Kubs

I bought new rods and pistons for my engine build and I am having the rotating assembly balanced with my factory crank. How should I have it done? I know the DM flywheel is externally balanced and the balancer is internal, right? Since I am low on cash I am forced to use the heavy DM flywheel and factory balancer for now, but if I have it balanced for those how will it effect my clutch/flywheel options down the road? Is it possible to have it internal balanced and neutral balance the FW (remove weight)?

Kubs

Oh I meant for this to go in C4 tech. Could a mod move it for me please?

Kubs

Anyone? I will be dropping the parts off this weekend and would like to know what to tell the machinist who will be doing the balancing.

mtwoolford

I've always had pistons and rings, rods and rod bearings, crankshaft, and flywheel balanced as an unit. I don't think that the flywheel being a dual mass would make a difference.

mtwoolford

on a side note, on my 96, I'm using a SPEC aftermarket flywheel which is externally balanced, but it appears that the balance is accomplished by a bolted in (not cast in) weight; other wise the flywheel appeared to be a (modified) neutral balanced unit. In other threads I've read of people having a new flywheel "match balanced" to the original flywheel, although I haven't had any experience with this procedure.

Kubs

Yes he is doing it all together. I guess my question is, is it possible to take some weight out of the DM to neutral balance it?

93VettePilot

It probably would be cheaper if you are doing a stock rebuild to just buy a crate engine from one of the local auto parts shops. 100,000 and 3yr warranty.

If you must use the dual mass flywheel then tell the balancer to balance the rotating assembly to factory specs.

I tried to have my dual mass flywheel zero balanced and it failed about 3 weeks after I installed it. So I went to a single mass with a sprung clutch disk.

racebum

if you're going racing get a single mass. the oem Lt1 camaro flywheel is a cheap way to accomplish this if you can't swing a fidanza just make sure you machine it down, what's the number? .080 or .100? can't remember exactly so double check. also, it's ALWAYS a good idea to have an engine balanced when you're doing a build! not only is engine life increased but it will drive a whole lot smoother

tpi 421 vette

I take it this is a 350? The front of the crank is internal balance, the rear of the crank is external balance. It is that way for all 1 piece seal engines. If you have a cast crank, you will probably have to stay external balance on the flywheel. Cast cranks generally don't have enough weight in the counterweights to internal balance. You would probably have to add mallory metal to the crank to internal balance. If you have a 4340 crank, the metal is more dense, and internal balance is alot easier.

mtwoolford

some aftermarket one piece rear seal cranks are neutral balanced, but of course they were designed this way from the get go....would it be possible or economically feasible to have your stock crank so modified (if that is your question) ? ... probably not.

For the same money or less money, you could chuck the dual mass flywheel...regardless of whether or not it can be resurfaced, it isn't going to last forever...and get any of a number of single mass flywheels. Aluminum (12 to 14 pounds), stock weight cast iron , light weight billet steel (21 or 22 pounds) or heavy weight billet steel units; they are available in externally balanced units which would match up with your stock style rotating assembly with no or a minimum of balancing. Thw main deciding factor would be your driving style and personal preference.

GREGGPENN

If Kubs wants to (re)use the DMF, match balancing is what I'd do. DMFs, flexplates, and standard (RMW) FW's are supposed to have the same weight offset. If they didn't, you'd need a different (engine) balance -- from the factory -- on automatic setups vs manuals. That's not the case. (Remember TPIs were used WITHOUT DMFs in F-bodies.)

IIRC, the offset is about 30g. If/when you swap to a new FW, just have your shop check to see if the FW offsets are the same.

93VettePilot

It is .090 (Alot) which costed me around $80. I love my new camaro flywheel and camaro clutch disk. It is a joy to drive around town and still has the holding power to manage the power of my 383 with AFR heads yet didn't cost near what some of the SPEC setups cost. I got the camaro oem valeo clutch disk off ebay for $100. Then you can get the corvette pressure plate and throwout bearing for about $200 from any of the auto parts chains with a lifetime warranty.

USAsOnlyWay

Now is the time to pick up that Al flywheel, which for your use would be perfect. And balance it, don't worry about that heavy DM flywheel. Tpi (Jim) provided some nice tips about it but either way I'd toss the flywheel as if you don't upgrade now, you may want to in the future and now is the best time to do it and make sure it is balanced for a more standard flywheel.

Also, take a look at ATIs balancers. If you want to go lightweight it needs to be an internally balanced balancer, so in my mind, this would also be a must.

Kubs

That is good info. I guess I will just have it done externally then.

I would love to pick up a lightweight FW but as it is I am scrapping the bottom of my pockets just to get it running. Things that I dont "need" right now Im not buying.

mrc24x

Mike.....,

I had my new 4340 crank neutral balanced but I wish I would have left it the way it came. Like TPI 421 said above, it took a lot of weight.

Kubs

Another thought, if I have it balanced externally with the DM flywheel, then later I am able to use an aluminum flywheel, I would just need one with a weight bolted to the back correct? I would not have to have the engine balanced again? If I dont use the DM can I still use the solid disc OEM clutch?

87bob

As I understand it the Steel flywheels spin with more inertia and the Alum spin up faster. So for a smoother transition the steel would be better. If you were racing the Alum would be better. Am I right here?

Kubs

You are correct. Drag racers like the heavier flywheels to help with the launch. My car is road raced where the lighter weight AL would be better.

96GS#007

Yes, you would just bolt the weight in place. It won't be 100% perfect (you'd have to tear it down and rebalance the rotating assembly again for that) , but it'll be fine

racebum

i ran that EXACT clutch and it held alright until i started drag racing on nitto 555R's with 360rwhp out of a 357ci miniram engine that clutch only lasted about 4 weekends with the stickier tires and i was able to slip it at launch if i didn't let it out quick.

i later upgraded to one of those XTD ceramic/copper ebay clutches one of the guys i autocross hondas with told me was alright. it sucked! thickness was off and it would make 2nd gear grid due to exactly this.

if you smoke that clutch racing it's totally worth the $$ to spend the money on a quality brand like exedy, centerforce, ram etc..