Balance Question

[gwri8]

I've finally started to rebuild a spare L28E N42block from a parts car I had.  It had not run in a veery long time.  I've torn it all down and saw nothing alarming as to the condition of the internals. Crank looked good and no scoring in the cylinder walls.   I've dropped off the crank to check for straightness and once ok'ed I'll have it polished and then hone and deck the block.  If the original pistons check out normal I'll probably re-use those.  My plan is to keep it stock, no cams or overbore, however I am considering balancing the crank and pistons/rods.   The final use will be for my 77' on down the road to replace the original engine that's got who knows how many miles.  The Question is whether or not it is worth the extra cost of balancing for a stock engine.  Would any horsepower gain be noticeable or would the result be just a really smooth running L28? 

[siteunseen]

I balanced my piston/rods combo.  Had to add a weight onto my triple beams, a railroad spike, to get them to handle the weight.  They were all over the place on weight so I took a die grinder and skint the heavier ones down to the lightest one.  The sides of the rods is what I ground off, easy to do.  I didn't have the crank balanced after all I've read about them being good from the beginning.  I could see grind marks on the counter weights and assumed that was from factory balancing?  I think it's worth the hour or so to do the pistons/rods.  Seems like they were around 800 grams and I ended up at 775, that's almost an ounce difference. 

[sweatybetty]

dont the counterweights on the crank need to match the piston-rod weight? i believe that is the goal

[siteunseen]

That would optimal I guess, hard to do at home though.  The machine shop I use just has a crank balancer that sits on a table.  If you could hang the crank from the ends with the rods and cups that might work.  That's some Nascar money right there. 

[madkaw]

I wouldn’t mess with it if it was all stock components that came from that motor. I think factory balance is fine if nothing was changed . I’d be more concerned with the condition of harmonic balancer and balance of flywheel and clutch assemblies .


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[siteunseen]

Do you run an aluminum flywheel Steve?  I think that is my favorite thing so far.  I want one for my 280 now.  They add the getty up in "getty up and go". 

[madkaw]

No- lightened a 240mm flywheel to 16 pounds .


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[siteunseen]

Hell yeah!  I might see how light he can get my 225mm.  Save me some dough ray me. 

My 225mm aluminum on the 240's like 10 lbs. Tilton or tifton I can't ever remember.  Got it for free with a car I bought and resold for what I paid but I kept the e31 head, f54 block ..30 over but dished pistons.  Triple 40s and some other stuff.

The guy was going by datsungarage.com to the tee.  Got married and it was in my garage soon afterwards.  Imagine that?!?

Edited November 21, 2017 by siteunseen

[gwri8]

Sorry to to be lax on this thread. Typical of slow motion progress this time of year for me.   Just got a call from the machine shop and he wound up boring to 20 over so new pistons are required.  ITM's from Rock auto are available.  Anyone have an opinion on these?  I'll have to check the weights of the new set of course and balance as necessary.  Looks like my learning curve is going to bend a little more.    Also the crank is good and got a polish and I'm looking at bearings.  Is there a "better" brand of bearings.  I know Clevite are standard but what about the Sealed Power brand?

[cbuczesk]

I've been using ITM on my race engines for a few years and have no complaints.

Chuck