Hi all you wise old owls.. I had the Lords blessing by acquiring a van norman boring bar and got working on it past few days.. all i can say is WOW! my first 5-6 cuts went pretty terribly, but now im producing mirror like finishes - heck its just incredible! Sooo - I have used a ball hone many many times, and now have a lisle rigid 15000 hone.. I am cutting to within 1.5-2 thou because this van norman produces such incredible results im not sure much more is needed- My plan is to use the rigid stones (wet kerosene/oil mix) and then finish up with the flex hone- Im worried about hitting the webs at the bottom with the stones - and wondering if there are some tips/creative ways to keep it from hitting? was thinking maybe a wood stop at the bottom or something- Im totally planning on building a diy honing setup with a donkey head and a vfd servo motor- but for now its probably gonna be a hand drill setup..
oops - the pics duplicated somehow. I dont have a torque plate but will be getting one ASAP, for now ill probably be honing with just the main caps. Another thing I need to deal with is ridge reaming - work the edge with a fine round file? im wondering about cutting a tapered 3.75"-4.25" aluminum cone with a 45 degree angle on the lathe about 1" thick with a drill attachment, and then gluing sandpaper onto it and running it from the top with a drill-
Building a setup to support the hone, and with a stop on it, is probably the best way to go. Either idea will work for putting a chamfer on the top of the bore. Don't go too fine on the file, though, coarse will work. protect the end so you don't gouge the bore with it accidentally. A sanding cone would not need to be as big as the bore (having a big one would probably just make it chatter anyways), use a smaller one, and run it slowly around the bore.
Finish looks nice , study up on crosshatch angles. If you have a dead block practice on that. The ball ones are more of glaze brakers , use the stone type.
1. Flip the honing stones on a quick, regular basis. This helps keep them clean and sharp on their cutting surfaces and wear more evenly. 2. Don't let the stones / cylinders get too hot, otherwise you'll get an erroneous readings with your dial bore gauge. Run a hand full of strokes, let it sit idle with coolant running in the cylinder for a couple of minutes, another hand full of stokes, let it sit and cool with oil running in the cylinder. Takes a little longer, but well worth the time. Mike
These guys have you covered for advice, I’m fortunate to have an engine machine shop at the school I teach at. Sent from my iPhone using H.A.M.B.
Something that escapes a lot of machinist . The edge on the bottom of the bore is sharpened after you bore ,If left it will tear up the skirts and the sharp edge will scrape all the oil off the skirts. A sanding cone works great down there also, take your time and round that edge off . Best of luck
Will boring a block on an engine stand effect the concentricity of the bored cylinders? Wouldn't there be some detrimental movement of the block? OR Would the movement of the block be in "sync" with the rotation of the boring tool?
hey guys thanks for the gr8 replies - torqued main caps on and got busy with the lisle hone.. tooka little getting used to but eventually i got it figured.. I couldnt see how one flips the stones around? The lisle model i have seem to only go one way - so i ohne from the under side.. Problem i had was leaving al ittle too much (3.5 thou) for honing.. That van norman leaves such a pristine finish im thinking of putting on the torque plate, cutting it to 1/2 thou and doing a quick finish hone with fine grit and pb blaster(which i used today - worked gr8 and stones stayed very clean as opposed to dry - they gunked up real fast). I did get a beautiful cross hatch.. but prefer honing less! It opens many doors for error. I have to say - the van norman leaves a smoother finish than the flex hone - what about just flex honing the surface? The van norman is cutting with incredible accuracy (1/2thou if that).. Might not need to true hone the bore but rather just run a crosshatch hone with the flex hone? fyi i managed pretty good today with my ridgid cordless drill and a 4amp battery - smaller less powerful tools give alot more feedback regarding stone tension etc - i dont think ill be going any bigger soon.. its quite satisfying honing I solved the ridge issue - just carefully ran a stone tapered bit around and chamfered it a lil - i think it will work a treat.
The tool makes a very small cut at a time - the concentric issue (afaik) comes down to using a torque plate and torquing down the main caps - thats the ideal setup.. the boring bar i use clamps down very tight onto the block and uses the deck surface at a guide.. you can center it any position in the bore - but since the most wear is on the thrust side about 1-3" down (imo) thats a good place to center.. the rest of the bore isnt as critical, thats what i think anyway ill probably get flamed - and a racer might disagree but for boating and general use i think motors are forgiving - ive had blocks with 7thou wear with 125 psi cold compression and running gr8-
Ideal would be to have the block squared and decked, then with the bar mounted to the square deck center and bore. But a many block have been done this way and have had many miles of happy motoring.
Thanks yes i read about that but forgot to do it today! waiting for the sleeve to arrive so glad I havent washed the block down! I messed up with the boring bar and gouged one pretty bad!
I have the same boring bar a yes they cut very nice. I had a torque plate at one time and I didn't feel comfortable setting the bar up with the torque plate between the block and the bar. I left .0035 if I used the plate. I used sunnen an100 stones to get to .0015. Then go to the finer stones to finish. You will be surprised how out of shape the cylinders get. Mikevv is right about keeping the cylinders cool when honing, it is really important. I move around a lot honing every other cylinder. If you let them get hot the center will shrink after it cools. If this happens you will score pistons. Using course stones to get up to a final finish hone helps keep the heat down.
Thanks dyce- im trying to avoid honing as much.. since the bar leaves such a smooth finish im really considering just the flex hone after boring.. or fine stones wet and then the flex hone- i seem more prone to making mistakes honing than with the boring bar. Im getting excellent results with the bar- Im planning to get a deck/torque plate with recessed holes so i can mount the bar ontop, but would be curious how true they are machined.. Does alu vs cast matter for the plate? do i need cast iron plates for cast heads?
Don't think you want a flex hone. Honing is a process of removing the threads you just put in the cylinder, if done improper you will roll the threads over and trap metal in the rolled edges and make for bad ring seal.
Correct! Also, if the finish is to rough chromemoly rings will chip. I recommend reading this https://www.enginebuildermag.com/2004/05/cylinder-bore-refinishing/
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