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  View original topic: AA connecting rods horribly out of balance!!! Goto page 1, 2, 3  Next
SamT Fri Sep 30, 2011 4:03 pm

I have built me a rod balancing fixture, it will get down to about +/- .5 gram, not perfect, but OK.

Anyways I'm balancing some AA 4140 I beam rods.
I had to remove as much as 7 grams from the small end (2 were light 2 were heavy) And as much as 6 grams from the caps. I have yet to balance for final weight, but suspect it will be a biatch.

Any one else had to remove this much material from rods? I read somewhere you should never have to remove more than 7 grams from a single rod.....

ralf Fri Sep 30, 2011 4:15 pm

consistent i guess...



rockcrusher found the same result on those rods LOL

modok Fri Sep 30, 2011 5:46 pm

just weld some more metal on the light ones

or lighten the pistons to match the heavy small ends

SELECTIVE ASSEMBLY, making engines fit together since 1885 :wink:

fivelugshortaxle Fri Sep 30, 2011 7:32 pm

Are the AA connecting rods really that bad? I've got AA H-beams......4340 chromoly

fivelugshortaxle Fri Sep 30, 2011 8:02 pm

fivelugshortaxle wrote: Are the AA connecting rods really that bad? I've got AA H-beams......4340 chromoly

You out there RC? Can I trust a shop that doesn't deal with VW's on a regular basis to get mine balanced?

modok Fri Sep 30, 2011 8:08 pm

balancing rods is universal
SBC, toyota, VW
all pretty much the same

The one thing that is really different, is when they try to put the flywheel on the crank.
People that never done it before won't know how.
My crank guy is GOOD, but he tried to put the flywheel on by hitting it with a mallet :roll:

fivelugshortaxle Fri Sep 30, 2011 8:09 pm

modok wrote: balancing rods is universal
SBC, toyota, VW
all pretty much the same

The one thing that is really different, is when they try to put the flywheel on the crank.
People that never done it before won't know how

Right...because one of the dowel pins is offset a bit.........

VIN Fri Sep 30, 2011 8:19 pm

fivelugshortaxle wrote: Are the AA connecting rods really that bad? I've got AA H-beams......4340 chromoly

IIRC he said they were a bitch and never again would he recommend those.

fivelugshortaxle Fri Sep 30, 2011 8:27 pm

VIN wrote: fivelugshortaxle wrote: Are the AA connecting rods really that bad? I've got AA H-beams......4340 chromoly

IIRC he said they were a bitch and never again would he recommend those. I'll be paying someone to balance them so it won't be that much of a bitch to me...Lol!.....if the machinist runs into major problems with them I'll just have to get something else...hopefully that won't happen cause then some a-hole on here is going to complain that I changed my mind about parts :wink:

mark tucker Fri Sep 30, 2011 8:38 pm

done many sets of v8 shit like that. be sure the fixture is holding them exzactly the same or it can be off a good bit. i thought I would make a quick rod hanger hear at home, made some parts on the lathe & mill,but did not have the material handy to do it as I wanted it(like the one at work) so I made it a bit diffrent. nope did not work no repeatabilty within 3 grams just removing the rod& reinstaling it.so I shelved it till I get time to make it the way it should be.It,s the simple things that give the most perplexing problems. hight ,angle of the dangle, distance,parralell,size of rod addaptors must be right. it,s a very easy job when you got the correct tools handy. and always recheck by removing & reinstalingx2 each endafter each end or you may be chasing your ass or not realy balancing them at all, but think you are.

modok Fri Sep 30, 2011 8:41 pm

SamT wrote: I have built me a rod balancing fixture, it will get down to about +/- .5 gram, not perfect, but OK.

Anyways I'm balancing some AA 4140 I beam rods.
I had to remove as much as 7 grams from the small end (2 were light 2 were heavy) And as much as 6 grams from the caps. I have yet to balance for final weight, but suspect it will be a biatch.

Any one else had to remove this much material from rods? I read somewhere you should never have to remove more than 7 grams from a single rod.....

Anyway
I'd say 5 grams is the most I'd expect to remove from either end of a rod that size
More than that and you need to start looking for WHY, and go after the all heavy areas rather than just what is easy to reach.

If you remove a lot of metal around the big end, the size and roundness should be checked to make sure it has not warped, assuming it was ever right to start with, and that may assume too much

oh well, you get what you pay for

ralf Fri Sep 30, 2011 8:42 pm

sell them to me like chinese cheap


if all goes wrong


it may be useful on a 20mm pin custom piston experiemnt

LOL

fivelugshortaxle Fri Sep 30, 2011 8:46 pm

ralf wrote: sell them to me like chinese cheap


if all goes wrong


it may be useful on a 20mm pin custom piston experiemnt

LOL


I may end up doing that...we'll see......I don't have unlimited resources like some on here so it will be a little bit before I can take them to the machine shop

mark tucker Fri Sep 30, 2011 8:51 pm

wonder if thats why my new 5.5 cb Ibeam rods are profiled?

SamT Fri Sep 30, 2011 8:51 pm

[quote="fivelugshortaxle] I'll be paying someone to balance them so it won't be that much of a bitch to me...Lol!.....if the machinist runs into major problems with them I'll just have to get something else...hopefully that won't happen cause then some a-hole on here is going to complain that I changed my mind about parts :wink:[/quote]

The labor to balance a set of rods this far out would far exceed the extra cost of a descent pair. I have an hour already in these and haven't even done the total weight balance, and I'm only shooting for within .5 gram, because that is all my fixture can do.

It

ralf Fri Sep 30, 2011 8:52 pm

its fine.. dont be so hard on urself..


remember a fact


alot can suggest what "they" dream to build bcause it is ur money...

but lets see if they suggest wat they actually build..


i dont care for last years engine or 20yrs ago engine..

myth is one thing, hearsay is another 2dollar hookey i wont touch


LOL

mark tucker Fri Sep 30, 2011 9:01 pm

ralf wrote: its fine.. dont be so hard on urself..


remember a fact


alot can suggest what "they" dream to build bcause it is ur money...

but lets see if they suggest wat they actually build..


i dont care for last years engine or 20yrs ago engine..

myth is one thing, hearsay is another 2dollar hookey i wont touch


LOL kinda like telling someone to go out and buy that old how to hotrod vw's book from back in the 70's, it's full of old up to date stuff.

RockCrusher Fri Sep 30, 2011 9:20 pm

The I-beam AA's are the ones we tried and like was said here.....I did say never again for those. As for the H-beams like 5lug bought, they SHOULD be better due to the way they are manufactured but no way to know until they are balanced. I don't think I will give AA the chance on the H-beams in our business just due to my dissatisfaction with the I-beams.

Those rods were cheap but far from thrifty. As a finished rod they will be fine but getting them to that condition really was a Biatch.

RC

fivelugshortaxle Fri Sep 30, 2011 9:24 pm

RockCrusher wrote: The I-beam AA's are the ones we tried and like was said here.....I did say never again for those. As for the H-beams like 5lug bought, they SHOULD be better due to the way they are manufactured but no way to know until they are balanced. I don't think I will give AA the chance on the H-beams in our business just due to my dissatisfaction with the I-beams.

Those rods were cheap but far from thrifty. As a finished rod they will be fine but getting them to that condition really was a Biatch.

RC

Well hopefully they will be fine.....they look to be very nice..of course I do have an untrained eye

RockCrusher Fri Sep 30, 2011 10:50 pm

fivelugshortaxle wrote: RockCrusher wrote: The I-beam AA's are the ones we tried and like was said here.....I did say never again for those. As for the H-beams like 5lug bought, they SHOULD be better due to the way they are manufactured but no way to know until they are balanced. I don't think I will give AA the chance on the H-beams in our business just due to my dissatisfaction with the I-beams.

Those rods were cheap but far from thrifty. As a finished rod they will be fine but getting them to that condition really was a Biatch.

RC

Well hopefully they will be fine.....they look to be very nice..of course I do have an untrained eye Check how a socket fits on all the bolts. If it fits nicely on all the bolts they are pretty good bolts. If some fit nice and others are tight or won't go then you might want to spring for some real ARP's. Had to modify several bolt heads on the I-beam rods. Those rods are just SOOOOO wrong in so many ways.



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