TJ5208 1,824 #1 Posted November 15, 2023 So I have been thinking about doing a diesel build for a long time. I want to know if I would end up just downgrading. I'm looking at a Hatz 1D81 it has 14 hp. The motor on my tractor is a P220g. I know upgrades for power would be easier on a diesel than on P220g. Just wanted your guys input on this. Share this post Link to post Share on other sites
ebinmaine 67,517 #2 Posted November 15, 2023 Comparing a 14 diesel to a 20 gas.. it's not exactly equal. Particularly because those Onans are known for having gobs of torque on their own. I'm not sure you'd find a difference and it may even be lower on the diesel. My other train of thought is this. If you have an Onan 20 horse it can only be on a 520. If it's hydraulic you're not going to see any difference at all so there's no point doing the change. If it's a 520 - 8, I wouldn't be messing around with a tractor that RARE just to do an engine swap unless something about the Onan was blown. 4 Share this post Link to post Share on other sites
Achto 27,577 #3 Posted November 15, 2023 (edited) 1 hour ago, TJ5208 said: I know upgrades for power would be easier on a diesel than on P220g. Up grading a Hatz is not as easy as you think. They are a complicated engine and very expensive on the initial cost to buy. The Hatz 1B40 in Radpferd has around a $2500 price tag new. As far as 14hp diesel compared to 20hp gas - Horse power is horse power, it's all measured using the same instruments. Torque is the big difference between gas & diesel. You will not notice any hp difference driving the tractor around other than the diesel will recover a bit faster on take off. If you are running a large implement like a 60" deck, the 14hp diesel will definitely get it spinning but might fall off in heavy grass when compared to the 20hp gas. When it comes right down to it, about 12hp is all you will ever get to the ground on a garden tractor. Yes you can weight it down, put bigger tires on, etc to try to get more to the ground, this usually comes at a cost of breaking things. Something has to and will give eventually, if not traction then a part. One thing that you would gain with the diesel is fuel economy. The Hatz will probably run twice as long on a gallon of fuel than the Onan will. Edited November 15, 2023 by Achto 2 2 Share this post Link to post Share on other sites
Achto 27,577 #4 Posted November 15, 2023 https://www.singlecylinderstore.com/Wacker-5100045046-Diesel-Engine-1D81S-319E?language=en¤cy=USD&srsltid=AfmBOopO0jyEEuhoK5z7dhJFjNWY4FJhUaZ5Hl6PLUgKu_wr4nCzfBB74zQ $!$!$! Share this post Link to post Share on other sites
Achto 27,577 #5 Posted November 15, 2023 More info for you. The Onan P220G test out with a maximum torque of 32lbft at 2400RPMs and 20hp at 3600RPMs The Hatz 1D81 tests out at 36.3Nm (26.5lbft) max at 2000RPMs and 10.1kw (13.54hp) max at 3000RPMs 2 4 Share this post Link to post Share on other sites
ebinmaine 67,517 #6 Posted November 15, 2023 59 minutes ago, Achto said: Torque is the big difference between gas & diesel. Excellent write up Dan! 1 Share this post Link to post Share on other sites
TJ5208 1,824 #7 Posted November 15, 2023 1 hour ago, Achto said: https://www.singlecylinderstore.com/Wacker-5100045046-Diesel-Engine-1D81S-319E?language=en¤cy=USD&srsltid=AfmBOopO0jyEEuhoK5z7dhJFjNWY4FJhUaZ5Hl6PLUgKu_wr4nCzfBB74zQ $!$!$! I found one for 500 that runs. 1 Share this post Link to post Share on other sites
TJ5208 1,824 #8 Posted November 15, 2023 43 minutes ago, Achto said: More info for you. The Onan P220G test out with a maximum torque of 32lbft at 2400RPMs and 20hp at 3600RPMs The Hatz 1D81 tests out at 36.3Nm (26.5lbft) max at 2000RPMs and 10.1kw (13.54hp) max at 3000RPMs So it's pretty much not worth it. Is there upgrades you can do to the diesel to get more hp and torque? 1 Share this post Link to post Share on other sites
TJ5208 1,824 #9 Posted November 15, 2023 24 minutes ago, ebinmaine said: Excellent write up Dan! Very true thanks @Achto 1 Share this post Link to post Share on other sites
Achto 27,577 #10 Posted November 15, 2023 1 minute ago, TJ5208 said: Is there upgrades you can do to the diesel to get more hp and torque? I don't know of any bolt on's. 1 Share this post Link to post Share on other sites
TJ5208 1,824 #11 Posted November 15, 2023 8 minutes ago, Achto said: I don't know of any bolt on's. Ok I have the 520h with a broken rod and was looking for a motor replacement. 1 Share this post Link to post Share on other sites
Achto 27,577 #12 Posted November 15, 2023 2 hours ago, TJ5208 said: I have the 520h with a broken rod and was looking for a motor replacement. That would make a good candidate for a diesel transplant. Other suggestion would be a Kohler M20 or a Predator 22 https://www.harborfreight.com/22-hp-670cc-v-twin-horizontal-shaft-gas-engine-epa-61614.html 1 1 Share this post Link to post Share on other sites
Handy Don 12,232 #13 Posted November 15, 2023 2 hours ago, Achto said: That would make a good candidate for a diesel transplant. Other suggestion would be a Kohler M20 or a Predator 22 https://www.harborfreight.com/22-hp-670cc-v-twin-horizontal-shaft-gas-engine-epa-61614.html Or a Vanguard twin or even a Honda. 2 Share this post Link to post Share on other sites
Streetrodchev 800 #14 Posted November 16, 2023 Rebuild the Onan Share this post Link to post Share on other sites
littleredrider 409 #15 Posted November 18, 2023 One of my 520s has a 10 horse diesel. I haven't had attachments on it, but I think it has more torque than the Onan. But I can't really give it a fare comparison, the diesel is hydro, and the Onan was an 8-speed. I have the other 520 hydro with the 22 horse Predator, it works good, but think it lacks a lil on torque compared to the Onan. What makes the diesel feel impressive is the traction with the ATV tires. I can go anywhere with these, and it will go thru it no problem. I had 23 degree Ag's, and they did good, but nothing compared to the Vampires. One issue with the diesel, since it's lighter than the Onan, sometimes its fun (or not) to keep the front end down..... 1 Share this post Link to post Share on other sites
ebinmaine 67,517 #16 Posted November 18, 2023 8 minutes ago, littleredrider said: I had 23 degree Ag's, and they did good, but nothing compared to the Vampires You have pics of these Vampires? Share this post Link to post Share on other sites
littleredrider 409 #17 Posted November 18, 2023 They are in the wider rims post were going back n forth on lol. 1 Share this post Link to post Share on other sites