PE-90 o520 conversion

Aircraft powered airboat discussion.
Post Reply
User avatar
skatercat68
Southern Airboat Member
Posts: 37
Joined: Thu Dec 19, 2013 12:09 pm

PE-90 o520 conversion

Post by skatercat68 »

i have started my tear down an i was wondering if i went with the lycoming 180 connecting rods and the standard 520 pistons would that be to much compression? would i have to use avgas or would pump gas 93oct of course be enough
14ft alumitech o-360 and sensenich 70" Q'
signcoc43
Southern Airboat Member
Posts: 350
Joined: Mon Dec 14, 2009 7:44 pm
Location: keystone heights fl

Re: PE-90 o520 conversion

Post by signcoc43 »

I got 10:1 and lyco rods. Im just having a hard time finding a starter that will stay together . Only avgas I was in a pinch and ran half n half boat ran like shizz. If I can't get av I don't go ride jmo
12 foot hamant fuel injected pe-90 520 conversion swinging a 68" ngq!!
" Yes my boat is slow!!!"
User avatar
AntiqueFarmEquipment
Southern Airboat Member
Posts: 171
Joined: Wed Apr 15, 2009 4:46 pm
Location: Palm Bay

Re: PE-90 o520 conversion

Post by AntiqueFarmEquipment »

I've got standard 520 cylinders with lycoming rods on my 6 cylinder conversion. Avgas only. As for compression my starter has a little trouble initially on a cold start but it gets it done!
12'6 x 7'6" Diamondback PE-150/520 Conversion
AFE
User avatar
skatercat68
Southern Airboat Member
Posts: 37
Joined: Thu Dec 19, 2013 12:09 pm

Re: PE-90 o520 conversion

Post by skatercat68 »

i was thinking of using the standard 8.5x1 piston and rods and decking the case .080.

does anyone know the standard throw on the pe90 crank? is the throw the same as the io520, i don't wanna lose compression if it is a shorter throw! keep in mind im not building a race boat, just a strong 4cyl
14ft alumitech o-360 and sensenich 70" Q'
User avatar
JT540
Site Supporter - V
Site Supporter - V
Posts: 1506
Joined: Mon Jun 18, 2007 8:12 pm
Location: mt dora fl

Re: PE-90 o520 conversion

Post by JT540 »

your gonna build too much compression. do one or the other not both! either deck the case 90 thousandth or run Lycoming rods and cut the pistons! if you do both the motor wont live long. and you will have to cut the hell out of the pistons to fit up in the cylinders. try to find round top pistons instead of the flat top so you don't have to machine the top edge as much.
"THE MORE I LEARN ABOUT WOMEN THE MORE I LOVE MY AIRBOAT"
Outlawaircraftengines
Site Supporter - I
Site Supporter - I
Posts: 1019
Joined: Mon Sep 04, 2006 9:49 pm
Location: Plant City
Contact:

Re: PE-90 o520 conversion

Post by Outlawaircraftengines »

I have a set of 6 that I removed that are cut. They had the case decked with lycoming rods.
Gary Barber
Outlaw Aircraft Engines
www.outlawaircraftengines.com
863-698-0383
User avatar
Bruce
Site Supporter - IV
Site Supporter - IV
Posts: 4793
Joined: Tue Feb 27, 2007 9:43 pm
Location: orange county fl
Contact:

Re: PE-90 o520 conversion

Post by Bruce »

deck the case .85 thousandths and itll run on pumpgas will run better on av thats how my gpu 520 is built now
12 foot Mamba "The Underdog"
Tired Gpu 520,Whirlwind Razor X
User avatar
skatercat68
Southern Airboat Member
Posts: 37
Joined: Thu Dec 19, 2013 12:09 pm

Re: PE-90 o520 conversion

Post by skatercat68 »

So leave the continental rods and standart compression pistons for the 520 and Deck the case .080 or .085 is the consensus?

What kind of compression "should" that give me?
14ft alumitech o-360 and sensenich 70" Q'
User avatar
airboatchris
Southern Airboat Member
Posts: 80
Joined: Sun Jan 09, 2011 7:50 pm

Re: PE-90 o520 conversion

Post by airboatchris »

I have done it both ways. I like decking the case better especially if you are doing a cam grind easier to get the overhead right. decking the case will change your push rod length (longer)
Tiara 285A on a 14ft lazer
User avatar
skatercat68
Southern Airboat Member
Posts: 37
Joined: Thu Dec 19, 2013 12:09 pm

Re: PE-90 o520 conversion

Post by skatercat68 »

I just sent the cam to aircraft specialties to be refinished. The crank looked pretty good. Still wanna have it put on a good micrometer to be sure.
14ft alumitech o-360 and sensenich 70" Q'
boobidges
Southern Airboat Member
Posts: 495
Joined: Sat Sep 29, 2007 5:06 pm

Re: PE-90 o520 conversion

Post by boobidges »

Angle valve 0520 cylinders, fuel injected pistons, h290 grind on cam, case decked .125. Starts fine, runs awesome. Only avgas. Don Davis told me I was around 9.5-1.had to shave the skirts on the pistons, and cut clearance in cylinder skirts .also had to shorten the pushrods.
Post Reply

Return to “Aircraft Power Only”