Piston pin clamp

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Mel King
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Piston pin clamp

Post by Mel King » Wed May 08, 2019 7:26 pm

Does the clamp face away from the cam or toward it? :?: I do not remember. :oops: What is the torque for the bolt? Thanks,MEL.


Kerry
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Re: Piston pin clamp

Post by Kerry » Wed May 08, 2019 7:59 pm

Bolt towards the cam.
Tension will depend on how well the cotter pin hole lines up to work correctly, fit a shaft or star screwdriver in the vice and slip the piston on through the centre ot the wrist pin while you tighen the bolt, never use the rod it's self to clamp in the vice when tighening, sometimes you need to swap bolts to have a happy tight and alignment for cotter.


Topic author
Mel King
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Re: Piston pin clamp

Post by Mel King » Fri May 10, 2019 4:36 pm

Could you post a picture of the correct position of the cotter pin? Thanks,MEL.


Kerry
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Re: Piston pin clamp

Post by Kerry » Fri May 10, 2019 6:34 pm

Mel,
Ford fitted the cotter so the head would hit the rod if the bolt should try to back out.
my choice is to reverse fit and one side of the cotter rapped and crimped around the bolt head and the other side crimped into the channel of the con rod, (others choice of fitting may vary)
Attachments
split pin 001.JPG
split pin 004.JPG


Wayne Sheldon
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Re: Piston pin clamp

Post by Wayne Sheldon » Sat May 11, 2019 5:12 am

Cotter pin should be snug in the hole, and crimped tight loop to tail (short half only) to prevent it from shaking itself loose and wearing till it breaks and falls out. Also, do not leave excessively long tails on the cotter pins. I have seen several engines where some of the cotter pins disappeared (person who's engine it was know they were there before!)
The loop of the cotter pin should be large enough to catch the rod and prevent the bolt from backing out. The amazing thing is, that often, even if the cotter pin takes a hike, the bolt will usually stay put anyway. Still, we have had enough discussions about the potential disasters befalling Ts with random bits of metal taking a ride in the wrong place, that we do not want to take any chances with those cotter pins.

And once in awhile, wrist pin bolts can and do back out a bit. I can't recall offhand ever seeing one, but I have heard of it happening. I had a modern replacement bolt STRIP its threads allowing the bolt to become loose. I recognized the subtle sound of a wrist pin knock from an earlier experience, and eased the car to the end of the tour. Had a devil of a time getting that stripped bolt out however once I got the car home.


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Re: Piston pin clamp

Post by Kohnke Rebabbitting » Sun May 12, 2019 4:11 pm

We have always used New lock washers.

Herm.


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Re: Piston pin clamp

Post by Allan » Mon May 13, 2019 5:02 am

I have removed more than one set of rods where the pinch bolt was wired around the rod. I have always done it this way. The advantages I seeare twofold.
There is no need to align the split pin hole to be able to fit a pin. The wire will thread through wherever the bolt head ends up tightened.
Wiring the bolt keeps some tension on the bolt head and helps to keep it tight. Also, the wire is tight and cannot move or wear as split pins do when the move in the hole.
Are there any downsides?

Allan from down under.

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Markus
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Re: Piston pin clamp

Post by Markus » Mon May 13, 2019 6:48 am

Hello Mel,
i start with a torque from 25 ft-lb when the hole is than in the correct position for the cotter pin, than thats it.

Markus


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Mel King
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Re: Piston pin clamp

Post by Mel King » Mon May 13, 2019 8:29 am

What about a lock washer and 30 ft. lbs ,would that work? :? MEL.

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Markus
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Re: Piston pin clamp

Post by Markus » Mon May 13, 2019 9:52 am

Yes, that will work. But 25 ft-lb is also ok. Do not overtighten.
At my actual project i do the same.
Lockwasher.jpg
Lockwasher.jpg (45.92 KiB) Viewed 5251 times
When you tighten that screw. DO NOT clamp the rod in the Vice. Use a Pin who fits in the Piston Pin.

Like this:
torque wrench.jpg
torque wrench.jpg (41.52 KiB) Viewed 5251 times


Kohnke Rebabbitting
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Re: Piston pin clamp

Post by Kohnke Rebabbitting » Mon May 13, 2019 2:07 pm

We use 30 lb's torque.

Herm.


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Re: Piston pin clamp

Post by Kerry » Mon May 13, 2019 6:05 pm

Markus,
You have some early produced aluminium pistons which didn't have oil holes drilled for the wrist pin. They have been kown to size the bin is not drilled, if you still have that engine apart I think it's a must do.


Kerry
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Re: Piston pin clamp

Post by Kerry » Mon May 13, 2019 6:09 pm

Sorry should spell chech :D seize.

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Markus
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Re: Piston pin clamp

Post by Markus » Tue May 14, 2019 6:34 am

Hi Kerry,

do you have any further information for this topic?

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