7118 Repower

[dmal195]

Hello I'm new to the forums but have been using Simplicity tractors for years. I have posted this question the other night and got a nice reply but I had the model of the tractor wrong in the subject. So I thought I would try again.

I have a 7118 that has been repowered with a 16 hp Briggs. I have the original motor which had a dropped valve seat when I got it. Its repairable so I've kept it. The Briggs has started to burn oil it's acting like a broken ring. So I'm working out what I want to do. I also have a 20ish HP Briggs apposed that is a fresh overhaul. I would love to put the 20HP in but not sure if the cylinders will clear the frame. I know I could just set it in and mock it up but would like to have a better plan before I take everything apart. So my question is has anyone on here done this before? I searched the forums and didn't find anything. Thanks

 

[PhanDad]

There wasn't a 7118, to the best of my knowledge.  If the 18HP engine that was in your tractor was a single cylinder Kohler, those engines were in the 7000 series tractors.  

Some pics of your tractor would help.  The reason it makes a difference, is the 7000 and 7100 series tractor frames are different.  Most of the 7100 series frames had the sides cut out for the opposed Kohler KT 17 and 19 HP engines.  

 

[dmal195]

Thanks for the reply. Not where I can get pics of the tractor right now. I know the 18HP Kohler Single was factory installed. My Grandparents bought it new. I will get pics when I can

[Brettw]

This will be interesting.  Maybe a rogue 18 horse left over engine from the 7000 series and the factory popped it in a 7100.  Hard to picture making 7118 decals for a limited run, but..........   Anyway, I have a 7119 that's been repowered with a M18.  Closest I have ever seen to a 7118, and there are a lot of them out there with either M18's or M20's as repowers.

Edited July 16, 2019 by Brettw

[dmal195]

So I finally made it out to the tractor and it's a 718. I had to many numbers in my head when I made the post. Sorry for the confusion. 

Back to my original question has anyone put an apposed Briggs in one of these?

Thanks

[Alltractoredup]

The briggs opposed twins were not very popular engines to my knowledge.  The frame would need to be notched out like the 7100 series Sovereigns.  I am guessing the Briggs may have solid state ignition but I am not sure so wiring may be something to consider.  

If it were me I would repair the 18hp. The Allis 718 and Simplicity 7018 are rare tractors

[dmal195]

The wiring doesn't bother me but I dont want to cut the frame. Would like to be able to return it to stock later

[TimJr]

Parts for the OHV Kohler 18hp like that are pretty tough to find.  At one time pullers liked them and killed a lot of them.  Pretty obsolete now.  I agree it would be cool to have the correct engine in it, but you are going to need to do some searching and forking over cash to get parts for one of those.

[wwbragg]

30 minutes ago, dmal195 said:

I dont want to cut the frame

From a flat surface, measure to the center of the driveshaft of each engine.  The difference is how much you need to raise (or lower) the replacement Motor off of the frame.  Now measure that distance off of the frame to see if the cylinders will clear the frame.  If not, use a different replacement.  

Edited July 27, 2019 by wwbragg
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[GardenTrACtorguy]

Glad to hear about another Allis 718!  I have one that I put a K361 one back in after a previous owner put a 12 horse in. (Half regretting it as I can not get it to run right.😥

[dmal195]

Well I can't being myself to cut the frame on this tractor it's too nice for that so it looks like I'll be rebuilding the 16 horse that's in it now. Back in the day you could buy a piston and ring set and a new rod fairly cheap now it looks like it's going to be a couple hundred bucks. Oh well what do you do.

[kwt]

A dropped valve seat doesn't sound like that big of a deal to me. I've never even seen an overhead valve Kohler single, but it just seems too cool to me to let it sit under a bench somewhere. I personally would tear down the Kohler to at least see what is really wrong with it.

 

http://www.kohlerengines.com/engines/onlinecatalog/pdf/tp_1288.pdf

[MrSteele]

I inherited one in a Cub Cadet. Same thing happened. Exhaust valve seat decided to come loose. I found a used head that solved the cost problem. Got the used head for $20, a new one is available for around $160. I have considered piening the old one back in like was done on cast iron engines. Not sure how well it will work on aluminum, though I was told it would

On 7/26/2019 at 8:44 PM, TimJr said:

At one time pullers liked them and killed a lot of them.

The engines are self destructive, don't need pullers to kill them, they do it nicely on their own!

[kwt]

7 hours ago, MrSteele said:

I have considered piening the old one back in like was done on cast iron engines.

I piened one back in on an 11hp horizontal aluminum flathead vintage ~ 1990. Never had another problem.

[MikeES]

11 hours ago, kwt said:

A dropped valve seat doesn't sound like that big of a deal to me. I've never even seen an overhead valve Kohler single, but it just seems too cool to me to let it sit under a bench somewhere. I personally would tear down the Kohler to at least see what is really wrong with it.

Open up the K361, you may be surprised at how little damage may have been done.  Many of the lower end parts are interchangeable with the K341 (16hp). 

Best case a new valve, valve seat, maybe mill the head so it is flat, peen in the valve seat and away you go.

Worst case is wreaked piston and cylinder damage.  You can overbore it, but the oversized pistons are $$$.

[kwt]

That 11hp briggs that I piened the valve seat back in? That is ALL I did to it. Reused the same head gasket. They quit running right away when a valve is held open.

[dmal195]

I have looked at the Kolher and it wouldn't take too much to fix it. I'm just not that familiar with them. The tractor has all ready been converted to a 16 hp Briggs, so I pulled the briggs out last night and pulled the head to see how bad it was. Standard bore so should be able to bore it oversize and a new piston and rod, a gasket kit and maybe a bearing or 2 grind the valves and back together.  Where does everyone get there briggs parts. I've been doing some looking at my normal suppliers (I'm an auto mechanic during the day) and there prices seem high. 

[TimJr]

You can't compare Briggs or Kohler parts prices to car parts prices - it will hurt your head.  Pistons are stupid expensive compared to most auto pistons.

However, remember you get what you pay for - do you want some knock off piston, or one like what has been in the engine for the last 30 years?

Pretty sure for OEM on an iron Briggs, you can only buy a standard or .020" over piston anymore.  They obsoleted the .010 and .030.  Correct me if I am wrong, but that was true as of a couple years ago.  I simply can't understand why they did that.  At the very least, I can't understand why they didn't keep the .010 and .030 pistons if they needed to cut inventory down.  Who is putting a new standard piston into a 30 year old engine?  Give me the .010 to do a proper rebuild on a used original engine and give me the .030 for one that had a bad bore or for a 2nd rebuild.

I want to say that the .020" under rod is NLA for the Briggs also - at least from Briggs.  I could be wrong on that.

There is aftermarket - I guess just do some research and get some good opinions on durability.  Also - talk to whoever is doing your machining - they may have some valuable opinions on parts quality from the aftermarket.  In years past, the local machine shop would talk about how widely aftermarket small engine pistons would vary for actual diameter.  OEM pistons were consistent and accurate on OD.

A K series Kohler has much better aftermarket support due to the tractor pulling business.  Parts might not be cheap, but you can get some pretty awesome rods and pistons for a K series, including rods that use insert/shell type bearings.

[oldsarge]

A K341  16hp would drop right in. and make a great machine   A B&S twin takes frame cutting and re-enforcing.My uncle's shop did more than one when valve seats  overheated out!!!!

[dmal195]

Thanks for all of the advice. This is such a great site!

Right now funds are tight so buying a motor to put in this is not in the cards. If I can I'll rebuild the Briggs that was in it. I don't want to cut the frame to install the twin.