How do I mount the prop??

ao.frog · #1 06-03-2008, 03:16 PM

Hi.

I'm about to mount the prop and have searched the forum to find out how to mount the prop on the correct studs, but haven't found anything that makes sense..

On the pic below, you'll see that the "wheel" with all the tooths for the starter, have a "0" engraved.
The engine flange however, has nothing??

If I understand things correctly, it's very important to mount the prop correctly?

Can anyone tell me how or where I can find info for mounting the prop?

The engine has not been turned yet, (It's treated with "3-year storage oil" from the factory)

Engine: EXTREEM IO-360-B1AD2 w/ dual P-mags & Roller Lifters
Prop: MTV-15-B/183-402 PROPELLER, MT with a P470-1-A spinner.

Thanks!

Rivethead · #2 06-03-2008, 03:50 PM

The way I understand prop mounting to be is this. As the #1 piston is coming up to the top of its compression stroke the prop should be at about the 11 0'clock position and being pulled down to about the 9 O'clock position as it reaches TDC and ignition. This allows you to have good leverage, good balance, your hands leaving the arc of the blade and the ability to naturally step back and away from the spinning prop as the engine starts. It seems that proper mounting takes into account no electrical system or in our cases a worse case senario.

szicree · #3 06-03-2008, 04:00 PM

As far as I know, one of the bosses on the crank flange is slightly oversized so that the ring gear only installs one way. As for the prop, I've read lots of theories on the "best" position.

az_gila · #4 06-03-2008, 06:49 PM

Quote:

Originally Posted by szicree

As far as I know, one of the bosses on the crank flange is slightly oversized so that the ring gear only installs one way. As for the prop, I've read lots of theories on the "best" position.

The flywheel has one hole (the one with the "O") that is larger than the others. One of the drive lugs on the crackshaft is also oversize.

The flywheel will only fit on in one location... which makes sense since the timing marks are on the flywheel...

The prop location is usually set by the manufacturer... on my Tiger it is 1-7 o'clock with the engine at TDC, when standing in front and looking aft at the engine.

Some more details here..

http://www.lycoming.textron.com/supp...ions/index.jsp

The oversize drive lug is only 0.030 larger than the others, and the part of the bushing that protrudes from the flywheel is the same diameter as the other five bushings.

gil A

PS .. don't ask a youngster what direction 1 o'clock is... they only speak digital....

mannanj · #5 06-03-2008, 07:16 PM

Alf:

On the bottom right side of your first picture there is a small hole drilled into a flat spot on your starter housing that has been "faced off". That hole can be used to time the engine. It will allign with marks on the starter ring gear as you swing the engine into BTDC "Before Top Dead Center" and TC or TDC "Top Dead Center.

Comes in handy when timing the mags. Hope this helps.

Steve · #6 06-04-2008, 07:12 AM

The flywheel / ring gear has 2 sets of timing marks. The marks on the back side are are for use when using the engine case seam as the timing reference. The front timing marks are used when using a .100 pin (approx) slipped into the alignment hole in the starter housing.
Either way, as said above, with #1 piston at 25 deg BTDC install the prop pointing at 8 o'clock and 2 o'clock (/). That way, the engine will shut down with the prop oriented in the 10-4 (\) position.

Steve

Tom Martin · #7 06-04-2008, 08:37 AM

This information will be in the manual that comes with the prop.

Bill Dicus · #8 06-04-2008, 12:33 PM

Several posters have noted the prop can only be installed one way. Strictly speaking this is correct but a persistent person can force it on at least partially when indexed incorrectly. This happened to a friend who bought an RV-8 with a Whirlwind (I think) prop from Steve Raddatz. An airport precautionary landing was made for some prop misbehavior, the prop removed and sent off for repair. It is remounted incorrectly indexed and forced into place, then torqed down by an A and P. The prop obviously was not functioning properly and the repair was costly and time consuming. PM me if you'd like to talk to the then owner. Bill

szicree · #9 06-04-2008, 03:44 PM

Actually I think all posts have said that the ring gear can only be installed one way; the prop has six options -- twelve if you put it on backwards

Larco · #10 06-04-2008, 04:17 PM

It has been established that the flywheel can go only one way if care is taken to find the larger dowel. So the C/S has 6 holes, 2 are not recessed and 4 are where they fit over the alignment dowels. It can go on two ways both are correct because they are 180 degrees apart. Give us a report on the Advanced Flight Systems EFIS after you fly. Larry