"57 Lark Piston Problems

PyrogfromDubc

Recruit
Joined
Apr 17, 2010
Messages
2
I recently got a '57 Lark from a salvage yard for about 40 bucks. Other than cosmetics, it didn't have a cowl and it seem to be stuck from disuse. I tore it down and found slight surface rust inside the bottom cylinder. I deglazed it to take off the rust and cleaned the cylinders. I tested the piston's fit and I can move top to bottom, but there's alot of resistance even after rinsing it with wd-40. It's tough to slide. The sounds is alot rougher than what I felt it should be as well. Any ideas?
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: "57 Lark Piston Problems

Very hard to say from here whether or not you are ok.

Start by taking some measurements.

Put the rings in the bore of the cylinder, your end gap should be 0.007-0.017, no more, no less

Now measure the piston ring groove, it should be 0.005-0.0065

The gap between the piston and the cylinder wall should be 0.0035 to 0.004

Finally the bore of the cylinder should be 3.0625", check it in many spots to ensure she is not oval or warped.

If all is well, and she is still stiff, are you sure the rings are installed correctly on the pins? NO issues with ports?
 

PyrogfromDubc

Recruit
Joined
Apr 17, 2010
Messages
2
Re: "57 Lark Piston Problems

Thanks for the starting point. I'll measure and post the specs in day or two when I get a chance. And I don't think it's the pins. I made sure to line up the rings correctly as I was putting in the pistons. As for the ports, I'll take a look soon as I get a chance. Thanks
 
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