I am about to begin the assembly of my LD9.

I have custom made pistons from mantapart, and eagle h-beam rods, and a new-to-me and nearly new new crank...

I know i dont have the means to balence a crank... but i threw my rods and pistons on precision digital scale, and the weights were all over the place. no 2 parts were the same weight... i think that is kinda odd.. i mean we are not talking tons different.... but like my pistons... all were within .2 grams of eachother, but the one was like .5 grams heavier than all the rest...

the rods were all pretty close, but not perfect at all...

so i am just curious, how anal should i be about this? i mean i could make things PERFECT if i wanted to, but is it needed? my scale goes to like 0.001 grams or something crazy... to the point where if i take a dremel sanding wheel to it for 2 seconds... i can see the weight change on the scale.

next question.... is where do you take material off to balance them? i dont want to compromise anything structurally... so far i have just been taking off lil raw casting nubs and things from the overweight piston... obviously not touching anything machined.

and then the rods... these have no raw castings... it is all shiney hard machined steel.... where can i shave material to balance these out?

You can take off some where the thin long part connects to the large crank connection, at least that's what a guy at a reputable engine shop said. Did that on his rods and his engine spins over 9,000 RPM and holds up no problem, so I guess that's one place to do it. I know I have to take off TWENTY GRAMS from one of my rods because I had 3 good rods of Eagle's old style, and had to order one of their new style which is beefier.


2001 Olds Alero (LD9)
650 whp / 543 ft-lb
@turboalero

the shop that did mine just sanded a little off of the side of the rods where their flat... dont know if thats the best way of doing it, but it got the job done.



Riddle me this... riddle me that...

i would have a shop do it.

Vincent Morris wrote:i would have a shop do it.

I would recomend this also, or at least ask them where they take it off, and with what. I would agree with the locations to remove materials that have been suggested so far, but I personally dont trust myself with this work at a home garage. If you have a freind or someone who does this type of work, have them help you, so you can learn the correct process while doing it.

John Benham wrote:

Vincent Morris wrote:i would have a shop do it.

I would recomend this also, or at least ask them where they take it off, and with what. I would agree with the locations to remove materials that have been suggested so far, but I personally dont trust myself with this work at a home garage. If you have a freind or someone who does this type of work, have them help you, so you can learn the correct process while doing it.

EXactly, take it to a shop.











~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ

yeah but the whole point of this car is to BUILD a fun driver car.... not BUY one or HAVE it built for me (which is essentially the same as buying one)

I am trying to do as much of the work as i can myself. this car is a personal growth experience.

Yes i am sure they can do it better... but i wouldnt learn anything from it, and i am sure my doing it will still be better than not doing it at all. (unless i screw it up and break something)

but hey.... that is how i got where i am now... spun my rod bearing in a learning experience... and now rebuilding the whole freaking engine....

you live, learn, and come out way ahead... with a much lighter wallet....

but often the experience is well worth every dime. (well that and the look on the face of V8 owners as you hand them their ass, that is priceless)

if i could go back in time... i would have made myself spin my bearing about 2 years ago....

there are plenty of places to learn and do things yourself, trust me when I say let a shop do it. Your motors internals are no place to make a rookie mistake..


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find a place that will let you look over thier shoulder....I totally understand wanting to do it yourself, but I would watch on the sidelines your first time...

there's no shame in letting professionals do some of the work. you will be putting the engine in yourself, so you will have plenty of 'i did the work' pride, trust me.



Riddle me this... riddle me that...

z yaaaa (the riddler) wrote:there's no shame in letting professionals do some of the work. you will be putting the engine in yourself, so you will have plenty of 'i did the work' pride, trust me.

Exactly.

Do you think people go out and spend $50,000+ on machinery to their own machining and balancing? No one does, everyone takes they parts to a reputable machine shop to have their work done.


- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.

yeah i dont do body work or paint, so i take it to the professionals. i dont do machine work, take it to a professional. i cant see spending all the money on the motor build just to "think" you did it right and be wrong. thats why they own a machine shop...

Ken let someone who has years upon years of time and experiance with thta crap, atleast if they screw up they pay for yoour @!#$, when u mess it up you will pay more than before


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