Thoughts on 440 source ultralight crank

[TexasRoadRunner68]

Any thoughts on the ultralight 400-512 stroker crank? It’s a $150 upgrade from the normal one. Apparently they shave 4 lbs, some coming off the flange. For the 440 crank it seems more significant at 6.5lbs removed.



Worth it for $150 or basically something unnoticeable in most applications?

 

[66Satellite47]

As I read the website, it's more than just milling the flange to a star shape, they undercut the counterweights to reduce that rotating mass, in addition to reducing the counterweight diameter. Seems like a good match with lite pistons. But I never had one. If you are going to really spin the motor 7000+, sounds good to me, even the better rod bolts, chamfered rod bearings also make sense to match the crank fillet radius. But I'm not spending your money!

 

[TexasRoadRunner68]

As I read the website, it's more than just milling the flange to a star shape, they undercut the counterweights to reduce that rotating mass, in addition to reducing the counterweight diameter. Seems like a good match with lite pistons. But I never had one. If you are going to really spin the motor 7000+, sounds good to me, even the better rod bolts, chamfered rod bearings also make sense to match the crank fillet radius. But I'm not spending your money!

I definitely want the upgraded rod bolts, chamfered bearings, and will probably go with aluminum main caps. I already have their girdle setup.

It adds up for sure, but I’d rather do it right while it’s apart.

 

[66Satellite47]

I definitely want the upgraded rod bolts, chamfered bearings, and will probably go with aluminum main caps. I already have their girdle setup.

It adds up for sure, but I’d rather do it right while it’s apart.

What you get from the ultralight option is a motor that will spin up quicker. Is that important? It also MAY be easier on the bearings.

 

[gkent]

Their aluminum main caps are not machined to the 440's main bore size, they're low deck size. So you have to find a shop that can machine them - good luck with that. You're better off spending a few bucks more for another brand like Indy's.

 

[66Satellite47]

I think he is saying the aluminum main caps wil be machined for the low deck crank size. Maybe I'm wrong. I read the Source site saying the caps need to be machined for the crank you have.

 

[gkent]

I thought what I was saying was pretty clear !!!

 

[snakeoil24]

Stay away from aluminum main caps

 

[TexasRoadRunner68]

Stay away from aluminum main caps

Would you just stick with the stock caps? That’s my plan otherwise. I just heard the aluminum caps help absorb some shock and help the main webbing survive longer. Realistically my goal is 600 hp/ 600 ft lbs and it probably won’t see too much hard abuse since it’s a street car.

I definitely would prefer to do it right the first time and not have to mess with it later though.

 

[steve340]

Even manufacturers of aluminium blocks fit steel caps - they must know something. Stock is better than alloy.
A correctly clearanced stock set up with studs is most likely going to be fine.

 

[snakeoil24]

Would you just stick with the stock caps? That’s my plan otherwise. I just heard the aluminum caps help absorb some shock and help the main webbing survive longer. Realistically my goal is 600 hp/ 600 ft lbs and it probably won’t see too much hard abuse since it’s a street car.

I definitely would prefer to do it right the first time and not have to mess with it later though.

Yes especially if block is 67 or later

 

[snakeoil24]

Would you just stick with the stock caps? That’s my plan otherwise. I just heard the aluminum caps help absorb some shock and help the main webbing survive longer. Realistically my goal is 600 hp/ 600 ft lbs and it probably won’t see too much hard abuse since it’s a street car.

I definitely would prefer to do it right the first time and not have to mess with it later though.

Yes

 

[gkent]

600 hp/ 600 ft lbs and it probably won’t see too much hard abuse since it’s a street car.

Pfft, I built that and didn't even bother with a girdle!

 

[dvw]

I wouldn't bother with the light weight crank. Heck my new pistons are over 100 grams heavier than the old ones. That's close to 2 lbs of weight that is starting and stopping at a very high rate. Car just went 8.98 best ever.
Doug

 

[steve340]

If your car is heavy it will probably go better with the heavier crankshaft. A good balance job needs to be done in any case.
The lighter crank just helps the engine speed up a little faster.
If it was a very light car such as a Super Modified or something like that it would a good idea.