Rebuilding an EG33.

[akschu]

Forum,

I'm looking seriously at building a EG33 engine for a Bearhawk (I know it's not an RV, but I live in Alaska for Pete's sake) because I would much rather have a liquid cooled setup for comfort and reliability in cold weather.

I don't much like the complete kits from Egg or others so I was thinking about buying an overhauled engine and a PSRU. I found this engine on ebay and like what the guy is doing:
http://cgi.ebay.com/ebaymotors/ws/eB...m=130225289996

ECUtune engines are built to exacting specifications and fully documented. These engines are built to happily run high torque at high rpms.

High silicon aluminum bearings further enhanced with the same ct1 anti- friction coating used by nascar teams are used for both the mains and rod bearings. All bearings are caged and each crank pin and journal is machined to achieve exactly the desired oil clearance within a tolerance range approximately 20 times more acurate than factory specifications. Each bearing bore, journal or pin diameter, and resulting oil clearance is included in the documentation provided to the purchaser. Sets of highly ballanced H-beam rods with ARP 2000 rod bolts put together especially for ECUtune are used.

You get the idea.... The rods and pistons are shown on his website:

http://www.ecutune.com/svx_rods.htm
http://www.ecutune.com/svx_pistons.htm
http://www.ecutune.com/svx_bearings.htm

These engines are designed for high rpm racing under boost.

Now I know that building a racing engine with race engine ports and camshaft timing is not a good idea for aircraft usage, but I think building racing engine rotating assembly is a good idea because it has much better tolerances, oiling, and balance. I called the guy and talked to him about it and he said he would run a totally different porting and cam timing package in an airplane engine. He said he would put the peak torque around 5000-5500 rpm. He also seemed to know this engine very well.

Now for my questions:

1. Is this engine worth the money to get the tighter tolerances, stronger/lighter rods/pistons, arp studs, grooved deck etc?

2. How complex is it to add a small turbo to the engine for a couple of lbs of boost? I don't want anything crazy, just want a little more torque and perhaps economy.

3. Is expecting 230hp for take off and 175hp continuous over working this engine?

4. Which PSRU do I run? I've heard good things about the autoflight one out of New Zealand.

5. What is the fuel economy like compared to a lycombing? Can I expect to see a little better GPH given that I'm not cooling the engine with the fuel?

6. Which is the best engine computer to use? Real world or SDS?

That is enough questions for now....

Thanks,
schu





"

[Mike S]

Matt, welcome aboard

Guy in Canada, named Ross, should be chiming in on this-------also, Egg is a member here, and he should also have input.

For me, I totally agree with your comments about using racing technology to make the engine smoother, and more reliable. Just resist the temptation to get every last HP out of the engine, reliability is king in this arena.

Good luck

[rv6ejguy]

Originally Posted by akschu

Now I know that building a racing engine with race engine ports and camshaft timing is not a good idea for aircraft usage, but I think building racing engine rotating assembly is a good idea because it has much better tolerances, oiling, and balance. I called the guy and talked to him about it and he said he would run a totally different porting and cam timing package in an airplane engine. He said he would put the peak torque around 5000-5500 rpm. He also seemed to know this engine very well.

Now for my questions:

1. Is this engine worth the money to get the tighter tolerances, stronger/lighter rods/pistons, arp studs, grooved deck etc?

2. How complex is it to add a small turbo to the engine for a couple of lbs of boost? I don't want anything crazy, just want a little more torque and perhaps economy.

3. Is expecting 230hp for take off and 175hp continuous over working this engine?

4. Which PSRU do I run? I've heard good things about the autoflight one out of New Zealand.

5. What is the fuel economy like compared to a lycombing? Can I expect to see a little better GPH given that I'm not cooling the engine with the fuel?

6. Which is the best engine computer to use? Real world or SDS?

That is enough questions for now....

Thanks,
schu





"

Given the work required to do all this, it is a bargain.

Use stock cams though, you want the power band to stay down where the factory has it for aviation use and you should not mess with the valve train without proper validation in aircraft IMO.

You need to add a properly matched turbo to get good altitude performance. It is somewhat more complicated but the difference in performance will be substantial and cruise fuel economy may be better by permitting lower rpms for the same power. If 230/175 hp is all you ever want, you don't need the turbo.

For PSRU units, I like the Marcotte and Autoflight due to the prop/ crank offset for cowling clearance.

The fuel economy will be in the ballpark with an O-540. I would not expect it to be much better if any.

I build the SDS stuff so I may be biased. We have sold hundreds of systems for Subarus and several for the EG33 specifically. We have a lot of experience with these engines on the ground and in the air. We have some specific parts to make installation easier like crank sensor, wiring and ability to drive the OEM coils.

Check what RWS can do for you too though. Tracy is a good guy.

[CNEJR]

You need to look at Bud Warren's LS1, it would fit a Bearhawk perfect, weighs less than a IO540, fuel burn is about 11-12 per hour, 350hp. Generally cruise at about 2900. Bud really wants to do one for a Bearhawk and his drive is super smooth, has about 700 hrs. flight time, now. Many drives have been bought and are in preparation for flying. Check out Geareddrives.com. You won't be sorry.

[akschu]

rv6ejguy,

Thank you for taking the time to answer my questions, I'm still gathering information, but so far the EG33 looks like a good setup.

CNEJR,

Thanks for your response.... yes I have looked at the geared drives unit, but have some concerns with it:

1. It's very expensive. He wants $30k for a FFW when the engine is $4600. I'm really only able to toss $20k at it.

2. The system does weigh less than a angle valve o-540, but it is at least 50lbs heavier than a parallel valve o-540 which the bearhawk specifically requires because of the weight. The designer states that you need to keep the engine weight down to 400lbs, but some people are putting in o-470s which I figure are about 435lb. I have looked at the weight and balance and it doesn't mess up the CG that bad, so its certainly possible, but I'm not sure that it's worth 100lbs of weight over the subie when the airplane isn't supposed to see more than 260hp and flies very well on 170hp.

3. Testing. The LS1/geared drives/GM computer combo is for the most part untested. From what I understand the wheeler had a Bud built 383 with a carb.

Perhaps your right that the geareddrives setup is the better solution, but it does add a bunch of weight and it is very expensive. Keep in mind that many builders are running o-360s in this plane.

Perhaps I'll call Bud in the morning and talk to him about it.

Thanks,
schu

[rv6ejguy]

Yes, weight is the big thing here, the LS engine alone is almost 100 pounds heavier than the EG33 and the V8 redrive will certainly be heavier than ones for the Subaru. The Warren packages would be nice for a big Lancair but will demand some empty weight and C of G alterations for RV10s or the Bearhawk.

A new 3.2L V6 Honda package is in the works for the Titan T51 replicas. This may fill the gap in the 200-225 hp range with a fairly lightweight package using a widely produced, respected engine. Two PSRU options are being developed- a chain drive and a new offset gear drive from the experienced people at Autoflight in NZ. I'm not sure why the Honda engines have never caught on much in aircraft until now. We've just done some testing on the coil on plug ignition to be sure these will be reliable when driving them with our ECU. Looks good so far. Development is proceeding in both the USA and NZ on this one.

[akschu]

Ross,

I agree that the honda may be more comparable to a parallel valve o-540, and Jason Day at Vesta has the 3.5L and the 3.7 which are around the same weight as the subaru.

My primary concern with the honda is that it's untested. There aren't really any of them flying. Also, I just don't think that the rotating assembly has the strength of the subaru. Take a look at this:

Engine Bore Stroke RPM Piston Speed
Lycombing 0-360 5.125 4.375 2700rpm 1968fpm
lycombing o-540 5.125 4.375 2700rpm 1968fpm
Subaru EG33 3.815 2.95 5000rpm 2458fpm
Honda 3.5L 3.5 3.7 5000rpm 3051fpm
Chevy LS1 3.90 3.62 4000rpm 2413fpm

Because the Honda is an under-square engine, but still needs the RPMs to make it's power you have very high piston speeds and you are doing it with 2 less main bearings. Also, as you know the subaru engine has a large amount of crank journal overlap which makes things very strong.

Another interesting thing is that the subaru and chevy have similar piston speeds at takeoff rpm. Setting the chevy for 3000rpm cruise and subaru at 4000rpm cruse the piston speeds are still fairly similar at 1810fpm for the chevy and 1966fpm for the subaru.

This information basically tells me that the subaru is a better aircraft engine than the honda because it's setup for high rpm torque, where the honda engine is more built for low end torque, which is nice in a car, but doesn't do me any good in an aircraft when I still need 5000 rpm to get rated hp. It also tells me that the chevy and subaru are fairly similar when it comes to piston speeds the difference being that the chevy gets me another 100hp for another 100lbs.

Another factor is that there is a guy that lives within an hour of me putting a EG33 in his bearhawk which means I have someone to share notes with and he also has the mount all figured out. As with any conversion, the installation is everything and I think I will have a better installation with a EG33.

Anyway, I'm not totally decided yet, but I'm not really thinking I'll go honda, so the real question is whether the v8 is worth the 100lbs and the CG problems it will likely impose.

schu

[rtry9a]

AKSCHU,
Im curious if you've looked at the Mazda Renesis engine. From your requirements, it sounds like it might be the perfect fit. It is significantly lighter than the Lyc 540's and Subi's (abt the same as the 320/360 series), and it can provide 250+hp as long as you want in a small, durable, and smooth running water-cooled package. It also has affordable redrives and engine mgmt systems available.

[akschu]

My understanding of the rotary engines is that they need a turbo to make the HP I want and that they run real hot.

Being that a subaru is a AWD car, they are extremely popular in AK so I can get parts anywhere, where the rotary is a bit more difficult to come by.

I'll take a look at them, but so far I'm inclined to stick with what I know and rotaries are uncharted waters for me.

schu

[rv6ejguy]

Jason Day seems to have many projects on the go simultaneously with props, drives, engines and mounts. I can't think that any of these will have accumulated any significant flight time any time soon as he seems to be years behind delivering product. Not to cut down his efforts, just reality in this business getting reliable, proven designs into the air. I personally prefer conversions where the people doing them have their own test mule. That's what I like about Tracy Crook and Bud Warren. That speaks volumes in my book.

Schu, You have researched this well. I too like the EG33 for its short stroke, robust design and good power and peak torque numbers at relatively low rpm, only 1000 rpm apart. The engines are not plentiful but there are a number flying and we are helping the other fellow in Alaska a bit plus a couple others here in Canada with ex Crossflow engines..