Four Stroke Valve Train Lubrication
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Four Stroke Valve Train Lubrication
I have a concern with the lack of oil making it to the top end of my four strokes. My little Saito .30 especially. I have done searches and basically found threads that the over all conclusion has been they seem to keep their integrity despite very little oil migration and to manually lube them occasionally if you choose to worry about the fact. I can't begin to claim more knowledge than the engineers at Saito, OS, etc. but has it been tried or even discussed here that it may serve well to maybe add some nipples to the rocker covers so the crankcase vent is routed first low on the rocker cover(s) then from a higher nipple to a vent hose? The idea obviously being that the rockers, valve guides, etc benefit from the oil expelled from the factory vent before it is ejected? I would think there is enough blow by to prevent the crank case from puddling?
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I assembled it with a little Lubriplate. After a solid four or five hours of flying I expected it to be washed away when I checked the valve lash. I know W8YE and Hobbsy have done plenty of R&D. If it ain't broke don't fix it I guess. Thanks for the advise.
#6
I drizzle oil (castor) down the pushrod tubes and all over the rockers/rocker shafts, valve springs, etc. when I adjust or check the valve lash. There's always oil on the valve train parts but a little extra never hurts.
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I don't waste it down the pushrod tubes but make certain it gets on the rocker shaft, the pushrod pivot and especially the tip of the rocker arm where the tip moves in an arc and tries to move the valve stem back forth. Easier sliding is good there.
#10
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Years ago, I happened to mention that I had aquired an older High Compression Saito 80GK...(an old flying buddy gave it to me because it had a broken valve spring, and bad bearings)
Bill Robison kindly offered to do a machining operation for me which entailed opening the spring pockets in the head, because the new springs are a bit larger O.D. than the old (and no longer available) version.
Anyway...long story I will attempt to shorten...he and I had a rather long phone conversation about seeing dry valvetrain components on certain Saito engines, especially when mounted w/ cylinder upright. ("Inverted" , w/ cyl. hanging straight down, seems better for rocker and valve tip, pushrod end(s) lubrication)
I don't remember now if Bill actually did the modification, I think he did, but I tried one method...it was to block off the backplate vent, and the oil and case venting would have to go up the pushrod tubes and out the rocker covers. I used a Dremel cut-off wheel (the thin, rather fragile dk. brown ones) and cut a shallow groove in each lifter...about .015" deep, approx. and that let the case gasses get past the lifters, and up the tubes...then a small hole in each rocker cover, at the rear for venting out a small nipple for fuel line drain...
It worked...but I don't know as it was absolutely necessary....(I like to tinker, and since Bill also had seen dry top ends like I have, we figured why not try it)
Back then, I was a "mister fixit" for a couple of LHS's and had worked on many different brands and sizes of engines...but I haven't done that since '08...
Bill Robison kindly offered to do a machining operation for me which entailed opening the spring pockets in the head, because the new springs are a bit larger O.D. than the old (and no longer available) version.
Anyway...long story I will attempt to shorten...he and I had a rather long phone conversation about seeing dry valvetrain components on certain Saito engines, especially when mounted w/ cylinder upright. ("Inverted" , w/ cyl. hanging straight down, seems better for rocker and valve tip, pushrod end(s) lubrication)
I don't remember now if Bill actually did the modification, I think he did, but I tried one method...it was to block off the backplate vent, and the oil and case venting would have to go up the pushrod tubes and out the rocker covers. I used a Dremel cut-off wheel (the thin, rather fragile dk. brown ones) and cut a shallow groove in each lifter...about .015" deep, approx. and that let the case gasses get past the lifters, and up the tubes...then a small hole in each rocker cover, at the rear for venting out a small nipple for fuel line drain...
It worked...but I don't know as it was absolutely necessary....(I like to tinker, and since Bill also had seen dry top ends like I have, we figured why not try it)
Back then, I was a "mister fixit" for a couple of LHS's and had worked on many different brands and sizes of engines...but I haven't done that since '08...
Last edited by proptop; 03-23-2014 at 08:28 PM.
#12
That area is probably the least lubricated area of a 4-stroke and thus I agree should get a dab of oil sometimes. My Enya 4-strokes have very tight cam follower (lifter) bores so the oil I drip down the tubes doesn't go very far very quickly. I'd assume Saito makes their engines with similar tolerance.
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The valve guides and stems get plenty of oil, there is oil in the fuel and in the exhaust and as mentioned, oil is hard to keep out of places you don't want it, so it will walk right up the valve stems, no problem,.Auto engines have valve stem seals to keep oil from walking down valve guides and making the engine smoke.
I guess I need to, "state things more betterly", I don't disagree with placing oil down the pushrod tubes, it's just something I don't do because there nowhere for it to go.
I guess I need to, "state things more betterly", I don't disagree with placing oil down the pushrod tubes, it's just something I don't do because there nowhere for it to go.
Last edited by Hobbsy; 03-25-2014 at 04:27 AM.
#18
#19
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Positive pressure in the exhaust port will force oil into the rocker area while negative pressure in the intake port will pull oil from the rocker area.
#20
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I'm just guessing, but I think the stack-up of tolerences might have something to do with why some engines are lubricated just fine...no problems...but if the stack-up of tolerences ends up on the tight side, there is inhibited oil flow?
Some guys, myself included for the most part, report no lubrication issues...but there is the odd occasion where a tight one goes out the door, and it might run a bit dry in the rocker / cam area???
Some guys, myself included for the most part, report no lubrication issues...but there is the odd occasion where a tight one goes out the door, and it might run a bit dry in the rocker / cam area???
#21
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I think valve train lubrication is less of an issue if the engine is mounted inverted or horizontal.
Using an inlet check on the rear W/an outlet check on the front also helps. Saito claims it keeps the crankcase cleared of potentially harmfull accumulation of blowby & moisture. It is standard on the dual carburetor version of the 300T & is used to pressurize the fuel to feed the high mounted dual carbs. This is a picture of the bottom of my FA300TTDP.
Using an inlet check on the rear W/an outlet check on the front also helps. Saito claims it keeps the crankcase cleared of potentially harmfull accumulation of blowby & moisture. It is standard on the dual carburetor version of the 300T & is used to pressurize the fuel to feed the high mounted dual carbs. This is a picture of the bottom of my FA300TTDP.
#23
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They are usually about $60 but they sure are handy as the cage acts like a 3rd hand to keep the jaws positioned.
#25
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Like most every tool I have ever purchased, the caged puller has proven to be handy in many instances. I rarely pull my 2 jaw puller out of the tool chest anymore.