77 Satoh Beaver S370D wont start, low compression

[Ilikeurtractor]

Should be good to go then. That will definitely save a bunch of time and money.

 

[HomesteadOC]

Everything should arrive friday. Ill have to take the pistons to a machine shop to have the rods heated and the pins pressed in, everything else I should be able to take care of myself. I need to get the rest of the engine power washed or at least scrubbed up with some simple green so I can paint the whole thing after the head and pan get re-installed.

 

[HomesteadOC]

Just got the pistons and gaskets in, and I wanted to head to the machine shop to get the pins pressed in. The only problem is the new pistons dont have arrows on them to point the direction of the front of the engine. Has anyone installed these new style pistons before? I dont see a description of which was is which for the pistons, or rods in my maintenance manual. Any help is appreciated.

New piston top, which way do the reliefs go?

Side view to show orientation of the rod.

Underside of new piston.

Old piston top and side with artow towards front of engine.

Underside of old piston.

Connecting rod side with lettering and nub on the crank side

Back side of rod, no lettering or nubs

 

[HomesteadOC]

So I got some advice from the machine shop, they say rod lettering normally faces the front of the engine, and after reviewing videos of my old pistons attached to the rods thats how they go. The reliefs match up with the valves so they are on the injector side of the engine. My newest problems are the machine shop marred my piston and then cracked it on the side when they were trying to press the pin out. They paid me for the piston, and didnt charge me for pressing the other side correctly. The owners son did the first one and messed it up, but the owner did the second one flawlessly. I told him Id give them a shot at pressing the new one.
My other problem is I really dont know how to put on my valve seals. They are really tight and dont want to go on. The new ones are from NCW and look pretty whimpy compared to the stock ones, Im not sure if they are correct for this engine.

 

[HomesteadOC]

Also, I just noticed that the valve reliefs do not line up with the valves. They do not run parallel with the piston pin, is this normal? Both pistons look the same, but they have the same markings in the reliefs (from same casting).

 

[Agvg]

Pictures?

 

[HomesteadOC]

Pictures?

Pictures are 3 posts up for the pistons. No pictures of the valve seals right now, but my valve stem measures 14.05mm and the outside of the seal measures 14.45mm. So that means the metal band and the rubber inside it have to be 0.40mm. Also the reliefs inside the seal dont match up with the stem groove. Ill post some pictures of what Im talking about later today.

 

[Ilikeurtractor]

The valve seals from NCW did not work for me either (see page 7 of this thread). Does your oil pan gasket match? I bought two of them that didn't. I mentioned that to Wynn at NCW last time I spoke to him. It "kind-of" lines up but is difficult to get to seal even with sealant.

 

[HomesteadOC]

The valve seals from NCW did not work for me either (see page 7 of this thread). Does your oil pan gasket match? I bought two of them that didn't. I mentioned that to Wynn at NCW last time I spoke to him. It "kind-of" lines up but is difficult to get to seal even with sealant.

My oil pan gasket lined up, but its not completely square and equal on all sides. You have to flip and rotate until it lines up with the pan, but once its there it matches perfectly. I remember you said something about the pan gasket so that was the first thing I checked, but I didnt remember what you said about the valve seals. Where did you end up getting your seals? I found a NOS set of 4, but Im not sure how well they would hold up over time without being oiled. The OEM versions look way better than the replacements, same with the gaskets. The ones from NCW look pretty cheap compared to the ones I scraped off, the head gasket especially. The OEM valve cover gasket is rubber and the ncw one is similar to cardboard. My exhaust gaskets are metal and NCW are cardboard like as well. I know NCW have the best prices and Im not sure what the other gasket providers are selling, but it would be worth paying their prices if I was going to get OEM style gaskets.

Do those pistons look ok? The relief cut is pretty close to the edge, and the pin is not parallel with the axis of the relief. I saw a set of pistons for a larger bore with the same relief cut, but it was further from the edge. It almost looked like they took that one and milled it down to make this one.

 

[Ilikeurtractor]

I'll have to double-check the oil pan gaskets. Maybe I made the wrong assumption they were symmetrical and that's the problem as I don't remember flipping them and rotating them in every direction. The place that installed new valve guides for me were able to make some work from a GM engine. They had to machine off some of the guide post if I remember correctly. I didn't really pay attention to what they exactly did but they got it to work.

Others have said the head gaskets from NCW were not as good but I haven't really had a problem with them, at least for sealing the cylinders. The metal rings take care of that which is the same as OEM. I did have one engine that leaked coolant and oil out the side of where the head meets the block so I put a thin coat of RTV around the oil and coolant passage ports before assembling now and haven't had that happen since.

So far I haven't experienced any issues with the relief-type pistons (other than harder than expected starting) but who know what will happen in time. I don't really know why the reliefs are randomly laid out on the piston crown. It would be nice to know the history behind these pistons. Maybe the supplier took flat-top pistons and ran them through a CNC to cut that pattern because it was handy and they knew the orientation didn't matter anyway. I can only speculate. Flat-top pistons are available from other suppliers but at higher cost. Probably worth the difference though.