Need some pistons Knurled

[Fordestes]

I am trying to find someone here in okla. to knurl 4 model A pistons I normally do my own but my Knurlizer is down at the moment, The shop I always used have no clue as to what I am talking about. this is for a set of pistons for my A but the engine no doubt is from a Gleaner Combine, it has the industrial 4 ring pistons ,I dont want to bore it at this time, it seems someone installed the wrong rings in it , the ring end gap was .125 and the cylinders have very minimal ring ridge. appreciate any help.

[J Franklin]

I'd call a few more shops, knurling is nothing new. When you find a good shop keep them over the last ones!

[jack backer]

Get a good close look at your ring lands before knurling they might not be worth it

[Fordestes]

Originally Posted by J Franklin

I'd call a few more shops, knurling is nothing new. When you find a good shop keep them over the last ones!

That is what I did I called many and got laughed at and told to try wal- mart etc., The shop I used since 1972 no longer does it , it seems the only people that handled the task have since moved on to retirement etc. I have knurled pistons in many seasonal tractors and various ag machinery engines also in the old days we did it to dirt track engines so we could run more clearances, been doing it for for the past 50 plus years so I agree knurling isn't new it seems to have faded with time.

[Fordestes]

Originally Posted by jack backer

Get a good close look at your ring lands before knurling they might not be worth it

That is one of the first things I checked , if the lands are not cracked I use a piston salvage tool called a Manu -lathe by perfect circle. especially if the pistons are of the un common variety. the set up alone for custom pistons sometimes exceeds the cost of the complete engine ,so I take into consideration what the engine will be used for when I try and re use certain parts.

[Joe K]

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Left over from a rebuild I have "skirt expanders" which apparently were used in lieu of knurling. I imagine the expansion might be more limited than a knurl.


Joe K

[J Franklin]

Maybe try a general machine/metal shop and not just an automotive machine shop. They profit from parts sales it seems.

[Kurt in NJ]

I have a small one that mounts in a vice, it uses a roller on the inside of the pistons to apply pressure so it only works on pistons that are smooth inside.
I was making a VW engine for a welder, all my parts were collected from the junk piles of 2 vw garages , this included knurling the pistons , the only new parts were 4 exhaust guides and the gasket set.
One day late on a friday a out of town guy got towed in with a bad engine and i sold my welder engine.
30plus years later the guy comes to the shop and walks up to me and told me the story about him getting the engine, wanted to know what i had done special to it, I was somewhat embarrassed to say it had been made out of the “junk” parts collected from other garages.
His reply was that it had lasted the longest of the 25 engines he had used (he was a traveling school picture photographer, drove a lot)and he had been curious what i did that made that engine special —— was it the knurled pistons?

[Richard Knight]

Air cooled engine, extra clearance and knurled pistons, no doubt in my mind that would help to extend the life. Of course the owner must have changed the oil regularly.

[Joe K]

Originally Posted by Kurt in NJ

His reply was that it had lasted the longest of the 25 engines he had used (he was a traveling school picture photographer, drove a lot)and he had been curious what i did that made that engine special —— was it the knurled pistons?

Air cooled "bug" engines were good for about 70-80K. I can see the knurling might "carry" lubricant and extend the life.

Sort of an oil "decontrol" ring placed at the most effective place.

My wife's bug at 85K was "fill up the gas, add a quart of oil."

Joe K

[Kurt in NJ]

I had aluminum foil shims behind the inserts to tighten the bearings, even the piston rings were used—- cut the top ring grooves with a ring groove carbon cleaner wider to use oil ring rail as spacer—- I have experimented a lot with repairs.

[roy green coupe]

Check out line2line coatings, recommended to me by total seal rings. Used a lot in racing.

[Synchro909]

I remember my father back in the 60s trying to get the last out of the engine in his "run to work car". He had the pistons expanded by blasting them from the inside with steel shot. That car went for years after his "rebuild" which was basically a lick with a hone in the cylinders, expand the pistons, new rings and reverse the bearing inserts top to bottom. All old school things but heck, they work.

[Fordestes]

Thank to all who have offered to help me out , I decide to see what was the problem with my Perfect Circle Knurlizer, It sat unused for quite sometime and the Mud Dobbers made a home in the air regulator and air inlet fittings, Luckily I figured it out and all is well ,my pistons are no doubt from a Gleaner Combine , They are the 4 ring type, the last person to replace the rings must have used some junk , the end gap was .125 all the way through, I knurled them and fitted to a clearance of .002, also what is the rod to crank clearance. is .002 too much? there is .0009 crank pin taper, Next I need a couple of usable exhaust valves ,if anyone has a couple they want to sell , I would appreciate it , I am going to use the car for around the state and when the pre 45 meet comes up at Chickasha Okla. I hope to find a good core engine to really do a good re - build for the long haul. Many thanks. Fordestes

[J Franklin]

Get the valves new as you will want to set the clearance on installation, they're inexpensive anyway. I think .002 on the rods is good.

[Fordestes]

Originally Posted by J Franklin

Get the valves new as you will want to set the clearance on installation, they're inexpensive anyway. I think .002 on the rods is good.

I forgot about grinding the stems and seats for valve adjustment. I was still in overhead valve mode of thinking. will the new style valves work with factory valve guides , are the stems the same diameter ? I am trying to get this done so I can drive the car and build a more solid engine later , are the add on filter kits worth the money ? are they a snake oil set up ?

[Synchro909]

Originally Posted by Fordestes

I am trying to get this done so I can drive the car and build a more solid engine later , are the add on filter kits worth the money ? are they a snake oil set up ?

Obviously for a show car, a filter is out of the question but for a driver like mine, I wouldn't be without one. I work the engine in my Phaeton very hard and on a long trip, I watch the gauges. Normally, I see 25 psi at 50 mph and 170°. After a while, I start to see the pressure drop at the same speed and temperature. By the time it is down to 23, I figure the oil has lost its guts so I change it (the cheapest 20W50 available feeding only the middle main bearing under pressure). I can almost set my watch by the regularity of changing oil at 3,500 miles. I wouldn't dream of going anywhere near that without the filter.
Having the filter will allow you to stretch your oil change intervals out and thus save money. Unless you only do a few hundred miles a year (why own a car), the filter kit will pay for itself.
BTW, that motor has done 50,000 miles and is still going.

[J Franklin]

Stock valves are available.

[Randall]

Originally Posted by Fordestes

I forgot about grinding the stems and seats for valve adjustment. I was still in overhead valve mode of thinking. will the new style valves work with factory valve guides , are the stems the same diameter ? I am trying to get this done so I can drive the car and build a more solid engine later , are the add on filter kits worth the money ? are they a snake oil set up ?

Here is a video I made a while back setting valve lash by grinding the stem
https://www.youtube.com/watch?v=13nFFtFWkKU&t=4s

[McMimmcs]

Why do they knurl pistons ? Wayne