Experience with installing cylinder block over pistons?

[FormerGlory]

Any tricks or specific guidance when installing the cylinder block?

[cowboy1157]

I did my top end last summer and I managed to borrow a ring squeezer from a yamaha mechanic (that I know) and it made it easier. That was on the third time we put it together. The other 2 times wise it was three of us and we put the center pistons in first then the outer pistons. You might find a ring squeezer at an auto parts store. Hope this helps.

[natemoen]

The two times I have done it I just did it by hand. Wedged something in the rotor to hold the center 2 piston up and set the jugs down and then just pinched the rings together and tapped the jugs down. Wedged the rotor and repeated with the other 2. Took me about 20-30 minutes total. No need to mess around with other things.

[xssiveone]

I got some pieces of plastic pipe, cut 4 half circles, and some worm-gear hose clamps. Lubed everything up good and positioned the plastic pieces and clamps on each piston and tightened the clamps. It compressed the rings and the cylinder dropped on the center pistons. Repeated on the outer ones and it was done.

[ViperRon]

a different way

No matter what procedure you use make sure and install the gasket and O rings between the motor and cylinder head before you start anything because a common problem is to be slitting the cylinder down pistons installed before it crosses your mind. You can use form a gasket sealant but should still have the O rings installed. If you have shaved the heads and don’t use the gasket make sure the carbon was cleaned from pistons and heads as the clearance changes.

When doing mine I got the rings at the very minimal gap and I have large hands this makes pistons hard to guide in keeping rings straight at times. The way I installed the cylinder head was with all pistons installed in the cylinders and alligned before putting it on bike. To do this you need to fabricate the shim to go under the cylinder just like the other procedure. You need the fabricated tool to remove the wrist pin to also guide it back in. And the retaining ring for the inside of the wrist pin needs to be installed in the piston. You rotate the engine till cylinders 2 and 3 are at their highest point. You slide the cylinder head down till the rods just have enough room to slide in the wrist pin. You slide the piston down till the pin can be inserted. Wrist pins should be inserted back into the piston they were removed from. Most wrist pins are tight so you need to lubricate it and use the tool used to extract the pin to put the pin back in. Once the pin is in make sure and put clean rags around the rods covering entrance to the engine then put the retainer ring in. If the ring slips and falls into the engine it can be a real problem finding it. Once you have 2 and 3 in then allow the cylinder to slide down over the pistons. The next step takes a little caution as you balance between rotating the engine till pistons are equal and sliding the cylinder head down. The goal is to get the cylinder down close enough that you can slide the wrist pins into 1 and 4 without pulling 2 and 3 out. When the retainers are in 1 and 4 you are done.

The benefits of this procedure are that pistons are easier to install in the cylinder out of the bike. You do not need to struggle with any device to try and compress the rings to slide them in. There is less chance of rotating rings from their offset positions.

The only negative is if you drop the retaining ring in the engine by mistake.

I have done 7 bikes of this design this way since it was explained to me by a dealers mechanic in the 70’s. His theory was that it can be hard to hand compress or use a tool or hose clamp in that space without rotating the rings. He decided on this procedure because he had to pull apart some bikes with compression values quite different between cylinders on new rebuilds. Each time he found that when pulling the piston out the gap on compression ring one and two were close to even. I am sure there is talent here on this site that can install them with their eyes closed no problem. I personally see the benefit of knowing the rings did not turn on me.

[GLoweVA]

I did mine last summer. I ended up breaking one of my rings while doing it.
The tricky part was the fact that 2 are up while 2 are down. So, after you get the first 2 in, (I suggest #2 & 3, the inside ones) then the second set. I had to rotate the engine a few degrees to get the 2nd set up some, that's when the 1st set poped back out. While getting those back in, I snapped one of the rings.
You definitely need some kind of tool to hold at least one set of rings in while you can use your hands on the other piston.
I wish I had 2 tools to hold those rings in while I tapped the head back down.

+1 on the gasket. I should have replaced mine, now I've got a little oil leak around the base. Not bad, just a little messy.

Just be careful and take your time. A 2nd set of hands may be very useful.

[natemoen]

As to the gasket, you can use anaerobic gasket maker. It will not set until you get the jugs and head torqued down. Doesn't matter if it takes you 2 hours or 2 weeks to get them on, it stays unset until torqued, so you can take your time.

Or you can use a gasket. But definitely replace it with something.

[TADracer]

Hose clamps and a piece of wood always works for me. Prop the #2 & 3 pistons up high with the wood and do them first then do the 1 & 4. As the clamps slide down on the piston, remove them. Simple and cheap!

Sorry I dont have any pics of this.

[GLoweVA]

If you're gonna use hose clamps, I suggest getting really wide ones or you'll have to use more than one for each piston to hold all 3 rings in. Don't tighten down too tight on them or they won't slide down and off.

[FormerGlory]

Excellent info, and thanks to all.

[Ken Talbot]

... A 2nd set of hands may be very useful...

More than very useful! This also gives you a second set of eyes to watch that everything is going in as it should, no rings are binding up, etc. Two pairs of hands, two sets of eyes, take your time, and you'll be okay.

[79XS11F]

I agree. Its a 2 man job. One lowering the block squarely over the pistons while the other feeds the rings into the bores.
Rob

[ddragon63]

Being a engine guy i'm a firm believer in right tool for right job. For about $40 or $50 you can buy a VERY good ring compressor with interchangeable rings for different sized pistons. The one I own is made by KD tools you can get them off the net or from a good tool shop or parts store. These are the handiest set i've ever owned. I've used them from 5 hp B&S to 1000 hp Drag Car motors. They are the simpleset design and easy to use.. small price to guarantee you dont fold over a oil ring retainer or break a ring unknowingly on assembly. just my .02 YMMV

[crazy steve]

Only problem being is you need two sets....

[ddragon63]

Only problem being is you need two sets....

and 4 hands