Breakdown of engine is pretty easy!?
12-07-2005, 01:44 PM
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Breakdown of engine is pretty easy!?
Today I tore down an OS 40LA as far as it could be torn down, cleaned it and put it all back together again. It wasn't as difficult as I thought it would be. I am a very mechanical type person so I am used to doing stuff like this but I was wondering, are all engines this easy to tear down? Engines such as the larger size 2 strokers? How about 4 Strokers, I know they are a little more involved, are they fairly simple to disassemble for cleaning and reassemble? Thanks...
12-07-2005, 02:11 PM
#2
RE: Breakdown of engine is pretty easy!?
No.
You may get a 2-stroke with a piston ring which must be compressed before it will go back into the cylinder, or a cylinder sleeve that will go in any number of ways but will only work if installed correctly.
As for 4-strokes, sometimes getting the cam timing right can be a nightmare!
You may get a 2-stroke with a piston ring which must be compressed before it will go back into the cylinder, or a cylinder sleeve that will go in any number of ways but will only work if installed correctly.
As for 4-strokes, sometimes getting the cam timing right can be a nightmare!
12-07-2005, 04:38 PM
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RE: Breakdown of engine is pretty easy!?
A guy gave me a motor that he couldn't get to run right. I took it apart and turned the sleeve around the right way and it ran just fine. It pays to look at things carefully and make notes before the tear-down.
12-07-2005, 04:59 PM
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RE: Breakdown of engine is pretty easy!?
as far as 2 stroke sleeves go it is easy to check to see if they are installed right as the exhaust port should open first on the down stroke,some have a pin in the case that aligns with the sleeve,4 strokes do not have ports but as stated above the cam and vlave timing vary by manufacturer
12-07-2005, 05:33 PM
#5
RE: Breakdown of engine is pretty easy!?
Another thing to pay attention too is the piston and rod assembly.
A lot of times--the side of the rod that faces forward and is closest to the crankshaft counterweight will have a small chamfer or bevel in the rod bushing.
This is because the crank pin is not machined to a perfect 90* angle right where it comes out the back of the coutnerweight. The crank pin will have a very small shoulder on it. It is necessary to machine a slight bevel in the rod bushing to ride on this part of the crank pin.
Just make a note of which way the piston/rod assembly is facing when you take it out. Some pistons have an arrow or other indication mark on the top. This isually points towards the exhaust port.
Bearing removal:
Strip the engine down to a bare case. Toss it in the oven at the lowest setting you can get. (helps if your wife is out shopping when you do this) Wait about 10 or 15 minutes.
Remove the case with an oven mitt or heavy glove. Turn it up so that the rear bearing is facing straight down. Tap the case down on a 2x4 or other piece of soft material--so you don't damage the case. A couple taps--and the rear bearing will fall out.
Front bearing. Hold the case in the same position. Get a wood dowel thats close to the size of the crank. Insert dowel through the back of the engine and stand it up on end. Hold the dowel in place solidly against the front bearing. Tap it down a couple times on the 2x4. Front bearing will pop out.
Bearing installation:
Freeze bearings for at least 1/2 hour in a plastic bag. Stick them in the freezer.
Heat case in the oven again for 10 or 15 minutes.
Remove bearings from freezer and get them ready. Get the case out of the oven and drop the bearings in. Set them in the case with a wood dowel and a couple light taps from the end of a medium screwdriver. (NOT A BIG FRIGGIN' HAMMER!!)
The wood dowel should be big enough that it makes contact with the outer ring(race) on the bearings. You don't want to exert heavy forces in the inside ring(race) of the bearings. Thats a sure-fire way to ruin a bearing.
A lot of times--the side of the rod that faces forward and is closest to the crankshaft counterweight will have a small chamfer or bevel in the rod bushing.
This is because the crank pin is not machined to a perfect 90* angle right where it comes out the back of the coutnerweight. The crank pin will have a very small shoulder on it. It is necessary to machine a slight bevel in the rod bushing to ride on this part of the crank pin.
Just make a note of which way the piston/rod assembly is facing when you take it out. Some pistons have an arrow or other indication mark on the top. This isually points towards the exhaust port.
Bearing removal:
Strip the engine down to a bare case. Toss it in the oven at the lowest setting you can get. (helps if your wife is out shopping when you do this) Wait about 10 or 15 minutes.
Remove the case with an oven mitt or heavy glove. Turn it up so that the rear bearing is facing straight down. Tap the case down on a 2x4 or other piece of soft material--so you don't damage the case. A couple taps--and the rear bearing will fall out.
Front bearing. Hold the case in the same position. Get a wood dowel thats close to the size of the crank. Insert dowel through the back of the engine and stand it up on end. Hold the dowel in place solidly against the front bearing. Tap it down a couple times on the 2x4. Front bearing will pop out.
Bearing installation:
Freeze bearings for at least 1/2 hour in a plastic bag. Stick them in the freezer.
Heat case in the oven again for 10 or 15 minutes.
Remove bearings from freezer and get them ready. Get the case out of the oven and drop the bearings in. Set them in the case with a wood dowel and a couple light taps from the end of a medium screwdriver. (NOT A BIG FRIGGIN' HAMMER!!)
The wood dowel should be big enough that it makes contact with the outer ring(race) on the bearings. You don't want to exert heavy forces in the inside ring(race) of the bearings. Thats a sure-fire way to ruin a bearing.
12-09-2005, 03:49 PM
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RE: Breakdown of engine is pretty easy!?
Is ripping an engine down common practice? Is it wise to do this and if so how often? I have been in this hobby a little over 2 years and really don't know how much maintenance is required for engines other than the usual After-Run-Oil after running for the day and Marvel Mystery Oil or ATF if you are storing for a longer period of time. I see some people rip them apart to clean and yet others never touch them that way. I don't mind ripping them apart as I love taking things apart and putting them back together again, especially when they work after your done... he he he 
How often if ever should you rip your engine down to give it a good cleaning and how far down do you take it apart to do this, both 2 and 4 strokers? Thanks in advance...
How often if ever should you rip your engine down to give it a good cleaning and how far down do you take it apart to do this, both 2 and 4 strokers? Thanks in advance...
12-09-2005, 04:50 PM
#8
RE: Breakdown of engine is pretty easy!?
I don't take them apart unless they are broke or getting so low on power that it's time to rebuild.
I've personally never worn one out. I did rebuild an OS46FX that was given to me by a friend. He wore it out in the first gallon because he wouldn't listen to me and kept running it stupid rich during the break in. He never could understand why it wouldn't turn a 10-6 over about 8000RPM.
I replaced the internal parts (piston, ring, cylinder, rod, wrist pin, bearings) with the ringed heli parts (OS46FX-H) and slapped a full tuned pipe on it. YEEHAW!! Cost me way too much $$--but it was a runner after that.
IMO--tearing an engine apart unnecesarily is not a good idea. Keep it clean and run it on decent fuel. If it runs good--don't screw with it.
I've personally never worn one out. I did rebuild an OS46FX that was given to me by a friend. He wore it out in the first gallon because he wouldn't listen to me and kept running it stupid rich during the break in. He never could understand why it wouldn't turn a 10-6 over about 8000RPM.
I replaced the internal parts (piston, ring, cylinder, rod, wrist pin, bearings) with the ringed heli parts (OS46FX-H) and slapped a full tuned pipe on it. YEEHAW!! Cost me way too much $$--but it was a runner after that.
IMO--tearing an engine apart unnecesarily is not a good idea. Keep it clean and run it on decent fuel. If it runs good--don't screw with it.
12-09-2005, 08:57 PM
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RE: Breakdown of engine is pretty easy!?
Thanks for the help Rcpilet. Rebuilding an engine can cost more than just buying a new one sometimes... 
But if you can get several more years out of it, what the heck...
I remember someone saying that After-Run-Oil is a 50/50 mix of Air-Tool Oil and ATF, is this true? If so, does it matter what brand air-tool oil and or what grade ATF? I have some Campbell Hausfeld Air-tool oil and Super Tech Dexron-III Mercon ATF. Is this ok?
But if you can get several more years out of it, what the heck... I remember someone saying that After-Run-Oil is a 50/50 mix of Air-Tool Oil and ATF, is this true? If so, does it matter what brand air-tool oil and or what grade ATF? I have some Campbell Hausfeld Air-tool oil and Super Tech Dexron-III Mercon ATF. Is this ok?
12-11-2005, 02:01 PM
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RE: Breakdown of engine is pretty easy!?
It's all in the details. If you take one apart the tolerances can be as close as .0001 "..
The parts can be very small, such as the pin that keeps the ring from turning or the teflon pads (if they have one) on the end of the piston pin. some rods can only be installed one way with oil holes. As others mentioned the sleeve alignment is important also. So it isn't very complicated, but don't miss a detail. Jim
The parts can be very small, such as the pin that keeps the ring from turning or the teflon pads (if they have one) on the end of the piston pin. some rods can only be installed one way with oil holes. As others mentioned the sleeve alignment is important also. So it isn't very complicated, but don't miss a detail. Jim
12-11-2005, 05:40 PM
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RE: Breakdown of engine is pretty easy!?
Straight air tool oil is fine. ATF is fine. There isn't anything making one greatly better than the other. As long as you don't use WD-40. Promise you'll never use WD-40 in an engine.
Some of the engines I run have been blueprinted by engine builders. Those do not ever, ever, get taken apart unless the expert does it. Nothing will ruin a good set-up faster than an amateur taking it apart. So I don't!
Another thing I avoid is disturbing the piston/sleeve. Those parts wear into a fit, and it is runs right and starts like it should, I don't want to mess up that fit.
Some of the engines I run have been blueprinted by engine builders. Those do not ever, ever, get taken apart unless the expert does it. Nothing will ruin a good set-up faster than an amateur taking it apart. So I don't!
Another thing I avoid is disturbing the piston/sleeve. Those parts wear into a fit, and it is runs right and starts like it should, I don't want to mess up that fit.
12-13-2005, 12:04 PM
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RE: Breakdown of engine is pretty easy!?
Another thing I avoid is disturbing the piston/sleeve. Those parts wear into a fit, and it is runs right and starts like it should, I don't want to mess up that fit.
That is a good point, I wasn't thinking of that, it is probably best to not mess with the sleeve/piston for that reason alone, unless it is absolutely necessary. I guess just removing the back plate, glow plug, muffler, and maybe the carb would be the most ever needed for cleaning/storage prep. Thanks...
12-15-2005, 09:11 AM
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RE: Breakdown of engine is pretty easy!?
To be honest with you, I am not sure why WD-40 isn't any good, maybe because it is too thin. I just know that in a few posts that I have read, most people have indicated that you can use pretty much any oil that repels water and lubricates except WD-40. I would like to know more detail myself, maybe someone can fill us in as to why. Thanks...
ORIGINAL: Villa
What is the negative with using WD-40?
What is the negative with using WD-40?
12-21-2005, 08:25 AM
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RE: Breakdown of engine is pretty easy!?
Villa - Here is an answer from another post from (Rodney) about WD40 and why it isn't good to use. There may be more than one reason, but here is at least one good one:
(Rodney)
So apparently the WD40 will loosen up already rusted areas and cause undesired wear.
(Rodney)
Do not use WD40 for long term storage. If you use it for cleanup or anything, rinse it out well with a good oil. Never use it in an older engine unless you want to agravate the wear as, any rust already present will be turned into a nice abraisive compound to accelerate the wear of the engine the next time you use it.
