Thread: Picked up my Son's engine yesterday.

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Ah, that makes sense, Jerry. I thought the balance sheet would show what the parts were before the balancing and after they were done, but evidently it isn't done that way. It will be cool to see those pictures of the ones you will be balancing, thanks.

It turns out the people who balanced the engine are right down the street from my shop. The mechanic who is a few doors down from us told me one time that they were there, but I never knew exactly where. I looked up Cornell Balancing on line, and it looks pretty impressive............they balance EVERYTHING, not just car engines.

Now I have to pick up a ring grinder and ring squaring tool so we can get that phase started.

Don

Subscribed.
Looking forward to the engine build.

Originally Posted by jerry clayton

edit---I did go start to read the Harley write up and it is totally wrong for a V8 auto engine----the v twins are nowhere near the same running /balance requirements as the automotive engines, so disregard everything that artical says.

I won't take the time to read the harley link but will explain the numbers on the balance card.

On a 90* V8, you have 2 rod/piston assys on each crank journal. The weight for the bob weight is made up of the TOTAL of wt of 2 BE(big end) of the rod s plus 2 bearings, this weight is arrived at by supporting the SE(small end) of the rod and weighing the big end. So that is how they got ROTATING WT 1329---663+663+3= 1329-----------RECIPERCATING wt is total of only ONE SE ROD, PISTON ASSY(piston,pin,rings,locks) as the 90* offsets the other one ---SOOOO the Bob Wt is total of ONE piston,pin,rings,locks,SE rod plus weight of 2 BE rod ,2 (4 halves) bearing inserts and an allowance for oil weight.
Then with the 4 bob weights made up, one is attached to each crank rod journal and the balance job goes forward from there--

I will try to take some pics of one of the balance jobs I will be doing this week and try to post them---if I end up with both internal and an external weighted crank I'll try to show some differances--of course then there are the internal front/external rear cranks from GM LT1/4 engines???????????????

I guess I misunderstood the question. I thought an explanation on how the numbers were generated was requested, not how to balance the engine? I'm bad. I do think the Harley article does explain how gravity is used, what the rotating and recip weights in grams was all about, and determining bob weight mass and placement. You balance engines, I am only a customer of folks that balance engines, so Don, go with the pro.

No, actually that info was what I wanted to understand. I read through it and learned a lot. Thanks,



Don

Very informative! As usual not as simple as I thought.

Originally Posted by jerry clayton

edit---I did go start to read the Harley write up and it is totally wrong for a V8 auto engine----the v twins are nowhere near the same running /balance requirements as the automotive engines, so disregard everything that artical says.

I won't take the time to read the harley link but will explain the numbers on the balance card.

On a 90* V8, you have 2 rod/piston assys on each crank journal. The weight for the bob weight is made up of the TOTAL of wt of 2 BE(big end) of the rod s plus 2 bearings, this weight is arrived at by supporting the SE(small end) of the rod and weighing the big end. So that is how they got ROTATING WT 1329---663+663+3= 1329-----------RECIPERCATING wt is total of only ONE SE ROD, PISTON ASSY(piston,pin,rings,locks) as the 90* offsets the other one ---SOOOO the Bob Wt is total of ONE piston,pin,rings,locks,SE rod plus weight of 2 BE rod ,2 (4 halves) bearing inserts and an allowance for oil weight.
Then with the 4 bob weights made up, one is attached to each crank rod journal and the balance job goes forward from there--

I will try to take some pics of one of the balance jobs I will be doing this week and try to post them---if I end up with both internal and an external weighted crank I'll try to show some differances--of course then there are the internal front/external rear cranks from GM LT1/4 engines???????????????

Jerry,
Thanks for posting the explanation. I knew where the numbers came from to establish the bob weight, but I did not have the piece about the offset and only needing one reciprocating mass.

Don,
I have the same information for my engine, and I came to the conclusion that it really does not provide me with any value, other than verifying the balance process. I'd like to watch it being done some time, just for grins.

i was hoping Jerry would post on this as i did try to tell you on the other post were there is a shot of one my customer s crank were i had to add mallory to . if jerry show s some of his stuff .if not i have 7 sets of rods i am rebuilding and balancing .don as for ..what it was ..for weight not to many times do i log this less it,s a screw up job that i fix.or some thing way off were i will tell a customer. they will get a call if way off as it gets $$$ very fast when your plugging mallory metal in a crank. the pistons and rods first get checked were the heavy ones get work down pin end and big end get sanded down on the belt sander till they are all at less then a gram to the light piston and rods.on pistons if not far off take a die grinder and work a round the underside of piston and the pin boss and trim metal off then sand with a sanding roll . if off alot then the piston will go in the piston vise and get trimed in the mill

Thanks, Pat. Only two motors I have had in my life were balanced, one is the 355 Chevy I bought in that Camaro ex racer, and now Dan's Olds. The Chevy pistons have what look like drilled depressions on the underside of the piston heads, as if you took a drill press and slightly dimpled them underneath. I expected to see the same thing on the Olds pistons, but instead found those areas near the pin boss, like you described. I guess the reason is you want to take weight off of where it is heaviest ?

I'm starting to look for a ring filer. I can't afford an electric one, plus I think we could control a manual one better and have less chance of over filing a ring. Summit has them, and I see K and D makes one also. Looks like it will cost about $ 80-$100. I am also going to get the spacer to push the ring down into the bore, and am leaning toward the one that has the screw on it to fit various bore sizes.

Any suggestions there?

Don

on pistons the die grinder with a carbide bit then a sand drum or roll up is how i do the pistons i do not use a drill some times i will go in with a ball mill and make a cross in the piston to get the weight out it looks alot better then a hand full of drill marks .yep many years i used a mill hand file that i clamp on a engine stand with a hose clamp did over 50 engines this way . i have a hand crank piston ring filers $50. i do not know how many rings sets i cut with it . as for squaring the rings i still use a small starrett precision square that i set at 1 inch and walk it round the deck to square the ring .i use a dressing stone on rings after cutting them .if you fail to dress the end gaps your will cut up the bores Oh you only need to cut one side of the ring .

Here is a link that is long,but explains a lot.

Weighing the Benefits of Engine Balancing: Engine Builder

Its amazing the difference a well balanced rotating assembly makes. My sons motor is smooth (with the exception of lopey idle) compared to my motors years ago.

However, I wouldnt have my unbalanced Road King any other way and thats coming from a once certified KAW tech. Ive ridden the balanced Ultras and dont really care for them.

David

Pat, so you don't put the ring on the filer and take a little off of both edges ? Where do you get the dressing stone you mentioned. I have a couple of stones but they are a little too course, I think.

I have also read it is a good idea to take some 400 grit and lightly wipe all around the circumferance of the rings to remove any burrs, do you suggest that? The article also said to wipe the rings with a red scotchbrite to remove the factory coating.......do you like that idea?

I like the suggestion to use a square to set the ring depth at one inch, that will save me from buying a tool made for that purpose.

Don

Don you don't need an electric filer, get yourself one of these and go easy as its very easy to remove too much Precision Piston Ring Filer - Speedway Motors, America's Oldest Speed Shop

Not sure what spacer your referring to but i just use a piston to push the ring square in the bore when checking gaps.

Ring expander here Piston Ring Installation Tool - Speedway Motors, America's Oldest Speed Shop

Originally Posted by Itoldyouso

Thanks, Pat. Only two motors I have had in my life were balanced, one is the 355 Chevy I bought in that Camaro ex racer, and now Dan's Olds. The Chevy pistons have what look like drilled depressions on the underside of the piston heads, as if you took a drill press and slightly dimpled them underneath. I expected to see the same thing on the Olds pistons, but instead found those areas near the pin boss, like you described. I guess the reason is you want to take weight off of where it is heaviest ?

I'm starting to look for a ring filer. I can't afford an electric one, plus I think we could control a manual one better and have less chance of over filing a ring. Summit has them, and I see K and D makes one also. Looks like it will cost about $ 80-$100. I am also going to get the spacer to push the ring down into the bore, and am leaning toward the one that has the screw on it to fit various bore sizes.

Any suggestions there?

Don

you can use a hand file two file the ring only need to file one side of the ring . clamping a hand file down works the best i used a american pattern mill file. the stone i use is a dressing stone hard arkansas stone this are also call dressing sticks Enco . mc master carr . as for sanding the ring i use 400 wet with WD 40 and just clean up the ends were ring is gaped sand paper on glass or some thing flat hold the ring flat to the sand paper . i never sand the hole ring or sand the face of the ring as they are lapped and i do not screw with it but you do dress the burs off the face of the ring were you recut it .a ring gapper can be pick up for 50to 60 bucks can send you one if needed . you should try a old ring to get the hang of it .any questions on any thing just call me i talk better on the phone then i post

For all of you guys that want some dressing stones---when you are around your machine shops, ask for some of there discarded hones from the Sunnen Ck 10----there is always a good amount left over