[dco43054]

First post in a long while. But it finally has become time to do something with the Onan B43G on my '86 JD318, and I thought I'd get some advice from the experts here.

The tractor still is in great shape with about 1,100 hours total time. The hydro drive and hydraulics are working fine. It has a 50" deck and 2 way blade, weights and chains. So it it set up pretty well.

The worst part of it is that is missing the badge on the grill. Must have lost it somewhere over the past 26 years!

But at this point, the engine needs attention. There is oil leaking down the right side of the frame. I just noticed it at after cutting season ended. Went down to the barn one day and noticed a little puddle on the floor. Haven't popped the covers to see where it is coming from.

I could tell it was down on power the last couple years. The oil leak just reinforces the need to do something with the engine. I've spent the last couple hours reading 318 engine threads. Some people think the Vanguard repowers are the way to go. Some think that rebuilding the Onan is mo' better.

I don't think I'm in a position to rebuild the Onan myself. I've got above average mechanical skills, but haven't rebuilt an engine in a long while, and don't have the right tools to clean up the cylinder bores. Before I made that decision though, I thought I would ask those of you who have done one.

For reference, I see that Kustom Lawn & Garden sells long blocks for $1,400 plus shipping. Small Engine Warehouse sells Vanguard 18's for $1,550 plus shipping. For the hassle of tearing down/refitting the components to the long block, it seems that the SEW 18 would be the way to go, and then I could sell the Onan and recoup some $$s.

Anything else I should be thinking about. I know there are some that have had issues with SEW, but it seems overall, their reputation it good.

The only other issue I have is that the mounting holes in the front supports on the mower deck have rounded out a bit. I could always get them filled and redrilled.

This has been such a great unit that I hate to sell it and get something else. I've owned it since '97 and the only thing I've had to do is change fluids and dress up the points, change plugs, some belts, other minor things. It seems like it would be worth the money to repower it and hopefully it would go another 15 years.

So - what do you all think?

Many thanks!

Dave

 

[biker3777]

First off you have a real simple motor to rebuild.Most likelyall is wrong is worn rings and the oil leak is from the filter.Go buy you a cylinder hone and do the ring job yourself.Rings will be under 40 bucks,head gasket 8 $ eack and oil pan gasket ?I reuse mine.If you have above mechanic skills you can do it.$ bolts to remove the driveshaft,4 bolts to get the engine out,4 bolts to get the oil pan off.

 

[boomers_influence]

dave
rings alone are seldom the total problem.
my first suggestion would be a leak down test.
this will tell you where you are loosing the compression,
and thusly the power.
valves can be a problem also.
the last B 48G i did had both exh. valves bad.
an earlier B 43G had both intake valves bad.
if you can feel a lip at the top or bottom of the cylinder,
it is most likely needing a bore job.
good luck. boomer ( the used onan engine parts guy )

 

[dco43054]

Thanks, gents.

I do have a compression tester and will do a compression test before I do anything.

I am concerned that if there is wear in the cylinder that it will ned the ridges reamed from the top of the bores, and then the cylinders refinished. And if i get into those expenses, will I end up with something close to the cost of a long block, or repower.

I was also wondering about the bearings. I've run the recommended nondetergent straight 30W in it. But given how much dust, etc. gets thrown around while mowing, I was concerned about bearing wear.

 

[mikebramel]

I dont want to say a compression test is a waste of time but with a leak down test the air can POUR out of the valves and it can still read like new on the compression test. If you have kept clean, sufficient oil in there I dont see why you would need new bearings at only 1,000 hours.

Do a leak down and see where you are at

 

[biker3777]

If you have serviced it you will probably not have a ridge.Glocem is ringing his 420 and it only had .005 wear.I agree with Boomer and I have done rings,valves and guides on the b43.But is is a call you will need to make,the guides are pricy but if the valve stems are not sloppy the guides are ok,but I would put the new seal on the ext valve but your are not going to spend a lot of cash if you do it.

 

[boomers_influence]

dave
NON detergent OIL ??????
you have a filter, you WANT detergent OIL.
boomer

 

[dco43054]

dave
NON detergent OIL ??????
you have a filter, you WANT detergent OIL.
boomer

The local JD I bought it from said the mfr's recommendation was a non-detergent straight 30W. So, that's what I've been using for the past 15 years!

I tend to follow what the manufacturer recommends. Especially on the detergent vs. non-detergent front. I had always heard that changing to detergent without a complete and effective flush could loosen deposits and plug up small oil passages. Since the tractor was 11 years old when I bought it, I just continued on with the Mfr's specs.

 

[boomers_influence]

dave
the problem, is the person that told you
NON detergent oil is WRONG.
Onan never used non detergent oil in your engine.
there are no small oil passages in an onan engine.
thank you. boomer ( the used onan engine parts guy )

 

[D-Dogg]

On the subject of oil:

Manuel says 30 Wt is good from freezing to 104 degrees out. API service spec SD, SE, SE/CC, or SF. If you are getting your 30wt from the JD dealer (Torq-Gard), it has detergent additives.
See: http://www.greenpartstore.com/assets/images/Oil_Sales_Guide.pdf

I think a lot of us confuse 30 wt oils. Some say "straight 30 wt" and assume it to mean non-detergent though this is not the case. To tell you the truth, it's getting a little less common to find 30 wt non-detergent for my old splash lubed engines.

 

[rscurtis]

I had three of those engines on stump grinders, the worst thing you can do to an engine. All suffered from premature ring wear from the poor factory air filters. Biker is correct, replace the rings and go. As mikebramel said, the bearings should be fine as long as the engine was not run low on oil. I even had one of these engines I re-ringed twice, still using the original pistons. When you're done you'll have a good engine and $1000+ dollars in your pocket. And ditch the ND oil, it's not recommended in any engine.

 

[dco43054]

Thanks again for all the info.

And I can't believe I've been putting in the wrong oil for so long. And it's a PITA to find, too!

I even bought the owner's manual when I bought the 318. It clearly says SD/SE/SF oil. Oh well, you learn something new every day.

 

[biker3777]

Jd 30wt torq guard,cant go wrong

 

[dco43054]

And I did go down to the barn last night and pop the right side cover. Anyone who guessed "oil filter loosened up causing oil leak" was correct. Never had that happen before. Tightened the filter about 1/8 turn.

If it gets nice (as in warm) this weekend, I'm going to bring it up to the house, clean the engine up, change the oil, and test the compression. I don't have a leakdown tester, but I will take a look to see if any of the local auto parts shops offer one for rent.

 

[D-Dogg]

I even bought the owner's manual when I bought the 318. It clearly says SD/SE/SF oil. Oh well, you learn something new every day.

I like ole Manuel too. He is one smart hombre. :trink40:

 

[rscurtis]

Don't worry about the compression. I don't even own a compression tester. If the engine starts fine and doesn't have excessive blow-by, the compression is OK. If it's burning oil, it needs new rings anyway.

 

[dco43054]

Compression is about 90 in the left cylinder, 100 in the right. Not bad for 26 years old and 1,100 hours.

I appreciate all the input. It would be nice to get a fresher motor in it. Have to figure out what I wan to do this year.