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1978Simplicity7016H

New 7790 Diesel

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1978Simplicity7016H

Finally got around to bring this 7790 home. Its in pretty good shape and runs great! The only attachments it came with is a front and rear ball hitch and a moldboard plow, but I already have a good collection of attachments.

I cannot believe the power this Lombardini has. No matter how much I tried with a 48" deck and my tiller, this diesel will not hesitate. The deck belt will slip before it taxes the motor at all.

This is the 7790 that Elliott (Simplicity7013H) and I drove at the Monterey plow day. It was the one for sale at the GOTO. He was about to put it on eBay and my dad thought we won't find one closer (about 15 mins from my house) and one in such good condition.

The PO that hosted the plow day is also going to have a garden tractor pull so I plan to bolt on a 3-speed from my 7010 and take it down there. Elliott is hoping to put a tractor together for the pull too.

Here it is. It is running in the pics so it doesnt smoke too bad, but is noisy. I dont know why people say they smell, I actually like how it smells, kind of like vanilla?

image.png

image.png

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427435

I love mine-----------it's the go-to tractor for tilling and snow blowing because it uses so little fuel.

One word of caution------------be sure the cooling fins are free of grass. I bought mine cheap because it was burning oil due to the original owner not keeping the fins clean. That lead to overheating and rings that lost their temper.

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1978Simplicity7016H

So.... I found out why it smells good--- Phil put some scent stuff in the diesel.

I got the 7010 split last night, so tonight going to put it in the 7790.

More pictures to come I have to go.:D

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1978Simplicity7016H

More Pictures!

As you can see I even tried through tall weeds with the tiller and it wouldnt work the motor!

image.png

image.png

Ya that was fun cleaning the tiller out afterwardsm00

image.png

Mark- tonight I will look at the cooling fins, but when I first brought it home I felt it when it was running and it was blowing air, but better safe than sorry!

I cant wait to put the snow blower on it this winter!:D

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MikeES

Daniel when you bolt on that 3-speed be sure to go through the axle and check all the keyways and keys, before the pull.

With the torque of the diesel you will quickly find the weak links.

When my friend switched from a modified Kohler 16hp to the stock diesel 7790 he broke a tube axle and differential. In a hard pull they will hang in there much longer than a gas engine and put a lot of strain on the driveline.

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1978Simplicity7016H

Ok, well I got the three speed bolted in. The brake/ clutch rod fits with the hydro lift lines, but shifter will not. Oh well, I dont want to cut the decal over the shift hole anyway, so I am trying to make a shifter rod in which you reach your hand under the fender to shift.

Mike: do you think the hydrostat would be better for the pull since not all of the power is put to the axle tube? If so, maybe I will put the 7116's trans on. I do NOT want to break the wider, NLA 7790 axle tube, which is the main reason I wanted the three speed. The gear transmission isnt in perfect condition but I have seen axle tubes looser. The inside keys on the tube are good, and the keys on the hub are OK, but not sloppy.

DIFFERENTIAL: lock or not? Least change of breakage? Although much rather it break than the axle.

WEIGHT: I was thinking the wheel weights and two donut weights bolted face down on a non-trip dozer blade frame (no blade) on the front. Will that be enough?

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PhanDad

Very nice tractor; I've been following this thread.Interesting you should mention the axle tube is NLA. I came across this anomaly recently:The tranny parts list for my 75th Ann and other Sovereign's of that era:

AxleTube_PartNo.JPG

And info on it from Jack's database:

AxleTube_Jacks.JPG

Notice the mfg#'s this part fits - all diesels. So maybe the diesel axle tube isn't NLA. And if you bring up Jack's database parts schematic for the 75th (mfg#1692889), it doesn't have the tranny page. So I'm pretty sure the Simplicity parts listing is wrong. My understanding is the diesel axle tube is longer. Anyone have any idea how long a diesel axle tube is?

AxleTube_PartNo.JPG.cbca51f8b6f83819f2a15ce79446ddfe.JPG

AxleTube_Jacks.JPG.b59c759b589f3e3ffc60f4c8113d40ed.JPG

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Simplicity7013H
quote:Originally posted by 427435

Why would the diesel engine up front change anything in back? I'm going to have to look at mine closer and compare it to my 917.


id="quote">
id="quote">It doesn't. The axle is just longer so it could accommodate a larger size of tire.

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1978Simplicity7016H

I don't know how much wider the diesel axle tube is, but its definitely wider. Somewhere on here I read that Simplicity was planning on putting wider tires on the 7790, but it never happened.

I ended up and put the hydro back on the 7790. I didn't want to cut the decal and the hydro lift lines took up most of the center 'channel' above the bgb plate. The clutch linkage fit, but the shift linkage would not. I didn't want to tear it all apart nor did I want to show up to the pull and have to flip the fender every time I wanted to shift.sm00

Now I plan on putting the 3-speed on a 3415S of mine. Put a 1987 Briggs cast iron 32cu in it (with Magnetron ignition) that I fixed up that came from a scrap yard and use it as the 'serious' puller. You know, then straight pipe it with ag tires, weights, and other things to dress it up. Is there a need make the top engine speed faster? Or is 3600 OK for pulling power? I will still take the 7790, but I'm not going to overwork it and break that tube, I guess you could say I am a bit scared I'm going to break it.:I

Thanks everyone for the compliments, it will be taken care of. Stored inside and I checked over all of the fluids. Not going to be a main mower.:D

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MikeES

The Diesel will work fine with the hydro, you will transfer the most power with the hydro full forward, run it there if you can, and let the engine pull down.

I would NOT use wheel weights, use hang on weights, if they will let you. Wheel weights will put extra strain on the axle tube and diff., especially if you have one wheel spinning faster than the other.

You do NOT want to lock the diff., good way to go directly out of bounds, and makes it very hard to drive around. We even took the springs out of our diffs and never had any problems with "one wheel wonder". We put the spacers in from the older diffs, made them much more durable...the springs can compress and the spiders gears can lose some surface contact and break.

In garden tractor pulling you control tractor direction and traction with sifting your weight from side to side.

For the novice weight sifting is the opposite of what you think...if the tractor is going right it means the left tire is getting more traction, so shift your weight to the right to unload the left tire. That is why a locked diff does not work!

The 16hp Briggs should do OK. If they will allow it go ahead and set the governor to 4000, it will be safe and get you a little more speed in the beginning of the pull (more momentum), under load the Briggs (without modifications) will settle in where it wants to anyway (about 2800).

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GardenTrACtorguy
quote:Originally posted by 1978Simplicity7016H

Finally got around to bring this 7790 home. Its in pretty good shape and runs great! The only attachments it came with is a front and rear ball hitch and a moldboard plow, but I already have a good collection of attachments. I cannot believe the power this Lombardini has. No matter how much I tried with a 48" deck and my tiller, this diesel will not hesitate. The deck belt will slip before it taxes the motor at all. This is the 7790 that Elliott (Simplicity7013H) and I drove at the Monterey plow day. It was the one for sale at the GOTO. He was about to put it on eBay and my dad thought we won't find one closer (about 15 mins from my house) and one in such good condition. The PO that hosted the plow day is also going to have a garden tractor pull so I plan to bolt on a 3-speed from my 7010 and take it down there. Elliott is hoping to put a tractor together for the pull too.Here it is. It is running in the pics so it doesnt smoke too bad, but is noisy. I dont know why people say they smell, I actually like how it smells, kind of like vanilla?image.pngimage.png


id="quote">
id="quote">Great find!

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1978Simplicity7016H

Thanks for the comments and replies!

Mike: in that case In will take off the wheel weights and put on frame weights. I tore the 3415S out of the storage container and is now in my shop. Currently with a Vickers hydro, but since it leaked oil so bad I gave up on it. Next is to split it and bolt the gear trans. on. Then to get the motor out of the 7116 (the one from the scrapyard, trust me, it sounds bad but it is a strong runner, it was thrown out since the cam lobe was wore down? I put a new cam shaft in it.) and to clean it up and mount weights.

Ray: thanks for the offer but I will take it easy with the 7790. If I have time maybe switch tranmissions with the 7116.

Jason: thanks for the compliment. I had my eye on this tractor the first time I saw it. I didnt even know Phil had it until the plow day. He used to work for my dad so I know him fairly well. He didnt want to sell it at the plow day, but I told him I would be interested if he wanted to sell. I have to say, its a pretty cool tractor! VERY POWERFULL!! I have yet to hear it lug down!

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1978Simplicity7016H

Elliott- not really, the 7116's motor does not have a starter, and I want to put a S/G on it, then after the pull I will put it back in the 7116.

For right now it is a choice motor since it is a strong runner with magnetron ignition (then I won't have to worry about points and condenser affecting ignition at the pull, just reliable pointless ignition)

The 3415's motor came with a cracked rod

Would you rather me break the 7116s axle tube and I can replace it or break the 7790 axle tube, and chance not being able to replace it?

I probably won't even have time to tear the 7116 trans off.

I don't use the 7116 anyway since I have to pull start it every time I want to use it.

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Simplicity7013H
quote:Originally posted by 1978Simplicity7016H

Elliott- not really, the 7116's motor does not have a starter, and I want to put a S/G on it, then after the pull I will put it back in the 7116. For right now it is a choice motor since it is a strong runner with magnetron ignition (then I won't have to worry about points and condenser affecting ignition at the pull, just reliable pointless ignition)The 3415's motor came with a cracked rodWould you rather me break the 7116s axle tube and I can replace it or break the 7790 axle tube, and chance not being able to replace it?I probably won't even have time to tear the 7116 trans off. I don't use the 7116 anyway since I have to pull start it every time I want to use it.


id="quote">
id="quote">Ok just wasn't sure

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427435

I think that added weight on the wheel would put less stress on things than weight added to the frame. Weight on the frame not only increases the weight on the ground and traction force (same as wheel weight) but also puts a vertical bending load on the axle tube.

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Simplicity7013H

Found pictures from the plow day! Daniel on the 7790 before he got it:D The PO was nice enough to let us both take it plowingdOd

daniel.jpg

7790.jpg

front7790.jpg

plowday.jpg

Im on the Landlord and Daniel is on the B10

daniel.jpg.cdffc65047f1fa3d58d36864f0e197b4.jpg

7790.jpg.ad60d678cb0426b9d5c223c4741d44a9.jpg

front7790.jpg.3652fd1e1c7031bde40c1ea659af6309.jpg

plowday.jpg.2d08e8851e39a633a5753d6ce2711867.jpg

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