470-vs-482 Differences/Similarities

The information regarding dimensions, part sources (i.e., BBC rods, etc) for the 470 cu in combination is readily available on the Tri-Shield web site, but I can't seem to find out much about the 482 combination (other than SBC rods).

So, what does it take to achieve 482" with a production BBB? Bore and Stroke sizes?

Is one size "better" than the other (disregarding the likely 1+ HP and/or Ft/Lb per cu in increase with 482")?

 

That's the most simple and concise explanation I've seen on this topic. Thanks for posting that Wiz!!

 

Here is the latest version of the 482 from Tri Shield. Molnar 6.8 rods and Autotec 4032 alloy pistons.

 

Scott, any chance of getting a picture of the piston skirt, inside of the piston and the spec sheet on the box? Thanks.

Larry

 

Hi Larry,

Here are the pics you were looking for, and the specs.

470/482 AutoTec Pistons-





Specs for the 470/482 AutoTec Pistons

• 4.350 Bore
• 4032 Material
• 1/16 comp 3/16 oil rings
• 1.775/1.725 Compression distance
• 26CC dish
• .300 deep Symmetrical valve reliefs
• 640 G Piston 142G pin
  
• .990 pin bore
• minor bore size and CD changes are free.
• Wire locks included
• straight pin (no offset, runs at .003 clearance for NA applications)
  
• $679/set

JW

 

Speaking of the 482, the latest version of the Diamond 482 high compression is also in the building, I took a few pics of that also.





Specs for Diamond 482 High Compression piston

4.350 bore
1/16 comp 3/16 oil ring standard, .043/3MM available as an option (pictured)
2618 material
.300 symmetrical valve reliefs - 10CC
.990 Pin
Standard pins and spiral locks included- standard pin weight is 185 G- 149 G H-13 pin available for and extra $136.00
Piston weight is 600 G
CD 1.725
customizeable- changes are $8 for each change, per piston
NA running clearance spec is .0045, pin offset .030 for low noise when cold
$779.00 per set

 

SO. MUCH. WANT.....

 

Thanks Jim! ...... They look great!

Larry

 

Got one right here

 

Jan, that doesnt look like it'd be a good fit for your car at all. You should send it over to me immediately so I can get it out of your way....

 

with the pistons on the 470/482 and from the look of it the 6.8" rod length also stays the same with the difference being the size of the big end, I'm guessing the expense of offset grinding the crank would be about equal?
the upside as I've read of going to this setup over a stock length rod and crank is the lessening of the side pressure on the cylinder wall due to the longer rods. Is there a significant increase in power(hp/torque) moving up to the 470/482 for that added expense? I'm trying to keep the idea that a larger displacement is the way I want to go but for that extra money I'm leaning back to just going .038 on the .030 block I have and having the crank polished and just assembling a 464.
I guess my question becomes, just how much extra am I or anyone looking at to have a crank ground for the stroker? I also have read the trishield rods eliminate extra work over a BBC or 5.4l ford rod . It just seems like a lot of extra work and expense if the gains really aren't there on a street engine. I think the money would be better spent on a roller cam setup and the Ta heads to keep my budget better/lower to slip it by swmbo.

 

Jim do you have any insight regarding the piston weights for the diamond vs auto tech? I see the numbers posted but the lack of a dish has to effect the # as well.

Also have you experimented with rolling over the sharp edges on the valve reliefs or do you leave them alone? I normally remove any sharp edges on the pistons, just curious about your thoughts on this.

 

Jim can grind your crank, but check with a local grinder to save on shipping. I have a local crank grinder who will do my offset grinding very reasonably.

There is some advantage to the lesser side loading as Jim can speak to that. But the real benefit is for zero-decking; there will be much less work needed to zero deck a production piece setup.

 

AutoTec:
"640 G Piston 142G pin"

Diamond:
"standard pin weight is 185 G- 149 G H-13 pin available for and extra $136.00
Piston weight is 600 G"

 

if one is getting new pistons and can select the compression height no matter which combo so to me no matter which option is selected, one will zero deck the setup. The extra comes from the crank grinding. And if one decides to forgo the new rods on a 464 to save some money.
I'm just trying to get in my noggin, how much more it will cost and how much power increase we might see for that extra coin.

 

I believe JW has Crankshaft Suppy in Minneapolis MN grind the offset crankshafts.

Again.... I feel if JW uses them they must be good. I spoke with Crankshaft Supply (Roger) a while back and he was very informative and after conversation they get my vote.

Larry

 

Your power increases comes from the induction.
The bore/stroke combos and how they are derived are often based on borrowing designs or parts from other platforms' having enough availability to either ease machining concerns and/or offer attributes shared by those designs.
The stock parts are easily bested by what's out there for other brands' designs in performance parts.
So many of these engine designs have way more beef than needed in the cranks that we can machine down dimensions to borrow parts or slightly alter existing parts and come up with more convenient stroked packages.
They save money sometimes by eliminating related machining operations that would have previously been necessary to make it all work.
You get performance increases when lightening things up and durability by using tougher parts than stock.
If using a common bearing size, you now have the ability to rebuild somewhat inexpensively if needed.
So if the question of "what's the 482 worth over the 464 power wise?" and you plan on using a stock-ish top end intended for 500 hp...the answer is minimal gains for the cost, but a much tougher engine in some regards.

 

with the idea that the power isn't much but the outlay of cash becomes several hundred I think the 464 with that money spent on a jw or other port job on the Ta heads for more performance for the same dollar is a better outlay for me. Others with a bigger budget might differ. I'm not into, "I've got a bigger. ....engine". I want the most power I can get to the ground for the least amount of money.