Weight variance in T2 Rods

[BLASINTEBO]

I recently purchase "New T2 Rods" from another member on this board.

I got the rods, but they appear to be Reman.

I weighed them and these were the numbers

.70 kg
.70 kg
.71 kg
.71 kg


My concern is that the .1kg variance will cause my engine to prematurely fail.


Should I be worried over this?

[turbovanman]

No!

[Dan Culkin]

Quote:

Originally Posted by BLASINTEBO I recently purchase "New T2 Rods" from another member on this board. I got the rods, but they appear to be Reman. I weighed them and these were the numbers .70 kg .70 kg .71 kg .71 kg My concern is that the .1kg variance will cause my engine to prematurely fail. Should I be worried over this?

The way you listed it, it seems like your scale is only good to increments of 10 grams. All 4 rods could be between 704.99 grams and 705.00 grams, per that measurement.

[BLASINTEBO]

You are exactly right.

That is why I listed it like that... because my scale is only accurate up to 10 grams....
therefore, I would have had to list it like this:


700 grams
700 grams
701-710 grams
700 grams


Thanks...


I just know that I want my engine as balance as possible and, worst case scenario, lets say the rods were exactly this


691 grams
691 grams
710 grams
691 grams

Should I be worried?

[Dan Culkin]

Quote:

Originally Posted by BLASINTEBO You are exactly right. That is why I listed it like that... because my scale is only accurate up to 10 grams.... therefore, I would have had to list it like this: 700 grams 700 grams 701-710 grams 700 grams Thanks... I just know that I want my engine as balance as possible and, worst case scenario, lets say the rods were exactly this 691 grams 691 grams 710 grams 691 grams Should I be worried?

I don't know off the top of my head what a good spec would be, but I think 19 grams might be getting high - it's about 2/3 of an ounce.

If you can find a "piston matching" weight spec, that should give you a better idea.

[89acclaim]

You could try to match up the pistons with the rods so you have the lowest variance between them.

Daniel Merrill

[Andre Parker]

Can you borrow one from someone that reads a little lower?? You can sand on the bottom of the cap which is where we sanded them at the shop I worked at. The closer you get everything to the same weight, the more power you can make because you can rev a little higher and not have as much bad harmonics.

[BLASINTEBO]

Thanks, that's some good advice.

I will try that out and see how much of the weight I can take off of the heaviest ones.

I didn't know how much the weights come into play, but I think if I take to two heaviest and offset them against each other it should help.

[Putter]

The bottom of the cap is called the balancing pad. Remove material evenly and carefully there and try to get the rods close to each other. A 4cyl relys on equal piston/rod weight to balance the engine.

When i get my t2 rods in i'm going to balance the rods as close as i can get them (hopefully under 2grams from each other) and the same for the pistons, if they ever come.

From what i remember talking to some engine builders, they try to get balanced parts down to +-1 gram vairance between parts. I think thats being quite picky, but then again when can one ever be too picky?

[GLHS0658]

There is rotating mass and recipricating mass. You want to balance the pin end first. You will need a rod balancer to do this. After all the "pin ends" weigh the same, you then weigh the entire rod. Pick the lightest one and leave it alone. You then make the other 3 rods weigh the same as the light one by grinding/sanding the "balancing pad" as stated before. 1 gram is not being picky, it is normal practice. Picky is getting an expensive scale that goes down to .1 grams (yes that is "point one")
You should also do your pistons. Most pistons that come in a set are weight matched but it doesn't hurt to check, or make it better.

Mike

[BLASINTEBO]

I suppose waiting until I get pistons would be beneficial... before I start taking material off any of the reciprocating mass.

I bought a set of used (but nice condition) stock cast pistons.... as I still haven't decided whether to do a quick fix and use those... or wait till I can fully build the motor how I want it.

Or... if I should wait a lil onger and get the forged pistons.

I figure until then, keep reading the board.

But the more I read the more I find evidence to support either or.

Things such as... 2.2 stock pistons are plenty strong.

Or putting the forged piston into the T1 block adds stregnth...

Or, also, so many good parts coming onto the TD market... like TU SS header.

Sweet.

But all the stuff I want adds up to serious $$$.. and I just want to be driving asap.!

[turbovanman]

Just becareful balancing rods, I have heard that they weigh both ends of the rod, and also spin balance them with the pistons. I would be call a machine shop that balances them or have them balance everything, its cheap, around $100, and cheaper still if you screw it up and then your whole engine vibrates badly or wears out prematurely.