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o-320 to io-320 Conversion

jerry98b

Well Known Member
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So my local tech advisor said that all jugs have the ports for the fuel injectors, but I'm pretty sure my o-320-e2a doesn't. If my jugs don't, I'm fairly sure that you can't just drill and add them so I'd be looking at all new jugs and might as well convert the 150hp to 160hp.

So my question is. Do I need to start shopping for new jugs?engine.jpg
 
You could look into going with an EFI system like SDS or Fly EfII that can have the injectors boss welded onto the intake runners. This would require fuel system and electrical rework.
 
You don’t have the ports milled into the head in the location to left of your pushrod tube. A cylinder shop could do that. Jugs are hard to come by these days and can run 1500-2000 dollars each if you can find them. Going to the SDS system may be an easier option. Removing jugs and re-breaking in your cylinders is a lot of work.
 
Anyone ever try using the primer ports for injectors?
One problem, losing the MP line pickup if this is a CS prop...
 
My engine started life as an O-320. I had it overhauled and converted it to an IO-320. One of the cylinders needed to have the modification to add the injector port. It was done by the cylinder shop.
 
Anyone ever try using the primer ports for injectors?
One problem, losing the MP line pickup if this is a CS prop...
Manifold pressure can come from a tapped hole in the servo downstream of the butterfly. Eliminates need for pulse damping orfices etc. Don at AFP approved this for my Model 150 injector install.
 
How hard could it be to drill and tap the cylinders in place.
It's aluminium and is easy to drill.
Remove the intake pipes before drilling.
Use a vacuum cleaner and grease.
You have to take messurement from a cylinder that allready have the holes
drilled.

Good luck
 
Last edited:
How hard could it be to drill and tap the cylinders in place.
It's aluminium and is easy to drill.
Remove the intake pipes before drilling.
Use a vacuum cleaner and grease.
You have to take messurement from a cylinder that allready have the holes
drilled.

Good luck
It’s hard and it’s at a weird angle. This is why god made man build jigs for this kind of stuff. You’re are just asking for trouble. It’s 1/8 MPT threaded hole you get one shot at tapping it straight and making sure the threads are not buggered up. If you mess it up, you’re taking the cylinder off and spending 2-3 weeks with a downed plane and probably going to spend 750 dollars getting your cylinder repaired. Not too many places around weld on cylinders anymore. Gibson maybe? Ly-Con
 
Anyone ever try using the primer ports for injectors?
One problem, losing the MP line pickup if this is a CS prop...
I have used the primer ports on my older cylinders with success.
Welded a bung on the intake tube for the MP line.
Required going thru the baffling but has not been an issue.
 
I'm also needing to locate fuel injection parts for my conversion.

I have the servo unit, but looks like I need distributor (manifold valve), injectors, lines and a mechanical (engine driven) fuel pump? I guess I need to make a WTB listing in the classifieds section.
 
I'm also needing to locate fuel injection parts for my conversion.

I have the servo unit, but looks like I need distributor (manifold valve), injectors, lines and a mechanical (engine driven) fuel pump? I guess I need to make a WTB listing in the classifieds section.
I got my distributor / spider off of eBay and sent it to Don at Airflow Performance for rebuild. I seem to recall that you can use one designed for 6 cylinder engines and just plug unused ports.

Lines and injectors, I purchased new from Don.

Fuel pump - the usual suspects - Spruce, AirPower, etc.
 
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