Where are you pulling weight from on the big end??

[Tippy]

Need to take 1 to 2 grams off a few rods.

A few surfaces I ground on didn't do much.

Where's the most bang for the money?

[bpu699]

I just got my rods back from Ollies... They balanced to 1 gm and they take it off the ends. Porsche does it to 9 gms.

Lots of posts on here say you should only take it off the side where the bolts bind.

If Ollies, which is pretty much one of "the" Porsche machine shops takes it off the ends, then it seems that's the way to go...

I did it because it couldn't hurt. Though I do question the value, as there is no way the pistons are within 1 gram after any use and carbon build up. Each piston has variable amounts of carbon, that alone throws it off way more than 1 gm...

Bo

PS. Are you balancing your pistons and wrist pins as a unit?

[Tippy]

They did the weight removal on the spline on the very bottom of the cap?

[bpu699]

its the very end of the rod, at the outer most part of the big end on the cap. Is that the spline you refer to? At work, so can't send pics...

[Tippy]

Yes, that's it. I'd be reluctant to remove material from there. Worried it'll weaken it structurally.

These things get out of round as it is

[gtc]

Here's how mine were done. You can see the corners ground down on the left rod.

[bpu699]

Originally Posted by Tippy

Yes, that's it. I'd be reluctant to remove material from there. Worried it'll weaken it structurally.

These things get around as it is

I hear you. I read all the threads suggesting that's not how its done. Yet, Ollies is an extremely well known and thought of shop, and that's how they did it...

I can tell you that the amount taken off looks to be very little. Looks like someone took some fine grit sand paper and polished the ends of some of the rods...

One of the rods, oddly, also had some polishing on the small end...

Has anyone ever seen a rod break in that spot?

[Tippy]

gtc, I saw JFairmain do his that way. How much did that remove?

[bpu699]

Here you go... Here is another well known Porsche shop Costa Mesa R&D

https://www.youtube.com/watch?v=QLpiF0E0EJU

Also taken off by polishing the ends...

[Tippy]

Originally Posted by bpu699

Here you go... Here is another well known Porsche shop Costa Mesa R&D

https://www.youtube.com/watch?v=QLpiF0E0EJU

Also taken off by polishing the ends...

Hmmmm, I need to look more into this. I always assumed the mass was on the big end. The big end is flailing around with centrifugal forces. Thought that's where you'd want the mass removed.

[bpu699]

Originally Posted by Tippy

Hmmmm, I need to look more into this. I always assumed the mass was on the big end. The big end is flailing around with centrifugal forces. Thought that's where you'd want the mass removed.

On mine 2 were left alone, 3 had polishing on the big end, one had polishing on both ends...

If you look, they don't just put it on a scale. They weight both ends separately?

[Tippy]

Yes, that's called moment-weight

[Catorce]

You're sure both ends are actually round? Why isn't a machine shop doing this for you?

[Tippy]

Originally Posted by Catorce

You're sure both ends are actually round? Why isn't a machine shop doing this for you?

I really don't know how to answer these questions......

Is this another belief that only machine shops can do these tasks?

I'd bet most machine shops use the most basic of tools to perform this task. I've used very high-end equipment that required the government to know I moved the machine 3" over to the right on its stand.

Does this answer your questions?

[Catorce]

What I am getting at is that a shop like Competition Engineering will recondition and rebalance a set of rods for under $200, and they don't need to post on the internet to ask where the weight will come off.....

It's not that ONLY machine shops can do them, it is that they do them ALL THE TIME and for very little money, and they are 100% right.

I am not averse to doing my own machining. I have a 3 axis CNC mill in my garage. But motor shops are set up to do rods easily and cheaply.

Just another counterpoint.

[boosted79]

[boosted79]

[bpu699]

Originally Posted by Catorce

What I am getting at is that a shop like Competition Engineering will recondition and rebalance a set of rods for under $200, and they don't need to post on the internet to ask where the weight will come off.....

It's not that ONLY machine shops can do them, it is that they do them ALL THE TIME and for very little money, and they are 100% right.

I am not averse to doing my own machining. I have a 3 axis CNC mill in my garage. But motor shops are set up to do rods easily and cheaply.

Just another counterpoint.

If you have a qualified machine shop that's close, then you are very lucky.

I had to send my rods out... as most do.

Add about $100 to shipping back and forth...

But I would rather send them halfway across the country to make sure its done right.

We are really lucky we have highly respected machinists that do this stuff... and mailing packages is WAY cheaper than it used to be. Shipping heads to Cgarr, was $30-40 heavily insured...and those puppies weighted 40lbs in a very large box...

Folks do these things themselves if they can, as its enriching to do it and learn how its done... Some people golf, some disassemble and reassemble porsches...

The "smart" thing to do is to just send your motor to a reputable shop to rebuild. In the end, it would be cheaper than doing it yourself, assuming you are realistic about how much time it really takes...

But wheres the fun in that?

Plus, if we all sent everything to an engine rebuilder, we couldn't engage and enjoy the company of pro's like yourself on the internet!

[Tippy]

Originally Posted by boosted79

Is that your rig? Home built?

[Tippy]

Originally Posted by Catorce

I have a 3 axis CNC mill in my garage.

When can I swing by?!

I'll bring beer! 😂