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Press Pins
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Author:  BigBlockBanjo [ Fri Nov 24, 2006 10:43 am ]
Post subject:  Press Pins
What's the best way to install press-fit piston pins? Should I let someone else do it? I'm working this one on a budget, but I do not want to ruin a rod. Any help appreciated!
BBBanjo
Author:  ROADRUNNER7169 [ Fri Nov 24, 2006 10:57 am ]
Post subject: 
for one thing they have to be pressed in and i would not try it unless you have experience or extra pistons and rods to practice
Author:  BigBlockBanjo [ Fri Nov 24, 2006 11:05 am ]
Post subject: 
Well, we've done a number of tractor/diesel motors at the shop, but this is different. Those have rods the size of a Snickers bar, and only turn 3000 rpm MAX. I have /6 rods and will have fun up to 6000 rpm.
hhmmmm......
Author:  tophat [ Fri Nov 24, 2006 12:52 pm ]
Post subject: 
I am pretty sure that the rods and pistons need to be heated before pressing. I know that LA engines need to be heated first as I have a few 360 rods that somebody destroyed by attempting to cold press them.

I dont know how hot they need to be, but I am very sure they need to be heated.

Im sure somebody here knows how hot they need to be.


good luck

tophat
Author:  argentina-slantsixer [ Fri Nov 24, 2006 12:59 pm ]
Post subject: 
the wrist area on the con rod needs to be heated to dull cherry red before pressing them in. If you're to try with a mallet, use a wood or hard plastic mallet and if you have a lathe, line a tool of about 2x the lenght of the wrist pin, and line it in a fashion such as having the pin "stuffed" of this insertion tool while hammering on the same rod (you'll need to create a pilot of the same lenght of the piston pin)

other good idea :wink: woudl be using the stock pin to create a foating pin setup... you'll only need a honing tool small enough to get into the wrist of the con rod. The piston would have the correct amount of clearance since the pin already "floats" on the piston. A coupe of teflon stops on each side of each pin and you're done.
Author:  BigBlockBanjo [ Fri Nov 24, 2006 6:18 pm ]
Post subject: 
Yeah! I can make it a floating pin setup? Are there any downsides to doing this? Where can I get the teflon stops?
Forgive the questions, never tried "swapping" over before.
Author:  argentina-slantsixer [ Fri Nov 24, 2006 7:30 pm ]
Post subject: 
Quote:
Yeah! I can make it a floating pin setup?
Ive done so... I'm not 100% sure is right but hey, it works and saves skin of your behind when you're trying to do it all yourself (budgetwise or tired-of-your-crappy-machinistwise)
Quote:
Are there any downsides to doing this?
ability to run higer rpm ranges with less worries about a pin coming loose and scratching/damaging your mill
Quote:
Where can I get the teflon stops?
I purchased a teflon bar and turned mine on the lathe, but they are cheap, very cheap. I'm sure soon someone will chime in with more information...
Quote:
Forgive the questions, never tried "swapping" over before.
no sweat, you're welcome, sorry about not being able to help you out with 100% of the questions, but it's hard to tell where you can get some parts being like 10k miles away :wink: :shock:

(PS: not being a smartpants, where it says "downsides" I actually wrote upsides of the floating pin setup. I can't think of 1 single downside of using a float pin setup... if you do it yourself and cost you nothing, even a street engine would be safer to push the redline, answering in advance for those whom experienced enough, correctly advises against some "tricks" that aren't necessary in a street engine)
Author:  LUCKY13 [ Fri Nov 24, 2006 10:35 pm ]
Post subject: 
If you press them you need to be careful how you support the piston. Dont heat the piston, but it does help to heat the rod (not with a torch either) You can use a ketchen stove to heat them if you want, just dont get burnt. You can even freeze the pins. If done just right they will slip together but when the temp changes it will be locked down where you let it settle. So if yo udo it this way you need to setup some kinda stop that puts the pin in the right spot when you drop it in.

In the old days they would just press them in & out but had a good support built that formed & cradled the piston.

I dont think a shop would charge to much just to press the pins. If you have never done this before it might be worth the money even on a budget. But if you have done things like this then it want be to bad, just take your time and becarefull. You dont want to buckle the side of the piston or start a pin crocked. Thats why they went to heating is to avoid this.


Jess
Author:  slantzilla [ Sat Nov 25, 2006 5:01 am ]
Post subject: 
To float the pins you really need to bush the rod. I ran some steel-on-steel myself. We had some super coating put on the pins, but the rod ends beat out anyway. :shock:
Author:  argentina-slantsixer [ Sat Nov 25, 2006 5:24 am ]
Post subject: 
Quote:
To float the pins you really need to bush the rod. I ran some steel-on-steel myself. We had some super coating put on the pins, but the rod ends beat out anyway. :shock:
oh-oh.... my car is steel on steel... :cry:

what do you bush it with?
Author:  slantzilla [ Sat Nov 25, 2006 3:06 pm ]
Post subject: 
Bore out the small end and install a bronze bushing.

Steel on steel will work for a while, but it will beat the small end out. :shock:
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