Open Rockers
#1
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Open Rockers
I have been wondering if the early 4-stroke glow engines with open rockers have a problem with spitting fuel/oil from the lifters or valves? Are the rockers manually oiled before each flight? I would assume that their lifespan isn't too great. The reason I ask is that I have an old timer plane which I thought would be cool with exposed rockers since some of the actual fullsize vintage engines even had open rockers. Thxs. RS
#2
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Open Rockers
There is definitely a certain lure to the older open rocker 4-strokers! Yes, lube the lash point (between the push-rod and rocker arm) and where the push-rod meets the lifters before flights, but not too much oil as to attract unnecessary dirt. I have not run one myself, but I have never heard of any issues with spitting oil. I believe the reason for enclosing the push-rods was two-fold: one, to protect the fragile push-rods from being bent, and two, to provide some lubrication from normal running. These are cool looking engines, and would be right at home in an old-time craft. It would stand out on the flight line! Enjoy!
FP
FP
#3
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Open Rockers
Thanks for the info FP. That makes sense. This would be a plane which is only flown occasionally, so as long as it's not spitting fuel/oil all over the place I think I would like to locate a 40-60 open rocker. I have a Playboy Senior with an 84" wing which weighs just over 5 lbs. and can fly forever at 1/4 throttle with an OS FS40. Thanks again.
RS
RS
#4
Join Date: Dec 2001
Location: Upplands Vasby, SWEDEN
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Open Rockers
Hi!
I have been running those fourstrokes for the last 25 years and no oiling of the rockerarms are necessary as often as before every flight.
Of course oiling now and then can be done but it is not necessary to do so.
Regards!
Jan K
Sweden
I have been running those fourstrokes for the last 25 years and no oiling of the rockerarms are necessary as often as before every flight.
Of course oiling now and then can be done but it is not necessary to do so.
Regards!
Jan K
Sweden
#5
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Open Rockers
Hey all! I just picked up a Saito FA-30 open rocker engine. It was pretty gunked up but I cleaned it and is now purring nicely. I have a couple questions. First I understand that the letter marking on the mounting lug indicates it's date. Mine has a B. Any ideas of age on this? Also it has a pressure nipple on both the header pipe and muffler. It came with the crankcase pressure bleed hooked to the header. That doesn't seem right. Shouldn't the crank vent to air? Unless the crank puts out enough pressure to overcome the exhaust pressure.
FR
FR
#6
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Open Rockers
You are correct regarding the vent nipple on the crankcase. Leave it vented to open atmosphere. If you want, you can run a short length of fuel line to it and out of your cowl (if enclosed engine) just to keep it from spitting oil all over your firewall. Regarding the nipples on your exhaust, you only need one. I would suggest blocking off the one on the header tube, and use the one on your muffler for tank pressure.
FP
FP