A way to pass cylinder heads over pistons?

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happydaze
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A way to pass cylinder heads over pistons?

Post by happydaze »

I don't know why I always have to reinvent the wheel.. But as I replaced my 1 blown cylinder I decided to pull both heads and cylinders to check for anything abnormal and re-seat them with new gaskets.

So I have an engine with 6 cylinders sticking out and after about 5 seconds of thinking about this... it occurred to me that the normal piston ring compressor/pass into a cylinder would most likely not work since it is designed to work from the opposite side..

Faster to just do what is right and just take each rod/piston out, or does someone know a decent shadetree mechanic way of sliding the cylinders over the piston?

Thought I would ask. doesn't seem impossible and I can't imagine why there is a difference since these cylinders are independent.

Thanks!
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Re: A way to pass cylinder heads over pistons?

Post by Jerry Whitt »

Your question is formed in such a way as to not make sense. Perhaps we can help in you restate your question
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91blaze
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Re: A way to pass cylinder heads over pistons?

Post by 91blaze »

Seems like he's asking if you can put the piston cylinders on with the pistons in place already. As far as I know you can't do this due to some clearance issues, but I'm not 100% sure about it.
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Re: A way to pass cylinder heads over pistons?

Post by rowin4 »

I sure hope so as I plan on doing a ring replacement on my 110 engine. My plan was to pull one cylinder at a time, remove the rings, clean the ring grooves , put on the new rings and use a split clamp ring compressor to hold the rings in while the cylinder is slid back over the piston. Each cylinder is held in place with a short piece of pvc pipe over the cylinder studs to keep it in place. Make sure you remove / replace the shim block to cylinder gasket before replacing the cylinder onto the piston. Of coarse the cylinder will be cleaned and honed, and cleaned again before re-installing .
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Re: A way to pass cylinder heads over pistons?

Post by flat6_musik »

Maybe try this type of ring compressor......the brand is OTC.

http://www.ebay.com/itm/OTC-4838-6-Piec ... 01&vxp=mtr

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Re: A way to pass cylinder heads over pistons?

Post by bbodie52 »

If I understand your question correctly I believe you are asking if the pistons and rings can be inserted from the bottom of the cylinder or must they be inserted from the top. As shown in the first three illustrations different situations and different tools address ring compression and piston insertion from both the bottom or the top of the cylinder.
Piston Ring Install (1).jpg
Piston Ring Install (2).jpg
Piston Ring Install (3).jpg
Piston Ring Install (4).jpg
However, in 1964 a notch had to be added to the bottom of each cylinder for clearance to accommodate the longer-stroke of the 164 cubic inch crankshaft. The last illustration is from the 1965 shop manual. There is a cautionary note that specifically addresses the positioning of the piston rings in relation to the notch in the cylinder, when inserting the cylinders from the top of the piston.

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happydaze
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Re: A way to pass cylinder heads over pistons?

Post by happydaze »

I think I could have asked that 100 different ways that would have been better. Thanks Flat6! That ring compressor looks perfect. Mine is the traditional larger version that you would typically see.

Brad Mine are 64 cylinders, so I will pay close attention to the notching and its orientation.
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Re: A way to pass cylinder heads over pistons?

Post by 66vairguy »

Brad is correct - before the notched cylinder (1964 - 1969. BTW the 1964 cylinder is a one year only design.) the Corvair manuals showed you loaded the pistons from the bottom of the cylinder. With the notched cylinder it is possible, with great care, to load the piston from the bottom BUT IS NOT RECOMMENDED!

I took apart a LM engine and found three broken rings and scored cylinders because someone had loaded the pistons from the bottom and the rings caught the "cut out" on the barrel and were damaged.

BTW - If one of your pistons had a hole blown through it, then it is likely ALL the pistons have been exposed to damage, often subtle like deformation at the oil slot.
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Re: A way to pass cylinder heads over pistons?

Post by happydaze »

I appreciate the advice. Assembled the trouble bank of cylinders tonight. Went to rotate the assembly and it stopped at a 360° point in both directions. Never a good feeling. This being my 1st rodeo I realize I skipped a key easy step. Measure the old and new piston..

My compression height is off by .25" thankfully I was smart enough to check this now and not try to fire a seized motor. Some pictures for everyone's entertainment. Ugh. More money and time down the crapper.

The piston i ordered is STD height. Looks to be a GM piston originally? From the center of the rod pin is 1.75" replacement was 1.5"
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Re: A way to pass cylinder heads over pistons?

Post by happydaze »

The vast difference in piston size made me nervous. These have to weigh vastly different which I was uncomfortable with. Without another piston i couldn't tell. When I get my new piston i will remove another with the connecting rod and see at least what the assembled weight is. Not ideal I realize..
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Re: A way to pass cylinder heads over pistons?

Post by cad-kid »

interesting :think:
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66vairguy
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Re: A way to pass cylinder heads over pistons?

Post by 66vairguy »

When GM went to the longer stroke engine in 64 they moved the wrist pin location in the piston.

It looks like you have the wrong generation piston.
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Re: A way to pass cylinder heads over pistons?

Post by happydaze »

66vairguy - Absolutely correct! I was just posting this information for newbies like me and hopefully save someone some money and headaches.

I have a 64 block.. So I made the poor assumption all my internals were 64+ as well. So lesson 1. Don't assume this like I did. 61-63 are different pistons as stated above. Waist pin is in an entirely different spot and will effect the moment arm and the ability for the crank to fully rotate.. It does partially rotate - almost completely 359 Degrees to be exact..

I am a huge fan of Clark's Corvairs. The techs there are a huge asset and worked out my issue from the questions I asked.
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Scott V
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Re: A way to pass cylinder heads over pistons?

Post by Scott V »

happydaze wrote:Waist pin is in an entirely different spot and will effect the moment arm and the ability for the crank to fully rotate.
your not changing the the moment arm cuz the crank stroke & the rod length hasnt changed. as you found out the 60-3 pistons have more compression height than 64-9 pistons.

if you put a 60-3 piston in a 64-9 engine the piston will hit the head....like it did for you........& stop the crank from turning. if you put a 64-9 piston in a 60-3 engine.......the crank will turn fine but your compression will be way low.

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3Puttbob
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Re: A way to pass cylinder heads over pistons?

Post by 3Puttbob »

Hey Rowin4
Realize the post was 2 years ago, how did the cylinder/rings replacement go with the pistons still on? I plan on doing the same thing. I know Corvair intended that method only as a single ring job but, what the hey, why not all of them?
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Re: A way to pass cylinder heads over pistons?

Post by Peter »

You can try using a 4 inch ideal clamp/worm gear clamp. I used them to install motorcycle cylinders on pistons before. Good luck
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