77 Satoh Beaver S370D wont start, low compression

[HomesteadOC]

Just got off the phone with the super nice guy at NCW, pistons are designed to be off axis like that, the squared off nub is oriented toward the fuel injector port on the head. Factory valve seals are the 13mm variety that are included with the top end kit, mine are 14mm and apparently have been replaced at some point in time. He is including a set of the 14mm seals with the new piston and pin I had to buy. Ill have to check my piston when I get home to make sure I had it pressed on correctly. The bearing tabs are on the same side of the rod as one another and those point towards the fuel pump, my rods lettering are orientated towards the front of the engine and the bearing tabs toward the fuel filter so were all set there. But Im pretty sure I have the piston on backwards, Ill give an update when I can get home. As far as the relief on the piston goes, it burns more of the fuel that enters the combustion chamber, not less like ai said a few days ago in this thread. Im not sure how it affects the power, but they are called decompression reliefs so Id imagine the power is decreased with increased fuel burning and exhausts less smoke. Im happy with this compromise, I prefer to breathe less smoke when I operate the tractor. I havent actually driven it with the flat top pistons so theres nothing to compare it to, but less smoke is always better. I also prefer less noise, but Im not sure how I can do that yet. Maybe a stack with an extra muffler?

 

[HomesteadOC]

My piston reliefs were not machined, they have to be part of the cast because they have the same bumps and divets as each other. I guess theyre all like that so they all must be right or all must be wrong. I asked about the valve guides if the earlier version heads were larger and mentioned your 78 G154 and my 77 satoh beaver having the same issue with his valve seals. He says theyre speced in the manual at 13mm so our heads have to have been changed at some point in the 40 years theyve been around. That makes more sense than, he gave us the wrong ones, lol. Hes a super nice guy and just offered to send me ones that fit my 14.05mm measurement, he knew immediately after I told him the measurement what probably happened. Also got a better price on the new piston because I didnt have to buy the rings with it, so thats awesome. I bought a few things from stevens tractor website and the customer service wasnt really there, took days to respond to email and wouldnt answer the phone. This guy at NCW is on it, even on a saturday when the website says theyre only open M-F. Hes really knowledgeable, courteous, helpful, respectful, cant say enough good things about him.

Ill try the RTV around the oil and coolant passages on the gasket and hopefully prevent something in the future. Do you put it on both sides of the gasket? If only one side, which one?

 

[Ilikeurtractor]

The engine with the valve/decompression relief pistons I had put in actually smokes more than my other ones. I probably need to have my injectors checked for set pressure and/or cleaned so that could be contributing to the issue. I suspect a lot of the smoke has to do with the late timing of these engines more than the piston design. I have a hard time believing burning more fuel with lower compression results in less smoke but in reality it's probably not noticeable in otherwise identical engines.

The pattern in the pistons I installed in the bored out engine were definitely machined in. They could very well be cast as well though I suppose but not in mine. Cast parts typically have a grainy look to them like the inside of the pistons. Most, if not all, of the outside of pistons are machined after being cast. Maybe some piston crowns are left in an as-cast state but I don't think it is common and anything in the last couple of decades.

Yes, Wynn (I think that is the spelling) is a knowledgeable and helpful guy and fun to talk to. I thought he was the owner of NCW but he told me he wasn't.

You'll want RTV on both sides of the head gasket around the oil and coolant passages. Just a thin film applied with your finger and only extending around 1/4" to 1/2" around the passages. You can apply it to the head and block or to both sides of the gasket. I wouldn't do both. You want to minimize having it "press out" into the passages. Keep it away from the metal rings and piston cylinders.

 

[HomesteadOC]

I started draining the front and rear axle fluids and checked out the filter. Oil was very chunky and sludgy up front and the transaxle/hydraulic oil was greenish and thick. The filter screen was destroyed and Im not sure if I can replace that screen or I have to go with an entirely new filter for that. I was thinking it would probably be a good idea to add an inline screw type filter that could be changed without draining all 2+ gallons of hydraulic oil. Im sure someone has done this before on this tractor, maybe you got a video or some direction on which hose to put it on? Heres the video of the honing results using a stone hone, not sure of the grit its the one that comes on it from the auto parts store loaner. Id say its about 120 grit. Also theres video of my oil draining and filter, enjoy!

 

[Ilikeurtractor]

The hydraulic screen in mine was tore up too. Unfortunately those screen assemblies are hard to come by, but I wouldn't be surprised if Valley Power can supply them although I bet they will be pricey. The good news is you can install new screen material over the frames which should always be in good shape. I used this - 100% Copper 50 Mesh 270 Micron filter Sift Screen. You should be able to find it around (eBay) and you don't need much. I think I have enough to do a dozen or so assemblies although I doubt I ever will do that many. The tough part is getting the screen to conform to the tube so you can solder it along the seam. Making some sort of jig would be best, like a pipe that fits snugly over the top with a slit in it. I managed to awkwardly hold it in place and solder it but I wouldn't want to do a bunch of them that way.

 

[HomesteadOC]

Zip ties sound like the best solution, Ill give that a shot once I find the material. How did you decide on that particular 50 mesh in copper at 270 micron? Stainless seems like the stuff thats already on there. Any chance I can buy a piece from you good for 3-4 filter housings?

 

[Ilikeurtractor]

I just picked what looked close and was available. Anything is better than the hole size in the frame- lol I’m pretty sure the screens I’ve seen are copper. I don’t think stainless solders as well but maybe it does. Stainless would probably be better as it’s stronger but harder to attach I would think. I’m not sure why these screens are getting torn up but not all of them do. You can buy a roll of the screen for $19 shipped to your house off eBay. Since this probably won’t be your last tractor you’ll have plenty for your next ones

 

[PILOON]

I'd go fine mesh in brass and simply solder in an overlap fashion.
(I assume most are a 'cage like or basket design'.)

Repaired mine that way!

 

[HomesteadOC]

Copper will definitely solder the best. A friend said stainless and tack it into place, but that seems like it might not work so well and could destroy the basket. Anything is better than whats there, and Id like to add a remote filter on the return line so I can check and change it without draining the oil. Im not sure how your bolens or isekis do it, but the filter in the beaver is at the lowest point so you have to drain before you pull it unless you want to drain and pull it at the same time. Ive seen a lot of other tractors have them in a better location, like under the seat or next to the shifter. You ever try the remote spin on filter?

 

[fxrs55]

holy moly
I started reading this thread from a link in the Iseki forum.
I broke out in a cold sweat seeing all of the problems
HomesteadOC was having. talk about deja vu.
I also bought gaskets from NCW and the head
gasket started leaking coolant out the injector side
and oil out the air intake side. After all the work I
put into my tractor I was a bit miffed but you get
what you pay for. I ended up buying a factory
head gasket from Small Import Tractor Supply.

Small Import Tractor Supply - Home

The head gasket was $145 which is over twice
what I paid for the one from NCW. If you use
the one from NCW then maybe using RTV like
Ilikeurtractor said would work. How about a few
pictures of the whole tractor just because we
like to look. In order to get over the cold sweat
and shakes from reading this post I had to go
out to my garage and start My Iseki and drive
around the yard. Good luck with your tractor
when its fixed and running you will feel excited
that you fixed that tractor.