[Guest]

Hello and thanks for your time.I have an 86 cj with a 74 360,automatic trans,dana 300 combo.The trans and transfer case are original to the vehicle.The engine is from a car.I baught this as an unfinished project and there is an engine vibration.I have removed the fan to rule out a bent blade.Is this engine ballanced by the harmonic ballancer only or by the flexplate also?I do not know if the flexplate from the original 6 cylender is being used or if that is even possible.I assume it is the original converter.The vibratin is minor at idle and increases with rpm.Please dont be afraid to be technical as I am an auto tech and will understand.Thanks for any input,chris

 

[Guest]

The 360 is ballanced externally with the flexplate and the dampner. The 6 cylinder flexplate will fit but they have no external weight. You probably have the correct dampner (there is a part number cast into it, verify at the dealer) but if a 304 or a 401 dampner was used, that could be the cause, as well as a slipped outer ring on the stock one. Use a TDC checker to verify the timing mark. The flexplate will be harder to verify, as the weight is a rectangular piece of steel approx. 1 1/2" by 2 1/2" spot welded to the trans side of the plate between two of the converter bolts. You may be able to see it with the inspection cover off. Another way to check for the weight, try removing the 4 converter to flexplate bolts then rotating the converter. If it can rotate freely, the plate has no weight present and you can be sure it is a 6 cylinder one. If it only can move approx. 1/8 to 1/4 turn before it stops, it has a V-8 flexplate. Then you would have to remove the trans to check for a part number or to compare to a known proper 360 flexplate. The 304 and 401 plates have weights also, but of different sizes. If you need a new 360 plate, get one for an engine 86 or earlier as the ring gear position changed in 87 to accomodate a gear reduction starter. Hope this helps, good luck.