am i stupid?

[G_Body_Enthusiast]

ok before you say yes just read and THEN if you think i'm stupid go ahead and say so.

i starting polishing the crank to my 472. not sure why but the rough finish left by the casting process bothers me along with the lines it left and the sharp edges from machining. so i started polishing the crank throws and removing the casting lines. so far i've gotten most of the edges of the throws with some minor polishing around the journal areas. i started with 80 grit and then 120. i might go up another grit to get it nice and smooth. the 120 finish feels pretty good but still a little rough.

now i know it's not necessary so dont use that as the reason to call me stupid but...am i stupid?

 

[-83MONTESS-]

Removing casting flash is always a good idea because it helps deter the start of cracks thats why alot of people do it on their blocks or polish their connecting rods. Alot of people also remove it from the crank and add an angle to the throws to help "cut through" the oil to reduce windage. My Scat stroker crank has the edges of the throws cut into a blade to help with windage.

Heres a pic of an exagerrated example. Notice how the counterweights arent square and bulky at the ends like stock cranks are. If you go this far you will have to get it rebalanced though.
http://www.pureperformancemotorsport.co ... =uuxsnetzm

 

[hurst1979olds]

Another thing people do it take electrical tape and put them on the journals, then shot peen. The tape protects the machined surface. You can also do that with connecting rods. If it were me, I wouldn't spend crazy time on all that. Yes it does help and have its advantages. But the gain youll see is very minor if noticable at all in a street engine. An all out race engine is a different story.

 

[G_Body_Enthusiast]

you're talking about knife edging the throws and i was thinking about that when i got started but i think i might let a machine shop do the knife edging. i trust myself to polish the crank, not sure about knife edging the throws though. if the crank were to be knife edged it would weight less and make it rev a little faster but probably not enough to really notice it in a street car but hey, it's fun learning to do things like this. i'm also considering doing the same thing with the rods, one is especially ugly from the casting and i think it might be prudent to do the rods too. the rods arent that great from what i've read but the experience might be useful later on with other engines.

 

[G_Body_Enthusiast]

Another thing people do it take electrical tape and put them on the journals, then shot peen. The tape protects the machined surface. You can also do that with connecting rods. If it were me, I wouldn't spend crazy time on all that. Yes it does help and have its advantages. But the gain youll see is very minor if noticable at all in a street engine. An all out race engine is a different story.

i've read many an article about polishing cranks and all the neat little things you can do to lighten them to rev a little faster, shed oil easier, etc. i know in a street car it wont be noticeable but a slightly lighter crank, especially for one with BIG main/rod journals and throws might be a little helpful. i'm also doing this as i tend to get in a hurry sometimes for no good reason and this teaches me to slow down, take my time and pay attention to detail. this will help when i put the engine back together. i'll put up a pic or two later. i need to make a crank stand so it's easier to work on. it's still in the block as i haven't cleared the space where i put my cranks. last thing i want is this potentially falling over, that'll ruin my day and then i'll have to get another crank, 500 bucks or more.

 

[-83MONTESS-]

Do you plan on using a windage tray? By windage tray I mean a real one not one of the cheap screens.

 

[G_Body_Enthusiast]

Do you plan on using a windage tray? By windage tray I mean a real one not one of the cheap screens.

lol not really. i'm not sure if anyone makes me for cadillac engines. if somebody does it's probably cost prohibitive.

 

[FE3X CLONE]

I say why not do it if you have the time?

To me it's just more practice using different tools. If you don't try it then you won't be able to learn what works and what doesn't and won't have that knowledge to pull from later on when your working on other parts of the car.

I polished both of my spindles before I powder coated them:

And the lifter valley on the 455:

I also spent time polishing the beams on a set of 425 rods that I was going to use originally for my engine. Basically took down the casting flash, then hit them with scotch-brite roloc disc and then bead blasted them. They looked absolutely great afterwards and this also adds some strength to the rods by removing possible stress risers.

 

[pontiacgp]

Any time you smooth out rotating parts is not a waste of time nor is it stupid. Oil will drain off the part easier and since oil weighs something the mass will rotate easier. But that's not really answering your question....

 

[Pohlcat]

Alright now I'm stupid but as I understand all olds are blueprinted so removing metal won't throw the balance off?

Steve