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.

[78Eliminator]

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.Yep. I wouldn't worry about a marine motor having ridge issues. I mistook this tool for something else. Sorry about my earlier post...

[SuperWrench0166]

just try gently pushing them out they should come out realativley easy if anything use a block of wood and lightly tap them

[HOSS]

You may get away without using the reamer. Sometimes if the ridge is too high, the rings WILL crack when going back in.

[1stepcloser]

If you can feel a ridge with your fingernail, I would recommend having the block inspected by a reputable machinist. (Or at least someone who knows how to properly measure a cylinder)
The ridge represents cylinder wear, and if there is a ridge, the cylinders should be measured for both taper and concentricity. This will determine whether the cylinders can be simply honed with new rings (assuming the pistons are in servicable condition), or if they need to be re-bored with new pistons.
Not cutting corners here will ensure a long lasting and low maintainance foundation for your new motor. :)

[mister460]

Don't worry about it Miller. I've never used a ridge reamer and have never broken a ring or land. I s'pose it is possible but I've rebuilt MANY engines and never had to use more than a little tap to get them out. And as 78Elim said, marine motors almost never have a ridge. So dive in, stroke and poke that BB and build a monster motor! Just my dime and a half.

[gnarley]

Ridge reamers don't just remove the carbon they remove the ridge left from the original cylinder bore where the rings don't touch. On highly worn cylinders there can be some carbon at the top & if you ran a deglazer in the bore you'd remove the carbon only to find a ridge on the top & yes you can break rings pulling pistons out but not going in unless your real careless. Why in hell would you want to put one back together that had a ridge in it??? IF you have one torn down & it has ridges you don't need a ridge reamer you need a rebuild! :rolleyes:

[powerplay230]

If the piston slides out the top without hanging up on anything your fine. One question from the peanut gallery, why would you worry about damaging a ring on the way out?? I can see worrying about the piston if you hope to reuse or the cylinder wall. devil

[HOSS]

I am referring to going in. Who gives a half a rats ass ( no Chevy fun) if you break an old one.
I`ve broken them going in once on a ridge. I`ve also cracked rings just using ring compressor. Hell, I`ll admit it,,,, I`m human.
Point being, have a shop check the block, you may as already stated need a bore.
Gotta love those bench racers!

[miller19j]

I pulled the heads off last night and inspected the ridge. It is almost non existent. I am planning on putting a snap gage in it and taking a micrometer reading just for reference. But from the visual inspection I think it will come out fine.
I plan on taking it to a machinist and getting him to recheck my measurements and make suggestions on what to replace. I will be the first to admit that I am new to this and donÂ’t want to screw things up.
Thanks again for all your help I am sure that I will have more stupid questions to post as I get farther along on this project.

[superdave013]

Most of the time I just kick the rods and pistion out of the side of the block. A few of them at least! :D

[HOSS]

jawdrop But dave, doesn`t that get expensive?
Gotta love those bench racers!

[LeE ss13]

Here's the deal. In the 50's and 60's oils were no where as good as they are now. An engine with 80,000 miles on might have so much taper in the cylinder that you couldn't even get the pistons out without a ridge reamer. Temperature is a factor also. If someone ran a straight six without a thermostat for 80K, the front cylinder would have .020" wear to almost none in the back. The reason is (as stated in a Motorcraft bulletin), that "engine wear is 8 times as great if the oil is only 100 degrees F." I don't think this is much of a concern in an engine in a boat today. I doubt you could make much of a ridge in 10 years of running. If you do ... I still have my old ridge reamer bought new in 1959.
[ December 12, 2002, 08:34 AM: Message edited by: LeE ss13 ]