well heres my update i found out the flexplate was cracked...guess i didnt notice it because i was doing two things at one time...around here if it not a computer on the car dont anybody know whats going on, so i have to do it myself......
If u have a cracked flexplate i would recommend looking for other issues they typicallydo not crack on thier own.......noticed I was the only person in this thread to mention a cracked flexplate/flywheel can cause a vibration.....maybe I know a lil something after all........good luck I hope it all works out.
A casting number is not going to tell u if it was nuetral balanced.......also when u send out a crank with the balancer and flywheel or flexplate they match the 3 components. Sometimes they take weight just off he crank other times they take it off all 3 parts in that instance they are now matched. They only way you can change one of tue components is to have them either balanced as an assembly or take the part u are replacing and have its balance checked and then match the new part to Its balance........ Pretty simple really.....so if u do not know the history of said part/parts u have one choice to fix a vibration for sure......and that is to have it checked ad an assembly. Period. No casting numbers are going to tell u that nor can normal eyes but magic eyes which u seem to possess now that will catch it every time
From looking at the picture that you show of the motor, I would say that you need a 28 oz. flex plate. From what I have read, they didn't start using the 50 oz. flex plate until the mid 80's and then the engines were also using serpentine belts. Good luck with your project.
I guess you missed the part about "the chances of him running across a neutral balance 302 crank are slim and none" ? And you do not have to have anything rebalanced when replacing parts. No engine is perfectly balanced at ALL rpms. When you have one balanced, it's done to a target rpm range. (this from the guy who's done the few I had balanced) I've rebuilt many motors with new pistons (oversize and/or forged vs cast/std pistons, theoretically changing the balance) and never had them balanced. They all ran fine, no vibrations. Will you make more power by having one balanced ? Yea, but it's not something that MUST be done in EVERY instance. I was also correct in stating that he's got a 90% chance of getting it right just by checking the casting numbers on the crank (or block) before ordering a flywheel/flexplate. You can replace any 28 oz part with another 28 oz part (or 50 with a 50)and chances are also slim and none that it's going to throw off the balance. Done it too many times to not know I'm correct in this.
The change to the 50 oz crank was sometime in 1981. And they were still using V belts then, along with serpentine FEAD's (flat belts) There were also std rotation flat belt setups all the way up til 91 too.
I WORKED IN A MACHINE shop PART TIME for about 5 years as a journeyman(yeah that means I did it free just to learn)I am also an A>S>E master certified technician. I have been wrenching since I was 16 and I am 35(almost 20 years). I still learn everyday but I know for a fact that once you balance a crank/flexplate(or flywheel)/balancer and it was not neutral balanced(meaning the flex/flywheel/and the balancer are balanced to zero you should not just throw another balancer or flex/flywheel on it without rebalancing the entire assembly or balancing the replacment part to the original parts balance. If they did not touch the the balancer or flexplate then yes you can replace them with no issues. I am aware that it is a target rpm....they do the same with tires/rims most balancers are for 25-35mph unless you have a high speed balancer. I have seen a couple rotating assemblies balanced it is pretty cool process. My xp tells me I know I am right...... I think we will just have to agree to disagree on this issue. :Handshake
You're splitting hairs here. I said the chances are slim and none that someone has rebalanced it to zero (or any other number). He'll be fine without having to pull the engine and taking it apart only to find out the stock imbalance is in place. It'd be a shame for him to go thru all that work only to find out all he needed was a parts house flexplate to fix it.
your flex plate should have weights on it. ( unless balanced to zero) if there no weight, it either fell off or someone put on a 240/300 flexplate ( which bolt on and look the same) Now the question is do you have a 28 or 50oz imbalance? look for a clue on the balancer as to what year it is. Maybe it will be right (or wrong if someone pieced it together.
Here is an artical that is good reading, and explains the differences between an "Internally Balanced" and "Externally Balanced" motor along with pictures of the different flexplates and balancers for 28oz and 50oz. http://www.rowand.net/Shop/Tech/FordFlywheeslAndFlexplates.htm
yes my flexplate was cracked so i got the casting number and i found out the year of the motor is a 73 and that it came out of a torino or fairline... i also found out it take a 157 tooth 28oz flexplate...im waiting for it now but now im wondering if that motor was ran with that cracked flexplate messed up anything????? cause it had a bad vibration...guess i will see sometime next week.........
The block casting numbers are meaningless in regards to what the engine was originally installed in. Same block was used in ALL applications, not just the one indicated in the casting numbers.
