toddr 19 #1 Posted September 2, 2017 (edited) I was frustrated enough at constantly needing to remember to clean the blower screen on my 520H that I decided to fabricate a fix. It's not pretty, but so far it seems to work. I used 22g galvanized riveted together. I thought it was important to use the original screen and hardware to attach the shield as I didn't want to risk any hardware getting into the spinning blower. The hardest part was getting the side of the shield to clear the brake when depressed. The airflow seems good from the top and I haven't seen any overheating, but time and weather conditions might affect that. If I do have issues with air I can easily open up the top. Edited September 2, 2017 by toddr 4 Share this post Link to post Share on other sites
ericj 1,576 #2 Posted September 2, 2017 Looks good but, I have concerns that it would allow enough air flow in, especially at the bottom of the flywheel. Instead of pulling air straight in on the flywheel, you now have to pull have to pull it all in from what a 6"x18" hole at the top. You did real good from the looks of it forming it around the shroud. From the looks of it you have to drill out the rivets in order to remove it. If you were to shorten up the length enough to clear the pedal you could open up the top more to allow in more air ? Could you use hinges on the bottom and some kind of buckle or clasp that would allow you to gain access to the mounting screws easier ? with pulling air in from above will it allow even and proper air flow over the entire motor with out creating hot spots ? in another words does to much turbulence in air flow through motor. i like your idea though, it is a PIA when mowing with a lot of dead grass laying or when doing leaves. somebody on here used a 10" or 12" smoke pipe type ell and angled it up to stop the leaves and grass from getting sucked up on the screen. it takes me usually less then an hour to mow my yard so I just try and remember to brush it off eric j 2 Share this post Link to post Share on other sites
1995 520H+96+97 935 #3 Posted September 2, 2017 That should do the trick. 2 Share this post Link to post Share on other sites
ronhatch 405 #4 Posted September 2, 2017 Sorry Tod, but I also would be very concerned about air flow and over heating. 2 Share this post Link to post Share on other sites
DougC 2,641 #5 Posted September 2, 2017 I don't think you need an engineering degree to solve the problem or measure the cfm volume of air flow with and without your invention. If it works for you, that's the important thing! It's your 520H and your creation. Who knows, bu next year the guys telling you the sky is falling and you're going to blow it up might be trying to order one from you for their horses............ 4 Share this post Link to post Share on other sites
lynnmor 6,765 #6 Posted September 2, 2017 I had considered hanging a shaker screen out a couple of inches from the engine. Some agricultural equipment does that. So I throw the idea out there if someone wants to run with it. 2 Share this post Link to post Share on other sites
Marv 845 #7 Posted September 2, 2017 Take a look at this bulletin. Would it work? Marv Engine cooling screen.pdf 4 Share this post Link to post Share on other sites
toddr 19 #8 Posted September 3, 2017 Thanks for all the comments. Regarding removal and re-installation, I added 3/8 holes above each of the bottom screws and put a plastic cap over them. That allows room to put the screw head through. I am a bit worried about about air flow, but so far the air being pulled through seems sufficient. It's definitely better than the partially clogged condition it seems to be whenever I'm mowing. So I'm going to monitor the temperature and see if I need to open it up more. I think that engine cooling screen would help, would love to get my hands on one. 2 1 1 Share this post Link to post Share on other sites
1995 520H+96+97 935 #9 Posted September 3, 2017 10 hours ago, Marv said: Take a look at this bulletin. Would it work? Marv Engine cooling screen.pdf It will still build up leaves and chaff, just has a larger area and take more time to cover. A brush on the front and side of the rotating screen would help with the build up. Share this post Link to post Share on other sites
shallowwatersailor 3,213 #10 Posted September 4, 2017 (edited) The bulletin that Marv provided is probably the best solution. My 523Dxi pulls a lot of grass on to the three screens due to the high airflow (more than a 520-H requires) of the radiator fan. There is also an additional removable screen directly in front of the radiator itself that stops the fine dust. The last photo shows the screen removed from its bracket on the radiator. I have found that there is less grass chaff if I time my mowing to when there is a bit of moisture on the grass. Edited September 4, 2017 by shallowwatersailor 1 Share this post Link to post Share on other sites
WVHillbilly520H 10,369 #11 Posted September 4, 2017 I know the pain with the eMax as well as the 520s, but at least with the I can just reach up while mowing and brush most of it off and keep on going, but with the eMax if I forget about it ,it has a safety mode that will only let it idle when it clogs too much, Jeff. Share this post Link to post Share on other sites
MalMac 1,328 #12 Posted September 5, 2017 I had a couple of 520 H's, the one I used for mowing had a small rack I attached to carry a broom that I cut the handle down. I would just grab the broom while in motion stick it down there at the debri screen, give a couple of swipes and keep mowing. Finally got tired of that and fix it for once and all. Sold that 520, went back to C series for mowing and reassigned my remaining 520 and any future 520's to snow removal only. I have seen seen more than one 520 owner out there mowing oblivious to the clog grass screen. Wonder how many premature engine failures from this? The manual says keep the screen free from debris. Mow 30 ft and have to clean it off is purely unacceptable. Toro knew this and all they did was to say keep it clean. The 520 is a great tractor, just a pain to mow with. To to be fair though, I have seen some blind owners to Kohlers be clogged to. 1 Share this post Link to post Share on other sites
lynnmor 6,765 #13 Posted September 5, 2017 My Dad had a 16 HP Onan on a Sears tractor for years. As he became more feeble, I saw him mowing with enough debris on the screen to stuff a pillow. No amount of advice mattered and eventually I had to take over. The point is that the engine suffered severe abuse from this as well as other things he did, but that engine never gave up. 1 Share this post Link to post Share on other sites
toddr 19 #14 Posted September 18, 2017 Now that I've mowed a few times with this shield, I thought I'd give an update. So far it seems to work great. No problems with overheating, airflow seems good and it is such a pleasure to not have to clean that screen multiple times. Leaves do fall into the opening so I'm thinking of adding a wire grate on the top and it obviously could be a problem in winter with snow building up in it, so I'll take it off when I install the snow blower. But overall I couldn't be happier. I've also been doing some research. The John Deere 420 used the same Onan P220G from 1987 to 1991. It came stock with a shield that seems to have a similar opening smaller than the one I made and as far as I know doesn't cause any issues. Does anyone know why it might end up being a problem on my 520H and not on the Deere? 1 Share this post Link to post Share on other sites
1995 520H+96+97 935 #15 Posted September 18, 2017 Leaves fall in. When? I don't believe snow will bother, unless it is parked outside and it snows, then you start it. 1 Share this post Link to post Share on other sites
WVHillbilly520H 10,369 #16 Posted September 18, 2017 8 hours ago, toddr said: I've also been doing some research. The John Deere 420 used the same Onan P220G from 1987 to 1991. It came stock with a shield that seems to have a similar opening smaller than the one I made and as far as I know doesn't cause any issues. Does anyone know why it might end up being a problem on my 520H and not on the Deere? Not as much a problem but, the way the engine is mounted is the difference in the way the engine breathes and what gets caught up on the flywheel screen, there was a JD420 at the big Auction here in VA this past weekend that had already been changed over to a Briggs Vanguard spinning a 60" deck so what caused that?, I have owned 1 of my 520s since brand new in 1998 ,yes the grass gets on the screen but I still have the original engine with no heat related issues as of yet and you can see above that a water cooled with fan the grass issues are even worse I can't just look at the the side of engine I have to stop the tractor and physically get off and open the hood to check how much is sucked up/stuck to the radiator screen so a little brushing on the Onan while mowing was no big deal as this to me, some like foot pedal vs hand stalk hydro vs gear single vs twin and brushing the screen vs not having too, it's whatever you're comfortable with, Jeff. 1 Share this post Link to post Share on other sites
shallowwatersailor 3,213 #17 Posted September 18, 2017 (edited) The JD 400-Series have a screen on both sides, plus the engine sits with the crankshaft in-line with the driveshaft. The airflow is to the front of the tractor as on my 523Dxi plus the other 5xi models. Actually the Kohler CH engines do not move as the air as the diesel does so no grass accumulation, and are probably one of the best mowing tractors that were made. The JD 400-series are "keeper" tractors - actually a cut above the 5xi. Like Jeff mentioned, a Vanguard twin is the replacement engine. and there is a shop in Hastings, MN that sells kits to replace the Onan. Edited September 18, 2017 by shallowwatersailor 1 Share this post Link to post Share on other sites
WVHillbilly520H 10,369 #18 Posted September 18, 2017 11 minutes ago, shallowwatersailor said: The JD 400-Series have a screen on both sides, plus the engine sits with the crankshaft in-line with the driveshaft. The airflow is to the front of the tractor as on my 523Dxi plus the other 5xi models. Actually the Kohler CH engines do not move as the air as the diesel does so no grass accumulation, and are probably one of the best mowing tractors that were made. The JD 400-series are "keeper" tractors - actually a cut above the 5xi. Like Jeff mentioned, a Vanguard twin is the replacement engine. and there is a shop in Hastings, MN that sells kits to replace the Onan. John, Yep I was after that 420 and better looking 318 Saturday but I'm a cheapo they went for $750 and $900 respectively, Jeff. Share this post Link to post Share on other sites
shallowwatersailor 3,213 #19 Posted September 18, 2017 21 minutes ago, WVHillbilly520H said: John, Yep I was after that 420 and better looking 318 Saturday but I'm a cheapo they went for $750 and $900 respectively, Jeff. When I moved to Maryland, I had been looking for a year for a JD 430 diesel. Found a JD x355 with a two cylinder Yanmar but it's engine RATTLED. That was how I found my 518xi at a JD dealer - and the rest was history! I almost went "Green"!!!! 1 Share this post Link to post Share on other sites
Sarge 3,462 #20 Posted September 19, 2017 The best model they built in my opinion was the 455 - those were one serious animal and I wish WH had done a similar tractor . Between that sweet diesel engine and the locking diff in it you could do just about anything . Only drawback was working on them - nothing was easy for sure . Sarge Share this post Link to post Share on other sites
Pullstart 59,644 #21 Posted September 22, 2017 (edited) So band saws have a little wire brush/wheel that cleans off the blade after it passes through the work piece. As @MalMac mentioned, he had a little broom that he would pass by the screen. Why not get a dust pan broom and affix it to just brush the screen as it rotates? Or does the 520 stay stationary unlike the Kohlers? Edited September 22, 2017 by pullstart posted before I was done typing... Share this post Link to post Share on other sites
ronhatch 405 #22 Posted September 22, 2017 (edited) I don't own a 520 WH, but I do own a C-101 w/ a 42" SD deck. Maybe we need to think outside the box concerning this problem. Perhaps a better approach is to fix what's causing the grass build up on the screen to begin with. IMO that's the grass blowing out all over the place from under the deck rather then just the discharge chute. Like I said I don't own a 520, but I do know I have that problem - to a much lesser extent - with my Kohler 241 powered C-101. I have been experimenting this week with a SS baffle infront of my 42' SD WH deck to minimize 'blow out'. It's installed and ready to be tested. Now if only we could get some rain here in northern IL. so the grass would grow so I can see if all my work is for naught. If interested, please check out my resent posts in the 'Implements and Attachments' section under the title "Improving my 42" deck". I know baffles have worked very well on my AC B-10 and my 4016 Case decks. Edited September 22, 2017 by ronhatch Share this post Link to post Share on other sites
boovuc 1,090 #24 Posted September 23, 2017 Well you know I had to weigh in on this! I built an apparatus to stop the continued build up of clippings and leaves on the P series Onan screen many years ago. (I wish I had the pics but a few PC upgrades ago and the pictures are gone. I looked here and also couldn't find them in the archives or on my older posts). It was a lighter gauge ventilation collar, (air duct flange and elbow), I ordered from McMaster Carr. I think it was a 15" or 16" round flange and equally round 90 degree elbow screwed to the OEM holes. This permitted approximately the same volume of air to enter the cowling but with the intake at high noon. There was very little debris on the screen which was now mounted at the top of the elbow. It was GREAT! For about two mowings then it worked loose and also warped the engine tin enough to actually make contact with the flywheel. It also severely limited how close you could get to objects on the left side of the tractor which is the side you WANT to get close to objects with! Oh.......and it really looked STUPID. Think REALLY STUPID. Think Steam Engine looking STUPID! They made a PVC flange and elbow but the weight was similar and I feared it would erode the contact points without metal bushings. After working both my 520 and 416-8 Speed with the Onan for many summers without the steam-engine look induction system, I too fixed the issue of debris on the screen by relegating the 520 to front loader only duty and letting the 416-8 do snow plowing only. (Both are now with new owners). I like what you did Todd and it's a great piece of fabricating. A hell of a lot better design then I came up with! But I agree with the comments that it won't get enough air volume to cool that engine well. Over time, it will adversely effect the rear cyl valve seats due in part to less air intake and MOSTLY by the belt guard impingement and the damn oil filter impingement all affecting the rear cooling. (Plus the added HEAT that the oil filter is blowing off inside the cowling). I want to note Lynmor's father who had an Onan in his Sears Tractor may not have had a P series in it. (The Craftsman III and a few in the early 90's had P series but I think they were mounted inline like a JD). The older SS Sears garden tractors were the BF/BG and the cast-iron CCK engines and they were much better motors plus these were mounted sideways. These older Onan's could take some abuse from lack of maintenance. This is especially true of the CCK. The 400 series JD tractors also had their issues with the Onans but not to the extent that WH did with their sideways placement verses the inline placement in the JD's and many other tractors of the day including the Ingersoll-Rand/Case and Steiners to mention a few. My KT 17 Series II's in the C-175 and 417's have very large screens that make up the entire engine tin on the air intake side. Same goes for the horizontal Briggs twin used on some Wheelhorse tractors. They pick up debris but there is always a lot of screen open to allow air to move through. Better design for use in a side-mount set-up. Even the original KT 17 that didn't have the over-sized screen never plugged up like the Onans do. They didn't require an extraordinary amount of air. I know a lot of you guys love your Onans just as I love my K, KT series and Magnum Series Kohlers. Hey! Every engine has it's faults. I wouldn't hesitate running an Onan in a Steiner if I had lots of money to buy a Steiner. (Sorry! No Green machines for me)! Onans work and run great in tractors designed better for them and their crazy desire for airflow. I've just seen enough over the years to avoid them in a WH. Every original equipment Onan for Wheelhorse is now between 20 and 29 years of age. A non-issue for some Kohlers. A big issue for me if it's an Onan. 2 Share this post Link to post Share on other sites
boovuc 1,090 #25 Posted October 2, 2017 Well I did manage to find two pics in the archives here of the contraption I made to "fix" the leaf litter issues on the Onan air intake screen. I got another chuckle just looking at this mess though it did work and would be an OK design if it wouldn't wallow out the mounts and you had absolutely no trees, hedges or anything in your yard! Share this post Link to post Share on other sites