Is there an easy way put pistons into cylinders?

[50's OMC]

I have a 1951 Sea King (made by OMC) 5hp and I took the engine apart to check that the pistons, rings and cylinder walls were in good shape but now we are having a very difficult time getting the engine back together. When ever we get 1 piston ring into a cylinder, the ring on the other piston pops out of its cylinder again and so on. Is there a special trick/tool to make this process easier?? Thanks for the help.

 

[wilde1j]

Re: Is there an easy way put pistons into cylinders?

I assume you're using a piston ring compressor. If you are I can't understand why you are having a problem. You just slide the pistons into their bores, one at a time using the compressor. Very easy.

 

[boobie]

Re: Is there an easy way put pistons into cylinders?

When using the ring compressor shown above make sure the end gap in the ring stays aligned with the location pin in the piston.

 

[ONERCBOATER]

Re: Is there an easy way put pistons into cylinders?

maybe i am missing something but you said

"When ever we get 1 piston ring into a cylinder, the ring on the other piston pops out of its cylinder again and so on."

which leads me to think that you are working on more than one piston at a time... this confuses me, every time I have done a tear down on any multi cylinder engine I have always put 1 piston in at a time rings and all, and secured it to the crank (via connecting rod) then worked on the next and so on.... I am having a hard time envisioning having a piston that was inserted pop back out of its cylinder because you put another on, even if its connecting rod wasn't secured to the crank. I assume you are using a ring compressor and properly aligning the rings, heck it is late maybe i completely misunderstood your post.

Sean

 

[rodbolt]

Re: Is there an easy way put pistons into cylinders?

post a pic of that block assy.
I had an old 5hp seaking, everything on it but the block was OMC.
the block was kiekiefer.
the crank was one piece and the pistons loaded into the block from the crankcase side as there was no cyl head.

 

[wilde1j]

Re: Is there an easy way put pistons into cylinders?

Well, that would present a problem!

 

[bktheking]

Re: Is there an easy way put pistons into cylinders?

I'm lost on the "When ever we get 1 piston ring into a cylinder, the ring on the other piston pops out of its cylinder again and so on"

How is that possible, you put one in, put the conn rod cap on and torque the rod nuts. Then put the second piston in and torque them down. I've done them without a compressor, I just use my fingers to compress the ring.

 

[ThePartsMan]

Re: Is there an easy way put pistons into cylinders?

post a pic of that block assy.
I had an old 5hp seaking, everything on it but the block was OMC.
the block was kiekiefer.
the crank was one piece and the pistons loaded into the block from the crankcase side as there was no cyl head.

If it's put together like his you may try using a hose clamp on each piston as a ring compressor.

I have used clamps on chain saws that didn't have room for a real ring compressor. Plus once both pistons are started are started you can remove the clamps.

 

[blimp]

Re: Is there an easy way put pistons into cylinders?

I used zip ties for my last rebuild. hardest part was the transition where one zip tie moved off the first ring to the second. I used a small screwdriver to ease the zip tie onto the ring, while pushing the other one off, without touching the piston/rings with the screwdriver at all.

 

[boobie]

Re: Is there an easy way put pistons into cylinders?

I think Rodbolt is right. If anybody has a parts break down of the block it would be worth posting it here. Would answer a lot of questions. Seems I've seen what he's talking about "many yrs ago".

 

[bktheking]

Re: Is there an easy way put pistons into cylinders?

See this thread

http://forums.iboats.com/showthread.php?t=372213

The block in the pic looks like my 6 hp Merc, just a water cover and no head to remove.

 

[50's OMC]

Re: Is there an easy way put pistons into cylinders?

Okay, well the first thing I'm going to do is buy a ring compressor (yes I have put an engine together without one) and if I can't get the pistons in without taking them off the connecting rod, then I will have to put therm in one piston at a time then connect them back to the connecting rod like many suggested.

 

[F_R]

Re: Is there an easy way put pistons into cylinders?

Well, there was a special set of ring compressors made to do that job. They come apart once the piston is in the bore so you can get the compressor out. I sold my set and haven't seen another in many moons.

For those that don't know what we are talking about, the pistons go in from the crankcase side--yes similar to a Merc.

 

[Fed]

Re: Is there an easy way put pistons into cylinders?

I did a 3 cylinder Merc ages ago and I remember thinking I'd hate to do a tower of power. Very fiddly but swearing helps a lot.

 

[boobie]

Re: Is there an easy way put pistons into cylinders?

Hey F-R. I still have a set of those ring compressors in my tool box. Used them a lot on snowmobiles and found out they came in handy for all outboards also.

 

[Lone Duck]

Re: Is there an easy way put pistons into cylinders?

okay, well the first thing i'm going to do is buy a ring compressor (yes i have put an engine together without one) and if i can't get the pistons in without taking them off the connecting rod, then i will have to put therm in one piston at a time then connect them back to the connecting rod like many suggested.

bingo!!