Rods

[DANNY8]

Went to see how my motor was coming along 2day. The guys must have been on their lunch break coz no one was around. I went and sussed out my motor and saw most of the internals were back 2gether. Everything except one piston and rod.

When I got home a while l8r I rang them up and asked how it was going and apparently the rod needs replacing. The rest are ok but apparently the bearing must have been machined to fit when it was built. Not 100% sure wat he was tellng me, but the bottom line is I need another rod.

I took a 202 rod out there to him and he said he'll pop the gudgeon pins out, remove the pistons and measure them up 2gether to see if it can be used.

So 3 questions here.

1. Can a 202 rod be used on a 173? The rest are 173 rods as far as I know.

2. I've had the crank assy balanced using the current rods, if I switch one rod how much will that put the balancing out?

3. Does anyone here have a spare 173 rod lying around that they don't want?

Cheers.

[vkberlina]

Went to see how my motor was coming along 2day. The guys must have been on their lunch break coz no one was around. I went and sussed out my motor and saw most of the internals were back 2gether. Everything except one piston and rod.

When I got home a while l8r I rang them up and asked how it was going and apparently the rod needs replacing. The rest are ok but apparently the bearing must have been machined to fit when it was built. Not 100% sure wat he was tellng me, but the bottom line is I need another rod.

I took a 202 rod out there to him and he said he'll pop the gudgeon pins out, remove the pistons and measure them up 2gether to see if it can be used.

So 3 questions here.

1. Can a 202 rod be used on a 173? The rest are 173 rods as far as I know.

Never really played with 173s to answer this.

2. I've had the crank assy balanced using the current rods, if I switch one rod how much will that put the balancing out?

If they need to replace 1 rod it will throw the balencing completely out the whole lot should be rebalenced. Personally the rods should have been inspected by them first so they should wear the cost of rebalencing.

3. Does anyone here have a spare 173 rod lying around that they don't want?

Cheers.

best of luck

[Tree cutter]

The 202 and 173 rods are the same length. Blue motor rods are stronger than red motor rods and have bigger bolts. Early red motor rods are lighter than the later red motor rods

[DANNY8]

Thx a lot lads. If blue 202 rods are the same length as 173 rods, I guess the black 202 rods are the same as well? So using a black 202 rod and 5 blue 173 rods won't make any difference at all except putting it out of balance?

[vkberlina]

If it was my engine I would replace all of the rods and get the bottom end re balenced. do it while its all appart, theres a big difference between a well balenced engine and an out of balence one. it depends on how the weight is distributed on the rod ocmpared to the 173 rods. Have a good what to your engine builder, but just make a decision you wont regret once its in the car.

cheers
scott

[immortality]

i thought the best rods to use on the 6 cyl motors was the starfire rods(4cyl) as i'm told there stronger then the 202 rods etc

[Drewie]

They need to weigh the defective rod in grams and then weigh the replacement rod and if the replacement rod is heavier then it is simply a matter of grinding or polishing weight off the new rod until it matches the old one, then it should still be in balance. Both the big end and little end need to be weighed. If it is a lighter replacement rod then you have a problem, need to find one of the same or heavier weight. The rods are balanced by equalising the weight of all the rods. This is the way I have had motors balanced in the past by a very good race engineer.
Either that or find 6 new rods and have them all weighed and matched again.
Old rods can become out of round as well and the big ends may need to be resized, they machine a small amount off the bearing cap where it bolts together and then re-machine the hole back to a perfect circle once again.

[DANNY8]

Thx Drewie, I gave Chris Milton a ring 2day and he basically said exactly wat u said

immortality - yeah ur right mate, but apparently the blue and black motors had starfire rods anyways, so I'm guessing the rods I have are starfire rods.

[DANNY8]

If it was my engine I would replace all of the rods and get the bottom end re balenced. do it while its all appart, theres a big difference between a well balenced engine and an out of balence one. it depends on how the weight is distributed on the rod ocmpared to the 173 rods. Have a good what to your engine builder, but just make a decision you wont regret once its in the car.

cheers
scott

Thx mate. If the rod is weighed and is brought to the same weight as the original then the balancing should be fine...so lets hope it works out ok haha. I'll go see the engine builder 2morrow and have a talk.

[immortality]

there is a little more to it then that, the rods do need to weight the same but they also need the weight in the same place. i.e. if your rods have less weight at the small end then the new rod there is still going to be a balance problem etc. the engine rebuilder should really sort it at there cost anyways as they stuffed it up to begin with