Balancing

From what I've read (and I'm sure I'll be corrected if I'm wrong), "together." And you can even match up heavier pistons with lighter rods to make combinations of pistons/rods that are closer in weight to each other that way, making it so you don't have to remove as much material. I've read the answers to your questions that follow, but don't recall clearly what they are so I'll shut up for now. I mean I'll shut up for this one particular minute in time. :-)

info here you might find helpful. look at engine building/short block/static balance

Factory spec: 8 grams

MY spec: 1 gram, 2 g is easy to achieve with a cheap scale. It's also important to know WHERE the weight is on a rod, lenghtwise. They should match that way too.

Makes no difference. Shaggie had a good answer regarding mixing amd matching pistons and rods to get a decent set with minimal work, but since they ALL have to be SAME weight, and the weight should be located in the same area... ... the only way to do it right is to weigh each piece separately, and remove material from the heavier ones to match them with the lightest one. I do rods and pistons separately. New pistons today are pretty accurately the same weight, you rarely need to touch them.

Weights on a used set of stock rods are all over the place, I've seen

24g differences in a set of rods that came from the same engine. (Surely it was rebuilt by someone in a hurry before)

This would require a picture. The Bentley book has one. I might scan it and put it up on my website tonight. or maybe not :)

inside the piston, there are a couple bumps and bulges you can shave to 1/4 of their original height. But you have to remove a LOT of aluminum to lose 1g of weight. Luckily with good quality pistons (like Mahle) this is often not necessary. I wouldn't worry about that unless you find a difference. If you see a 5g difference in piston weights, you need a new piston. I don't think removing that much material would be safe/possible.

Jan

Depends on how well you want them balanced. Your manual will list the factory spec, but you can actually balance them much closer than that.

Balance all the pistons against each other. Balance all the rods against each other. Rods should be balanced not only for total weight but for weight distribution (known as end-for-end balance.)

The correct places are shown in your manual.

Inside the skirt you will see cast on bosses which have been turned down on a lathe to balance them.

I gather you don't have a manual. Get the correct Bentley for your model. There's no point in trying to do anything like this without proper guidance.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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And you gather correctly! Whatelse would you guys be doing if we all had manuals? It is on my list of things needed, but you guys are still a great source of info.

"Steve" wrote in news:NVo2e.112151$ snipped-for-privacy@twister.nyroc.rr.com:

Now that is getting answers to questions and then some!!!!!!!!!!

THANK YOU STEVE!!!

I have just spent some time looking around that site and it has answers to questions I did not know I had questions for.

The one on the left is *overkill*, and made for a race engine where long life never was important.

Jan

Jan Andersson wrote in news: snipped-for-privacy@rocketcom.mail:

The thoughts of drilling holes had come to mind, but I knew it was probably not good for a long life. LOL

What happened to the rods that were drilled? Did they bend or distort in that area?

These were carefully selected from used stock rods, magnafluxed, and machined *considerably* lighter, plus carefully balanced to less than 1g weight difference.

They lasted several seasons in an autocross car that saw dirt and pavement mix on track,

140hp and over 9000 rpm regularly. Each race lasts about 20 minutes and it's pure hell. 10+ races in a season, not counting winter season.

After that they lasted 2-3 years in my street bug, 8000rpm redline. (and a heavy foot).

After that they were shelved for a while, and then I built another

8000rpm streen engine with them...

At which point, during break-in, one of them finally died. Taking a case, piston, 2 cylinders, and a head with it to vw parts afterlife.

Still, pretty good considering these only needed to survive one race day.

Like I said, these were not designed to last. They were designed to be lightweight and cheap. :)

Jan

Oh yea, the rest of them still checked out ok, but I discarded them anyway.

Jan

Not so cheap then ;-)

Rich

Jan Andersson wrote in news: snipped-for-privacy@rocketcom.mail:

I would think that you could use smaller holes and still retain most of the strength. A street engine would/should last pretty well. Considering you ABUSED these rods on the track and the street. Most of us do not go that hard on our engines, as you do. LOL, no offense intended. My thought would be that they should last under close to normal use and with smaller holes and you could even add another hole or two and still hold up as well. But, I will not volunteer to test this theory until I am financially set for life, and at the current rate, that will be 10 years after death. LOL

I am just happy the wife has allowed me to expend what I am on my current engine. It would be different if I were single, but the benefits are not quite the same. Ahh well, enough on that subject. LOL

Know that feeling very well !!! LOL. Just had the ' Either Bus or Bug has do go'...speach... Managed to get away with selling the ICT's :-( for now...

james

The rest of the RACE engine is pretty worn out after one or two race days, so it should be rebuilt anyway. Imagine what happens when you run 20 minutes flat out on a dirt track, 8 cars at a time, with no air filters. The cylinder walls alone will get eaten away FAST, so the engine after a couple of races is no longer competitive.

Also race rules include "must sell" clause, cars are sold for a fixed (very low) price if there are any bidders after each race. Bidders each get one "bid", then the winner is drawn. Price is less than what you'd spend on a competitive engine. Team members often bid on each others' cars as protection, so the car stays in the team. Bidders must have valid racing license.

So.. minimum budget, maximum power, with strict parts limitations. (heads must be based on stock heads, no welding allowed near ports... not allowed to use true dual carbs, maximum of one carb throat per two cylinders.... displacement is limited to 1649cc in "foreign bodies" and

1800cc in beetles..)

Jan

Non taken :) These risks are taken knowing full whell what might happen. The street engines I used these in were my "experimentals". I.e. expendable, if I learn something in the process.

I've learnt a whole bunch of stuff... of what not to do ;)

hehe, same here... I'm sure many will be tempted to try this, and I say go ahead if you can afford to lose what you have invested in the engine. never gamble with more than what you can afford to lose... And don't come blaming me if something broke. I'm telling you right here, that something most likely WILL, when you push the envelope hard enough.

That's what I'm facing now, so I hear ya :)

Jan

Yep...the same with me...and I'm lucky guy, because my two soon are very happy when we all go for a ride on it... Joao

72 Super 1302