Z

zav6a

Well Known Member
Is there any way to tell if the crank is machined for the rear plug and has a transfer tube without pulling the front plug and looking?

O-320 B2A
Serial L1239-39
Narrow Deck
Out of a 58 Tri-Pacer

Has a hollow crank
Plug in case on nose where Governor oil line would go in
Governor pad

Read SI 1435 to no avail.
 
zav6a said:
Is there any way to tell if the crank is machined for the rear plug and has a transfer tube without pulling the front plug and looking?

O-320 B2A
Serial L1239-39
Narrow Deck
Out of a 58 Tri-Pacer

Has a hollow crank
Plug in case on nose where Governor oil line would go in
Governor pad

Read SI 1435 to no avail.
Click to expand...

The 1958 Tri-Pacer was specked out with a fixed pitch prop.

The 0-320 B2A is the same as the 0-320 A1A but set up for fixed pitch prop. The A1A was set up for a constant speed prop so that's why the crank is hollow in the B2A. Unless the engine spent some time on a different airplane since the Tri-Pacer, it is a safe bet the aft plug never was installed. I have a feeling it is a big deal to install it as Lycoming says the crank has to be sent to the factory if the aft plug is damaged.
 
From what I know (which isn't much) if it actually has a front plug in it then it's likely usable or convertible for FP or C/S. I'm not aware of any cranks that Lyc made that had a front plug and no rear plug (although who knows....they only made about a million variations)! So, in the end I'm not 100% sure, but fairly sure that if there is a front plug then there is/could be a rear plug.

The solid cranks are just that - solid, with no plug at all. My B4A had a solid crank in it, so there was no chance in heck that was going to go C/S.

My 2 cents as usual!

Cheers,
Stein
 
Unless someone installed the wrong shaft at some point over the years, The crankshaft that should be in that model is OK for Constant speed. Make sure the crankcase has a pipe plug installed in the nose area of the crankcase where the governor tube attaches and make sure the accessory housing has a machined pad to mount the governor drive to and you should be all set. As long as the pipe plug is present the case is drilled and machined for Cs and of course you need somewhere to mount the governor drive. Some accessory housing are not machined for that. The issue on the rear crankshaft plug is mute. If it is there, it has a hole in it and needs to be replaced and if it isn't there, you need to install one. They are a pain to install but it is done from the front and can be done with the engine assembled.
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."
 
SteinAir said:
From what I know (which isn't much) if it actually has a front plug in it then it's likely usable or convertible for FP or C/S. I'm not aware of any cranks that Lyc made that had a front plug and no rear plug (although who knows....they only made about a million variations)! So, in the end I'm not 100% sure, but fairly sure that if there is a front plug then there is/could be a rear plug.

The solid cranks are just that - solid, with no plug at all. My B4A had a solid crank in it, so there was no chance in heck that was going to go C/S.

My 2 cents as usual!

Cheers,
Stein
Click to expand...

BPE called during my engine build up concerning the aft plug. Was I going with a fixed pitch prop? If so, shall the aft plug be installed and punched or not installed at all?

If one were to go CS later, the punched plug would have to be replaced so what was the point of installing it and putting a hole in it? The plug was not installed. Seems like that would have made sense back in 1958 when the B2A was certified for the Tri-Pacer, but you never know. I get the impression installing the plug is somewhat of a challenge.
 
Plug

Thanks folks.

Just what I needed and hoped. I was spooked by the SI 1435 where they mention that some cranks have neither the transfer tube nor a land machined for placement of a rear plug.

I have enough info to tear it apart and will let you know what I find.
 
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