Author |
Message |
bugguy1967 Samba Member
Joined: January 16, 2008 Posts: 4338 Location: Los Angeles, CA 90016
|
Posted: Sun Oct 12, 2014 8:47 am Post subject: Best Place To Remove Weight On AA 94 B Pistons |
|
|
As the title says, one of my pistons is .9 grams heavier than the rest. I've already swapped around ring stacks and pins to get the closest numbers, so I need to remove material. I'm using a good quality scale, so my numbers are accurate.
Is there enough material on the underside of the crown to mill a little, or should I be just chamfering the inside edges of that piston? I could also cut away at the inside of the pin on a lathe. What's the preferred, and most professional looking method?
Also, in a running engine, does it make a difference to the connecting rods where the weight is (pin, piston, rings)? So, if I have a piston on #1 with a 300 gram piston and 50 gram rings, and a piston on #2 with a 280 gram piston and 70 gram rings, is the load on the rods still the same? |
|
Back to top |
|
|
modok Samba Member
Joined: October 30, 2009 Posts: 26740 Location: Colorado Springs
|
Posted: Sun Oct 12, 2014 11:40 am Post subject: Re: Best Place To Remove Weight On AA 94 B Pistons |
|
|
bugguy1967 wrote: |
So, if I have a piston on #1 with a 300 gram piston and 50 gram rings, and a piston on #2 with a 280 gram piston and 70 gram rings, is the load on the rods still the same? |
Correct! When you can't fix the piston, then we make a special pin.
1 gram is no problem. If there is no low hanging fruit just shorten the skirt all the way around, freehand. |
|
Back to top |
|
|
Casting Timmy Samba Member
Joined: August 04, 2012 Posts: 1221 Location: Kansas City, Kansas
|
Posted: Sun Oct 12, 2014 11:43 am Post subject: |
|
|
I think you could also put the heaviest two pistons on the front cylinders and the lighter two on the rear and just do minimal weight removal to get to matching piston/rings/pin |
|
Back to top |
|
|
Casting Timmy Samba Member
Joined: August 04, 2012 Posts: 1221 Location: Kansas City, Kansas
|
Posted: Sun Oct 12, 2014 11:45 am Post subject: |
|
|
I've also wondered if anyone cuts down the skirts just to make all the pistons lighter at times? I know some pistons are shorter than others, but the shorter pistons can sometimes have a shorter life span.
I've thought about cutting my skirts down a little to reduce weight since the pistons and cylinder kits from AA aren't a bad price at all. |
|
Back to top |
|
|
56vwoval Samba Member
Joined: March 21, 2010 Posts: 186 Location: nowhere USA
|
Posted: Sun Oct 12, 2014 11:49 am Post subject: weight |
|
|
Just bought a set of AA 92's and all four were within one half gram of each other. _________________ Remember guys and girls, you can be right or you can be happy with your significant other! You decide which is right at that time! |
|
Back to top |
|
|
andy198712 Samba Member
Joined: December 05, 2010 Posts: 1209 Location: Cornwall - UK
|
Posted: Sun Oct 12, 2014 12:41 pm Post subject: |
|
|
yeah mine were really close.
before i have removed material from the inside of the pin, it doesn't take much, weight of steel vs ally... _________________
Alstrup wrote: |
I like 5,5inchers in the rear at least. |
|
|
Back to top |
|
|
bugguy1967 Samba Member
Joined: January 16, 2008 Posts: 4338 Location: Los Angeles, CA 90016
|
Posted: Sun Oct 12, 2014 4:15 pm Post subject: |
|
|
I'm usually able to get them within .05 grams with parts swapping, but with this set, .09 is the best I could do. I'll remove from the pin on the lathe then. |
|
Back to top |
|
|
mark tucker Samba Member
Joined: April 08, 2009 Posts: 23937 Location: SHALIMAR ,FLORIDA
|
Posted: Sun Oct 12, 2014 7:51 pm Post subject: |
|
|
I never remove material from pins to balance piston,and never under the dome either. there is usualy enough flash or places to remove material.if you do some skirt work be sure to leave a sharp edge on the outer dia so it sheers off the oil from the cylinder,not tapered so it funnels it to the rings witch will be over whelmed. I supose a slight inside chamfer to the pin would be ok to tget the pins the same. above the pin on some pistons is a good place to get some too. |
|
Back to top |
|
|
bugguy1967 Samba Member
Joined: January 16, 2008 Posts: 4338 Location: Los Angeles, CA 90016
|
Posted: Sun Oct 12, 2014 8:27 pm Post subject: |
|
|
Yeah, I was only thinking of doing an inside deburring around the inside of the piston, not the outside. Also I wouldn't want to shorten the pin by taking material completely off one side. I was only considering taking out enough from the inside to remove .5 grams. |
|
Back to top |
|
|
mark tucker Samba Member
Joined: April 08, 2009 Posts: 23937 Location: SHALIMAR ,FLORIDA
|
Posted: Mon Oct 13, 2014 8:48 am Post subject: |
|
|
Ive never had an issue with pins not being the same weight,but Ive mostly used JE,manly,wizeco. witch is a totaly different ballgame then these things. if it is a straight through hole you could possiably hone it if you had a pin hone. or like stated befor a slight taper on the id. I dont remember how far out my aa 92's were. but I did a good bit of work inside them. |
|
Back to top |
|
|
|