raredesign

I need to build my motor to support 850+rwhp, and all posts relating to the stock aluminum block seem to be anecdotal, with some saying 1000+ and others ~750 max.

Given proper internals and hardware, what can this 4.6 3v aluminum block handle without the bottom walking?

I had considered a 302boss iron block as “marketing” posts declared it as twice as strong, yet some who actually have it disagree and regret not using the aluminum block.

Please help.

imp

From an Engineer's viewpoint, your questions are unanswerable. What basis is used to assume the "bottom end" will fail? Based on a "use time", a given engine may sustain enormous power levels, but for only short times. How long do you expect this block to withstand the power levels suggested? 5 minutes? No sweat. 5 hours? Hmmmmm.......50,000 miles? Impossible. imp

Dino Dino Bambino

The stock block is robust enough to handle 1000rwhp. With blueprinting it can withstand up to1500rwhp.
The only reason for using the Boss block is the extra displacement offered by the larger 3.70" cylinder bore.

raredesign

it will be clearanced well for flow, etc and have good tolerances. My concern is that I too have heard elsewhere the block can withstand that much, but do you know of any articles describing actual accounts, racers, or stress tests proving such? It always seems to be “I heard”, or “a friend of a friend”.

This is a huge decision and I have a ton into this project already.

Much appriated. Thank you.

raredesign

assuming the same standard of operation for calculating an aftermarket block rating.

danzcool

There is so much that has to be right when making big power. The biggest problems tend to be heat and rod related. Not using strong enough rods, they fold and give the block a window. go lean or detonate you can cause the rods to do the same, or just melt a hole in the pistons.
People say the teksid aluminum block is the best due to thicker walls and more material.
You can find some documentation on the various parts, for instance Manley rods have engineering reports, but I know at least a few engine builders put Manley rods rated to 750 HP in engines they rate up to 1500HP. This type of thing gets down to balance, the better balanced the more it can withstand.
In the end, given a choice I chose aluminum over cast iron, paying a premium for an aluminum block. In the end, when modifying, you have to plan on the idea you may blow up an engine regardless of how well put together it is, a batch of bad gas, fuel pump failure, sparkplug electrodes being burnt off, etc, can strike at any time.
But what do I know?

raredesign

Wow! Fantastic build! Is that the S&H Performance kit? I have the single stealth so hoping for 850rwhp.
Impressive numbers on the stock motor.

I grately appreciate the detailed reply you gave. I’m just concerned with the strength of the block itself give than the internals will be done right to allow it maximum potential.

Once I get my numbers I plan on lowering boost and going to shows.

Not sure if I am allowed to cross link but my build post is here: http://www.s197forum.com/forum/showthread.php?t=133254

imp

A good example of aluminum structural failure was seen in the '60s, when Corvette introduced their 427 engine with experimental aluminum heads. We had a block and heads in our dyno lab, where we installed head gaskets to determine design suitability. Head bolts torqued to Chevy's specs occasionally caused some of the supporting aluminum structure beneath the bolt heads to crack, and collapse. Not known whether those heads were used in production, possibly strengthened.


Someday I'll mention their big u-joint mistake, if someone asks! imp

danzcool

The turbo system is a custom kit by RET. But a pair of 60mm turbos with billet wheel should be similar. I believe they (comp turbos) claim each turbo is capable of 600RWHP at full boost... haven't hit full boost yet.
So as far as block strength, I melted two pistons due to a fuel and/or fueling issue, but the block was rebuilt. They were going to do 2 sleeves where there was heat damage... Since it was going to a machine shop anyway I had them sleeve them all for 3.7" pistons for 5.15L

Dino Dino Bambino

I've heard of stock powdered metal rods breaking (usually due to detonation) and windowing the block, and piston ring lands breaking (always due to detonation), but I haven't heard of a single primary block failure in any 4.6 3V putting down less than 1000rwhp.
Simple balancing and blueprinting of the 3V block will make it as stout as the Teksid. Indeed that's exactly what Livernois does in its 1500hp engines.