Ridge reamer?

[miller19j]

Ok please excuse my ignorance. I am new to engine rebuilding
In reading my rebuilding book it says that I need a ridge reamer to ream the ridges in the top of the cylinder before I remove my pistons. It seems to make sense but why couldnÂ’t I slide my pistons out the bottom after removing the crank? Am I missing something or can I just do it that way?

[78Eliminator]

miller19j:
Ok please excuse my ignorance. I am new to engine rebuilding
In reading my rebuilding book it says that I need a ridge reamer to ream the ridges in the top of the cylinder before I remove my pistons. It seems to make sense but why couldnÂ’t I slide my pistons out the bottom after removing the crank? Am I missing something or can I just do it that way?A ridge reamer is to clean the actual pistons, not the cylinder...

[miller19j]

Now I am confused are you messing with me 78.
My book shows a device in the top of the cylinder that is turned by a ratchet or a t-handle. According to the book if you donÂ’t remove the ridge at the top of the cylinder you will destroy your rings and possibly your piston.
I donÂ’t know if I can reuse the pistons or not but I want to leave my options open in case I can.

[flat broke]

No, A ridge reamer is to remove the ring of carbon etc that is sometimes at the top 1/4" or so of the cylinder. Depending on how tired your motor is you may not even need one. Don't worry about it until you have the rods loose and can see if you can push the piston out of the top of the cylinder. As far as why you can't pull them out the bottom, pull the pan and I think it will become clearly evident The way most blocks are designed there are major structural components in the lower areas that would make it impossible to get the rod and piston assmbly out the bottom.
Hope that helps,
Chris

[Kindsvater Flat]

I ridge reamer cleans the lip at the top of the cylinder where the top ring of the piston stops. If there is no or very little ridge there the piston will slide out. There is also a piston groove cleaner to clean the carbon out from between the ring and piston. Care should be used when using one because aluminum can be removed from the piston.
Usually the piston will not slide out the bottom because it will hit the block and not come out all the way. I'm sure some can be done that way but I wouldn't advise it.

[SuperWrench0166]

A ridge reamer is mainly only needed on high mileage motors or ones with lots of hours.
When the Pistons go up and down the top ring stays approx 1/4 inch below the deck surface. After many many times sliding up and down a ridge forms at the top of the Cylinder. This ridge is where the rest of the Cylinder wall has worn and this part hasnt plus excess carbon build up.
The Ridge reamer removes this ridge it rides on the worn part of the cylinder wall and cuts the
Ridge so its a smooth transition as the piston comes out. If the ridge is big enough it can cause broken rins broken ring lands in the pistons scored piston sides and otehr problem i have also seen a piston get stuck cause the ridge was so thick. I usually dont need one when rebuilding cause the ridge isnt that great.
On much older motors with a whole lot of mileage the older hi ash oils and crappy fuels it used to be a problem. but now you know what one is and if you want i can get a pic of one and post it.
I would just run my nail over the ridge if it isnt much dont worry about it.

[miller19j]

flat broke:
No, A ridge reamer is to remove the ring of carbon etc that is sometimes at the top 1/4" or so of the cylinder. Depending on how tired your motor is you may not even need one. Don't worry about it until you have the rods loose and can see if you can push the piston out of the top of the cylinder. As far as why you can't pull them out the bottom, pull the pan and I think it will become clearly evident The way most blocks are designed there are major structural components in the lower areas that would make it impossible to get the rod and piston assmbly out the bottom.
Hope that helps,
ChrisThanks Chris!
I donÂ’t have the pan off yet so I guess it will be clear when I get it off.
Like I said I am new to this and thought I would ask before I screwed something up. I have changed a piston from the bottom on a tractor when I was younger but a tractor is not a big block.
Thanks again for the info.

[SuperWrench0166]

I guess 3 of us posted at one time

[Kindsvater Flat]

SuperWrench0166:
I guess 3 of us posted at one timeYa but Chris is faster!!!! smilespi smilespi

[miller19j]

Thanks for all the info guys I really appreciate it!
It sounds like if I need a ridge reamer I will probably have to have the cylinders bored and new pistons anyway.