Well now I've gone and done it...

Gravy · Nov 30, 2014

First pix.

RegL · Nov 30, 2014

You got my attention.

Sent from my iPhone using TractorByNet

Gravy · Nov 30, 2014

RegL said:
You got my attention.

Sent from my iPhone using TractorByNet

Be patient. I'm really tired.

Reader's Digest version: It fits with no major modifications, but some machining is required. The first test run was very encouraging.

Gravy · Nov 30, 2014

The engine is a Subaru-Robin EH90. The EH90 and EH99 seem to be more or less rebadged variants of the Generac GTH990. The EH90 is rated at 35hp, and the EH99 is rated at 40 hp. Both are rated as 999cc displacement, vs 720cc for the Robin EH65 & 72 series. Once the bulky accessories are removed, the actual engine assembly is about 1/2 inch longer, 1/2 inch taller, and slightly narrower than the EH72.

The greatest difference is in the PTO attachment. The EH72 uses a smaller pilot diameter and bolt pattern that is missing from the EH90. That required drilling new holes and boring a new recess in the pump adapter flange. I have a tired old metal lathe that got it done. I would think a real machinist could do it for a couple hundred bucks.

Other than that, it was measuring, drilling, filing, a bit of welding, and the occasional bashing with a big hammer.

Gravy · Nov 30, 2014

And just in case anybody is curious, as the old Rolls-Royce ads said, the power is adequate.

PTWannaHave · Nov 30, 2014

Cool... How/why did this come about...?

BobRip · Nov 30, 2014

I want one! I think you realize that we want massive details. Get some rest now. Thanks for posting.

MuncyBob · Nov 30, 2014

sweet!

ponytug · Nov 30, 2014

Fantastic to see! Great job. You should be really pleased with your self and your work!

Thanks for sharing; this is wonderful to see.

All the best,

Peter

Gravy said:
The engine is a Subaru-Robin EH90. The EH90 and EH99 seem to be more or less rebadged variants of the Generac GTH990. The EH90 is rated at 35hp, and the EH99 is rated at 40 hp. Both are rated as 999cc displacement, vs 720cc for the Robin EH65 & 72 series. Once the bulky accessories are removed, the actual engine assembly is about 1/2 inch longer, 1/2 inch taller, and slightly narrower than the EH72.

The greatest difference is in the PTO attachment. The EH72 uses a smaller pilot diameter and bolt pattern that is missing from the EH90. That required drilling new holes and boring a new recess in the pump adapter flange. I have a tired old metal lathe that got it done. I would think a real machinist could do it for a couple hundred bucks.

Other than that, it was measuring, drilling, filing, a bit of welding, and the occasional bashing with a big hammer.

Frank Sorbello · Nov 30, 2014

Great work!

Gravy · Nov 30, 2014

Thanks guys!

I'm really excited and relieved that it worked at all. I'm trying to keep in mind that the new big engine may break something else downstream, but I'm also placing a good bit of faith in relief valves.

MossRoad · Nov 30, 2014

More pics!!!!
More pics!!!!
More pics!!!!

:laughing:

Frank Sorbello · Nov 30, 2014

Did you consider any other engines beside a Subaru?

MossRoad · Nov 30, 2014

Chevy small block was too wide.

Gravy · Nov 30, 2014

MossRoad said:
Chevy small block was too wide.

And the bellhousing bolt pattern is all wrong.

Gravy · Nov 30, 2014

Frank Sorbello said:
Did you consider any other engines beside a Subaru?

Frank,

I looked at everything I could find online. Kohler, Kawasaki, and Briggs Vanguard Big Blocks were all way too big in at least one dimension.

KMA · Dec 1, 2014

Very nice!

KentT · Dec 4, 2014

MossRoad said:
More pics!!!!
More pics!!!!
More pics!!!!

:laughing:

Yep, we need details, details, details...

My Kohler CH25 is approaching 1200 hours, and now puffs smoke on startup. I know I'm abusing it on these hillsides that are beyond its lubrication limits, and I'll be facing a replacement at some point...

Gravy · Dec 4, 2014

Details will come eventually. Right now I'm busy catching up on the stuff I put off while doing the engine swap. I haven't had time to finish up the details or run it much at all.

KentT - One nice thing about the new engine is that it's rated for 30 degrees slope.

Raw Dodge · Dec 5, 2014

I've been running my Kohler command 25 on side hills ans uphills between 25-35 degrees for years in my Steiner 420...my engines shutdown at 4psi oil pressure, its never shutdown once I even rolled it once and it never shut down as it went over the seat was held down by the ground so then safety only kicked in for a second and it kept right on running.. That engine has about 4500hrs on it now..I freshed it last yr ...was using about 8oz of oil per 25hrs... I bored cylinders 025 over, new intake valve seals all new gaskets new +.025 OEM rings and pistons, the crankshaft and rods were perfect,as was the camshaft and lifters.. This engine was run on Shaeffers X 7000,and Napa full synthetic oil since it had 50hrs on it. I think you guys are worrying too much about the side hills, just keep your motor oil level on the high side of the safe range..