O-320 E2d

I was looking at the Preview plans to determine what this is and it seems to be a 150 HP, fixed pitch crank, dynafocal mount O-320.

The plans mention that the front main bearing is the same as an O-235, though.

Is this a worry in general or is it not something to be concerned with?

Any experience with this particular engine, i.e. any specific care and feeding concerns?

Thanks for any info.

-Mike

I had this engine in my RV6, originally as 150 HP. I bought it mid-time and at OH changed pistons to higher compression for 160 HP. At the same time, I changed from a FP prop to a CS. In my case, the crank was hollow so I was able to make the appropriate changes.
The OH parts were readily available.
This was a great engine for the RV6.
(I also did an OH on an O 235 in my old Grumman TR2 and the parts were pretty expensive. They told me O 235 parts cost more because not as many engines were produced and they used parts specific to that engine. Don't know if that's true or not.)

vanlle2000 said:

Only drawbacks are sllightly higher fuel consumption (low compression) and inability to run a c/s prop.

Click to expand...

I'm thinking the lower compression is a benefit as you can run regular unleaded (87 octane) in the thing.

(Funny there isn't an auto fuel vs. 100LL forum.)

I ran a lot of mogas through mine when it was in the 150 HP mode. It worked fine but you need to run some 100LL in it too, for the lead. The lead will help lubricate the valve guides and seat the valves. I also found that running a mixture of about 10-20% 100LL in with the mogas helped keep vapor lock away. You will find that this can be a problem on warm days in late winter if the mogas is winterblend. (Bad combination.)
I also ran some mogas in the 160 HP version but you have to move up to the highest octane available for the higher compression pistons. I had similar results as before but eventually used 100LL exclusively.

I had an O-320-E2D in my RV-6A in stock form for 400 hrs, until it had around 2500 hrs on it. It then started making metal so I had Aero Sport Power overhaul it to 160hp. Currently running really well. If you can find a good one buy it.

In 150hp form the plugs fouled badly using 100LL - running on mogas apparently prevents this.

Pete

mlw450802 said:

The plans mention that the front main bearing is the same as an O-235, though.

Is this a worry in general or is it not something to be concerned with?

Thanks for any info.

-Mike

Click to expand...

This is a cost-saving "feature" of the -E2 series (and maybe other E models). The O-320-A, -B, -C and -D models have two seperate front bearings.

If you are rebuilding the engine, then ECI can machine the crankcase for the two bearing standard. It's service CM21 on this ECI Crankcase Service list...

http://www.eci2fly.com/Price_Lists/svc_cca.pdf

Not sure what the major difference between one and two bearings is, but the -E models are popular, but only rated for 150 HP as delivered.

gil in Tucson

... with a first run out O-320-E2G (ex-Grumman Cheetah) engine in the garage...

Mike,
The O-320-E2D is a great engine. Very proven in the reliability and durability departments. Be careful as most are not equipped to have a engine driven fuel pump. Installing one may make the engine require major modification or you will need to come up with an electric pump setup to replace the engine driven pump.
The bearing setup is strong and easily supports 160 HP operation, so weather you stay 150 HP or increase compression ratio to get 160 the bearings aren't a concern.
This engine although having a hollow crankshaft isn't set up for constant speed operation, so you should know it is for fixed pitch use.
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 you own risk."

Mahlon,
....if I rebuild my O-320-E2G to 160HP - which does have a engine-driven fuel pump - you are saying it's not worth converting the front bearings to a single one.... Just leave them alone???

gil in Tucson

If you are going to stay fixed pitch what would be the reason for the change? If you think the bearings are an issue...that's a none issue to me and I wouldn't pay to get the case converted. If you want to go constant speed one day and have all the other parts necessary to do so then converting the case makes sense.
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 you own risk."

Thanks Mahlon... the penny just dropped...

The gap between the two bearings in the other models is to feed the oil pressure to the CS prop through the hollow crank.

Since all of the -E models have solid cranks and are therefore fixed pitch, the one piece bearing is OK and cheaper....

And I originally thought it was something to do with bearing strength and it was for 1500 HP not 160HP...

gil.... nice to know how things work.... thanks again

I believe that some "E" models were actually shipped with hollow cranks. SB505 seems to show some were and I have seen engines that have never been torn down with hollow cranks.

All of the "e" series 320's had/have hollow cranks but some don't have the transfer tube in the hollow or the main nose bearing set up for constant speed. So some "e" series 320's are for fixed pitch only, even though they have hollow cranks and some are set up for fixed pitch but are constant speed capable.
The e models in the parts book that show 8 main bearings are the ones that are for fixed pitch only. The ones that show 4 main bearings and 2 nose bearings are the ones that could go constant speed from a crank and bearing perspective.
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 you own risk."