Page 1 of 1
Cast/Forged crank identification ?
Posted: Thu May 09, 19 9:47 pm
by morgan
OK chaps - got gearbox out and checked new torque converter fits (phew - it does) but it does look different.
Old one is huge, like 12"+ and the new one is 11". Same splines etc so all good. BUT the old one is externally balanced - which makes sense as it came off my old 318 and went onto my mild 440 - (cast crank engines i assume ?)
My problem is that the new torque conv is NOT externally balanced which the instructions suggest is fine if crank internally balanced (forged?) crank.
Does that make sense ? I dont want it to shake itself to bits ! Easy way to tell from the outside ?
Re: Cast/Forged crank identification ?
Posted: Thu May 09, 19 11:26 pm
by DaveBishop
you can buy a after market flexplate from B&M
Re: Cast/Forged crank identification ?
Posted: Fri May 10, 19 7:28 am
by John
A cast crank BB will have a damper double the thickness of a steel one, maybe youve been lucky and your motor didnt need a balanced converter
Re: Cast/Forged crank identification ?
Posted: Fri May 10, 19 7:57 am
by morgan
New engine has flex plate attached.
So plate matches engine - i was trying to ascertain if torque conv needs balancing.
If the flex does the balance then i am ok.
Will re-read. Maybe thats all it means - make sure you are using the right flex plate.
Ta...
Re: Cast/Forged crank identification ?
Posted: Fri May 10, 19 8:48 am
by Blue
No your convertor doesn't need balancing. Your new convertor might have large 7/16" bolts rather than the tiny 5/16" stock convertors come with, If it still has small bolts check that your new flex plate hasn't been drilled out for the larger bolts.
Re: Cast/Forged crank identification ?
Posted: Fri May 10, 19 9:30 am
by Dave999
would someone have used a cast crank in a v8 that sounds like it was built to race? i dunno..... its genuine question, are they good for 6000 7000 rpm?
or more...
i'd guess they are until they are not....
well if you have a balancing problem you will know the first time you drive from lower to higher rpm there will be smooth followed by horrible followed by better again as you drive through some nasty harmonic vibration...
Re: Cast/Forged crank identification ?
Posted: Fri May 10, 19 9:37 am
by morgan
Top info chaps. Bolt check when i get home.
Re: Cast/Forged crank identification ?
Posted: Fri May 10, 19 5:39 pm
by morgan
Yep; its all good. Both converters have 10" smaller holes fitting the orig bolts.
Interestingly you can see on the flex plates where they have been bolted previously. Old zonking great converter bolted on outside holes.
New engine used to use big holes, but has the small holes in the right place so all good.
Living and learning...
