Piston Knurling

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John Evans
Posts: 2040
Joined: Tue Jan 20, 2009 9:33 pm
Location: Phoenix ,AZ

Re: Piston Knurling

Post by John Evans » Wed Apr 04, 2018 11:05 pm

I had a Chevrolet 216 ci engine years ago that had no oil pump, dippers on the rod caps and cast iron pistons....and they were round too. It had a felt pad laid on the rocker shaft assembly as a drip oil supply from the mist from that whirling (3600 rpm max) ball of fire. An explosion going somewhere to happen...

BC
Sorry but they most definitely had oil pumps ,sold more than one in my auto parts career. Felt pad was a aftermarket item to quite the noise and help with lube as those engines had some issues with oil supply to the top end with age. Chevy 4's from the 20's did not have pressure feed to the rocker area and used those pads stock for lube. Worked on more than one of the above in my life.
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BClemens
Posts: 389
Joined: Sat Oct 08, 2016 10:04 pm

Re: Piston Knurling

Post by BClemens » Thu Apr 05, 2018 9:02 am

John Evans wrote:
Wed Apr 04, 2018 11:05 pm
I had a Chevrolet 216 ci engine years ago that had no oil pump, dippers on the rod caps and cast iron pistons....and they were round too. It had a felt pad laid on the rocker shaft assembly as a drip oil supply from the mist from that whirling (3600 rpm max) ball of fire. An explosion going somewhere to happen...

BC
Sorry but they most definitely had oil pumps ,sold more than one in my auto parts career. Felt pad was a aftermarket item to quite the noise and help with lube as those engines had some issues with oil supply to the top end with age. Chevy 4's from the 20's did not have pressure feed to the rocker area and used those pads stock for lube. Worked on more than one of the above in my life.
You are absolutely right - the 216 had an oil pump but by today's standards - it had no oil pump. I kept it running in a '37 Chevrolet for a number of years but finally upgraded the engine and driveline. Before that I installed an aftermarket kit to run an external oil line to the top end but the pump couldn't even do that... If it didn't have the dippers on the rods it would have destroyed itself early on. And you're right about the noisy top end...sounded like skeletons dancing on a tin roof. I thought about going to a 235 but was talked into a 283 - the beginning of the blow-up queens.

Harold_V
Posts: 17696
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Piston Knurling

Post by Harold_V » Thu Apr 05, 2018 3:21 pm

There was a distinct difference in those days between Chevrolet and GMC. The GMC 6 cylinder engines had full pressure oiling, including drilled rods providing pressure oiling to the wrist pins.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

BClemens
Posts: 389
Joined: Sat Oct 08, 2016 10:04 pm

Re: Piston Knurling

Post by BClemens » Thu Apr 05, 2018 3:49 pm

Harold_V wrote:
Thu Apr 05, 2018 3:21 pm
There was a distinct difference in those days between Chevrolet and GMC. The GMC 6 cylinder engines had full pressure oiling, including drilled rods providing pressure oiling to the wrist pins.

H
Yes, that was a merger that seemed to cheapen both. And now today the difference is a basic badge. At least GMC didn't make a car....Chevrolet, Buick, Pontiac and Oldsmobile took care of the car end. (forgot Cadillac - I drive a CTS-V presently)

I used to work some old marine engines that were a marvel in technology for I C engines. Continental, Gray Marine, Red Wing, etc. and then the old diesels. They were built to last a lifetime with massive main and rod bearings and some even had a second oil control ring under the wrist pin. We had an exchange program going with the Universal Atomic 4 marine engine - as fast as we could recondition them. I'm so glad I'm out of that! I will not change oil in a car any more either!

BC

dly31
Posts: 1052
Joined: Sun Jun 27, 2004 11:29 pm
Location: Northeast Alabama

Re: Piston Knurling

Post by dly31 » Sat Mar 16, 2019 10:52 pm

I well remember the piston knurling and Rancomizing machines. There were also flat springs that were inserted inside the skirts and pressed between the pin bosses and the skirt. There was a special plier-like tool to install them. They were called 'piston expanders'. There was also a hand tool with rollers that fit over the skirt. The inner roller was sharp edged and rolled grooves in the aluminum to expand the piston. This was during and just after WW2 when you had to make do with what you had. New parts were just not available in many cases. You had to get a special needs certificate from your local ration board to buy a tire and you didn't get it unless your vehicle filled some critical need.
Don Young

Herb Kephart
Posts: 6
Joined: Fri Apr 07, 2017 4:05 am

Re: Piston Knurling

Post by Herb Kephart » Wed Mar 27, 2019 8:42 am

I made a threaded device to go inside a piston skirt (aluminum skirt) that can force more ovality into it, and thereby increase its "size."

Have also made pistons by turning the heads from aluminum bar stock, and heliarc welding skirts on.

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