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Thread: Pistons, just curious
04-21-2007, 09:47 AM #1
I was digging through my junk and came across an old book I have had for many years. Leafing through the book I came across a picture of a piston knurler and a ring groove lathe. I can remember knurling pistons and remachining the ring grooves when I was a young kid working in a shop. I was just curious if anyone does this anymore. Coated pistons and today's tight clearances would seem to have made this a lost art. I personally would never do it unless I was directed to, it was wasn't worth the effort. Also does anyone still make their own valve seat inserts?
04-21-2007, 11:13 AM #2
I have made valves from blanks and modified piston ring grooves accept different rings I have even made tappets but I used a engine lathe and a cylindrical grinder, a place I worked for had a piston grinder going to scrap, even engine rebuilding shops are becoming scarce. I could not imagine Knurling working well with high silicon pistons. FWIW my 1975 repco engine service manual ( Engine reconditioners book) said that knurling was out of favour back then. Another thing I have done is cut reverse torsional taper faced piston rings out of plain square section rings, did wonders for the oil control on the compressors and antique engines that I did this to. I cannot imagine making money off this though.
04-21-2007, 11:24 AM #3
I have done this on only one engine rebuild and it turned out very successful. In fact it lasted a very long time I was told around 200K on the rebuild and it was running great when he sold the truck. I had someone else do the knurling and I fitted them to the bore. I haven't seen it done in a long time but, I do know someone who has a piston knurler (gathering dust in a corner) I was thinking about seeing if'n they would part with it cheaply but, it is also something I don't really need (ack!- I can't believe I said that) but, would be nice to have and play with. Yes, it is a lost art,but it would possibly be useful for rebuilding old engines in which pistons are no longer available or cost to much or where it is not critical. I never did make my own valve seat inserts.
04-21-2007, 11:40 AM #4
I hate to see this post go unanswered. The last time I had pistons knurled was almost fifty years ago by Master Motor Works in Sacramento. The shop foreman knew a young kid with little money to spare would blow that engine(B block, Crager head, etc...) sky high soon enough. He said as much when I brought it in. Having said that I would check with old car restorers or better yet old tractor restorer links to ask that question. As for valve seat inserts I can't help but perhaps someone will chime in. BTW the only valve seat manufacturer in the USA I know of is Tucker Valve Seat Co. in Odessa, Texas. They are reasonably priced in my opinion and will work with you. Thanks for reading this rather long tyrade. Mike
04-21-2007, 11:53 AM #5
Years ago in Los Angeles here was a car engine rebuilding shop called "Lou's Garage". They were a big company and advertised on T.V. and in newsprint.
For a low figure, they would remove the heads and pan and do a quick "rebuild". We're talking about honing, knurling pistons and even the insides of valve guides.
Instead of new rod and main bearings, they were very good at filing rod and main caps down a bit to tighten them up. Heh heh.
There were so many complaints, that the then new State of California Bureau of Automotive Repair finally shut them down.
I guess piston knurling has its place in the past but it's certainly not favored nowadays.
[ 04-21-2007, 08:33 PM: Message edited by: Newman109 ]
04-21-2007, 11:53 AM #6
We used to knurl a lot of pistons and had a hand powered gizzie to clean up ring grooves to a wider size and then we added spacers along side the rings. One of the garage customers wanted a very heavy knurl on the pistons so they had to drive them in, then cranked the engine with the starter until things loosened up a bit. Cars sat around the shop for days getting started and stopped and multiple oil changes before the customers got them. Seemed kind of silly to me at the time, but his overhauls lasted.
04-21-2007, 02:01 PM #7
Piston knurling....recently I picked up a brand new Lisle piston knurler in the box at a sale for $5.
Not sure what I'll ever do with it, but it looked too cool to pass up.
04-21-2007, 02:26 PM #8
In the days of dip and splash lubrication, the piston skirt to cylinder wall bearing area was a problem. Teardowns would usually show scored pistons. Knurling was a big help in maintaining a film of oil with greater consistancy.
With modern full pressure lubrication, that aspect of knurling has become redundant but until all the old cars are gone, I'd think that access to a piston knurler would be very valuable to some.
04-21-2007, 09:04 PM #9
I have a hastings piston knurler for sale as we speak, and it is cheap, however getting it shipped somewhere likely isnt
We used it mainly for old antique stuff that either parts couldnt be found or for those "parade babies" that only have to run a few miles a year.
Pictures on request
04-21-2007, 10:44 PM #10
Ahh the good old days! In 1965-66-67 I worked for a guy that remanufactured ignition points in Cincinnati. Contact Service Company We shipped local and had customers as far away as Calif. Our biggest seller was the GM set with the allen ajustment. We dissambled, cleaned, replated and silver soldered new contacts.
He had leftovers from when he manufactured Piston Skirt Expanders and long reach pliers to install them in frame. They were basicly a flat metal spring formed into a curve and heattreated. When installed they were susposed to expand the skirt when the engine got warmed up. This is back when we fixed things, not just throw them away and buy new.
My dad (worked at Carlton Machine Tool for almost 40 years) said they didn't really work.
I remember my dad knurling a lawnmower piston in a Briggs when I was a kid. That mower ran for years.
04-21-2007, 11:14 PM #11
04-22-2007, 01:55 AM #12
olddude, One of the first jobs I had when I started my job at a NAPA automotive machineshop back in 1973 was to knurl pistons on a Perfect Circle piston knurling machine. We knurled pistons for almost all of the shops in town at that time. That machine is still setting in that shop which is no longer in operation. I also recut piston top ring grooves for ring spacers. I used Perfect Circle Manulathe. I purchased one of these at an auction last summer, in very good condition. I,m into working on old engines so I think it will come in handy. I also found a hand operated piston knurling tool at a flee market.
04-22-2007, 02:25 AM #13
knurling a piston's gnarly enough,
but ring spacers?
THAT's old iron!
Any more, you can have a set of very good, modern- metallurgy pistons made for
about $150 a hole, and given the high cost of
everything else, it doesn't make sense to skimp...
Thus, knurling's not so popular...
04-22-2007, 03:37 AM #14
Sometimes you have to knurl pistons. I just spent a fortune to ship samples to several large aftermarket piston manufacturers. None could make me pistons. I am not talking about one or four pistons. I am talking about hundreds of pistons. I have customers clamering for new oversized pistons and no one is able to make them.
I have personally knurled a lot of pistons and opened up ring grooves to take the next width ring. I even admidt to making piston rings from scrap pipe. I have one old one lunger that has run fifteen years with homemade rings and a knurled piston. Soon the wonderful a$$holes at the EPA are going to outlaw all the replacement parts for your treasured whatever. What are you goingto do then? They already are keeping replacement O.E.M. blocks from coming from the small engine manufacturers. Next year the rest of the parts are going to dry up from the small engine manufacturers. Next the aftermarket is going to be skinned. The EPA is not going to kill my one lunger Kohlers as long as a South Bend lathe is standing by in my shop.
Valve seat inserts are still available cheap for any application. SBI, in Nashville, makes seats, guides, valves, and the rest for just about any thing imaginable. They also are the real company that supplies everyone else in north america with all their valve train parts. If someone supplies it, it is in SBI's catalog. If they go down, I am prepared to start grinding and turning. Until then, I am going to buy quality, cheap, valve parts.
04-22-2007, 05:48 AM #15
I hear what your saying but I'm surprised you couldn't get anyone to do a run of a couple hundred pistons.
The knurling I did was for the young kids who whated to race but had no coin. The old 283s with knurled piston,guides and rebuilt clutch and a used vette cam. Going racing for $500. It didn't last long but they were cool for awhile.
I kind of miss those old days, no rules, if it works fine, if not go to the junkyard and get another engine for $150.00
04-22-2007, 02:23 PM #16
I remember those Lou's Garage commercials very well! Seems like it was something on the order of $99.95 for an overhaul but that even sounds high 40+ years later. I can even remember some of the spiel: "...EXPAND THE PISTONS, SET THE TIMING, REFACE THE VALVE SEATS...!!! all delivered in that 'hundred mile an hour, full volume radio-speak.
But back to the topic, in 1971 I started in a two year automotive program at the local CC. One of the lessons was the whole Perfect Circle piston knurling course after which we were tested and awarded a "Doctor of Motors" certificate from PC. So piston knurling was still alive and well at that point.
04-22-2007, 02:27 PM #17
For me this thing of getting pistons made is becoming a real pain. I am going broke shipping samples to outfits, only to be told that there is not a chance of anything being made. I am open to suggestions, but I think right now all the piston shops are just too fat to step down and make small orders of a few hundred pistons. They want to make thousands of pistons at a time, I think.
Knurling is not for short pistons and high RPMs. Knurling is for bean can type pistons and lower RPMs. The bore must also be reasonable. Goose egg bores are not made perfect by rolling a little metal around on a piston. Knurling is defenitely not for race engines. Knurling is for a pump motor or an obsolete compressor. Knurling is for that old Chicago Pneumatic vacuum pump with the fifteen inch pistons. I only would knurl when I have no new piston to use. Knurling is what you do in the middle of the ocean, or the pocketbook is not able to support a necessary project.
To me, why race when you can not afford to race. Are you going to use your food stamps to pay the shop, to fix your engine? That sounds like my neighbors with their race cars and pulling trucks. Their kids only eat because of the generosity of we tax payers.
04-22-2007, 02:34 PM #18
04-22-2007, 09:53 PM #19
What kind of pistons do you need made? Maybe I'll have an idea?
04-23-2007, 01:43 AM #20
I would be forever in your debt if you have a source of low-volume current technology pistons.
As my handle suggests, I rebuild Packard and Studebaker V8s. I have checked every source in every catalog for years now and have not found anyone who will make Packard pistons.
Egge Machine makes cast aluminum "hole-fillers" for obsolete engines, but they are not really worthy of being called pistons - certainly not the equivalent of even the old original equipment, much less today's hypereutectic wonders. I only use them in show car engines.
There are dozens of racing piston manufacturers who will make a beautiful forged piston for $100-150 each. Forgings are strong, but because they expand more, they have to have more piston-to-bore clearance and thus are noisier and use more oil than OEM pistons.
Anxiously awaiting your reply.