65 Hipo Engine Balance

[mygt350]

Bob
That makes perfect sense to include the stuff unique to a standard. In the case of an automatic, wonder if they balanced the engine and  flexplate with auto trans mounted?

[Bob Gaines]

Bob
That makes perfect sense to include the stuff unique to a standard. In the case of an automatic, wonder if they balanced the engine and  flexplate with auto trans mounted?

I wish I knew for sure .

[mygt350]

Did auto transmissions have a removable access plate at front lower half that may be used to add weight if there was an imbalance issue? Know the standard shift plate was one piece. But since the torque converter mounts to the flexplate, the mounting bolts go thru the flexplate and thread into the converter. Only way to do that is a access plate. May be how they final balanced a engine with automatic transmission.

[J_Speegle]

Did auto transmissions have a removable access plate at front lower half that may be used to add weight if there was an imbalance issue? Know the standard shift plate was one piece. But since the torque converter mounts to the flexplate, the mounting bolts go thru the flexplate and thread into the converter. Only way to do that is a access plate. May be how they final balanced a engine with automatic transmission.

Since the lower access plate does not bolt to the flexplate it adds no weight to the rotating assembly just like the engine plate. It simply bolts to the bellhousing and because of this is was not in place when the engines were test run on the carriers.

There may be some confusion where some of use may have seen pictures of the engineering testing of completely assembled engines with transmissions and not the test running of the production engines before they were sent to the car assembly plant. Very different process

[gt350hr]

   "Adjustments " to the flex plates were done by spot welding various tabs of steel to the flex plate. On a manual , "plugs" were added to the round holes ( spring locator) or smaller tabs were added to the pressure plate by spot welding. My information came from Dan Nowak , a former DEP dyno operator.

[Helmantel]

   It was to counteract the heavier rods ( big end weight) It was also used on other "non production" engines like the Tunnel Port 302 and Boss 302 T/A engines.

I read that the reason for the hatched was to move some of the counterweight a little more inwards. The increase from 28 oz.inch inbalance to ~30 for the Hipo made the front end counterweight too heavy (too much bending forces) and so a 25 oz.in damper and 5 oz.in hatchet were used instead.

Any truth to that? It sounds logical in one way, but also like a lot of effort for a modest improvement.