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Converting engine FIxed Pitch to constant speed

WAM120RV

Well Known Member
I am in the middle of converting my RV4 from FP to CS and am posting this to correct some misinformation that has been given out when doing this. One of the things you will need to install on your engine is a prop governor drive.

For an engine like an 0-320 E2A which can be converted but does not normally have a drive it’s hard to establish which drive will fit this engine. Several people advised me any drive from a 320 or 360 will work. It was explained that all that differs is the unions coming out of them.

This is not correct!

Drives are built differently, some have a spacer at the drive gear end some don’t. The addition of the spacer means that the drive gear sits just over an 1/8 lower into the accessory housing than the one that doesn’t. So, with my engine one drive was perfect but the type with the spacer meant that the gear was only engaging with the mag drive gear by about 1/16”.

Ok it would work for a bit but how long before it caused premature wear.

The part numbers of the two drives are almost identical 75150 PF, and 75150 F PF.

It’s too hard to post photos on here but I will post on the Vans Aircraft Owners & Builders Facebook page.
 
Do you have clearance on your firewall for a prop governor? Stock firewall does not. Vans sells a kit to modify your firewall to make room for the governor. It consists of a one page instruction sheet, and a piece of stainless steel, and costs about $6 US. You will need to remove your engine to make this modification. If you need this kit, and can locate your own piece of 7” X 14” 26 gage SS, I can take a pic of the instruction sheet and email it to you, since you’re in England. I decided not to do this on my RV4, but did buy the kit.
 
Parts for the conversion from fixed pitch

This might help. Here is what a guy will need to convert his rear governor 320 or 360 parallel valve Titan engine to constant speed. Note that Lycoming SI 1435 has the instructions for doing this. Other manufacturers equivalent part numbers will work too.

AEL68317 gear
AEL75153 housing - studded
AEL71596 washer
MS16624-2087 ring
AEL74070 elbow- to the adapter
MS20822-6 elbow - to the crankcase
AEL75167 tube
AELSTD1930 hose – prop governor line support
AEL75165 clip
AEL68315 gasket
AEL72053 gasket
The rear crankshaft plug part # for the 320 and 360 engines is Lycoming® part # 61510 which is solid.

I know of no difference between the 320 and 360 so don't have any information on the spacer issue that you are experiancing.
 
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