Do flywheel's usually get touched when balancing a rotating assembly? My assumption is no, but I'm not 100% sure on that. When I put my short block together in 2010, I sent stock re-conditioned rods, TA 10:1 JE pistons, stock crank, Romac balancer and a manual transmission flywheel all to the balancing machine shop (sub-contracted by the machine shop doing my block). I recall only the rods looking like they were touched in the process. Too many years have passed to notice now if the flywheel was. Now that I have several years and practically 100k on the short block, and after rattling it a few times, oil pressure isn't what it used to be and I'm considering buying a pre-assembled short block, and if I do would it be a safe bet bolting my balancer and flywheel to one without having a balance issue? The crank was already 30 under and I expect to need a new one if I disassemble it, which means sending the rotating assembly out for rebalance, and given the mileage probably could use a boring and need new pistons, etc.
Depends on who built it, but typically the standard practice is to add/remove weight on the crank counterweights to attain the balance. When the aftermarket SFI flexplates came out in the 90's, that situation changed, because the offset weight amount and location was never consistent, nor did it match the factory flexplate. At that point in time, we started using a "master" flexplate , and correcting the SFI plates by drilling or adding weight. The very latest generation of budget SFI flexplates is the first one to not only have the correct offset weight in the correct location, but it also has the offset bevel in it, to correctly locate the torque converter. I have used about half a dozen of them now, and only one required just a tiny drill point to correct it to my factory master plate. Factory balancers and the TA repro are pretty much interchangable, just watch for the weight pins in the balancer outer ring, and move them in between old/new units are required.. Aftermarket SFI stuff is a different deal, your best to balance with the actual unit to be used. To answer your question, I can't imagine any type of professional machine shop offering an external balanced shortblock, without supplying the balancer and flexplate. There literally is no way for them to balance the assembly, without these parts. JW
Well I'm the one that assembled it and supplied all the parts to the machine shop. It is a manual transmission flywheel, not flex plate. I recall reading about the flex plate issues, do not recall seeing anything about the manual transmission flywheels. I cannot recall where I sourced the flywheel, I got it in 2007 or 2008. I'm not opposed to getting a new flywheel, but mine still has a machining or two left in it. It sounds like your opinion is, the Romac balancer alone is reason not to get an assembled short block? Hypothetical case, it may be best if I get a "470" rotating assembly from you with 4.360+" bore (currently is 4.35"), then get a local shop to check the balance with my flywheel and balancer while they bore and hone the block? The only other wild card in this scenerio is my deck height, I do not believe I zero-decked the TA 10:1 pistons, but may have taken it to 0.010" in the hole, would have to go looking for my record of the measuring it. **Edit** Looks like I just had the deck cleaned up, they are deep at 0.030" in the hole.
I would suggest sending the flywheel and damper to TriShield, so that the assembly can be balanced ONCE, and correctly. If you're buying the assembly from him, ask about piston-height options to get the pistons to--or near--zero-deck without cutting the block that much.
It's always better to have only 1 place build a motor, too many hands do things differently. I agree on having it balanced with the parts you plan to us. It's not too expensive to have parts shipped through fastenal, and process isn't to hateful either. Just shipped an transmission from Ohio to utah for a tick over 200. Took little more than a week. I bet a motor wouldn't be too hateful to ship either. I would assume 1 dampner to another, of flexplate/flywheel is the same imbalance effect. I just had an ati, called for adding 120grams to a location on the crank where you couldn't add weight.......no counter balance in that location . Put on a romac it called for removing 60 grams....so 180 grams different. The ati went back to summit for a refund The only way I would comfortable swapping those parts were if they were neutral balanced and everything was internal for the weights
In the case of a stickshift car, your best to have the entire flywheel, clutch disc and pressure plate all balanced with the crank. Ron has found significant imbalance issues in the past with various manufacturer's clutch stuff. I thought that you were considering buying an assembled shortblock from someone who rebuilt it, and wondering if you could just put your flywheel and harmonic balancer on it.. sorry if I misunderstood the question. And yes, I do custom compression height pistons to avoid excessive decking all the time. No extra charge with the autotec stuff. JW
Refresh my Buick memory, please. The OEM Buick Big Block damper is neutral-balanced UNTIL Buick pounds a steel pin (or three) into the holes along the perimeter during "final balance". Replacing dampers requires locating and driving-out the original pins, so as to re-install in the new OEM damper in the same relative position. An aftermarket damper CANNOT compensate for the "final balance weight pins" 'cause none of the aftermarket dampers have the bored holes that would accept those pins. The OEM BBB flywheel/flexplate ALSO is custom-machined during final-balance at the factory, so replacing the flywheel requires matching the new flywheel to the old one...or starting fresh with an aftermarket balance job. Is this correct?
My original hope was purchasing an assembled short block, then in a weekend swap the short block into the car. Minimal down time, but to do that requires accepting my romac balancer and manual flywheel. Pressure plates are another separate issue, I've had three different ones on this engine, so balancing to one IMO is a moot point. I agree about problems that come with having too many chef's in the kitchen on an engine build. I see two secondary options then, both require pulling the engine and waiting, but one would be to send trishield my balancer and flywheel and have JW assemble a whole short block for me, or two buying a 470 rotating assembly from JW and having a local shop do all the balacing and block work. I'm not yet at the point of pulling the trigger on doing this. I still drive the car regularly, and I'm still pushing hard to get my Firebird with a turbo L6 to Drag Week this year, so there is no urgency. Maybe once I have the Firebird running with the new engine reliably I'll be more okay with parking the Skylark for a long while.
Doesn't have to be a long wait.. simply order the shortblock you want, I will provide the cores, and when all the ordered parts are here, and the block machine work is done, then take the car out of service by pulling the balancer and flywheel, along with the top end, and send them to me via fastenal.. will cost around $100 to ship it.. then I will do the balance and assembly, and return a complete running engine to you, all dyno tested and ready to drop in your car.. Or, we can just do a shortblock.. and you can do the assembly work... another option to eliminate the core charges, is to simply send me the whole motor, I will use that to replace my core block and crankshaft. Low Fastenal shipping charges make that a viable deal these days, the core charges are way more than the shipping. JW
You probably wouldn't want to pay me on my cores, I know what I've done! Thanks Jim, I'll give it some thought. Meanwhile, I'll keep a wary eye on my oil pressure gauge
If you can find a core to send to Jim, you can keep your car going until you get your new short block. Then you'll be able to keep the engine that you have now to do a refresh on to be ready when you need it, or a core to play with at your leisure.
Not quite, can't drive the car without the flywheel and balancer, which is needed for the new short block!
Get new ones for the new engine so next time you won't have the same conundrum because you can use the old ones on the refreshed old engine? Dealers choice.
The issue of balancing a crank that has been balanced already is more of semantics. It will show up imbalances differently on every type of machine it's spun in and sometimes on the same ones later on. If you have a method or shop that works, stick with it. Shipping is cheap compared to build mysteries.
