Piston Identification

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namdc3
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Piston Identification

Post by namdc3 » Wed Apr 03, 2019 6:41 pm

Can anyone identify these aluminum pistons from the photos without me pulling the head? They say "Model T-HC" on the inside of the skirt. Does the HC mean high compression, or is it just a coincidence in model number?
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Mark Gregush
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Re: Piston Identification

Post by Mark Gregush » Wed Apr 03, 2019 7:32 pm

Put the piston at TDC and look thru the spark plug hole, if the top is domed they are HC, if flat normal. Understanding that T pistons come up out of the hole not even across like others.
I know the voices aren't real but damn they have some good ideas! :roll:

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walber
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Re: Piston Identification

Post by walber » Wed Apr 03, 2019 7:34 pm

I expect it stands for high compression but can't tell by these photos. On stock pistons the outer edge for about 5/'8" has an upward bevel and then the rest of the top is flat. Most high compression pistons have an even curved top surface, kind of a low dome.


George Andreasen
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Re: Piston Identification

Post by George Andreasen » Wed Apr 03, 2019 7:50 pm

It's the initials of the manufacturer.......Hang Chow, a well respected recycler of old beer cans in China......... :lol:

Of course I'm kidding. They're almost surely high compression.


Humblej
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Re: Piston Identification

Post by Humblej » Wed Apr 03, 2019 8:59 pm

Those wrist pin bolts should be safety wired, the cotter pins will not do anything to keep the bolts from working loose.

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Mark Gregush
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Re: Piston Identification

Post by Mark Gregush » Wed Apr 03, 2019 9:11 pm

I know the voices aren't real but damn they have some good ideas! :roll:

1921 Huckster
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Ruxstel24
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Re: Piston Identification

Post by Ruxstel24 » Wed Apr 03, 2019 9:34 pm

Yes, cotter pins work, but not bent that way.
Needs turned 90* and only one leg bent.


Les Schubert
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Re: Piston Identification

Post by Les Schubert » Wed Apr 03, 2019 9:49 pm

In regards to cotter pins there;
In my opinion NO!! Remove them and the bolts, apply Loktite and torque the bolts to 30 ft lbs!!

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namdc3
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Re: Piston Identification

Post by namdc3 » Wed Apr 03, 2019 10:24 pm

Thanks to all. Yes, they are domed as verified through the spark plug hole. I know it looks like the cotter pin will clear the rod and allow the bolt to turn in the photo, but it's actually long enough that it won't. I think the builder was of the opinion that using a long enough pin and bending both tails both prevented the bolt from backing out and halved the chances of the pin falling out. Thanks for the heads up, for sure, of course. If I'm reading your posts and the linked posts correctly, it's doing what it's supposed to do.


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Re: Piston Identification

Post by Adam » Wed Apr 03, 2019 11:07 pm

15,000,000 Model T’s were built with cotter pins in the wrist pin bolts...

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