pe-90 questions

Aircraft powered airboat discussion.
dang
Southern Airboat Member
Posts: 5
Joined: Tue Nov 15, 2016 5:21 pm

pe-90 questions

Postby dang » Thu Apr 06, 2017 12:23 am

I was recently given another pe-90, because it was locked up. I sprayed pb blaster all up everywhere and it is still stuck tight. Was able to loosen the cylinder base nuts, but cant get the cylinders to budge. I used to work on a lot of farm machinery, so I'm no stranger to getting old junk de-stuck, just don't want to break something because of there being a lot more aluminum in this thing. My gut says to balance it on the prop flange end, and fill up the whole case with used filtered auto tranny fluid and engine oil, and let'er sit in the corner for a while, till she learns her lesson. Any reasons that would be a bad idea?

Also, I'm missing the rear accessory case and oil pump. anybody set up one of these with a custom accessory case to run an auto oil pump? The gpu guy can get me an oil pump assembly for $90, so not the end of the world, if not. I'm comfy coming up with a home brew electronic ignition, but have not done a home brew oil pump like that.

Anyone know the difference in weight when the 470 or 520 cylinder swap is done, vs. the stock pe-90 cylinders? stock has plenty of power for what I need but a stock pe-90 is just on the heavy end of workable for my project. Any common tricks to lighten them up?

Thanks in advance.

User avatar
goldhunter_2
Site Supporter - III
Site Supporter - III
Posts: 8933
Joined: Mon May 23, 2005 7:17 pm
Location: Port Saint Lucie Fl

Re: pe-90 questions

Postby goldhunter_2 » Thu Apr 06, 2017 2:01 am

well whats locked up is the real question. most likely it will be one of the piston rings stuck to the old steel cylinder pump grease (works but messy) though custom fitting in the spark plug hole. I use Air pressure with custom sparkplug fitting but you have to be very very careful with the air so no one gets hurt.

weight difference is noticeable or worth worrying about between gpu, 470 and 520 angle valve cylinders

are there tricks to lighten up gpu's when doing conversions , Yes , plenty of them posted in old threads
.


Support our future , get a kid involved in the outdoors!!

:rebel:



.

dang
Southern Airboat Member
Posts: 5
Joined: Tue Nov 15, 2016 5:21 pm

Re: pe-90 questions

Postby dang » Thu Apr 06, 2017 9:41 am

Thanks for the tips, I am going through the aircraft power sub forum, reading everything related to pe-90, gpu 150, 470 or 250 swap.

I knew about the grease trick, but was a little bit chicken. I guess if you stay bellow operating psi, it shouldn't break anything that was worth running.

So far the only actual weight info I can find on a conversion, is 225 lbs. That would be super-d-dooper if that much weight reduction is possible. My pe-90 weighs 244 without a rear cover, oil pump, magneto, exhaust, carb, alternator or starter.

Is there an aircraft carb that is a good fit for a stock pe-90, as well as having enough range to handle a 470 or 520 cylinder conversion?

Thanks, Dan

User avatar
Deano
Site Supporter - V
Site Supporter - V
Posts: 4145
Joined: Thu Jan 06, 2005 11:16 am
Location: Inverness, FL

Re: pe-90 questions

Postby Deano » Thu Apr 06, 2017 12:17 pm

dang wrote: . . . My gut says to balance it on the prop flange end, and fill up the whole case with used filtered auto tranny fluid and engine oil, and let'er sit in the corner for a while, till she learns her lesson. Any reasons that would be a bad idea? . . .

On that note: I used to collect and resurrect old, given up for dead outboard motors which would generally involve soaking the power-head before attempting to 'break things free'. What I found to work best for that purpose was a ratio of about a quart of Marvel Mystery Oil in two gallons of diesel fuel. Don't know how much your case would hold, as to whether that would be feasible or not, but is a safe for aluminum. If you have an abundance of used ATF, you might try diluting that with diesel fuel rather than engine oil as it is less viscous and a better penetrator.

There are other, better methods for say, a cast iron block (such as sulfated molasses) but I believe there would be a good chance of deleterious effects on the aluminum in this case. I've intended to throw some old pistons in as a test the next time I play that game, but that hasn't happened yet.
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
- Carl Sagan

User avatar
John Fenner
Southern Airboat Member
Posts: 2526
Joined: Tue Feb 14, 2012 12:26 pm
Location: Miami(Cuba) Fl.

Re: pe-90 questions

Postby John Fenner » Thu Apr 06, 2017 12:46 pm

Grease gun adapted to spark plug thread, pump them off. But I would first fill crankcase with phosphoric acid to eat a lot of the rust away, cylinders likely junk anyway.
I never finish anyth,,,.


Lwells
Southern Airboat Member
Posts: 235
Joined: Sat Nov 15, 2014 9:18 pm
Location: okeechobee

Re: pe-90 questions

Postby Lwells » Thu Apr 06, 2017 10:33 pm

Anyone ever tried using wd-40?

dang
Southern Airboat Member
Posts: 5
Joined: Tue Nov 15, 2016 5:21 pm

Re: pe-90 questions

Postby dang » Fri Apr 07, 2017 2:44 pm

thanks guys, down here in texas diesel is about $2.20/gal, so will deff. top up with that after throwing whatever atf I have in. Getting ready to pull the th350 in my chevy 6.2 diesel truck to swap in a 700r4, and will filter whatever drains out of the th350 to start with. Fun fact. Mr. Marvel of mystery oil fame, I believe is same or closely related to Marvel, of Marvel-sheibler aircraft carbs.

dang
Southern Airboat Member
Posts: 5
Joined: Tue Nov 15, 2016 5:21 pm

Re: pe-90 questions

Postby dang » Sun Apr 09, 2017 8:46 pm

would anyone with a stock pe-90 cylinder, or a 0-470 cylinder be willing to weigh them? I'm trying to figure out how much of a difference it will be if I do the swap. Thanks.


Return to “Aircraft Power Only”

Who is online

Users browsing this forum: No registered users and 13 guests