Engine balancing use piston ring weights?

How much does a set of small block piston rings weigh (grams)? Does an engine balancer or crankshaft supplier/manufacturer need to take ring mass into consideration during final balance of reciprocating assembly? Thank you.

Ring weight is part of the total bob weight.

Rings.. Spiro locks if used, one set of rod bearings...they even figure in the weight of motor oil onthe parts

Well, i need to send in my request for the custom crank. I have weights for the rods (742g total weight and 492g reciprocating weight), 44g rod bearing, 680g TRW piston, and 154g piston pin. Just need the ring and pin lock weights because I don't have those yet and a close estimate should get me started. Thank you.

I'd wait until you had everything. But hey it's not my engine.

72Dart6pack said:

I'd wait until you had everything. But hey it's not my engine.

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Ditto

1.8 to 1.9 ounces about 45-54 grams for a .040 ring set (all 3)

Factory replacement 340 parts weighed on Mom & Pop store digital scale:

1 circlip no reading................1 circlip = 1.5g ?
2 circilps no reading...............2 circlips = 3g ?
1 oil ring, 2 circlips 5g
2 oil rings, 1 circlip scale bounce b/t 5g-10g
2 oil rings, 2 circlips 10g
1 top ring, 2 circlips 15g.......1 top ring = 16g ?
2 top rings, 2 circlips 35g......2 top rings = 32g ?
2 top , 2 clips, 3 oil rings 60g...3 oil rings = 25g ?
all above w/pin 215g............... pin = 155g ?
(154g published wt)
all above w/piston (.040) 950g..piston = 735g ?
(720g is published wt)

Note:
1 oil ring = 8.33g @ 3 oil rings = 25g ?

final estimated figures
2 circlips @ 3g
2 top rings @ 32g (5/65 or .78 or 2 mm)
3 oil rings @ 25g
1 piston pin @ 155g
1 piston @ 735g
total = 950g (same as Mom and Pop scale total)

Anyone know--does the TRW L2322F dome piston use two 1/16 compression ring lands or a 1/16 top ring land and 5/64 second ring land?

When I was in the Navy (early 70's) I once called Traco and asked them about engine balance. Seems to me they said something like "all our engines are to 1/4 gram or less." A quarter gram is not MUCH A quarter gram is about 4 grains, if you do any reloading

Is Traco a previous engine rebuilder? Are you sure they didn't mean 1/4 ounce?

dibbons said:

Is Traco a previous engine rebuilder? Are you sure they didn't mean 1/4 ounce?

Click to expand...

"History of Traco"

Culver City, California, 1986 - Jim Jones, Head Engine Builder of TRACO Engineering, buys the company from founders and famous engine builders Jim Travers and Frank Coon (TRAvers & COon). First Travers and then Coon retire after 3 decades of building TRACO, founded in 1957, into one of the foremost engine firms in the world. Jim Jones, hired in 1979, who helped build that reputation, continued to uphold "The TRACO Tradition" with the many projects that followed.

At that time about half the business was directed towards current race engine technology and engine rebuilds of race cars that were originally TRACO powered. That current technology was integrated into those earlier engine rebuilds and updates. Notable projects included Roger Penske's 1968 Trans-Am Camaro driven by Mark Donohue/Craig Fisher, Roy Woods Trans-Am AMC Javelin and Carl Haas's one of a kind Lola Can-Am car nicknamed Aircraft Carrier. One memorable race in 1992 was at Road America. It was the 20th reunion of Can-Am cars and Bob Lee's Jim Jones/TRACO powered McLaren M20, driven by Denny Hulme, started in the back of the pack. After 4 laps Denny took the lead and went on to win the race. Jim also built the engine for Charlie Hayes McLaren Group 7 sports car now owned by Bill Fraley and rebuilt the engines of the originally TRACO powered Lance Reventlow Scarab sports cars. So it seems that in addition to the current TRACO racing engine program, Jim had solidly established TRACO in the vintage race car engine market.

I'm sure I'd read some articles of what they were "into" that was in the Trans/AM days and they were local, some of use were talking about balance and how close it should be so one day I just called them.

A quarter gram is "what I remember". That was........how? many years ago? Nearly 50, anyhow. I do remember she sounded nice, LOL

I thought TRACO was a common generic engine rebuilder, now I see maybe 1/4 gram balancing tolerance could very well be the way they went.

the trw uses 1/16 rings both grooves