Rod balancing jig.
Discussion
Boosted LS1 said:
Scales won't be accurate at less then a gram and besides it's not needed. A spot of oil weighs more then that.
Scientific scales measure to 0.1, but as you say are they accurate at that? So, if you say a gram is close enough, I would still want to weigh them, and match the pistons pins and rods.Another question regarding crank flywheel clutch, and front pulley, is it worth having these dynamically balanced together after buying the individual components brand new? Pistons rods rings, clips and pins would need weighing to do this no?
Edited by mickrick on Saturday 17th August 17:22
You might expect it to be 0.1g and for them to be using accurate scales, they don’t.
Accralite pistons made by Omega are sadly not usually within 1g, I had a set of super light Mini pistons this week that were 2.5g out even on my scales. This is because they are done in batches of say 50 pistons or more which is the now minimum order with Omega, and unless the reseller takes the time to match them all into sets, there can be quite a difference.
If your buying decent kit like Arrow rods and you want to rebalance I would be sending them to somebody who knows what they are doing, Trevor Wilkinson at Andrews Precission is amongst the best. The work on his shelves are who’s who of motorsport.
You will be far better off spending your money on balancing the FULL rotating assembly including clutch cover which people rarely do.
Accralite pistons made by Omega are sadly not usually within 1g, I had a set of super light Mini pistons this week that were 2.5g out even on my scales. This is because they are done in batches of say 50 pistons or more which is the now minimum order with Omega, and unless the reseller takes the time to match them all into sets, there can be quite a difference.
If your buying decent kit like Arrow rods and you want to rebalance I would be sending them to somebody who knows what they are doing, Trevor Wilkinson at Andrews Precission is amongst the best. The work on his shelves are who’s who of motorsport.
You will be far better off spending your money on balancing the FULL rotating assembly including clutch cover which people rarely do.
mickrick said:
Boosted LS1 said:
Scales won't be accurate at less then a gram and besides it's not needed. A spot of oil weighs more then that.
Scientific scales measure to 0.1, but as you say are they accurate at that? So, if you say a gram is close enough, I would still want to weigh them, and match the pistons pins and rods.Another question regarding crank flywheel clutch, and front pulley, is it worth having these dynamically balanced together after buying the individual components brand new? Pistons rods rings, clips and pins would need weighing to do this no?
Edited by mickrick on Saturday 17th August 17:22
I balance the individual parts by hand and then send the rotating assembly to be dynamically balanced as an entity, less pulley and flywheel etc. Somebody may wish to swop those parts at a later date.
Thank you for the replies Gentlemen. I almost certainly will get the whole lot professionally done, but I like to have a play myself just out of curiosity. I have a lot of patience, and I don't like to rush anything.
I suppose I could get a jig made locally, as I don't have a lathe and a mill in my shed, yet. They are on the wish list
Neither have I bought any engine parts yet, I've been looking around, and I most certainly will go for Arrow crank and rods.
I was surprised to see they only worked to a gram though. Accralite do say on their website that they match sets to within a gram.
Of course if everything is out by a gram either way, that can add up to being quite a bit out at each end of the scale, so getting it all professionally done.makes sense.
Thanks again for the comments.
I suppose I could get a jig made locally, as I don't have a lathe and a mill in my shed, yet. They are on the wish list
Neither have I bought any engine parts yet, I've been looking around, and I most certainly will go for Arrow crank and rods.
I was surprised to see they only worked to a gram though. Accralite do say on their website that they match sets to within a gram.
Of course if everything is out by a gram either way, that can add up to being quite a bit out at each end of the scale, so getting it all professionally done.makes sense.
Thanks again for the comments.
Another couple of points..
Boosted is right, 1g on a 4-500g piston might not sound like much but its a massive amount when fettling amuminium by hand, can look very second hand. If the pins are pretty long and strong, you can achieve better results with a tapered stone in a die grinder in the ends of the pin.
Balancing the rods involves grinding through the shot peened surface layer, this gives rod manufacturers heart failure but have never seen or heard of doing this(Professionally) causing a problem.
To answer your question about balancing the full rotating assembly even though you have bought expensive pre balanced individual components, yes its very important, you have no idea how accurate the manufacturers balancing is and there can be a build up of tolerance mainly due to the fit of components, one of the worst items are 7.25" racing clutches, they are often a very poor fit onto the .100" register and give different readings every time you tighten it up onto the flywheel. I know Trevor Wilkinson swages in the feet of the clutch for a tighter fit.
Boosted is right, 1g on a 4-500g piston might not sound like much but its a massive amount when fettling amuminium by hand, can look very second hand. If the pins are pretty long and strong, you can achieve better results with a tapered stone in a die grinder in the ends of the pin.
Balancing the rods involves grinding through the shot peened surface layer, this gives rod manufacturers heart failure but have never seen or heard of doing this(Professionally) causing a problem.
To answer your question about balancing the full rotating assembly even though you have bought expensive pre balanced individual components, yes its very important, you have no idea how accurate the manufacturers balancing is and there can be a build up of tolerance mainly due to the fit of components, one of the worst items are 7.25" racing clutches, they are often a very poor fit onto the .100" register and give different readings every time you tighten it up onto the flywheel. I know Trevor Wilkinson swages in the feet of the clutch for a tighter fit.
It depends on the amount of cylinders as to how you go about it.
For scales just go to Ebay. I've got some cheapo digital ones that measure repeatedly to .01g.
David Vizard came up with a good and simple rod balancer I remember, but as things are these days, you don't often need to do it.
There is a lot of rod and piston snobbery, I recently weighed a £200 set of four rods and the difference between heaviest and lightest was .4g, the Wossner pistons and pins were within .1 of each other.
I put my £40 supermarket till receipt on the scales to show the customer, it weighed 1.1g.
For scales just go to Ebay. I've got some cheapo digital ones that measure repeatedly to .01g.
David Vizard came up with a good and simple rod balancer I remember, but as things are these days, you don't often need to do it.
There is a lot of rod and piston snobbery, I recently weighed a £200 set of four rods and the difference between heaviest and lightest was .4g, the Wossner pistons and pins were within .1 of each other.
I put my £40 supermarket till receipt on the scales to show the customer, it weighed 1.1g.
rod balancing jig....
just get some cheap scales and make one. One option....it really isnt difficult. Or use one of those clamp things you used to use in chemistry in school etc as a stand/mount
https://www.youtube.com/watch?v=oJ6f4D9GEiA
just get some cheap scales and make one. One option....it really isnt difficult. Or use one of those clamp things you used to use in chemistry in school etc as a stand/mount
https://www.youtube.com/watch?v=oJ6f4D9GEiA
227bhp said:
It depends on the amount of cylinders as to how you go about it.
For scales just go to Ebay. I've got some cheapo digital ones that measure repeatedly to .01g.
David Vizard came up with a good and simple rod balancer I remember, but as things are these days, you don't often need to do it.
There is a lot of rod and piston snobbery, I recently weighed a £200 set of four rods and the difference between heaviest and lightest was .4g, the Wossner pistons and pins were within .1 of each other.
I put my £40 supermarket till receipt on the scales to show the customer, it weighed 1.1g.
Interesting stuff concerning those new parts For scales just go to Ebay. I've got some cheapo digital ones that measure repeatedly to .01g.
David Vizard came up with a good and simple rod balancer I remember, but as things are these days, you don't often need to do it.
There is a lot of rod and piston snobbery, I recently weighed a £200 set of four rods and the difference between heaviest and lightest was .4g, the Wossner pistons and pins were within .1 of each other.
I put my £40 supermarket till receipt on the scales to show the customer, it weighed 1.1g.
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