what does it mean when the flexplate is externally balanced. I know what it means when the engine is internally balanced, but not the flexplate. for example. http://store.summitracing.com/partde...8&autoview=sku

 

It really doesn't mean quite exactly what it says.

It means, it has the stock 305/350 "internal" balance weight, mounted "externally" to the eye (outside the oil seal) like it needs to be.

Those terms lead to endless confusion and arguing, especially among people who don't understand what they REALLY mean (which is NOT the side of the oil seal that the weight is on) when applied to the 1-pc rear main seal motors. I would AVOID them if at all possible. "Stock" is a much better word.

 

so this wouldnt work for an externally balanced flexplate. even if you put a balance plate in between the flexplate and crank

 

That flex plate is for STOCK balance.

It is for an internally balanced motor with 1-pc rear main seal, where the rearmost internal balance weight is mounted on the flex plate, where it LOOKS TO THE EYE as if it is "external" even though technically it's not.

Put the words "external" and "internal" out of your vocabulary. They do nothing but cause confusion in this application. As evidenced by the fact that you are confused... you're not the only one.

If your motor is balanced to the STOCK spec, it will work. I suggest that you use the word "STOCK", not "external" or "internal", when communicating with your machinist.

 

I understand all this. so what you you say would be a good flexplate to use for a 1 pc RMS 383 stroker, which needs to be externally balanced.

 

No. I DID NOT say that.

I have said repeatedly that the words "internal" and "external" should not be used; stroker or not.

I said it would be a good flex plate to use with a 305, 350, or by extension a 383, that is balanced to the STOCK spec.

Leave the words "internal" and "external" out of it.

Determine if your "kit" uses STOCK balance. Most do. If so, then that flex plate is fine. Do not concern yourself with "internal" and "external" because all that will happen is you will either get confused yourself, or you will confuse your machinist; and no good will come of it either way. Eschew obfuscation.

If your "kit" does NOT permit the use of STOCK balance, send it back and get one that does.

 

Sofa, he needs a one-piece rear main seal 153-tooth flexplate for a rotating assembly that will have a weighted damper on the front end.

I think you can use that balance plate that goes between the crank and flexplate, but I can't say I know anyone who has.

 

i know this is what my crank needshttp://cgi.ebay.com/ebaymotors/ws/eB...9325&rd=1&rd=1
I have the 400 balancer with a weight on the front. i just need the flexplate figured out. Sofakingdom, I am confused, but please do not yell at me. I have not yelled at you.

 

No; more than likely, he needs a flex plate with STOCK balance. Like the enormous majority of the 383 "kits" out there with rods 5.7" or longer will provide. STOCK balance, for a 1-pc RMS application flex plate, means having the small weight that used to be part of the flywheel flange on the crank, that was forced to be moved off of the flange and onto the flex plate so that the flange could be round so that a seal could slip over it. In other words, an INTERNALLY balanced motor, with that last little bit of INTERNAL balance weight mounted on the flex plate, looking to the eye like it's "EXTERNAL" even though it's not.

Like I said, if the "kit" doesn't support STOCK balance, the thing to do would be to SEND IT BACK and get one that does. It's money well spent.

Who was it that said something to the efeect of "the bitterness of poor quality lingers on long after the sweetness of low price has gone"... ? Do you recall? A 383 "kit" that requires true EXTERNAL balance, and not just the stock little weight that a 1-pc RMS flex plate has, would fit that "poor quality" description.

I don't know of any of those "pork chop" weights made for 1-pc, anyway. I don't recall ever seeing one. Since people aren't building 1-pc RMS 383s out of stock 400 cranks and 5.565" rods and stock 350 pistons, they're not real useful or likely to sell in numbers high enough to make it worthwhile to mass-produce them.

 

The eBay listing for sure says use stock 400 SBC balance. So, you'd need a one-piece 400-type flexplate, which I've only seen in 168-tooth.

I haven't looked at the "porkchop" weights for awhile, but I recall them being available for one-piece RMS.

stroker, any reason you can't use a 168-tooth flexplate? Shouldn't be a problem with the bellhousing, mini-starter solves many a headache.

FWIW, if I was stroking a one-piece RMS block, I'd for sure get an internally (read: "stock" by sofa's defination) balanced crank. But, that's probably water under the bridge.

 

Yeah I just went and and looked at the eBay listing....

I sure wouldn't build a motor with that thing. See if that guy will exchange that mismatched pile of steaming .... fertilizer, for something a little more common-sensical.

That's a PERFECT, textbook-case example of why buying something that has the lowest price tag, while it may appear to be the "cheapest" (and might actually be the "cheapest"!!!), isn't always the least expensive. Let alone, the lowest total cost.

It's impossible for me to be sure what that crank really takes. In THE SAME sentence he says "400 ext balance", and then a few words later "stock 350 balance". These ARE NOT the same thing. In other words, what he has on that listing, is not consistent with itself. I can't interpret what he means by the 2 contradictory and incompatible statements. I would hate to be the one that tells you one thing, and it turn out to be wrong. I apologize for being just as confused as you are now.

I like this though:Great disclaimer!!

So I have no clue what flex plate will REALLY work with that .... object. It's between you and him now, I guess. Sorry I wasted your time and mine.

Good luck!!

 

Hmmm, all I see for balancing is "Balanced to 400 ext. specs, uses 400 balancer and Late 350 ext flexplate". Only reference I see to "stock 350" is with regard to bearing sizes.

Pretty sure he's saying one-piece with 400-type external balance, which again I've only seen in 168-tooth version for flexplates (have seen 153-tooth in flywheels).

Probably worth a "Got a question, call us! Raceparts Call 951-684-3814".

 

Right...

My best guess, from the verbage, is that he's saying it's set up for a 400 balancer and a late-model 350 flex plate which is for INTERNALLY BALANCED motors (as all 350s are) with the little weight on the flex plate. Some 305/350 FPs are 12.8" and some are 14". At the same time, it's for 5.7" or longer rods; meaning, the counterweights aren't "flat cut", meaning it's got enough CW in there to be internally balanced if whoever built it wanted it to be. I have NEVER in all my days seen a crank that's got full counterweights, uses an internal-balance (350) bolt-on on the rear, and an EXTERNAL BALANCE (400) bolt-on on the front.

Clearly, a very confusing and contradictory mess.

I'm afraid you'll have to sort it out between yourself and the seller.