What the Hell have they done this for?

[MR2 Rich]

After opening my engine today we found that someone at some point has done quite a lot of engine work (Arp studs, JE forged pistons). The most bizarre thing is they have machined off some of the metal off the Con rod caps at the bottom of the engine! But only 2. Why would anyone do this?

I have a picture of them but you may not be able to see what I mean. But it has been machine off out of the engine. Anyone ever seen this before?

[gavinda]

There are areas at either end of the rods where material can be removed for balancing.

[MR2 Rich]

Why only 2 of them though and on a standard engine and turbo?

[ashley]

My guess would be to equal weight the rods as well, but that's a lot of material to have to remove

[MR2 Rich]

Knowing all the missing bolts , loose screws and general crap engine build I think whoever built it didn't have a clue on what they were doing?

[bobhatton]

Knowing all the missing bolts , loose screws and general crap engine build I think whoever built it didn't have a clue on what they were doing?

Toyota stock rods are balanced as a set.
If the builder has used rods from two engines then the balance of the 4 rods would have been out.
The heaver ones will have had metal removed to balance the weights of all 4.
This is the correct thing to do on any engine rebuild if it is going to be making more power.

[ashley]

Only one way to know for sure- pull the rods out and weigh them all against each other

[MR2 Rich]

Yes you're right Ashley.

[bobhatton]

The little ends are balanced first so they are all the same on each rod, then the total weight of the rods are balanced by taking metal off the big end.

So rod balancing is not just getting them all the same weight, the have to be the same weight end for end.