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Lycoming Crank Nose Plugs?

jsharkey

jsharkey

Well Known Member
I have a new YO-360-A1A experimental bought through Van's.
It has an updraft carb and a fixed pitch prop.

Do I need to do anything with the the plugs in the nose of the crank or is it good to go as received. It came with a Lycoming Service Bulletin covering the steps needed to switch from FP to CS and vice versa.

It has a blanked off rear governor mount and the oil pipe running forward from that to the front crank bearing. The plug at the tip of the crank is intact and I have no way of knowing the state of the next plug back unless I remove the foremost one which I am reluctant to do if I don't have to.

I had assumed that the engine is shipped in one state or the other, i.e. FP or CS and that you only have to take action to change from one to the other - but I have a niggling doubt that this might not be the case.

What can go wrong if I don't get this right?

Jim Sharkey
RV6 - Almost there!
 
Trust but Verify!

If the supplier states that it is indeed set up for F/P and you trust them, then you should be OK.
Personally I would pull the front plug and verify that the rear plug is either gone of punctured. It is very cheap to replace the front plug for peace of mind. Most I have seen come with both plugs intact. If you run with both plugs intact, you can expect to blow the front seal in about 70-80 hours. I have also seen this happen more than once.
My motto is trust but verify!
BTW, most C/S engines are shipped with both plugs installed to minimize leakage during shipping.
 
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Since the oil tube...

Mel said:
If the supplier states that it is indeed set up for F/P and you trust them, then you should be OK.
Personally I would pull the front plug and verify that the rear plug is either gone of punctured. It is very cheap to replace the front plug for peace of mind. I have seen many that came with both plugs intact. If you run with both plugs intact, you can expect to blow the front seal in about 70-80 hours. I have also seen this happen more than once.
My motto is trust but verify!
BTW, most C/S engines are shipped with both plugs installed to minimize leakage during shipping.
Click to expand...


...from the blanking plate to the front port is installed, could the crank plugs be set up for CS operation, but be OK for FP operation due to the bypass channels in the rear governor blanking plate?

I thought that the "true" FP engines were shipped without the oil pipe even installed.

Check with your supplier, you should be good to go for FP, and an easy switch to CS in the future by adding the prop and a governor - in effect, the best of both worlds....:)

UPDATE - more details within this previous posting....

http://www.vansairforce.com/community/showthread.php?t=31233&highlight=cover+plate

Don't punch any plugs if you don't have to...:)
 
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Thanks for the quick replies - but some more ???.

Any way to tell if the governor blanking plate has the bypass slot without removing it? e.g. part marking

How do you remove the front plug without causing damage?

Where can I get a new front plug? - update $4.50 from Van's

How do you successfully replace the front plug? Tapping it in using a big socket as a drift comes to mind.

How difficult is it to replace the rear plug if it is pierced and you want to revert to CS?

Jim Sharkey
 
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Removing is easy, I got the method I used from Brantel on these forums. Put the ball end of a ball peen hammer on the plug. Give it a good rap with another hammer. Put a magnet on it and pull it out. I admit I was very skeptical, but it worked like a charm!
 
az_gila said:
...from the blanking plate to the front port is installed, could the crank plugs be set up for CS operation, but be OK for FP operation due to the bypass channels in the rear governor blanking plate?

I thought that the "true" FP engines were shipped without the oil pipe even installed.

Check with your supplier, you should be good to go for FP, and an easy switch to CS in the future by adding the prop and a governor - in effect, the best of both worlds....:)

UPDATE - more details within this previous posting....

http://www.vansairforce.com/community/showthread.php?t=31233&highlight=cover+plate

Don't punch any plugs if you don't have to...:)
Click to expand...

My engine was bought from Van's. Their web page says that all of the engines bought through them come set up for CS and that the rear plug needs to be punched for FP. Unless, I guess, the governor blanking plate has the bypass slot - but that might be a **** shoot. The front plug has to be removed for CS anyway and is in place for sealing during shipping. It looks like Van's/Lycoming expect the front plug to be removed regardless of FP or CS. For FP the aft plug is pierced and a new front plug installed.

It's starting to make sense:)

Jim Sharkey
 
Thanks

Chappyd said:
Removing is easy, I got the method I used from Brantel on these forums. Put the ball end of a ball peen hammer on the plug. Give it a good rap with another hammer. Put a magnet on it and pull it out. I admit I was very skeptical, but it worked like a charm!
Click to expand...

I just ordered a new front plug from Van's.

How did you instal the new one?

Jim Sharkey
 
Part numbers and pictures...

jsharkey said:
Any way to tell if the governor blanking plate has the bypass slot without removing it? e.g. part marking

.......

How difficult is it to replace the rear plug if it is pierced and you want to revert to CS?

.....
Jim Sharkey
Click to expand...

...are in the long VAF thread I referenced previously....:)

http://www.vansairforce.com/community/showthread.php?t=31233&highlight=cover+plate

It's easy to identify the blanking plates with slots.

I would call Lycoming before you do any unnecessary work.

If you go to CS in the future and have to remove a pierced rear plug and replace it, it's a lot more difficult than working on the front one.
 
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Thanks again...

az_gila said:
...are in the long VAF thread I referenced previously....:)

http://www.vansairforce.com/community/showthread.php?t=31233&highlight=cover+plate

It's easy to identify the blanking plates with slots.

I would call Lycoming before you do any unnecessary work.

If you go to CS in the future and have to remove a pierced rear plug and replace it, it's a lot more difficult than working on the front one.
Click to expand...

I didn't read the earlier thread all the way to the end or down load the pictures. Now I know what to look for.

A quick fumble and feel should give me what I need - after all what else are Sunday mornings for:)

Jim Sharkey
 
Reply from Lycoming

This is what Lycoming said. (Paraphrasing)

The engine with slotted governor blanking plate and CS oil line in place can be operated safely with a FP prop and the rear crank plug intact. (Not sure about a flat blanking plate and no CS oil line.)

The main reason for piercing or even better removing the rear plug is to allow easier oil circulation through the bore in the nose of the crank and therefore avoid the build up of corrosion causing contaminants that will eventually cause pitting and weakening of the shaft over time.

If you do leave the rear plug intact for eventual conversion to CS they recommend that the front plug be removed at every annual and the cavity bore cleaned and inspected for corrosion.

Jim Sharkey
 
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But if the front plug goes you lose oil pressure and oil right now. New engine 80 lbs. per inch square pretty much minimum. I think I'd be checking mine replacing is similar to removing except you stop before it becomes loose. Can be done with a large Ball Peen hammer and a brass rod. Bang Bang Bang you're done.
 
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Rivethead said:
But if the front plug goes you loose oil pressure and oil right now. New engine 80 lbs. per inch square pretty much minimum. I think I'd be checking mine replacing is similar to removing except you stop before it becomes loose. Can be done with a Ball Peen hammer and a brass rod. Bang Bang Bang you're done.
Click to expand...

What they were saying is that with the newer governor blanking plate and the CS oil line in place there is no pressure build up on the front plug so it won't let go - at least not because of engine pump level oil pressure. In this case the real reason for piercing or removing the aft plug is to get more oil flowing through the bore in the front of the crank. This will mitigate the build up of corrosive contaminants over time and therefore the potential for pitting and eventual weakening of the crank.

With the CS oil pipe removed and/or the older flat governor blanking plate installed oil at pump pressure will fill the cavity between the fore and aft crank plugs via the #1 main bearing journal and the cross tube. The only way for it to escape in this case, unless the aft plug is pierced or removed is by bleeding out of the bearing. This is very slow and maintains back pressure.

Regardless the recommendation is to pierce or remove the aft plug - but in the case of the newer design it is not to prevent the front plug from letting go.

Jim Sharkey
 
wv4i said:
Do NOT poke a hole in or remove the rear plug, whether going CS or FP. If you do, I believe the case has to be split to reinstall it.
Click to expand...

This is not true. But you will need to remove the prop to remove or install the plugs.
 
jsharkey said:
What they were saying is that with the newer governor blanking plate and the CS oil line in place there is no pressure build up on the front plug so it won't let go - at least not because of engine pump level oil pressure. In this case the real reason for piercing or removing the aft plug is to get more oil flowing through the bore in the front of the crank. This will mitigate the build up of corrosive contaminants over time and therefore the potential for pitting and eventual weakening of the crank.

With the CS oil pipe removed and/or the older flat governor blanking plate installed oil at pump pressure will fill the cavity between the fore and aft crank plugs via the #1 main bearing journal and the cross tube. The only way for it to escape in this case, unless the aft plug is pierced or removed is by bleeding out of the bearing. This is very slow and maintains back pressure.

Regardless the recommendation is to pierce or remove the aft plug - but in the case of the newer design it is not to prevent the front plug from letting go.

Jim Sharkey
Click to expand...

Oh I get it now. I'm just a little slow. There are some of those rear plugs out there that have been drilled and tapped for a set screw. When you want to go constant speed you just reach in with an allen wrench and replace the screw.
 
Crankshaft rear plug with removable drain or set screw

Rivethead said:
Oh I get it now. I'm just a little slow. There are some of those rear plugs out there that have been drilled and tapped for a set screw. When you want to go constant speed you just reach in with an Allen wrench and replace the screw.
Click to expand...

Jim (or anyone else),
I have never heard of a rear plug with a removable set screw before. Please tell me more about it. Is this a part available from Lycoming or ECI? If so, how about a part number? Is this an aftermarket part? Is it something that certain engine overhaul shops do? Any photos of this?
It sounds like a nice idea.
Charlie Kuss
 
chaskuss said:
Jim (or anyone else),
I have never heard of a rear plug with a removable set screw before. Please tell me more about it. Is this a part available from Lycoming or ECI? If so, how about a part number? Is this an aftermarket part? Is it something that certain engine overhaul shops do? Any photos of this?
It sounds like a nice idea.
Charlie Kuss
Click to expand...

It might be called out on SI 1435 on the Lycoming web site

http://www.lycoming.textron.com/support/publications/service-instructions/index.html
 
Rear Crankshaft plug with removable pipe plug in it

jsharkey said:
It might be called out on SI 1435 on the Lycoming web site

http://www.lycoming.textron.com/support/publications/service-instructions/index.html
Click to expand...

Jim
Thanks for the reference. It's referred to as an 1102 pipe plug. It appears that some crankshafts come from the factory with it. The down side appears to be that if the plug gets damaged, you have to send the crankshaft back to the factory for repair. :eek:
I've read SI 1435 before. I just never paid close attention to that difference.
Charlie Kuss
 
Angle valve 360 engines have the removable small plug style rear plug, and parallel valve 360 engines have the rear plug without the removable plug. The plugs are not interchangeable because the ID of the crank nose bores is different between angle valve crankshaft and parallel valve crankshafts.
Good Luck,
Mahlon
?The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
 
mahlon_r said:
Angle valve 360 engines have the removable small plug style rear plug, and parallel valve 360 engines have the rear plug without the removable plug. The plugs are not interchangeable because the ID of the crank nose bores is different between angle valve crankshaft and parallel valve crankshafts.
Good Luck,
Mahlon
“The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
Click to expand...

Mahlon,
I have an Angle valve (IO-360-A1A) I'm trying to convert to CS. My engine doesn't have the rear plug at all and I can't find a part #. Does Lyc make a rear plug that can be installed from the front like the rear plugs for the parallel valve engines or am I toast? You are right about the ID, mine is 1/2 smaller than the rear plug I bought from Vans.
Help.....


FP08072010A00003.jpg
 
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Update

I got my answer from the Lycoming tech rep, but I thought I would post it here for historical purposes.
Per Lycoming although it defies logic why someone would remove the rear plug assembly on an angle valve (plug w/a pipe plug in the center) they are installed from the front with a special tool and some care-that's how they do it at the factory. That means I don't have to split my cases! I ordered the plugs today (inner and outer rear) using the part numbers supplied by Lyc then I'll fab a tool that'll go inside that smaller crank ID. Wish me luck, but I think I adverted another constant speed conversion crisis.

This used engine is giving me an ulcer. I saved some money in exchange for some headaches...
 
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