Brownta 5 #1 Posted March 15, 2014 Has anyone done the leg work to see if any K&N filter is available? If you do a search for the 520 on the site all that comes up is the oil filters. I would almost bet the farm that they make something that will work on it. Share this post Link to post Share on other sites
Sparky-(Admin) 23,147 #2 Posted March 15, 2014 Exactly which filter are you referring to? Motor....tranny...or air filter? Mike........... Share this post Link to post Share on other sites
HorseFixer 2,013 #3 Posted March 16, 2014 I think he is referring to Air Mike. Share this post Link to post Share on other sites
Brownta 5 #4 Posted March 16, 2014 Yes the air filter. I run K&N HP-8030 on the engine and a regular Toro filter on the tranny. All the regular oil filters have anti flow back valves. The Toro brands do not have this. I ran a wix filter on the tranny once and it overheated. Apparently the anti flow back valves slow fluid flow. I got that from John Deere tech and have done no looking into it on my own. On a second note for the oil filters if anyone is interested, K&N makes 2 filters that fit the 520. HP-8030 and HP-8031. Both have the 1" nuts on the end, I run the HP-8030 because if is a taller filter, 5.25" vs 3.75" for the HP-8031. 1 Share this post Link to post Share on other sites
Hodge71 665 #5 Posted March 16, 2014 You were apparently using the wrong Wix filter on your hydro. All I use is Wix #51410 and NAPA #1410 (which Wix makes for NAPA) on my hydro. It is a true hydraulic filter not and oil filter. The Wix and NAPA filters are twice as good as Toro....Whatever you used was an oil filter for a car. Yes the air filter. I run K&N HP-8030 on the engine and a regular Toro filter on the tranny. All the regular oil filters have anti flow back valves. The Toro brands do not have this. I ran a wix filter on the tranny once and it overheated. Apparently the anti flow back valves slow fluid flow. I got that from John Deere tech and have done no looking into it on my own. On a second note for the oil filters if anyone is interested, K&N makes 2 filters that fit the 520. HP-8030 and HP-8031. Both have the 1" nuts on the end, I run the HP-8030 because if is a taller filter, 5.25" vs 3.75" for the HP-8031. 1 Share this post Link to post Share on other sites
Brownta 5 #6 Posted March 16, 2014 I will have to get one ordered. I would much rather use a wix. I have used them for years on my trucks. Thank you! Back to on topic, anyone know of a higher flow air filter that will fit on the Onan 520? Share this post Link to post Share on other sites
boovuc 1,090 #7 Posted March 16, 2014 I don't know of any. Even if they did make one, you would have to adjust the main fuel mix on the carb because of leaning. (More surface area meaning more air through the filter). To get more air, you would almost have to modify the air cleaner housing to accommodate it and I doubt K&N would make these for an obsolete small engine. If your 520 has the later "anti-pollution" carb, you don't have the easy ability to change the high speed mixture. Just my opinion but I just don't think you would gain anything other than the K&N can be cleaned and reused. Maybe some of the pullers can shoot my opinion all to hen! Share this post Link to post Share on other sites
Hodge71 665 #8 Posted March 16, 2014 (edited) I dont think anyone is join to shoot ya down Boo....I would say even with all the adjustments and everything if it was possible...you have get 1/10 of a HP so you'd have 20 1/10 HP Onan...totally not worth the cost of a $100 air filter.... Edited March 16, 2014 by hodge71 Share this post Link to post Share on other sites
boovuc 1,090 #9 Posted March 16, 2014 Thanks, Hodge. I always liked the analogy, if you build a better mousetrap, the world will lead a path to your door. If a K&N upgrade would impact a small engine for a reasonable amount of money, we could go to any auto parts store and they would have a row dedicated to them. Of course if no one ever tried or thought about these things, we would never invent anything. Share this post Link to post Share on other sites
Martin 2,133 #10 Posted March 16, 2014 another thing to remember, what ever 'high flow' element you put in there, the air is still just sucked through that tube that is in the top of the blower housing. and the carb throttle plate diameter is only going to flow so much air anyway and then its just a waste of money. i think a standard replacement filter would do just fine, anything more is just overkill...... 2 Share this post Link to post Share on other sites
HorseFixer 2,013 #11 Posted March 16, 2014 I guess I am one that likes building better Mole traps too! If they don't make it like I want, Ill build it myself. I often thought of the air restriction an Oil filter provides over the rear head. Being I just rebuilt the 520 Engine I was on a mission to do any improvement necessary in order to keep the rear head cool. Not only that but the peanut size oil filters that are used are too spindley for my purpose and I don't like getting oil all over MY RIDE! So I installed a remote oil filter kit with a LARGE FILTER that traps contaminants down to 20 microns with Nano Filter technology. Now I can change the oil filter with ease. Oh and installing an Inline oil pressure gauge on the dash was also a bonus! 1 Share this post Link to post Share on other sites
Martin 2,133 #12 Posted March 16, 2014 (edited) if you want to go bigger with the air cleaner, the p224 or t260 Onans had a taller high capacity air cleaner. i can't get dimensions as the engine is buried in the corner of the garage at the moment, but i think this added about 1 to 1.5 inches to the height. unless you get the opening to the air cleaner from the blower housing bigger, probably not worth the effort....... Edited March 16, 2014 by Martin Share this post Link to post Share on other sites
shorts 182 #13 Posted March 17, 2014 The down side of the K & N filters is that they don't filter as well as a stock paper filter, in an automotive application that is relatively clean or a high performance app. where the engines are gone thru and freshened up on a regular basis dirt contamination is not as big of a wear factor as it is in a working dusty field application. Just my $.02 worth. 2 Share this post Link to post Share on other sites
WH nut 553 #14 Posted March 17, 2014 I wouldn't run K&N Air filters on anything with a motor, they just don't filter well enough. And on a mower you are running in the worst conditions. 1 Share this post Link to post Share on other sites
rokon 64 #15 Posted March 17, 2014 (edited) Yeah, what shorts and wh nut said. Cotton gauze filters flow more air and they flow more dirt too. As pointed out also in previous posts, the smallest part of the intake tract will determine maximum flow of air into the motor anyway. With the exception of a snow thrower, every engine I have is equipped with a pleated paper type air filter. --Kevin Edited March 17, 2014 by rokon Share this post Link to post Share on other sites
Desko 624 #16 Posted March 18, 2014 For K&N's to filter properly you have to spray them with air filter oil which is more money wasted. Instead you could use it to make cool stuff for the tractor that helps the motor or transmission. Share this post Link to post Share on other sites
JackC 617 #17 Posted March 18, 2014 The 520HC (C = Commercial) has a larger air filter. They come up for sale on Ebay from time to time. I would go that way before going with a K&N which is probably designed more for air volume than filtering ability. Share this post Link to post Share on other sites
Hodge71 665 #18 Posted March 18, 2014 The 520HC (C = Commercial) has a larger air filter. They come up for sale on Ebay from time to time. I would go that way before going with a K&N which is probably designed more for air volume than filtering ability. 081_4334.jpg 081_4335.jpg Jack that is a gorgeous HC...hope I get one someday... Share this post Link to post Share on other sites
