Vacuum on 1968 GTS 340 4 spd.

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The 1st shop probably does not want to do just part of the job.... possibly wanting to be sure it is 100% A-OK, or perhaps pricing where their investment is... the crank balance machine is the pricey equipment.

'Splain to the 2nd shop how you are approaching this issue.
 
Tell him the history and the why.....and you piston part numbers. He may want to work the weights himself.... if he has standard Mopar rod data, etc.

I'll re-check the numbers for you. In fact, I'll post and PM the worksheet info.
 
Well he priced me $285. They charge $375 for complete balancing. If I pull out everything can I still re-use my rings and do I have to ball hone for cross hatch or can I just re-assemble and go. Just checking all avenues . Also when you did your sons 340 did they have to add any slugs ? He said some time you drill to remove weight but have to counter sometimes with a slug.
 
No added weight in your case IMHO..... since you have gone lighter on the pistons, then the weight ought to come off, not be added on. We removed weight (81-82 grams from each end counterweight) from a 273 crank, over towards one edge of the counterweight. The 273 crank is already factory set up for a lighter bobweight, so we would have taken even more weight off of a 340 crank. Our total bobweight was 1893 grams due to using lighter SCAT rods; you're not changing the rods, so it won't drop that much. (Hope all that makes sense...)

I suspect he was speaking in general about adding weight. (Did he know what nominal bobweight you would go from and to, before and after the piston change? If not, then he is likely just speaking in general and explaining the pricing.) Perhaps it is possible in very odd cases where you can't get the right amount off in the right place and have to add weight on the opposite side just due to that, but I have no direct knowledge of any such cases.. nor where you could add weight to the 'opposite side' on a SBM crank.

How many miles have been run? I would be inclined to keep the rings in order and arranged per pistons and not hone. You ought to mark the pistons with filed markings and group/tag the rings ahead of time and ask him to not swap rods or anything around so the bearings and rods and pistons can all be kept in order. Not sure it will make any difference, but not sure it won't!
 
nm9stheham said:
I'll re-check the numbers for you. In fact, I'll post and PM the worksheet info.
Click to expand...
Same Pin 132 weight as the 030?

Can you show me your calculation? So far I,ve found
Stock STD 340 Pistons 719/Pin 154
KB243-020 Piston 597 but can't find pin weight.(My pistons)
KB243-030 585 /132 (Not mine)
 
Kendog 170 said:
Same Pin 132 weight as the 030?

Can you show me your calculation? So far I,ve found
Stock STD 340 Pistons 719/Pin 154
KB243-020 Piston 597 but can't find pin weight.(My pistons)
KB243-030 585 /132 (Not mine)
Click to expand...
My apologies, KD..... I got sidetracked and forgot. Everything in grams.
  • The 1st 5 items were direct measured on our KB243-020 pistons. I confirmed this from my hand-written notes at the time of weighing.
  • Did you actually weigh your pistons? Or are your .020" piston weights take from data sheets? If real weights, your pistons look to be 22 grams or so heavier so the bobweight would be that much heavier. But that seems odd....the 585 gram number for .030" pistons versus our 575 grams for .020" pistons seems more likely correct.
  • The * weights are nominals, and I have verified that number to be pretty close on 2 sets of the standard heavy rods.
  • The ** oil weight is a pretty standard assumption.
Our KB243-020 weights with stock heavy rod weights
Rod bearing set 44
Ring set 59.25
Pin lock set 4.25
Pin 131.5
Piston 575
*Rod small end 240
*Rod big end 518
*Rod total 758
**Oil on journal 4
Reciprocating factor 0.50
Reciprocating weight 1010
Rotating weight 1128
Bobweight 2138

Stock numbers
Rod bearing set 44
*Ring set 65
Pin lock set 2
Pin 154
Piston 719
*Rod small end 240
*Rod big end 518
*Rod total 758
**Oil on journal 4
Reciprocating factor 0.50
Reciprocating weight 1180
Rotating weight 1128
Bobweight 2308
 
Looks good to me. I'm going to just do the crank.
Thanks for all your help.
To be continued.
 
Well I got the crank back and motor back together. I just have to bolt the 4 speed back on it and hopefully install by weeks end. Things are crazy. Signing purchasing sale today on house so I only have 6 weeks to finish car, empty garage and the rest of the house . Wish me luck !
 
Well got a two weeks extra before closing on house so that helps. Hoping to drop motor in after work today then button things up by Saturday. Resealed the 4 speed all looked good in there.

20190423_190519.jpeg
 
MopaR&D said:
Nice! Do yourself a favor though and get rid of that Fram filter
Click to expand...

Yeah I know. Funny thing is I got 200k on that motor using them. This is the last of a case I had. I've been using Wix or Napa gold with my other RB Dart.

Well motors in. Everything under is completed. Now just need to lower and finish engine compartment.

20190424_140046.jpeg


20190424_140654.jpeg
 
OK, after some clutch issues that are ironed out, the car is back together and running nice and smooth but the carb needs some jetting as it wants to stall without choke at idle until fully warmed up. My buddy says he has a 20 year old Holley 650 double pumper new in the box I can have . I have a bunch of Holley jets and parts.
Any suggestion on what primary and secondary jet size to start off with? 340 20 over, around 10.5 to 1, Eddy heads ? 20 Years old I have to open it up to inspect.
 
Woo-hoo! Glad it has worked out....!

All of this is a joint effort in a lot of ways..... I know I've learned lots from all sorts of gear-head friends over the years, and it's a pleasure to be able to pass some of it along.
 
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