Mikelly Posted December 26, 2002 Share Posted December 26, 2002 After some discussions with Pete's engine builder I have decided to go external balancing on the rebuild of my 383 stroker... Looks like I'll need to get another harmonic balancer (External), a flywheel setup for a Tremec or Richmond tranny, and start assembling. Other than rings and main bolts, and cam bearings, I'm pretty much ready to put this thing back together... Oh, I forgot the new oil pump pickup! Mike Quote Link to comment Share on other sites More sharing options...
pparaska Posted December 26, 2002 Share Posted December 26, 2002 Mike, I did a bit of research on finding a harmonic balancer for an external balanced SB that's not 8" diameter. The only one I could find was $300+ dollars. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted December 26, 2002 Share Posted December 26, 2002 Mike, not trying to be nosey or anything, but why the decision to go external vs internal? Cost? It will be interesting to see how you solve the possible issues with the harmonic balancer in trying to get a reasonably priced one that's the correct size. Arg more money... Davy Quote Link to comment Share on other sites More sharing options...
Mikelly Posted December 26, 2002 Author Share Posted December 26, 2002 Actually I sold a 6.25 inch HJC unit on this site a while back. I've seen several in Jegs and Summit that aren't larger than 7.5 inches that sell in the $220-300+ Range... Davy, Pete's builder claims that the amount of weight used in balancing the assembly actually puts undue stress on the crank at the #2 and #4 caps and can actually do more harm than good in a 383 application. He swears that externally balancing a 400 Crank is the only way he would go. He was also VERY happy to take money out of his pocket to tell me that, and then gave me an address where I could send the parts to if I still insisted on doing it. Guy seems to know what he is tlaking about... Referenced some technical manuals to double check him with. Mike Quote Link to comment Share on other sites More sharing options...
DavyZ Posted December 26, 2002 Share Posted December 26, 2002 Wow, that was something I had not heard of before, but I don't doubt it at all first glance. The fact that he steered you away from putting more money in his pocket would make you trust him. Good thing. Keep us updated on the engine build progress Davy Quote Link to comment Share on other sites More sharing options...
pparaska Posted December 26, 2002 Share Posted December 26, 2002 I think some more detail is needed here. The guy that was saying this told me the same thing. I believe it's mostly an issue with cheap imported cast 3.75" stroke cranks, as the strength is already questionable due to material and casting quality, as well as the size of the throws, etc. No doubt a purpose built internal balance 3.75" stroke forging would be fine, or maybe even an external balance one that was balanced internally later. Better material and process, better dimesions, etc. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted December 26, 2002 Author Share Posted December 26, 2002 Exactly... Guess I didn't make that clear...However, with the abundance of Stroker cranks out there being of the CAST and Nodular type, and most being made by SCAT (Like Mine) you really have to build to the limits or get a good crank... The crank I'd like to get is $800... So it depends... I know a lot of guys out there running 383s externally balanced and doing just fine. Mike Quote Link to comment Share on other sites More sharing options...
Mike C Posted December 27, 2002 Share Posted December 27, 2002 I have heard no negatives about internally balancing the external crank, but it does make sense. It is also expensive. If you operated at high engine speeds (6500+) for extended periods of time (road racing, Bonneville, Nascar) I'd so go internal, but I think your choice to stay externally balanced doesn't do any harm as that is the way the crank was designed. The real fix is to buy an internally balanced crank to begin with, but then it is no longer a "cheap" way to get more cubes, but an expensive rotating assembly that will require and expensive set of rods and expensive block, etc. I think Fluidamper has a 6.25 external dampener for $300? Quote Link to comment Share on other sites More sharing options...
Mudge Posted December 27, 2002 Share Posted December 27, 2002 I dunno, and I'm not an experienced engine builder, but there are internally balanced 422 LT1s that run just fine... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 28, 2002 Share Posted December 28, 2002 Hey,FYI, I bought the Summit 6.6 external balancer.$224.50,and it's a pretty decent unit.(tested to 18000 rpm) The strange part is that it is the same as the internal balancer,with a weight bolted to the inside.The instructions say to just remove the weight if you want to change it to internal.Maybe they're all like that,this is all new to me. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted December 28, 2002 Author Share Posted December 28, 2002 Well HELL... Scratch ALL OF THAT! I just made a sale on a set of control arms and TC Rods AND found an Internal Balance 4340 Crank on EBAY for $400! Guess what I'm buying? Mike Quote Link to comment Share on other sites More sharing options...
John Scott Posted December 28, 2002 Share Posted December 28, 2002 When I sent my Scat 9000 6" 3.75, internal balance to the engine balancer, it came back with a small counterweight at the rear. Designed to run a regular internal balancer. (should have kept my original fluidamper, Mike, as I bought another!) but apperently even the "internal" Scats, and other brands often need touching up with a counterweight. Why change an externally balanced crank to internal, unless you're trying to fool someone looking under the hood that it's a 350? I chose the 9000 for the issues of recip weight, flywheels, balancers ect. I personally don't know the limitations of the 9000 series for sustained racing abuse, but from what the Scat rep said, it can handle a lot of hp, and make for a durable street motor. John Quote Link to comment Share on other sites More sharing options...
Mikelly Posted December 30, 2002 Author Share Posted December 30, 2002 Looks like the Crank I was biddingon isn't prefered to be internally balanced with the parts I have. Guy was nice enough to not hammer me for the bid retraction. He also runs an engine assembly house and offered me another crank, and to have me ship out my rods and pistons and balancer and he'll balance everything for me on an eagle 4340 forged crank, and the total cost would be less than $800 for everything, purchase of the crank and balancing... Gonna call him today and sort it all out, but just read their feedback and they have VERY good comments! Mike Mike Quote Link to comment Share on other sites More sharing options...
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