77 Satoh Beaver S370D wont start, low compression

[HomesteadOC]

Looks just like mine did except my front cylinder had the stuck rings and the rear rings were free but had the lower compression similar to yours. A hone and new rings should get you back in business. Usually I would have the head gone through with new valves, valve grind, and seals but this last one I didn't. I would still recommend installing new seals but I think if you just do a quick lap of your existing valves that should be fine. On mine the rods had numbers punch-marked into them. Keep the numbers together on the rod and cap. I can't remember if the numbers went to the right or left of the engine, but seems like it was the right. It does matter according to the manual and it says in there somewhere.

Yeah, got to get the seals and a valve spring compression tool. Im hoping the auto parts store has one to lend. Ill have to check the manual for valve seal size, I havent seen them specifically on any of the online stores. Where did you get yours? Ill see what everything looks like before I buy new valves, theyre pretty stocked with carbon but Im hoping for a diamond in the rough. I was also considering a self done port and polish type of job, something to grind down the casting marks and gasket match. Is this advisable? This guy does a really nice job and makes it look easy.

 

[Ilikeurtractor]

I think I purchased seals from NCW but now that I think about it they were the wrong size and so is their oil pan gasket. You might want to try other sources for those. A port and polish isn't probably not going to gain you much. All good experience though.

 

[HomesteadOC]

What about the rings or valve cover gasket from NCW? Where there changes in the pan through the model years? My KE70 is probably one of the early models, what year is your Bolens?

Got the valve cover, oil pan, coolant and intake manifolds parts washed and media blasted, they look great. The coolant manifold has a lot of corrosion and some pin holes that go all the way through. Im going to see if it can be welded, if not maybe jb weld or rtv. Ill post a video a little later, its hard to video media blasting, but Ill get one of everything when Im done. Ill be parts washing the head tomorrow, is that safe for media blasting? What about the valves?

Also, what about engine paint? Im trying to find a blue that matches the closest. My choices are ford blue, ford dark blue, old ford blue, and gm blue by rustoleum. They all look pretty close, especially ford blue and old ford blue. I need to order it before the valve cover and oil pan go back on, probably shouldve figured it out before I media blasted them.

 

[Ilikeurtractor]

NCW can supply "square" or "keystone" rings as can most importers. The keystone ones are claimed to be better to prevent sticking. I believe you can use either. I can't remember the details, but the manual says something about engines with serial #s below 51,000 having a different style of rings. I'm not sure if this is just the square vs. keystone type or something different. My engine with the low serial # (<= 19,000) had a thinner top ring so I had the pistons machined to make the new rings fit. I don't know if keystone rings require a piston with a matching "keystone" groove. I'm sure some time spent searching the web will answer it or call the guy at NCW. He is pretty knowledgeable about them. They can provide the correct valve cover gasket.

I'm not aware of changes in the oil pan, but maybe there was one.

The G154 was a 1978 so the serial # is probably close to yours.

Generally just a parts wash on the head and valves is fine unless you have some stubborn carbon. You don't want media getting into places it shouldn't be. Not sure about paint matches for Satoh.

 

[HomesteadOC]

Got the valve cover, oil pan, intake manifold, coolant port, and bolts parts washed, and media blasted. I just parts washed the rocker assembly, I wasnt sure if the media blasting would hurt the rockers. Im not 100% sure I shouldve blasted the head and oil pan bolts, I mightve blasted off a protective coating in the process. The oil pan bolts were pretty rusty, but the head bolts were not too bad. The coolant port had a lot of pitting and corrosion and after media blasting some holes were found. I had a welder patch up the aluminum for me. He said he was practicing and not to expect much, but I think he did a great job considering how thinthe aluminum was. Heres a video of the cleaning progress so far.

 

[HomesteadOC]

I found the reason for my low compression in cylinder 1 despite the freed up rings...that piston is cracked:confused3:
Im checking prices on new piston and ring combos, Im thinking I should probably replace both pistins at the same time. Ive read somewhere that the early models had trouble with piston cracking because of the extra oil holes. Mine have 5 holes each side of the piston and the new ones might have 3 or 4, I think? Im going to be calling on NCW once they open up this morning and see what they have for me.

 

[Ilikeurtractor]

Please post pictures of the cracked piston if you can. I haven't seen this yet. Check for bent rods too - this will be obvious if you look closely. The one I had was bent at the top so it wasn't noticeable until it was removed from the piston. If you are going to replace pistons you might want to strongly consider boring it out. I know that means a lot more work and money but new pistons and rings aren't cheap and no use putting them into a block that is near needing it anyway. I would suggesting buying a dial bore indicator off eBay. They are not super cheap but a great tool to own. I think you can get one for under $70 off eBay. This will help you with the condition of your cylinders and help you make the final decision.

I would recommend getting "flat-top" pistons too, not the ones with recesses in them that I bought from NCW. They said they couldn't get flat-tops in 0.020" over (if you go that route). From experience, the lower compression makes it harder to start.

 

[HomesteadOC]

I really really really dont want to pull this whole thing out and rebore. Ill see if I can borrow a dial indicator and well see what we can find. The rods look good, I cant notice any bent or flexed areas, not 100% sure about the bearings though. This is my first rebuild and first time working on a diesel, so I cant really say whats good or not. The video below is pretty slow moving so it should be easy to tell if something is really wrong that Im not experienced enough to see glaring at me.

As far as hones go, Ive seen the ball and expandable type. It seems the balls might be more idiot proof, so Im looking at those. Do I need to find a 73mm (2.87”) one or do I round up to the nearest size? Do the pistons from NCW come with the rings installed?

 

[HomesteadOC]

Price with shipping from NCW for 2 new pistons with pins and rings, upper gasket set with valve seals, and oil pan gasket is around $410. The only pistons available were the decompression style, he says they use 2.2% more fuel and pollute less. There are 3 versions of pistons for this engine, the early style flat top with square rings that I have, an 80s model to help reduce emissions that was also flat top but with a keystone top ring, and the new version with the decompression reliefs, and keystone top ring. The price is nicer than anywhere else Ive seen, but it sounds like version 2 is the one I probably want so I can have the higher compression and the reduced pollution with stronger pistons. I will probably end up not paying extra for a new set of version 1 or 2 pistons. My buddy is going to let me borrow some gauges that are not dial indicators, but will tell me if Im out of tolerance. The guy at NCW says anything over 73.05mm needs a borin’. I didnt get a quote on oversize pistons, but Id imagine theyre priced similarly. Where Im saving the money is the piston/ring/pin combo and the gasket combo. Even though its a top end gasket kit, it should come with the oil pan gasket imo. I get the gauges tomorrow and will be able to test tomorrow evening, Ill keep you posted. Meanwhile Im going to spray down the crankcase area, and cylinders with some brakleen and then some wd40 to prevent rust. Im still trying to get my hands on a valve spring tool, I forgot to ask the autoparts guy for a loaner when I dropped off used oil yesterday.

 

[Kernopelli]

As far as hones go, Ive seen the ball and expandable type. It seems the balls might be more idiot proof, so Im looking at those. Do I need to find a 73mm (2.87? one or do I round up to the nearest size? Do the pistons from NCW come with the rings installed?

I have used a 3" ball hone on a B&S Vanguard 72mm bore before with excellent results. I have also used a self expanding brake cylinder hone on my K3f engine with what I would judge to be similar results. I am sure you know that both are only designed to deburr and surface finish. If you are going to have to buy a hone, stick with the ball type for a few bucks more. Since no actual measurements have been taken yet, I will mention that if an over bore was needed, I have a set of Sunnen expandable stone cylinder hones that I've used several times to actually overbore .001"/.25mm before....not as easy as a boring bar but it works. I assume the very similar ( and cheaper!!) Lisle brand hone would give the same results.

I am going to make a guess here and say the rings will likely have to be a separate purchase.