cam lubrication
Dar,
I was with him when he bought that engine at a small hobby shop about 30 miles north of here in Berlin Heights. It was a consignment so we don't know anything about the original history of the engine. |
RE: Saito 115 cam lubrication
ORIGINAL: Ernie Misner Thanks XJet. What kind of trouble could I get into by pulling the cambox cover off (Saito 82) to take a peek in there? Wreck the gasket.... or? Ernie Paul |
RE: Saito 115 cam lubrication
Saito has approached this problem in a different way on the Saito 40A R/C and C/L engines. Notice the crankcase vent in the right side of the cam box. But also notice that they have cast a boss there to have enough meat for the threads. Macs Headers makes a nipple with a flat flange on the backside and a retaining nut on the outside that would work well on the Saito 100, 115, & 125
http://image2-6.rcuniverse.com/e1/ga.../lg-168867.jpg http://image2-6.rcuniverse.com/e1/ga.../lg-168866.jpg http://image2-6.rcuniverse.com/e1/ga.../lg-168871.jpg |
RE: Saito 115 cam lubrication
Dar, I agree with everything you have said here. I recently acquired my first four stroke model engine, an Enya .46. I have completely disassebled it and noted no abnormal ware on the cam lobes or tappets. There are two holes approximately 3mm in diameter in the dividing wall between the cam box and crankcase. I don't believe the camshaft drive mechanisim receives enough lubrication. I have an idea to circumvent this problem and I'll let everyone know if it works. I just have to decide which of my engines to shoose to serve as a lab rat.
Bill |
RE: Saito 115 cam lubrication
The OS four stroke engines with the sealed rear bearings have a cross drilled crankshaft from the center cavity to a point in front of the bearing for oil passage.
However on the OS 70 & 91 Surpass II and Surpass I the only difference is cadmium plating and the cross drilled hole. Therefore you need to be aware of what you have if you are mixing and matching parts |
RE: Saito 115 cam lubrication
THAT's what I'm talkin'bout!
Bill |
RE: Saito 115 cam lubrication
ORIGINAL: Ram Jet Dar, I agree with everything you have said here. I recently acquired my first four stroke model engine, an Enya .46. I have completely disassebled it and noted no abnormal ware on the cam lobes or tappets. There are two holes approximately 3mm in diameter in the dividing wall between the cam box and crankcase. I don't believe the camshaft drive mechanisim receives enough lubrication. I have an idea to circumvent this problem and I'll let everyone know if it works. I just have to decide which of my engines to shoose to serve as a lab rat. Bill Have you had a failure in that area with an Enya four-stroke? None of my Enya four-strokes have displayed a problem with camshaft/lifter/gear lubrication at all. Some of my Enya four-strokes are getting very old with many, many hours of operation logged on them. We have to remember that the oil in the crankcase is whipped into a mist that permeates the engine well, except in some cases where there is insufficient circulation. None of my Enya engines have displayed the slightest problem, but I am bad for loading up my engines, two and four-strokes, with lots of ARO just to be safe. I've even used regular motor oil for lubrication in the lower crankcase of four-strokes. You'll get some strange stains on your model when you do that, but it doesn't seem to affect the finish permanently in most cases. It even looks kind of realistic, if you know what I mean? Ed Cregger |
RE: Saito 115 cam lubrication
I had 5 Enya 46-4C apart last year or two, and 4 of the 5 showed rust in the cam box. There is no circulation there and the area is relatively enclosed with only those two small holes to let oil in or out. I'm considering adding the OS Alpha type oil passages to the one I have left. This would certainly keep oil flowing through there.
I think the positive crankcase vent system will soon be added to all model four strokes. I think it can be added to Saitos just as well. I haven't tried it yet, only because I have just a couple of them. |
RE: Saito 115 cam lubrication
You are right about the motor oil. I have had a-lot of very happy two cycle outboard motors that ran just fine on 30 wt engine oil/gas mix. Back in the 60s you would say "Two cycle oil - WHAT?" The Enyas may be OK because, at least on my .46, there are those two connecting holes between the cam box and crankcase. Upon tear down I noted the smallest little caged ball bearing assembly I have ever seen and man was it guncked-up with old castor. I cringe at the thought of having to replace it someday. I am concerned about the plain bearings on the ends of the cams though. I'd rether the crankcase breather exit the cam box and not the crankcase. There is not much to encourage the oil mist to enter the cam box.
Bill Bill |
RE: Saito 115 cam lubrication
I've got something in mind involving a Perry Pump and the PCV idea is right there in the mix.
Bill |
RE: Saito 115 cam lubrication
ORIGINAL: Ed Cregger N2ECW ORIGINAL: Ram Jet Dar, I agree with everything you have said here. I recently acquired my first four stroke model engine, an Enya .46. I have completely disassebled it and noted no abnormal ware on the cam lobes or tappets. There are two holes approximately 3mm in diameter in the dividing wall between the cam box and crankcase. I don't believe the camshaft drive mechanisim receives enough lubrication. I have an idea to circumvent this problem and I'll let everyone know if it works. I just have to decide which of my engines to shoose to serve as a lab rat. Bill Have you had a failure in that area with an Enya four-stroke? None of my Enya four-strokes have displayed a problem with camshaft/lifter/gear lubrication at all. Some of my Enya four-strokes are getting very old with many, many hours of operation logged on them. We have to remember that the oil in the crankcase is whipped into a mist that permeates the engine well, except in some cases where there is insufficient circulation. None of my Enya engines have displayed the slightest problem, but I am bad for loading up my engines, two and four-strokes, with lots of ARO just to be safe. I've even used regular motor oil for lubrication in the lower crankcase of four-strokes. You'll get some strange stains on your model when you do that, but it doesn't seem to affect the finish permanently in most cases. It even looks kind of realistic, if you know what I mean? Ed Cregger As rule i am adding oil in crankcase before use to get valve gear lubricated and after use to prevent rust. Enya are well made to last foreve so long the engine get good maintenance. |
RE: Saito 115 cam lubrication
Yes, it seems that blow by is the only thing relied upon to lubricate everything below the piston crown. I just doesn't seem too smart.
Bill |
RE: Saito 115 cam lubrication
ORIGINAL: DarZeelon I own just one such engine, which I traded for a used one with another prominent member of this forum. Despite any fear I had, this Saito .72 has so far given me no trouble at all. But from all I have read here, I think perhaps I am lucky... |
RE: Saito 115 cam lubrication
ORIGINAL: Ram Jet Yes, it seems that blow by is the only thing relied upon to lubricate everything below the piston crown. I just doesn't seem too smart. Bill See at the modern 4 stroke engines, there are breather nipple mounted near or in same zone where valve gear are placed and the oil fog will enter into the valve gear first before breather nipple. It provides safe lubrication.. Even in modern Saito engines have not always had breather nipple placed there where valve gear are in their place. Stupid that Saito engineers did not learn of other engineers of OS,Magnum etc to put the nipple in the right place .. [:o] |
RE: Saito 115 cam lubrication
Right on Motorboy. I have given thought to drilling and tapping my cam drive box to accomodate the crankcase breather nipple and plugging the factory installed nipple.
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RE: Saito 115 cam lubrication
ORIGINAL: Ram Jet Right on Motorboy. I have given thought to drilling and tapping my cam drive box to accomodate the crankcase breather nipple and plugging the factory installed nipple. |
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