I just received a 13lb flywheel in the mail yesterday from Dominic
I've read about the advantages of having the engine rotating mass balances, especially in race engines and those that see high rpms a lot. I am putting this med weight flywheel in my stock 1.7 for AX when I do a side-shift conversion in Feb.

What's the best plan for installing this flywheel?

Some say (i.e. Jake Raby) that if you can't dynamic balance every last bolt then don't bother.

I'm thinking I want to send this mildly used flywheel for balancing. Would it be a waste of time and $$$ if the internals of my engine are not part of the balancing (i.e. crank)??? I can remove the clutch and PP (and bolts and gasket(?)) have this entire assembly sent for balancing...that seems like the best plan, but means having the car up on jack stands for the duration of the machine shop work

Any referals to a competent shop in the SF Bay area close to Oakland are greatly appreciated!

balanced flywheel is meaningless. you really do have to do everything.
Pressure plates can be significantly out of balance. Rods are never the same nor are Pistons.

You can reduce the amount of material to take off if the flywheel and crank are indexed to the best balance. which means you don't use the roll pin anymore.

225.00 plus shipping is Not that much from Raby.

Define High RPM..... Autocross normally doesn't see high RPM for long duration. Rather short sprints to 6 grand which your heads will be all out of Umph by then anyway.

High rpm = 4-6k for 1 minute. So, not too bad really.

What is $225? Complete engine balancing?

Jake does have prices on some of his services. Just go to his site and find the balancing section. He explains what is all needed and to what degree of balance he will do.

I know of a place about 100 miles from here that said he could do a balance for 150.00 but would not talk specifics like 10ths of gram and everything from the fan to the pressure plate. So he didn't pass my interview.

You have straights in Autocross that are a minute long? I'm moving

Hell I only get about 15 seconds of WOT on the straights of our local road course.

IMO I would have the flywheel zeroed, then add the pp and have that zeroed (usually just welding on some washers for instance).

If the internals were not balanced, then yeah that sucks, but no reason to add more imbalance to the system. You might get lucky and they offset each other, but that is a statistical "not gonna happen".

In theory the engine was all zeroed before it was built, so zeroing anything you add is best. Again, even if the internals weren't zeroed, anything that gets added should be zeroed for your best bet.

when I went with a lightened flywheel and new clutch package back when I had the IV in my car, that is exactly what I did. Glad too because the lightened flywheel I got was outta whack and regardless of previous balance, that could have only made matters worse.

Also, if someone before f'd up and balanced everything with the flywheel, but didn't zero the flywheel (in other words worked the crank to match the flywheel) then that would be 1. bad - that guy should be found and shot, but 2. means you may want to have the existing flywheel checked, then if it is outta whack, maybe match balance this new one to it. If anything, it is running as is so matching what you had should work.

I'd say balance the flywheel & PP. Mark the bolts that hold the PP to the flywheel. The farther something is from the centerline, the bigger the impact on balance. So the six bolts the hold the PP on should be marked so that they go back in the same place each time, but the bolts that hold the flywheel to the crank don't really matter.

There is a place here in Napa that can do it. The guy's got a killer machine and knows how to use it. I'd guess a week for him to get to it and around $100.

Any form of balancing is better than none. Yeah it is best if you can do everything, but there again some is better than nothing. Any engine will benifit from balancing, it is only noticed at higher RPMs, but it will work for anything from 1 rpm, to 10K or higher. Balancing allows the engine to use its power in a way that is most efficent. Instead of fighting with itself, it can use the revolution to move the car.

BTW, pump reapir places can be used to do this also, pumps have to be balanced, or else they tear themselves apart in very short order.

Jay's Precision Machine in Santa Clara. He does excellant work.

Randal, does he repair 2.0L heads?

Yes he does. You can look at my heads that he completely redid after i bent the valves. He also installed dual springs to support the cam that Jake specified and supplied.

The only thing with Jay is that he is always busy. You have to get a committment on delivery and then expect more than one trip to get your parts.

OK - kinda what I figured. Get em balanced cause it is better than nothing, but not as good as doing it all.

One more clarifying Q:Just flywheel, flywheel bolts, PP, and PP bolts? Is the clutch disk part or this rotating equation?

I'm starting to think a lighter PP might be cool, then I could get one, do the balancing on my new parts, swap em in quicker with less down time. I like to drive my 914!

Mark - I'll be sending an email soon. I've got 50% of my powdercoat stuff cleaned and ready and need to tear apart the rest this weekend. I'll plan to drop and pull apart my engine soon, then bring you a bunch of stuff for powdercoat and probably do the balance in Napa - quotes have been mostly $100-$150 but I haven't called any pump repair facilities yet.

Dan - I got my new KONIs installed up front with mucho assistance from the tips you wrote that I found in my *search*. Thanks!

I have something interesting you guys might enjoy.

Suppose you balance a crank to zero. (Close as we can get)

Then you seperetly balance a flywheel to zero.

Then you match the flywheel bolts weights the same.

The assumption would typically be that if you now bolted the flywheel to the crank with said matched bolts.

And you put this combination on a balancer. It should run about zero balance as a pre-balanced assembly..

And you might be very WRONG.

I have done this myself. On a high end Sunnen digital balancer.
(Note I caliberated the balancer twice in this process to make sure I wasn't getting bad data)

I assumed that the package would be almost zero and not need any or very little metal removed.

This was not the case. When you hang a 14 LB flywheel on the end of a crank. It changes the harmonics of the crank. It also changes how the crank TWISTS. Thus the mass of the crank throws are moving a bit and changing the balance of the crank.

I was yanking metal out of that crank for hours. And each time I re-spun it up. It would change dramatically.

Please understand. I am not a machinist. I don't really know shit about this. I just hang out with guys that do.

So I suggest to you the following. Just because all of the pieces of a reciprocating assembly are matched in weight.
Does not automatically make a balanced "COMPLETED" assembly when bolted together.

When a type IV crank is spun up on the balancer with Flywheel, FW bolts,
and bob weights to equate what the rod, rod bolt, piston, pin and keeper weights. The crank MAY balance out differently.

AS far as the PP. This is also part of the equation. And must be indexed at the time of balancing to make sure it all goes back together with the same index. (FW and bolts also)

I wish I could explain all the reasons for this. problem is I don't know the answers.

I have simply seen this happen at other high end machine shops. And have encountered the same myself on 2 of my own builds.
(note: both times I chucked the crank and used another one. And yes they were magged for cracks)

AND.... This does not always happen. In fact it is rarely happens.
Some assembly simply balance out dead on or relatively close when assembled. And some are a serious cluster fuck to get it back to zero after ALL the pieces are put together and placed back on the balancer.

So I reiterate. I don't know shit. I just don't want to see one of the guys have this anomaly happen to them.

For myself: I have all the pieces of the assembly balanced as a WHOLE after each piece is weight matched and the crank and FW are balanced separately.

I wish Jake was here. He probably knows the answer to this anomalous stuff.

Just something to think about.

Clayton

Clayton, I'm with you 100% and what you said is important to keep in mind. But, IMHO, it's bolting together zero'd components will get you closer to zero to start.

more detailed response
I would guess that the reason some bolt together and balance out near zero and some don't is do to where the imbalances are. If you happen to get two or three components there are heavy on the same 'side', then those weight imbalances will be exacerbated. But I'm speculating.

McMark,

I just re-read your last post for the 5th time...

I get it...!!!!!!!!!!!!!!!!

You may well be correct. It may be the imbalance from side to side of the FW..

Interesting stuff.

Also there is something I forgot to mention in the last tirade of mine.

On an opposed engine like the Porsche/ Suby and BMW motorcycle engines.

If once the piston, ring pack, pin, rod, rod bearings, pin keepers, rod bolts have been weighed and matched.

Then that data is punched into the balancer. THEN and only then is the crank balanced with all of this additional data. (else it don't work)

I shouldn't have to use BOB weights on the rod mains to balance the crankshaft if my weight data is correct on an OPPOSED engine.
I have tried it both ways. On the same crank. I got a hair different readings using bob weights VS pure data calculations.

Since I am old school.. I trusted my gut and went with the bob weight setup, plus PP,FW,bolts and only punched in the weight of the disk as a balancing parameter. (And I hand balanced that on a set of razor blade straight edges after making/machining my own center point)

I dunno.... Maybe we should get a REAL EXPERT HERE to tell us how it works.. In detail.




Just to add to the confusion.
Lemme give you another scenario.

Lets say I set a bone stock 2.0 crank on the balancer.

The digital readout says I need to take 10 grams off the factory CW next to #1 and 30 grams off the CW at #4.

I then do exactly that. I drill/grind off that amount as per the spec.

I spin it up again... One would assume that now the crank SHOULD be relatively close... NOT....!!!!!!!!!

Once this metal is removed.
The whole crank takes on a different personality.

Now the readout may tell me to take off more metal or possibly add some metal (mallory metal or welding rod to add weight) on to get it right.

Every MINUTE change in the balancing creates a different challenge.

Sometimes it goes very fast.... Sometimes it takes hours.

And this is AFTER the crank has been magged, straightened, polished...whatever. Note: TYPCALLY the only thing left after the balancing is micro polishing the journals.

YUP... rotating assembly can be a bugger at times.

Type IVs are usually pretty easy. Fiats can be a really NOT FUN experience.

Just more anecdotal stuff to think about.

Sending the balancing act to Raby makes more and more sense unless you really trust your machinist. IMHO.

I am my own machinist most of the time. Just takes me 10 times as long.
I do everything SLOW and methodical.... That how I learn. saves mistakes.

Speed comes with time and familiarity of the equipment and the parts.
most
McMark. Have you had these anomalous balancing things happen in any of your builds???

Cause I think that when a fella picks up his stuff from the machinist for balancing. He is STUCK with trusting the process. He has NO WAY to know if the work is accurate. He can't measure the quality of the rotating balance job.

All he can do, if he has a very good scale, is to weigh the parts and see if they match in weight... Thats it......

Kinda scary if you are as paranoid of machinists like I am.
Cause in my brief time on this earth.
And as little as I know.
I now know more than a few of the guys that do automotive machine shop for a living. And these same guys are doing work for guys just like us.

And thats just bugs the shit out of me.

So who do ya trust to do the work? Interesting question for each man to answer for himself.

Ain't life a trip.....

Lemme know if any of this makes sense to you.

Clayton

Chris: Have you talked to Ashland Grinding in Hayward? They were recommended by Dima Elgin. They did my complete engine assembly for $175. I just haven't got it running yet to give a reference. The individual components were right on though.

Thanks Bill - I will be sure to give them a call when it is time. The consensus here means I gotta drop the engine, get the old PP out etc first. Unless I buy a new PP and bolts

Getting a new PP and bolts? Why?

C

Yes.. I am here. Here is the answer.

http://www.aircooledtechnology.com/dynamic-balancing.htm

Our turnaround at the present is about a week.We have mandrels, jigs and experience pretty much only pertaining to the TIV engine. Whether it's a 5,000 RPM daily driver, or a 9,000 RPM production race engine I have a service for it.

New pressure plates are HORRIBLY out of balance, they are BY FAR the most out of balance components that can be introduced to the engine.

Smart people buy TWO pressure plates and have us balance them BOTH to the engine for now and for later should they break one or wear it out. Most of my engines come with two pressure plates because the engine has the capability of outlasting the pressure plate and swapping to a non balanced and non indexed component will compromise my job absolutely!

Balance is just part of it, INDEXING components exactly as they were balanced is the key for correct dynamic balance. With my service you even get the pressure plate bolts indexed to their same position they were balanced. Thats value over gross price.

Thanks Jake
DO you guyz have new pressure plate bolts in stock? I'm making a list; new exhaust studs, copper gaskets, flywheel bolts...and more!

Yes, in stock.