Crosley engine 2.5 bore. Trying to hone out some of the ridge at top of bore. I can't use a v-8 type hone with 4" stones as block and head are one piece and cylinder is only 4-1/8 long. I have a hone with 2" long stone and am getting results but not very fast. So how may rpm and what for lube?
^^^^^^^^^^^ As he said, the block and head are a 1 piece casting-IE the ridge is at the top of the cylinder, inside the casting. This pic would be looking from the bottom of the block up to the head combustion chamber, where the ridge would be, correct? Might need to find someone with a boring bar?
If I was doing this first I would use a very short hone about 1 inch long at the most to removing as much of the ridge as possible. Then once most of the ridge was removed I would then use the 4-1/8 hone to then square everything as much as possible. When I hone I use a Makita battery drill or a Milwaukie electric drill not sure the RPMs but both work fine with mineral spirits on the stones. Ronnieroadster
Seb, why don't you contact Ronnie Roadster, and bring your block down to his shop in Wallingford, Connecticut. Since you live in Rocky Hill Connecticut, it is about a 20 minute drive for you. I think you will be impressed with Ronnie and his shop.
I started out as Ronnie suggested with a 1" long brake cylinder hone using wd40 for lube at 150 rpm. Got pretty close and switched to 2" stone hone, still using wd40 and intermittent brake clean. I got a little farther to the point of slight visual left. I am using a mill for power as I need a positive stop so I don't crash the stones into the combustion chamber and can have some kind of stroke for crosshatch or is crosshatch a minor point. I will try mineral spirits and ronnie is noted.
I have continued honing using Mineral Spirits and having way better results. Not that much faster but I can feel and hear what the hone is doing. Arm gets tired. Good thing only 4 cylinders! Thanks for help.
Auomotive machine shops have a special boring head for blind cylinders. Often required for outboards and motorcycles. What you are doing is the hard way. jack vines
You are absolutely right. No doubt about it. YOU find me a shop. All I found no longer have the equipment or the desire.
Honing oil is as much about flushing the stones as it is about lubrication. A number of things work, including cooking oil. Factors that might influence your results include the spring load you put on the stones and RPM.
Agreed. I think I have to find some co****r stones. What I have is supposed to be 220 grit but finger feel seems finer. Working on second cylinder looks more like corrosion than wear, cylinder taper is at .001. If the factory didn't put chrome rings in I wouldn't be having so much fun.
I found some course stones today but they are 4' long. I may cut them in two and and drill new mounting holes and have at the present cylinder that looks more like corrosion [deeper] than ring ridge. I have a Snap On micrometer type ridged Hone but it is 5" long and don't think it would work well in a 4" long cylinder.
I don't understand how it can be done with a honing stone without also cutting the cylinder wall while cutting the ridge. You mentioned having a mill. I would use a boring bar in the milling machine. It could be set just slightly smaller than the current bore size and a quick plunge or two should clear the ridge away. Wouldn't it be better to just rebore the engine to a larger size? If the block and head are one piece, how do they do a valve job on it ? Good luck with it .
We're on the wrong coast for you, but do outboard and motorcycle blind holes on a regular basis. I'll ask my machinist if he ever remembers boring a Crosley. Do you have the pistons in hand you plan to use? jack vines
Bag the brake cylinder hone- you need a rigid hone head like an Aamco or better yet a Sunnen. Your hone speed should be about 450-500 RPM ideally. Using mineral spirits is ok- but consider about 20-25% 30 wt motor oil with it. With a rigid hone head, you can relieve a portion of the stones so the hone only cuts at the very end until you get the cylinder straight. Good luck.
I got a small ridged hone coming, guessing from pic that stones are close enough to end so as to get close enough to the combustion chamber squish area to cover the top ring. My plan to just clean the ridge was to allow for crankcase milling to raise compression. First cylinder I did worked out well but extremely slow but only a .001 taper. Second cylinder bit me as ridge seems to be more from corrosion than wear, cylinder still only has .001 taper but can't tell how much more I have to go to clean. I am going to do a little more then make some p***es in the other two bores to see what they look like.
The ridge in the cylinder is most likely from boring not wear and like you they didn't want to hit the raised part of the combustion chamber and left the ridge. Most Crosley blocks are like that. I think that is why Crosley pistons have a big taper on the top, as not to hit the ridge. Not easy to hone out. A mill or small boring bar is what you need to get it out and someone to do it.
You need a blind hole cutter. Like this from Kwik Way. Could be used in a mill with the right tool holder.
The ring is what makes the ridge, not the pistion it's self. If you don't cut the ridge out you stand a good chance of breaking the ring land under the compression ring when the sharp edge of the ring hits the ridge. I've seen that in a couple of guy's home rebuilds that they didn't cut the ridge with a ridge reamer and just ran a hone through the cylinders. I don't think that the adustable hone that I have in my tool box that is as old as I am would cut that ridge without eating up the cylinder wall too. You can actually overbore a block with it as it cuts straight but you work your **** off in the process. Ideally you would use a cutter similar to what jpm49c showed with a boring bar. Then adjust the cutter so it only cuts the ridge out.
Crosley is a whole different world. There is no removable head. No blown head gaskets. They left a ridge in the bottom of the cylinder when boring because you bore from the bottom up and did not want to hit the raised area in the Turbulator Block. This is a cutaway of the Crosley COBRA (Copper brazed - tin block) and a Cast iron block. . The cast iron block is basically the same with the Turbulator (Sir Harry Ralph Ricardo design for power ) raised area in the later blocks. COBRA and early Crosley cast iron blocks did not have the Turbulator raised area.
JPM49C Thank you for the pics. I have a Bridgeport mill. I have a Wallhopper Boring Head that can face. I am making a micrometer stop for it. With block up side down I figure to pick up the cylinder wall and the depth I need and feed out with the boring head to the stop then feed up boring the cylinder, making p***es and adjusting the micrometer to get cylinder size. I want to establish Turbulator height for equal compression in all cylinders. The ridged hone I just got with a little t******* will get close to the end of the bore as far as ring area goes. The mill quill has proven to be tight enough for a strait bore but I will check with a dial bore gauge; I have several blocks to practice on. I have one block cut apart close to combustion chamber to practice with Newway valve seat cutter too. All I got to do is get the energy to do it!
If I were using the mill and boring bar.........I would spray ****m blue on the surfaces. Then bring the boring head down till it touched and then back off a couple thousandths. Then I would begin adjusting the diameter for the boring bar, lowering it into position and rotating the spindle by hand.......till I felt it get resistance. Then raise it slightly, turn on the spindle and take a cut at that diameter. Then if all went well, adjust the cut as needed. Someone mentioned that the step is there not from ring wear, but from the original boring of the cylinder. Since the step is so close to the top of the cylinder, have you measured how far the ring land is from the top of the piston? It could be that its not an issue and save you a lot of work. I think I would do the old trick of putting some putty on top of the piston and see how much clearance you actually have. What I'm thinking is that if the piston goes that close to what is the head surface, there would be no real quench space and the compression ratio would be very high.....maybe there is some space there OR maybe I'm just wrong.
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