Performance upgrages fot the 084.

**buster** · 05-01-2009, 02:45 AM

Has anyone heard of any preformance upgrades available for the 084 engines? I heard the
aircraft experimernters have come up with a theory that it should be no problem to get 1 hp per cu. inch. Seems they say it is a must to beef up the headbolts with Helicoils to spread out the stress. They tend to pull headbolts out of the case and throw cylinders otherwise. That's just a start. It would be interesting to check out any other mods available!

Dave

**chuckitt** · 05-01-2009, 08:51 AM

Hey Buster, Ron converted his intake to mount the Solex carb and gained 500 RPM. We took 4 cylinders and had the base milled down .020 to increase the compression but haven't had time to put them on a motor. Stratton Airboat ACC is making us 2 big plenium intakes that we will try. So no news now but it's coming.
Thanks, Chuck

**Wildfowl** · 05-01-2009, 10:19 AM

Hey Buster,

The best information I have found on the o84 is on the Yahoo o84 experimenters group. Latest discussion was on water injection...like the WWI-II fighter aircraft.

There is a very timely discussion now on the max power out of the o84.

Here is a link http://groups.yahoo.com/group/A084Experimenters/

Mostly geared for aviation but some airboaters there and all are welcome no matter what the application. Very sound reliable advice.

From what I have read...those engines were not built to build. You do get better performance (couple hundred rpm) by just taking off the stock air breather. A modern carb will help as well and is comonly reported to imporve operation.

The engine does not breath well above 36-3800 RPM so building it up by the opinion of military mechanics is not worth a lot of time, or money and you will most certainly be buying maintenance and reliability issues. Overheating and headbolts. It will be interesting to see the reslults of the Max Power thread.

Read back and you will get the low-down on everyting from fuel injection to super charging to electronic ignition to dual plugs to stroke and bore to .....

Check it out and decide for yourself...one of the mechanics has blown several of them up experimenting... See the water injection thread reply from "Les." There is a summary on all that has been experimented.

**buster** · 05-02-2009, 01:51 AM

Hey Wildfowl, and Chuck,

I HAVE been watching that 084 Experimenters group for a few days. I agree with you both, and I am now of the opinion that it may be unwise to go much beyond carburation, and exhaust mods. on that engine. Water injection may help some, mainly with cooling, but I feel the weight, cost, and all the tinkering involved, would not yeild worthwhile results!

I also think that an airboat is something that most folks want depend on to go when they are ready, and get them back without a lot of problems along the way. If radical modifications are done to the 084, It may not be all that dependable! JMO

Thanks, Dave

**Wildfowl** · 05-04-2009, 10:08 AM

Well....Yeah...and the fact you dont have a Sitka chasing you around trying to hurl lead in your arse or worse.

You can probably get by without the H2O conversion.

That o84 ... that is a great engine all by itself.

imported_Papee · 05-04-2009, 11:18 AM

I agree with Wildfowl, I've been running the 084 for almost a year now on my boat. The engine is very reliable in it's stock form. I do run direct drive. The motor has it's limits, if you don't have the carb set up just right it will run hot and they don't like that. Like I say, I am running direct drive with a 52x24 prop and When the low water levels come this year I believe I will be seeing a top speed of around 35 mph without hurting the motor. I use the prop as a governor and keep the rpms down to a safe level to make the motor more reliable. I also run a bigger, heavier hull than most at 16 feet.

You guys that are building the smaller hulls with reduction drives should see higher speeds than I get. Every motor has it's limits. I will be putting on one of Chucks intakes and a solex for better carb tuning then making the spark plug mod he has shown then call it good for this one.

**buster** · 05-05-2009, 12:00 AM

Hey Wildfowl,

Did I miss something, or am I just dumb? What the heck is a Sitka

Maybe they don't have any in Minnesota

Thanks, Dave

**Wildfowl** · 05-05-2009, 10:54 AM

My bad Buster... A sitka is a small black tailed deer.

Stuka's and Shrike's are German aircraft fighters and support/bombers.

**Duane Scarborough** · 05-05-2009, 07:45 PM

Wildfowl,

I guess it just slipped past me. I read "Sitka", but thought "Stuka". I sure wouldn't want a Junkers Ju 87 (aka Stuka) on my backside.

They were seriously bad news for thier time.

Edit: I guess they weren't ALL that bad after all. We don't speak German now, do we?

Duane

**Wildfowl** · 05-06-2009, 11:19 AM

Yeah...they gave the Allied escort and fighters a hard time along with the Messerschmidts (sp?)

That is why the water injection was "deployed" and was called WEP for War Emergency Power. It is my understanding that it was only to be used in battle and only than when you "needed" the extra power to save your skin. Way too hard on the engines but acceptable to save a plane or pilot(and most likely used to shoot something down). The pilots had like a five minute burn max total/sortie

I dont want to sound like the History Channel. Just thought it applied to the H2O question.