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IO-360-M1B - Fixed pitch but prepped for C/S..

Tram

Well Known Member
So, I'm a long way from making this decision but right now we are planning on going with a fixed pitch prop.

Spent 15ish years in a 6 with a FP and had no complaints, not looking to start the debate up.. :D

All that said, planning on ordering an M1B when the time comes from Vans and I figure it'd make the most sense to just go ahead and get it setup from the get go for C/S just incase plans changed several years down the road.

What needs to be done in the initial order - just let them know we'd like the hollow crank?
 
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I ordered a Sensenich carbon fiber fixed pitch propeller + IO360-M1B combination. The engine came prepared for constant speed. I think all M1B engines are configured like this. I had to convert the engine for FP which is easy to do, no poking holes in the crankshaft like illustrated in the Vans manual.

The conversion starts at post#17 of this thread.
https://vansairforce.net/community/showthread.php?t=190965&page=2
 
Ya as far as I know the M1B from Van's always has the hollow crank. It will also come with the governor drive/pad and the oil line to the front.
 
I ordered a Sensenich carbon fiber fixed pitch propeller + IO360-M1B combination. The engine came prepared for constant speed. I think all M1B engines are configured like this. I had to convert the engine for FP which is easy to do, no poking holes in the crankshaft like illustrated in the Vans manual.

The conversion starts at post#17 of this thread.
https://vansairforce.net/community/showthread.php?t=190965&page=2
If you remove the oil line to the governor pad you must poke the hole (or remove the inner plug).
 
Just me

I did not do it this way by removing the oil line.

Just make sure the front crank plug is in and the governor cover has the milled slot. Leave the tube and stuff as from the factory. Easy peasey.

For cs, add governor and pop the front plug out of crank. Done and done.

Too many people have damaged cranks trying to remove the line and puncturing the rear crank plug; that was the old school method and dont need to do that with the new engines.
 
If you remove the oil line to the governor pad you must poke the hole (or remove the inner plug).

I am not an expert in Lycoming engine so don't take my advice. This was the instruction by the Lycoming tech rep and I followed the instruction to the letter when converting from CS to FP in order to keep my engine warranty. Even Vans tech support told me to contact Lycoming. The local A&P, a very reputable guy, would not agree to punch any hole into this new engine, and adviced me to call Lycoming instead.
 
I am not an expert in Lycoming engine so don't take my advice. This was the instruction by the Lycoming tech rep and I followed the instruction to the letter when converting from CS to FP in order to keep my engine warranty. Even Vans tech support told me to contact Lycoming. The local A&P, a very reputable guy, would not agree to punch any hole into this new engine, and adviced me to call Lycoming instead.

It is in the plans. See the attached image.
 

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I am not an expert in Lycoming engine so don't take my advice. This was the instruction by the Lycoming tech rep and I followed the instruction to the letter when converting from CS to FP in order to keep my engine warranty. Even Vans tech support told me to contact Lycoming. The local A&P, a very reputable guy, would not agree to punch any hole into this new engine, and adviced me to call Lycoming instead.

As others have pointed out Lycoming requires the inner plug removed or a hole punched. An alternative is to leave the oil line in place with the proper cover on the governor pad. Not poking the hole will result in high oil pressure between the two plugs forcing the outer plug out and a significant oil leak in flight. Not good.
 
lycoming

So the Lycoming tech rep told me to not poke any holes in any plugs, leave the governor line in place and make sure the governor cover had the slot milled in it. I followed the factory recommendation. I believe the hole poking comes from the old days when the governor cover did not have the milled slot connecting the governor oil tube to the center of the governor pad. Without the slot, the tube would not allow the hollow crank area to vent and oil pressure will blow the front plug. Many people have damaged the cross tube in the crank trying to poke a hole int he rear cover; this is why I chose to leave the line in place and verified the governor cover was the correct one for fixed pitch props.
 
If you have a new IO-360-M1B engine and want to use it for FP then I recommend you get the Lycoming factory guidance for the conversion.

These are the instructions from the factory tech rep:

" I’ve got a couple illustrations I’ve attached to this email to show the process for pulling off the rear prop governor drive assembly and installing a block-off plate. You would remove the four gray-painted nuts (one of them is circled in green), and pull the drive assembly straight out. Cover plate p/n 69106 and gasket p/n 69551 would get installed over the hole and secured using the plain washers and nuts you removed, replacing the 4 used lock washers with new lockwashers p/n STD-475. The nuts will get torqued to 17 ft-lbs.

On the front of the engine, you can either put an AN cap on the elbow (something like an AN929-6), or remove the elbow and put an STD-783 allen plug into the case, using a little bit of Loctite 564 on the first 3 threads.
" (The elbow remains after the oil line is removed)

The drawing shows the picture of the block off plate that is installed after the governor is pulled out. This also necessitate removing the oil line which is quite easy to do.

This is the link to my post showing the the block off plate after it is installed.
https://vansairforce.net/community/showpost.php?p=1493386&postcount=19
 

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If you have a new IO-360-M1B engine and want to use it for FP then I recommend you get the Lycoming factory guidance for the conversion.

These are the instructions from the factory tech rep:

" I’ve got a couple illustrations I’ve attached to this email to show the process for pulling off the rear prop governor drive assembly and installing a block-off plate. You would remove the four gray-painted nuts (one of them is circled in green), and pull the drive assembly straight out. Cover plate p/n 69106 and gasket p/n 69551 would get installed over the hole and secured using the plain washers and nuts you removed, replacing the 4 used lock washers with new lockwashers p/n STD-475. The nuts will get torqued to 17 ft-lbs.

On the front of the engine, you can either put an AN cap on the elbow (something like an AN929-6), or remove the elbow and put an STD-783 allen plug into the case, using a little bit of Loctite 564 on the first 3 threads.
" (The elbow remains after the oil line is removed)

The drawing shows the picture of the block off plate that is installed after the governor is pulled out. This also necessitate removing the oil line which is quite easy to do.

This is the link to my post showing the the block off plate after it is installed.
https://vansairforce.net/community/showpost.php?p=1493386&postcount=19
PhatRV
I don’t mean to give you a hard time. My only reason for posting was that I did not want others to take your advice and end up with a major unexpected oil leak, particularly in flight. There is a reason that Van’s instructions and the Lycoming service instructions exist. To prevent the front plug from being pushed out by oil pressure.

Did your factory tech rep tell you why you should ignore Vans and Lycoming’s instruction?

Is there something different with the IO-360-M1B that allows not removing or poking the back plug?

At minimum the factory rep should tell you why pressure will not build up and push out the front plug. There may be a very good reason but you have not shared what that is. (I hope you are correct)

For what it’s worth I poked the hole on my O-320-D1A and now have over 700 hours on it. If I had to do it again I would have left the oil line in place as PilotjohnS describes.
Steve
 
If you have a new IO-360-M1B engine and want to use it for FP then I recommend you get the Lycoming factory guidance for the conversion.

These are the instructions from the factory tech rep:

" I’ve got a couple illustrations I’ve attached to this email to show the process for pulling off the rear prop governor drive assembly and installing a block-off plate. You would remove the four gray-painted nuts (one of them is circled in green), and pull the drive assembly straight out. Cover plate p/n 69106 and gasket p/n 69551 would get installed over the hole and secured using the plain washers and nuts you removed, replacing the 4 used lock washers with new lockwashers p/n STD-475. The nuts will get torqued to 17 ft-lbs.

On the front of the engine, you can either put an AN cap on the elbow (something like an AN929-6), or remove the elbow and put an STD-783 allen plug into the case, using a little bit of Loctite 564 on the first 3 threads.
" (The elbow remains after the oil line is removed)

The drawing shows the picture of the block off plate that is installed after the governor is pulled out. This also necessitate removing the oil line which is quite easy to do.

This is the link to my post showing the the block off plate after it is installed.
https://vansairforce.net/community/showpost.php?p=1493386&postcount=19

Ya you need to quiz Lycoming a little more on this. That picture I posted was directly from Lycoming Service Instruction 1435. (which applies to all direct drive engines) The oil has to go somewhere, certainly don't want it to go out the front plug...

Personally I would have followed what John S recommended (which has also been recommended in the past by well respected engine builders). Also worth noting that his recommendation came from Lycoming too as mentioned in his last post.
 
I called Tyler at the Lycoming and he confirmed that by removing the oil line from the rear governor drive and plug the forward crank oil port, there won't be any oil coming from the rear governor to pressurize the forward hollow crank area. This case is only applicable for the rear-mounted governor like the IO360-M1B. The Lycoming engine that has the forward mounted governor works differently so the description I posted doesn't work for that type of configuration. I think the forward mount governor always pump oil into the hollow crank and thus, a relief hole must be punched out to prevent oil pressure build up in this area (just guessing from studying documentations of different IO360 engine types for the last month)
 
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