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Discussion Starter #1
Hello all.

I just bought a 446 from my Captian for $350 in nonrunning condition. It came with a mowing deck, 3point, and furrow plow. Overall it is in very good condition with the exception of the engine. According to him, he had just started it and had it sitting at idle. Shortly after it began to begin making a knocking noise and then shut down. This all happened with in a few seconds.

Well, I have already pulled the engine out and began to disassemble it. What I have found is a broken cam gear and the cam is very loose in the bearing hole. I haven't gotten the cam out yet because I didn't have a spring compression tool (I will Monday.) I am worried that the bearing hole may be out of round. I am also at a loss as to what caused all of this damage?

I have already talked to a local Onan dealer and sourced all of the parts to do a partial rebuild including both cam and crank gears, cam bearing, gasket set and rings for about $400. I would like to find a used set of gears to save some money but haven't had much luck so far. Any suggestions on where to save a little money for this rebuild?

I have also considered an engine swap if I can do it without hacking up this tractor. I read a little on the vanguard swap but am not a huge fan of this engine. I feel they are Inferior to the Onan that is in it. Any other engine suggestions? A Honda, Kawasaki or some kinda diesel would be awesome if could do it, like I said, without hacking up this tractor. My plans for this tractor is to use it as a work horse. Very little mowing will be done with it, as I have a ZTR for that.

At this point any guidance would be great.

Thanks, Chad
 

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The simplest and most long-lasting solution is to do a complete and thorough rebuild of the existing Onan. Don't try to save bucks by going with used parts because those might fail on you sooner than you'd like. Do it right, do it once. That Onan has probably been in that tractor for over twenty-years. That should tell you something about the durability of these engines. Case chose them because they were the BEST that could be had at the time. Had it not been for stringent pollution standards, Ingersoll would still be using Onans today.
 

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I agree that a total quality rebuild is the best answer if you want a tractor that will operate pretty much as new for another 30 years with little additional expense. Most of the engine swaps fail, in my opinion, because they alter the tractor in ways that make it virtually worthless in the resale market; exhaust systems must be cobbled together, the front PTO must be changed to electric, custom pump mounts must be fabricated and the hood often has to be modified to fit the engine. With these changes an Ingersoll dealer will likely not want to work on it so whoever owns it will have to be self sufficient in repairs.

On the other hand, if just want a workhorse, don't care about the looks and don't have any intention of selling it for a long time then an engine swap can be a cheap way of have a strong functional tractor. If you don't need to use a mower or snowblower then you can forget about the front PTO and any engine of about 12 hp or more will do the job.
 

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Discussion Starter #4
Any idea what could have caused a failure like this? I 100% trust the guy I bought it from and the history of its care and use. It still had a case full of oil in it when I disassembled it so starvation is probably not the case. My good friend and the guy that will help me rebuild this thing is a small engine mechanic and though he has never rebuilt a Onan, he has rebuilt hundreds of engines and has never seen one do this. I will likely rebuild the Onan that is in it after doing some more research. I plan on replacing the cam bearings, cam(if it is damaged) cam gear, crank gear and rings for good measure even though it didn't burn any oil and has good compression. Should I do anything else to it?

Thanks, Chad
 

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Sorry if you find this to be a bit blunt but anything less than a full rebuild is a waste of time and money. The block should be stripped clean. The cylinder bores should be check for "roundness" and size. Boring them ten or twenty thou is likely in order. The valves should also be done including the guides. The crank should be checked for size and ground if needed. That means new pistons, rings, wrist pins, connecting rods, cam bearings, crank main bearings, cam gear, crank gear, all gaskets and seals and the cam should be profiled to check for wear.

If this mechanic has never worked on an Onan before, then he should join the Onan site at Yahoo for guidance. No matter how good a mechanic he is, Onan's are not like other engines and there are lots of helpful tips he can use to save time and make sure that you are getting the best possible end result. Don't let his ego get in the way here or both of you may be sorry afterward.
 

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Discussion Starter #6
Thanks for your reply. I don't know if I am ready to spend $1k on parts for an engine. I never said anything abot him having an ego. I made the claim about his experience, not him. He knows the special needs of the Onans, he has just never rebuilt one. This guy is very maticulous with everything he does so I know it will be done right.
 

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Chad,

CGT's suggestion to join the Onan engine group on Yahoo is a good one--there are number of very experienced Onan experts who post there regularly and they have seen everything. They will likely tell you that you must determine what caused the cam gear to self destruct and not just replace it or you will repeat history.

CGT's advice to do a "complete" rebuild will result in an engine that should give you 3000 hrs or more of trouble free service but if the engine has relatively low hours and you find the cylinders are within spec then you can probably get by cheaper. If you go the cheaper route maybe you'll only extend the engine life by 500 or 1000 hrs instead of 3000, you pay so its your choice.
 

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Thanks for your reply. I don't know if I am ready to spend $1k on parts for an engine. I never said anything abot him having an ego. I made the claim about his experience, not him. He knows the special needs of the Onans, he has just never rebuilt one. This guy is very maticulous with everything he does so I know it will be done right.
Currently, repower kits are about $1400.00 using either a Vanguard or a Kawasaki twin. However, the hood must be raised at the front to make these engines fit. You have to modify the OEM wiring harness to accept the different engine. Often the sides of the hood must be bent outward for clearance.

You end up abandoning the tried and true mechanical clutch that is easily repairable and fully adjustable for a very expensive non-repairable, non-adjustable electric clutch and you have to carve a hole in the dash to install the switch that controls it.

Sticking with the Onan involves none of the above. There is no "engineering" needed and the longevity of the Onan is a known factor. The current replacement cost of your tractor alone is likely six grand or more at the dealer. These are not your big box store el cheapo lawn tractors that use low quality engines, trans-axles and stamped steel parts in order to meet a price-point. Yes....parts for Onans are expensive but they are high quality parts for a high quality engine used in a high quality, true garden tractor.

If you buy a Rolls-Royce, then expect to pay RR prices at the parts counter. But in return, you will get an engine with a very long life expectancy if it is serviced properly.

As for my comment about ego. I know how some seasoned mechanics think. Their attitude is that they know it all because they've been rebuilding engines for twenty or more years. I said what I said because of my own experience in this area and I was trying to tip you off that ego might get in the way of you getting an engine that would last as long as it should. One small mistake can make all the difference. You came here looking for advice and it's advice you are getting. What you do with it is entirely up to you.

After all, it's your money, your tractor and your time.
 

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OK, well.... Im going to take a slighty diferent tack then the rest here.....

Ya, it would be best to do a full rebuild on it, and it WOULD be worth it, but I also know that some times it comes down to eather doing what has to be done, or not doing it at all... Frankly we sometimes have to cut corners and work with what we have. That being said, I would probably use the new gears, and not mess with used...

Next up is the Q about repowering.....

Well frankly a repower will cost you more... That being said, I am not a big fan of the later 16hp Onans myself... If I was not using it for mowing, I would probably be looking at eather one of the Vangard twins, or serching for a oil burner to swap in
 

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"That being said, I am not a big fan of the later 16hp Onans myself..."

Ingy 444, Not meaning to be judgemental, but how much experience have you had with the later Onans? From my experience, both the B series and the P series have a proven track record of 2000 plus hours with a good trouble record, on average! They have been out of production for 20 years, and still running fine, Yes, some have had broken rods, or valve issues. Can you name me an engine which has not? Even the Linamar's seem to be doing well from a service stand point.

I see no reason a person should hesitate to to rebuild an Onan! MHO <G>
 

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LOL!! Oh I know just one of my little qurks :D :D... I have a little experance, but not alot with them. It may be unfounded, but I just see a lot with busted rods.. Agean just kinda a personal preference.

Now a old cast iron Onan... or the later 18/20 hp ones... I have no issues with at all.
 

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LOL!! Oh I know just one of my little qurks :D :D... I have a little experance, but not alot with them. It may be unfounded, but I just see a lot with busted rods.. Agean just kinda a personal preference.

Now a old cast iron Onan... or the later 18/20 hp ones... I have no issues with at all.
I understand, Paul! I have rebuilt far more "K series" engines, than I have Onan's! But quess what, it is because I have had experience with them for 60 years! Only 25 years for the Onan! Any good engine is going to develop a record of problems when they have been as heavily used for as many years as both the Onan and the K series!

I currently have 4 Onans with broken rods, because I have been seeking those tractors out! I also have one BS Voyager with the same problem. I find that in most cases, these tractors display a definite "maintenance" issue. I also have a '78 and a '79 446 that are original and run like tops!

Personally doubt that I will ever run a one lunger again, accept under 10 HP.
 

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Discussion Starter #13
I got the engine apart today and found that the cam bearing was the point of failure. And by the looks of it it has failed before while in the original owners possesion. I know this because someone has tried to knurl the bearing surface on the block to help hold it in place. Talking to two different local Onan specialist, they both agree once a bearing spins, the block is trash.

At this piont I need pretty much a new engine. I know I can't replace it with a new one for less than $4-$5k but if I do a rebulid I'm going to be at least $1200 into it. And it is barely worth that much after I get it back together. I have some decisions to make over the next few days as to rebuild it or part it out and make my money back. I need a tractor but I don't have that kind of money to fix it right now. This really sucks because I just sold a Cub 682 with a 17hp castiorn kholer with 300hrs on a rebuild:banghead3

Thanks, Chad
 

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Chad,

There is another alternative and that would be to simply install a good running used engine. I've purchased several for $500 or less and they have a lot of hours left on them.
 

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Discussion Starter #15
A $500 Onan in good running condition? Where? I have looked and found nothing. Guess I have to wait.
 

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Contact Joe Hemmi at Joe's Outdoor Power on ebay or Daniel Haas <[email protected]> and they may have something--both reputable people who will not sell you junk. You can also post a message on the casegardentractorgroup and the Onan groups on yahoo.
 

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Another option would be to find a good block with the cam and use your pistons rods and crank. I have a couple of blocks that broke rods. I could mike one out, assuming your engine was in good shape, other than the cam.

Shipping on a block with cam and valve train should be reasonable. I would be willing, if you are interested. $50 for my time, plus shipping.

Send a PM if interested.
 

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Discussion Starter #18
Magnum, You say you have a block cam and valve train for $50 plus shipping? Shoot me a shipping quote to a business at zip 74146. I may go with that. There is one on ebay right now for a little cheaper but it is sold as-is. My crank, rods, pistons, cam and valves are all in good shape just the block, gears and front bearing is shot.

Thanks, Chad
 

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Magnum, You say you have a block cam and valve train for $50 plus shipping? Shoot me a shipping quote to a business at zip 74146. I may go with that. There is one on ebay right now for a little cheaper but it is sold as-is. My crank, rods, pistons, cam and valves are all in good shape just the block, gears and front bearing is shot.

Thanks, Chad
I'll strip it out, mike the cylinders and get a weight. Will try to get it done tomorrow.

But you need to send me a PM, because I have difficulty getting back to threads if no new posts.
Just left click on my avatar name, then click "private message." Give me your complete address.
 

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Discussion Starter #20
Will a 18hp of the same vintage work in my frame? I'm pretty sure it will since they came in the 448's which shared the same frame right? I did notice that the 18hp's have a bigger crank shaft on the pump side.
I have also found a couple of engines without the front pto/fan setup. Can I swap on my flywheel and use the shaft off of the engine from the 446?

These are what I have found so far.

http://cgi.ebay.com/John-Deere-318-...5|66:2|65:12|39:1|240:1318|301:0|293:1|294:50

http://cgi.ebay.com/onan-2-cyl-16-h...0?hash=item3a3d3d94ef&_trksid=p3286.m20.l1116
 
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