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496 BB with internal balance

PostPosted: November 29th, 2014, 9:44 am
by legerwn
When I had this engine put together the builder internally balanced it, at the time it wasn't a big deal.

I have managed to break some teeth off the flex-plate and now need to replace it.

I tried looking up a internally balanced flex-plate for a BBC gut come up with nothing. I see they offer the BB balance weight that is added on to the crank so they must offer a flex-plate that does not have the weight welded to it.

Anyone have an idea of what flex-plate I can use?

I guess I can get the 454 flex-plate and grind the weight off.

I do have plans to pull the engine in the future to have it stroked to a 540 but am not ready to do this right now.

I'm going to pull the broke flex-plate to see if I can see any balancing marks on it to make sure I don't have the have the new flex-plate balanced before the install.

thanks for any help, Neal

Re: 496 BB with internal balance

PostPosted: November 29th, 2014, 10:28 am
by grumpyvette ... 1129052466 ... 32&vxp=mtr

ID ALSO POINT OUT THE OTHER OPTION, you should think about

if your replacing a ring gear, on a flex plate or flywheel, this is the route ID take, as its sure to keep the balance correct and any decent machine shop can replace a flex plate ring gear, but be aware fly wheel ring gears are generally heated and clamp on the flywheel as they shrink as they cool, flex plate will generally require careful TIG or MIG welding to hold them in place as flex plates are far thinner and more flexible

sold as a separate replacement part


Re: 496 BB with internal balance

PostPosted: November 29th, 2014, 1:07 pm
by Wilson1
If you need an SFI tagged flex plate, just call B&M and ask for a 164 tooth internally balanced flex plat. Any BBC Flex Plat without a weight will work.

Re: 496 BB with internal balance

PostPosted: November 29th, 2014, 2:01 pm
by legerwn
Thanks for the info,

I still have to pull it and see if its broke anywhere other than the teeth to know if I can just replace the outer ring.

It will more than likely be quicker if I just order another one or see if one of the local parts houses have one in stock.


Re: 496 BB with internal balance

PostPosted: November 29th, 2014, 5:54 pm
by legerwn
While I was making a degree wheel for my distributor I found the culprit for the broken flex-plate, the rotor had came loose, screws backed off and it was loose in the cap.

I replaced the rotor/cap around 8 or so months back,

when I replaced the cap and rotor it didn't come with the little star lock washers it came with bevel washers (MSD billet).

I will lock-tight them in from now on.

Neal :x

Re: 496 BB with internal balance

PostPosted: November 29th, 2014, 6:55 pm
by grumpyvette
yes, it took me and most of us years , but eventually youll realize the importance of doing all the little seemingly trivial steps like use of loc-tite and anti-seize on threads where its applicable, during the assembly or maintenance process,you learn to carefully test and inspect problems and not to assume you know whats wrong without testing.and you learn to take the time to read, checking the shop manual for assembly instructions, rather than assuming you know exactly what your doing, and that the quality of the components used is frequently more important than the price paid within reasonable limits, of course. but you'll rarely if ever save money in the long run using the least expensive components.
I can,t count the times I,ve seen what appeared to be huge mechanical failures , come down to either lack of proper assembly or lack of proper maintenance.
I well remember purchasing a 375 hp 396 BBC from a friend who swore it "THREW A ROD OR SPUN A BEARING" so I bought a replacement 454 cubic inch, 450 hp engine! An engine that I bought from him as he thought it was nearly worthless and taking up floor space in his garage, an engine that I took home hoping to salvage a few parts, after I bought it for peanuts, and put it on an engine stand, and did a total disassembly, and inspection, turned out to have a busted rocker and two broken valve springs

Re: 496 BB with internal balance

PostPosted: November 29th, 2014, 9:09 pm
by Strictly Attitude
when I was playing with my timing When I was changing springs and bushings. I found the same loose screws on my rotor glad I caught it before anything bad happened