CONVERTING LYCOMING -320
Richard Bibb
from low compression (150hp) to high compression (160hp).
My understanding is that *all* that is required is to change the pistons,
but I suspect there are a few caveats to go along with it.
This is for an RV-4 project and I would like to know the pros and cons of this
before I tear into a perfectly good engine.
I know this will make it a non-certified engine but that doesn't bother me as I
will have an uncertified prop and uncertified airplane to go with it.
Thanks,
Richard
--
Richard Bibb
Cisco Systems, Inc.
703-715-4031
FAX: 703-715-4044
Harry Bawcom
As I understand it, the E2D has the O-235 configuration for the front main bearing.
This bearing surface has the same area as the mainbearing on a 160 hp engine but is
in two sections. This configuration was never certified at 160hp. No reason why it
won't work but the engine must then be experimental. The only change is pistons.
My conversion was done during a major overhaul by a certified shop.
No problems have resulted from the change. 200 hours SMOH.
Steven Jensen
>Does anyone have experience/advise in converting a Lycoming O-320-E2D
>from low compression (150hp) to high compression (160hp).
>
>My understanding is that *all* that is required is to change the pistons,
>but I suspect there are a few caveats to go along with it.
>
>This is for an RV-4 project and I would like to know the pros and cons of this
>before I tear into a perfectly good engine.
>
>I know this will make it a non-certified engine but that doesn't bother me as I
>will have an uncertified prop and uncertified airplane to go with it.
>
>Thanks,
>
>Richard
>
>
I've got an 0-320-E2D in my RV-3, 150 hp. I don't know how to change to 160hp, BUT:
If you do, you must burn 100LL instead of 80/87. 100LL has four times as much
lead in it as 80/87, and this tends to accumulate on plugs, and valves. My
friends with 160hp RV-4's really envy my clean plugs - I have had to clean them
just once in 300 hours of operation, whereas the 160hp RV-4's must clean plugs
every 20-30 hours or so. What is happening to their valves during that time? And
other parts of the compression chamber? Don't know. 150 horses gets me up and go -
100LL sounds like a pain in the bedoddy ...
Rod Farlee
Petersen STCs are available for them to burn 93 octane premium unleaded
autogas in many certified airframes (the STC isn't needed for an Experimental).
It would be good to bring the engine up to current ADs (metal carb float and
hardened exhaust valve seats are the relevant ones for burning unleaded
autogas).
--
Rod Farlee, r...@sadtler.com, (215) 382-7800
Bio-Rad, Sadtler Div., 3316 Spring Garden St., Philadelphia PA 19104
Kerry Kurasaki
>One writer comments that 160 hp Lycoming O-320's must burn 100LL. Not so.
>Petersen STCs are available for them to burn 93 octane premium unleaded
>autogas in many certified airframes (the STC isn't needed for an Experimental).
>It would be good to bring the engine up to current ADs (metal carb float and
>hardened exhaust valve seats are the relevant ones for burning unleaded
>autogas).
>
And I guess if you *really* want to experiment, one could always play
with water injection. My *guess* is for that size engine, the extra weight
would cost more than the extra HP generated.
Mike Best
>Does anyone have experience/advise in converting a Lycoming O-320-E2D
>from low compression (150hp) to high compression (160hp).
>
>My understanding is that *all* that is required is to change the pistons,
>but I suspect there are a few caveats to go along with it.
Hmm, I'm away from my log book but I'll try. I've done this and have an
(untested) O-320 engine hanging on the back of my hangar queen. I believe
that the O-320-E2A conversion makes the resultant powerplant an O-320-D2A
(again, relying on memory). I don't recall that I did anything extraordinary
during the rebuild of this engine (with supervision mind you) than to use
the larger displacement pistons. I did some unrelated things like chrome
the cylinders and balance the reciprocating parts but that's it.
Oh, you will want to make sure that you don't install spark plugs that are
so deep that the piston bangs into them!
>This is for an RV-4 project and I would like to know the pros and cons of this
>before I tear into a perfectly good engine.
Gosh, I haven't even run my engine yet so I don't have either a pro or a con!
>I know this will make it a non-certified engine but that doesn't bother me as I
>will have an uncertified prop and uncertified airplane to go with it.
Right, that why we call'em experimental (gulp).
Mike Best
Mike Best
>As I understand it, the E2D has the O-235 configuration for the front main
>bearing. This bearing surface has the same area as the mainbearing on a
>160 hp engine but is in two sections. This configuration was never certified
>mental. The only change is pistons. My conversion was done during a major
>overhaul by a certified shop.
Harry's right, I recall that the Lycoming technical support (Bob Walters)
stated this to me. I have been using Harry as my pioneer while I pretend
that I'll fly my Long along his one day :)
>No problems have resulted from the change. 200 hours SMOH.
Geez Harry, ya don't have to rub it in!
Mike Best
Doug Bloomberg
Just use the higher compression pistons. What does it get you. RV-6
flyers flying side by side cross country. the 160HP burned 1 gal less
an hour. Same prop, same airframe. Better effieceintcy in the 160hp
engine.
Doug Bloomberg
RV-6
Charles A. Smith
> the 160HP burned 1 gal less (per hour than the 150 hp O-320)
> Same prop, same airframe. Better efficiency in the 160hp engine.
There's two sides to this argument, of course. If you figure fuel
cost-efficiency, and compare mogas to 100LL, then the answer comes out
differently. For example:
150 hp burning mogas ==> 8 gal/hr @ $1.20/gal = $9.60 per hr
160 hp burning 100LL ==> 7 gal/hr @ $2.20/gal = $15.40 per hr
So, you pays your money and you makes your choice. Now what we really
need is a mogas burning 180 hp Lyc. What's the status on that? Can it
be done without some special water injection system?
--
Cap Smith Assistant Prof. of MIS
c...@selway.umt.edu University of Montana
Richard Bibb
>In article <28cf78$4...@highlander.solbourne.com>, do...@solbourne.com (Doug Bloomberg) writes:
>> the 160HP burned 1 gal less (per hour than the 150 hp O-320)
>> Same prop, same airframe. Better efficiency in the 160hp engine.
>
>There's two sides to this argument, of course. If you figure fuel
>cost-efficiency, and compare mogas to 100LL, then the answer comes out
>differently. For example:
> 150 hp burning mogas ==> 8 gal/hr @ $1.20/gal = $9.60 per hr
> 160 hp burning 100LL ==> 7 gal/hr @ $2.20/gal = $15.40 per hr
>
is whether the fuel system can handle it without vapor-lock problems.
Sure super-unleaded mogas costs 10-20 cents more than regular but you should
still come out ahead. And who says you have to open the throttle all the way
anyhow. Based on all the psots I'll probably make the conversion but probably
more because I now own a 150hp engine and want a 160hp engine and not for all
the other, quite valid, reasons given.
Glad I generated some useful discussion.
Orval R. Fairbairn
I believe that Peterson Aviation has an STC for mogas in the 180 hp
O-360 Lyc. This engine, like the 160 hp O-320, was originally
certificated fo Grade 91/96 fuel.
Check with them.
Peterson Aviation
Rt 1
Minden, NE 68959
(308) 832-2200
--
Orval R. Fairbairn Mtn View, CA (415) 969-4351 (h) (408) 756-1473 (ofc) ..
1946 Johnson Rocket 185 NC 90204 | .___. . .
EAA 25947 (life), Board of Directors: | . |___||> . . :
CA Pilots' Assn, CRAMP <: . . -----: