Panic Button

I picked up my short block yesterday and they gave me the balance sheet. I have no clue what it means, if this is good or bad. The sheet say balanced in HINES MICROCOMPUTER Balancer. Here is the info:

RODS Big End- 574
INSERT- 44
TOTAL= 615
TIMES RODS/THROW x2 1230
OIL- 4
ROTATING WEIGHT- 1234

PISTONS- 598
PINS- 151
LOCKS- 5
RINGS- 70
RODS SMALL END- 225
TOTAL RECIROCATING- 1049

RECIPROCATING FACTOR- 1049
JOB WEIGHT- 2283

Reed Jensen

That is information that he needs to determine the size of the bob weights to attach to the crank while he spins it up... those are the weights of the pieces in grams. Your pistons weigh 598 grams each... the wrist pin is 151 etc etc... V-8's use the pistons, wrist pins, and connecting rods as part of the counterweight for the opposing cylinder. 90 degree V-8's have a "perfect" primary balance and an even firing order with a power pulse every 90 degrees of crankshaft rotation. There are small "secondary" imbalances that become "buzzing"....Whereas an inline 6 doesn't need bob-weights on the crank when it is spun up to test for the balance. Does that answer your question?

jackie-fpc

eat mny shory

Michael1

Reed, I think you have this backwards. A 90 degree V8 with 90 degree crank pins between pairs of cylinders is unbalanced in the primary mode, and is balanced in the secondary mode. That's why you are able to balance it with weights on the crank. The balancing done is to cancel out the rotating primary couple (rocking force), so the weights are set opposite to each other at the two ends of the crank. As you mentioned, the inline 6 is balanced in both primary and secondard modes.

Michael

MESABALANCING

The Easiest Way To Interpret This Paper Work Is To Determine The Weight Of Your Components We Also Provide Our Customers With That Type Of Paper Work This Becomes Handy Any Time You Need To Replace Any Internal Parts And Its Also Information Needed During The Balancing Process . All V Type Engines Require Bob Weights For Balancing The Only Thing That Changes Are The Reciprocating Factor In Different Angle Engines The Only Engines That Do Not Require Bob Weights Are In Line Engines And Rare 180 Degree Crankshaft Engines Used In Ferrari And Also Very Common In Sprint Car And Drag Boat Applications And I Still Take The Time To Make Up The Weights To Get The Balance Perfect In Them Because Those Engines Are Very Hard On Main Bearings. Hope That Answers Your Question Easier Laz Mesa

Reed Jensen

When I say primary balance... I'm talking about an assembled engine with pistons and rods installed. When I mentioned secondary imbalances.. those are the minor ones caused by the rod angulation. We are both in agreement on the balance of a 90 degree crankshaft... we're just using differing words to describe it....

Reed Jensen

I'm aware of the 180 degree crankshafts that Ferrari uses. They were also used in Offenhauser engines. But... and this is a But as big as Jennifer Lopez's... Even though the throws are set at 180 degree intervals. The cylinders are still opposed by 90 degrees and there is a power pulse every 90 degrees like in a Chev engine. The difference is the firing order, Also in the way the engine is balanced.

dyno

Chris is that a short block from Dyno flow?

Panic Button

Yes it is. I was surprised, no extra "hidden" costs, the price they quoted is the price out the door.

dyno

so what did you buy? I've been looking at there stuff for a couple of years but was waiting for someone else to take the plunge....guess your it!Lets here about your combination heads,intake...????are you going to dyno it?did you check any of the clearances? I think I'd have to grab some plastigage and check a few before I threw the pan on.