FG 33R cam gear timing adjustment
03-01-2017, 04:23 PM
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FG 33R cam gear timing adjustment
Hi guys,
I have a Saito 3 cylinder FG33 R since some years.
I live in Brasil and have no access to spare parts. Three years ago, when I bought the motor on running in I switched ignition cyl2 with cyl3. Because the drawing is looking onto the motor from the back..
I do not know if this, or the oil I used lead to a fatal main rod bearing being totally "eaten" out.
I had a new main rod made by a friend who is good in machining parts and the engine gave me lots of fun for two year. I switched to another oil MOTUL 800, which makes a real difference. With this oil all my motors are clean and shiny when opened.
But this December, on a hot day my FG33R it started to sound funny.. ..but I did not land anyway... hehe..
When I landed and showed the motor to a friend it blocked.
I dissasbmbled it and saw, that one of the connecting rod link pins had gotten loose. Probably because the crank pin spacer, that was supposed to hold the piston rods in line had dissapeared (hot climate.. I made it myself of Delrin.. which stand up to 170... ).
Anyway I had my friend make me a crank pin spacer of bronze, a new rod link pin.
However I had to dissasemble the whole engine.
Now I am not sure how to assemble e Radial Engine.
My question is: To assemble the cam gear housing I have to put the cylinder 1 in OT and put the gear with the marker looking downwards.. OK. But on Cylinder 2.. Does the crankshaft have to be in OT for the cylinder 2.. or for cylinder 1? Same for Cylinder 3?
I would really appreciate if somebody could explain the logic.
I just started the engine and it runs.. but just does not sound right. It might be that I missed one teeth in one of the cam shafts.. I had every cylinder align to its own OT while mounting the cam gears.
Thanks in advance.
Yours P
I have a Saito 3 cylinder FG33 R since some years.
I live in Brasil and have no access to spare parts. Three years ago, when I bought the motor on running in I switched ignition cyl2 with cyl3. Because the drawing is looking onto the motor from the back..
I do not know if this, or the oil I used lead to a fatal main rod bearing being totally "eaten" out.
I had a new main rod made by a friend who is good in machining parts and the engine gave me lots of fun for two year. I switched to another oil MOTUL 800, which makes a real difference. With this oil all my motors are clean and shiny when opened.
But this December, on a hot day my FG33R it started to sound funny.. ..but I did not land anyway... hehe..
When I landed and showed the motor to a friend it blocked.
I dissasbmbled it and saw, that one of the connecting rod link pins had gotten loose. Probably because the crank pin spacer, that was supposed to hold the piston rods in line had dissapeared (hot climate.. I made it myself of Delrin.. which stand up to 170... ).
Anyway I had my friend make me a crank pin spacer of bronze, a new rod link pin.
However I had to dissasemble the whole engine.
Now I am not sure how to assemble e Radial Engine.
My question is: To assemble the cam gear housing I have to put the cylinder 1 in OT and put the gear with the marker looking downwards.. OK. But on Cylinder 2.. Does the crankshaft have to be in OT for the cylinder 2.. or for cylinder 1? Same for Cylinder 3?
I would really appreciate if somebody could explain the logic.
I just started the engine and it runs.. but just does not sound right. It might be that I missed one teeth in one of the cam shafts.. I had every cylinder align to its own OT while mounting the cam gears.
Thanks in advance.
Yours P
03-02-2017, 11:03 AM
#2
You can check each cylinder by removing the valve covers. On each cylinder put it on 0T or top dead center. Determine if you are on the compression stroke (top dead center, 0T) or the overlap stroke (both valves slightly open) at 0T.
Get the cylinder 0T and on the overlap stroke with both valves open? The overlap must occur through 0T or the cam timing is wrong!
Do this for each cylinder.
Get the cylinder 0T and on the overlap stroke with both valves open? The overlap must occur through 0T or the cam timing is wrong!
Do this for each cylinder.
03-02-2017, 02:37 PM
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W8ye, thank you very much for your reply.
I used it to control what I had done. But I found an even simpler explanation. To ajust start with cylinder 1. Then turn 120 degrees to cylinder 3, then turn 120 degrees to cylinder 2. This is the firing order and if done like that the cylinders should also be on OT twice when the valves get activated (overlaP) and when the cylinder fires all valves closed). The motor runs now, It looks ok.... but heck would I like to know IF i missed a tooth or two when I assembled this cam gears...
Since I had no plastic that would withstand the temps I did the crankshaft distance pin from bronze... This might have added some weight, since all my pistons have also already lost some parts of their shirts (I cannot buy new ones here in Brazil) the engines vibrates quite a lot. But it works. Will fly it until the next break down. Thanks. P
I used it to control what I had done. But I found an even simpler explanation. To ajust start with cylinder 1. Then turn 120 degrees to cylinder 3, then turn 120 degrees to cylinder 2. This is the firing order and if done like that the cylinders should also be on OT twice when the valves get activated (overlaP) and when the cylinder fires all valves closed). The motor runs now, It looks ok.... but heck would I like to know IF i missed a tooth or two when I assembled this cam gears...
Since I had no plastic that would withstand the temps I did the crankshaft distance pin from bronze... This might have added some weight, since all my pistons have also already lost some parts of their shirts (I cannot buy new ones here in Brazil) the engines vibrates quite a lot. But it works. Will fly it until the next break down. Thanks. P
