timing marks & ring compressors

[BruceM]

Hey fuelfarmer, I really like your piston insertion by crank rotation into wood blocked-up  cylinder approach.  I have normally done the lower the cylinder over the piston mounted to crank method.  It's a two man job and it's not fun for the guy holding the cylinder up.  Next time I'll give your method a try.  Thanks!

[xyzer]

I guess I am odd...I drop my piston from the top down. The rod fits in the bore so why slide the bore over the piston? Or am I missing somthing?

[dieselgman]

The slightly more sensitive piece of the puzzle is correct fit of (and protection for) the rod journal and bearing... on the smaller engines, we always fit the connecting rod by itself and then assemble piston, followed by the cylinder. Mostly a matter of personal preference and habit. Of course the cylinders on the smaller engines are fairly lightweight and can be handled with one hand, leaving the other free to manage the ring compressor and piston. To each his own ?

dieselgman

[BruceM]

Dave, if you're doing the piston down approach, how do you keep the piston from dropping down after the last ring slides in?  I tried it once, it made me  nervous about scratching the cylinder liner even with two guys. (One supporting the rod from below.)   I suppose you could bind a rag around the end of the rod, and put padding over the crank, and then do it solo.

[xyzer]

I never had the extra hands so I was stuck to my own devices. If you are going to check the squish clearance you might have to do the process again. I used a rag setting on the rod journal and paid attention on the last ring. I suppose to add or remove the shim between the barrel and case you could pull the liner piston assembly if the piston stays in the bore. As to scratching the liner I polished the outer edges of the rod journal to prevent this with a wrap of tape, and it will also give the rod end more clearance to fit down the bore. I know.....removing .05 grams of weight from the rotating mass will disturb the Indian fine balancing job. My first 6/1 I did it this way but on my second 6/1 the rod didn't fit the hole! I looked it over and it had some serious flashing to prevent it fitting. A trip to the belt sander fixed it. That tells me they must fit the piston into the bottom of the cylinder at the factory or they did this one that way.

[38ac]

The rod won't always go down through the bore. The last engine I did it wouldn't. For those i turn the clylinder block upside down on the bench and install the piston rings one at a time squeezing them with my fingers. Then install as an assembly.

[Quinnf]

I think I brought the little end UP through the bore and engaged the wrist pin, then slid the skirt down through the bore and squoze each ring in turn with weed-whacker string and they slid down one at a time.  Used Gravity as 3rd hand.

Like I said, there are lots of ways to skin a cat.

q.

[fuelfarmer]

One good thing about working with parts of suspect quality, I can make some of the parts even though I am not a machinist . One of the valve stem cap thingies went missing so I cranked one out on a lathe that I can sneak into a shop an use. Great fun for a plow mechanic.

[fabricator]

I just wrap the big end with electrical tape and put pieces of rubber tube on the cap bolts and drop it in from the top, I had to clean up the big end to even get it to fit down through the bore.

[fabricator]

BTW FF, that thing is really cranking.

[Zero_G]

When I assembled mine, I tried to use a ring compressor and slide the jug down. The tool got caught up and jammed in the chamfer at the bottom f the sleeve. I ditched the tool, and just did it with my hands, It went on just fine.