[spaceace77084]

Ok, here's a question my buddy asked me last night that I don't know the answer to. I told him I would ask the experts on Team Chevelle.

He is having a 396 over haulted. It's been bored 30 over by his mechine guy. The crank was also balanced to his block with the harmonic balancer and pistons, cam and rods were ordered for the block and crank he is using. The crank has already been installed as well as the pistons. Now he is having second thoughts about using that crank. The question he asked me is how easy/hard would it be to remove that crank and put in a steel crank? Would it be as easy as taking out the crank and having it miked for specs and then just have the new crank fit those specs and have it balanced with the harmonic balancer he already has? I'm not sure about the answer.

Any suggestions? I know a little about engines but his one is way over my head.

 

[Tom Mobley]

most all 396 cranks are steel. did he find one of the cast ones?

if he changes the crank it'll need to be balanced to the rods and pistons, he should have a balance card with all the info so he shouldn't have to dis-assemble all the pistons and rods and re-weigh and all that.

I'd be checking to be sure it isn't already a steel crank first.

 

[d1_bradley]

And, his harmonic balancer and flywheel are zero balance (no counter weights). You should be able to replace either one without issue. I know the techs check them, but they 'shouldn't' be ground on or specialized to a particular rotating assembly.

Why is the post title "454 crank question for the experts" and you say its a 396? If he's putting a 4" crank in a 396, ignore my answer above.......... (maybe, unless he did an "internal" balance on the rotating assy)

 

[VinceS427bb]

is he using a cast 454 (4'') crank in a 396 or
is he using a cast 396-402 crank in a 396 or
is he using a cast 496 (4.25) crank in a 496???

if switching from a cast crank to a forged crank there are going to be some differences in weight (balance) because of the different weight of pistons/rods/etc...
if this is the case it should be a simple matter of having the replacement crank balanced to the pistons/rods/rings you have now.
you also will need to insure the type of flywheel and balancer are correct for the crank you want to use.....

 

[spaceace77084]

My mistake, The title should read 396 not 454. It's a 396 engine.

 

[BillK]

George,
The crankshaft is balanced to match the weight of the pistons, rods, rings and bearings. So ... if he changes crankshafts, the new one will have to be balanced to match his parts.

By the way, and this is just my opinion .... I would not wate the time or money .. the cast crankshaft will be fine in most applications.

 

[SWHEATON]

George,
The crankshaft is balanced to match the weight of the pistons, rods, rings and bearings. So ... if he changes crankshafts, the new one will have to be balanced to match his parts.

By the way, and this is just my opinion .... I would not wate the time or money .. the cast crankshaft will be fine in most applications.

======================

2x that!