Non-louvered Hoods, Onans & Dash Towers

[leeave96 490]

We talk about how heat sensitive the Onans are, yet on the 416 tractors, no louvers in the hood and very few posts about loose valve seats on the 16 hp Onans. Any thoughts about this?

Looking at pics of the 416 tractors, it looks like my 314-8, i.e. hood's plain face comes down over the battery and over the top of the dash tower vs my 520H where the hood is cut to fit around the instrument panel. I like the simpler hood and dash tower, more open access IMHO. Are the dash towers easily interchangeable?

Wiring - we read lots of posts about the 520H wiring and potential problems with it. What about the wiring for the 416 with Onans? Don't see a lot of posts on wiring issues with those. I gather without the mass of instruments on the 520H, the 416 Onan powered tractors have a simpler and more reliable wiring set-up?

Any comments would be welcome.

Thanks!

Bill

[MalMac 1,332]

You asked some very good and interesting questions. Hope some of the Onan guys chime in here. I am not a fan of that cantankerous motor, but I am always looking for ways to try and understand it better. Right now the feud  between it and I are on a cease fire until I get more understanding of it's ways. It's obviously not giving in.

[Martin 2,133]

While I agree about the 416 /520 valve seat comment......

the 416 has just as many wiring issues as the 520. All the wiring issues are related as it's basically the same harness that has the issues on either tractor. The extra gauges they can be a problem, but you will find the majority of electrical problems are ignition or starting circuit/safety switch related.

Most all 3,4,500 series tractors have wiring problems if they have been neglected, the wiring on the tractor itself is similar on all of them, same fuse holders, safety switches, relays and especially connectors.

Engine harnesses on the Onans are almost the same whether it's a 16 18 or 20, same goes with the starting and ignition if we are comparing the P engines.

Sent from my iPhone using Tapatalk

Edited March 29, 2014 by Martin

[Kelly 1,033]

I think we hear more about the 520 because there are more of them out there than the Onan powered 416.

 

    Just a observation on my end but I have owned more than a dozen 520's closer to 20 of them, and have never owned a 416, not sure if the price was close to buying a 520 and less 416's sold and more 520's not sure, but personally I've only seen a couple 416's and hundreds of 520's

[cheesegrader 433]

I thought the Onan 516, 518, and 520 were all the same block, with minor adjustments to tweak the horsepower.

I dont think there is any difference in the valve seats.

I think Kelly hit it on the head.  You don't hear about problems in the lower horsepower Onans because they are rare, and the 520's are common.

[shorts 182]

A couple of thoughts about the ONAN engines, first I think that Kelly is on the right track that their appears to be a lot more 520's than other WH's with ONAN engines so we talk about them more. Now for the other thought, ONAN is/was in the power generation business and the engines were designed with the purpose to power generators, the cooling systems work real well in that application, minimal air flow restrictions on the PTO end of the engine. the service points, oil filter and ignition and fuel system are also readily accessible in that application. Also consider that the generators tend to be used in a cleaner environment and that the generator heads have their own cooling needs that also help move air past the engine.

 

At some point ONAN started selling stand alone engines to anyone who wanted to buy them, early on they went into other forms of generators, specifically welders, then they started to show up in garden tractors mounted with the crankshaft front to back with non restricted cooling air flow, (D series and the green machines) with minimal issues.  It seems that when WH turned the engines sideways and restricted the air flow with a PTO belt guard and then marketed the machines to homeowners that didn't fully understand the need to keep the dirt and grass clippings cleaned out of the cooling fins and shrouds that valve seats became an issue.

 

Part of the product development process involves putting a product into production, selling it,  monitoring the results and then making changes as issues arise.  When you see a 20 year old product that has issues and we are aware of them it's up to us to resolve the issues to keep a classic machine running and performing up to their potential.

 

Boy it that sure sounds like I'm an ONAN fan, personally I like the Kohler engines more but I don't think that we should look badly at the other parts and pieces when we don't first look at the big picture and make some allowance for the technology available when these components were designed and built.

[ericj 1,579]

in my area i personally think the 416 is more available and you see a lot more of the 416. with that being said most of the 16 hp onans that i have found have blown rods. i have a 90 416-H that has low compression on 1 cylinder can't remember which one right now, so it will be interesting to see. the reason the onans pop valve seats is definitely caused by over heating the motor. but i believe most of that is caused by a lack of maintenance, not keeping the engine clean, then ad an oil leak in to the mix and you have a lot of grime that restricts air flow causing an over heating issue. i do believe the louvered belt guard will help but not totally necessary if a little preventive maintenance is done. this is just my personal opinion, that and a dollar just might get you a cup of coffee

 

 

 

eric j               

[HorseFixer 2,013]

 

While I agree about the 416 /520 valve seat comment......

the 416 has just as many wiring issues as the 520. All the wiring issues are related as it's basically the same harness that has the issues on either tractor. The extra gauges they can be a problem, but you will find the majority of electrical problems are ignition or starting circuit/safety switch related.

 

 

 

I think we hear more about the 520 because there are more of them out there than the Onan powered 416.

 

   

 

 

.

 

 It seems that when WH turned the engines sideways and restricted the air flow with a PTO belt guard and then marketed the machines to homeowners that didn't fully understand the need to keep the dirt and grass clippings cleaned out of the cooling fins and shrouds that valve seats became an issue.

 

 

 

 

The reason the onans pop valve seats is definitely caused by over heating the motor. but i believe most of that is caused by a lack of maintenance, not keeping the engine clean, then ad an oil leak in to the mix and you have a lot of grime that restricts air flow causing an over heating issue. i do believe the louvered belt guard will help but not totally necessary if a little preventive maintenance is done. this is just my personal opinion, that and a dollar just might get you a cup of coffee

 

eric j               

 

 

 

             

Lots of good information here. When I selected the 520-H to take on the responsibility of becoming the next SNOW CHUCKER II I had heard all the stories and knew what I was up against. For many hours I studied this and talked to many people. The Conclusion is that a lot of these failures were caused from HEAT. Being  a 35 year HVAC contractor if there is one thing I know it is heat transfer and airflow as I have delt with it my entire life. I sat on a bucket and ran my newly acquired 520-H that came from  Steve WH500Special in O fallen, Ill.   I sat there with a digital Infrared temp gauge and shot everything on the engine and wrote down the readings. The highest temp readings of course were from the exhaust! Now look how they have the exhaust all jammed up half way under the hood.      Right there above the rear head, right there by the FUSE HOLDER and all those brittle charred wires! Yep it didn't take me long to figure that one out!   During the resto of this tractor I ended up just about rewireing the whole tractor. I knew right then and there the exhaust had to GO! There was too much heat back in that area and it didn't need anymore so that's what I did.I welded and fabricated an exhaust manifold and "Y" branched the exhaust into a Farmall Muffler out towards the front of the tractor. After much research I installed a remote Oil Filter which removed the restriction of air across the rear head. My opinion the following are problems of the valve seat problem and other heat related problems with the wiring not necessarily in order. Many of these problems have been listed above by others.

 

• Grass & Dirt Packed In Head Fins Causing Air Flow Restriction Causing No Heat Transfer To Cool Engine.
• Oil Filter Blocking Air Flow.
• Swinging a 60" Mower Deck (High Strain On Engine).
• No Cool Down Time After Mowing Shutting Tractor Off Abruptly After Mowing Or Straining Engine.
• Mowing Or Working Tractor In High Heat Conditions.
• Exhaust Heat Buildup And Restricted Ventilation In Rear Quadrant Above Rear Head.
• Blocked Ventilation From PTO Belt Guard.

I love my Kohler Engines, But the Onan Just doesn't give up. If the valve seats were an inherent problem then how come the front head doesn't have this problem? Simple the problem is cause by heat. Take many of these condition I have listed above and combine them you are in for rear valve seat and wiring and fuse block problems.  I guess this is my two cents on the subject.  

 

~Duke   

 

 

 

 

 

 

 

 

 

[JackC 617]

I am a huge ONAN fan.  I bought a 416H with an engine that has a broken rod on the back cylinder.  As eric said the 16s tend to break rods and the 20s tend to throw valve seats.  I did buy a used rod for the 16 and plan to replace the rod and put the engine back in operation.  I also bought a 520HC with a bad valve seat on the back cylinder.  I did buy a used block for it with good seats and cylinder walls for $50 bucks and I intend to put a good motor together.  I can't see going nuts rebuilding the ONANs with expensive new parts since there are too many good deals on used engine blocks and parts and even complete tractors with good engines.  If you know about the heat issues on the wheel horse application and if you are careful they will give you over 2,000 hours of great service.  As far as the louvers on the hood are concerned I have a few 520HCs, (C is for Commercial) that have no louvers and again as long as your are careful you should not have problems.  The carburetors on the ONANs do not like the ethanol crap.

[Desko 624]

Well the ONANS are good motors other than the vale seats heat is a concern to the engine but I don't think its to blame on the oil filter as the twin Kohlers have the oil filter in an almost exact same spot and they do not pop seats(if they have them) never opened up a Kohler but I know that in the cast iron ones had seats cut into as one with the block .

[boovuc 1,090]

In regard to the louvers on the hoods of the 520 and none in the 416 and others.........those louvers really don't do much if anything in regard to cooling the 20 horse Onans. There is nothing to draw are into the louver and even when the tractor is sitting still, very little heat comes through those slots.

[can whlvr 994]

I know one of our Ontario members had a 416 that blew the valve seat,so it does happen,and from what ive seen of his horses they are very well kept

[leeave96 490]

Great info - thanks!

One thing I don't like about the louvered hoods is that if you get some rain on the tractor, the engine isn't covered and if you leave the air cleaner off the Onan, water can make its way into the engine....don't ask me how I know.

[boovuc 1,090]

  It happens! Over 40 years a few of mine "got out" of the garage or shed and were out overnight.

 

And your correct about the louvered hood and rain, snow, debris, etc. (I shy away from any louvered hood tractor that was left outside for any length of time). The 312-A had a louvered hood and I found 2 within the past couple years that I simply saved parts off of. It helps in their deterioration though the single Kohler isn't as prone to electrical issues as the Onans are.  

[can whlvr 994]

I put a hood on my 312-h from a 418,its louvered and I don't like it all,its also hard to repaint as its near impossible to sand all the slots