Aluminum vs, Cast Iron Block

[Cobra #3170]

One huge plus for aluminum blocks is ease of repair, last year I lost oil pressure in a long corner. The trapdoor Aviad pan failed to pick up and my Accusump finally ran out of oil. Number one rod was snatched by the crank and snapped off at the big end (Accusump fed at the rear of the block). The rod made a hole in the side of the block, then jammed the cam which resulted in damage to three lifter bores. I also lost two sleeves plus two adjacent rods. The piston with what was left of the rod flew up and cracked the head which pulled one head stud loose in the block.
All this damage was repairable thanks to an aluminum block. If I had an iron block I would have been buying a new one.

[fostereast]

Out of curiosity, how much did the repair cost you?

[Cobra #3170]

I don't have a breakdown that shows details of each specific item on block repair. The block cost was around 3k for two new sleeves, alinehone, lifter bore repair, welding, redecking and other minor work. The engine was quite a bit more but that involved all new cylinder heads, cam, lifters, 3 Carrillo rods, crank repair, new dry sump system and tank, manifold machining, dyno time, FI tuning etc. so total cost would not be relevant. This was an early Shelby block that had superb machine work, so I wanted to save it.

[Commodore]

A little off target but how will state DMV's view a 'replica'/'new'/aluminum block for emission certification? Would the aluminum block/engine be classified as a 'new' engine with standards for it's year of manufacture or as a replacement part for an pre '70's engine?
RB

[FFR428]

Originally Posted by Commodore

A little off target but how will state DMV's view a 'replica'/'new'/aluminum block for emission certification? Would the aluminum block/engine be classified as a 'new' engine with standards for it's year of manufacture or as a replacement part for an pre '70's engine?
RB

With both the Pond and Genesis blocks having a C5AE-H casting number and a 65 date code I don't think it would be an issue unless you tell them. After all there were aluminum FE blocks in the 60's too. I'd try to pass it off as original 65 equipment.

JMO..

G.

[philminotti]

Not to get too far off topic, but in most of the Northeast including our great police state of CT, the date code of the block has ABSOLUTELY nothing to do with emissions certification. Currently in CT, the emissions standard to which a car is held to is based on the year in which it is first registered. So, even if you go to the Smithsonian and grab Orville and Wilbur's 1903 aircraft engine and drop it in your shiny new Cobra, you're being held to the current standards. That's what all the SEMA legislation is about!!!

phil

[82ACAUTOCRAFT]

Originally Posted by Commodore

A little off target but how will state DMV's view a 'replica'/'new'/aluminum block for emission certification? Would the aluminum block/engine be classified as a 'new' engine with standards for it's year of manufacture or as a replacement part for an pre '70's engine?
RB

You are over estimating our civil servants! unless you happen to deal with an enthusiast!!!!!!!!!!!!!!!!!!!!!!!

[Barry_R]

Aluminum blocks work just fine for street use. Nothing wrong with them. But all things being equal an iron block will make more power - if maximum power is a factor for the application. The weight advantage can be significant in a Cobra.

All NASCAR blocks are iron, and most if not all Pro Stock blocks are iron. They've actually gone to higher density, heavier grades of cast iron (compacted graphite or CGI) to add strength and for more power yet. Somebody mentioned the architecture and they were correct, along with thermal stability.

I'll give you a single simple example - there are several others - but you can actually measure and visualize this one. If you set up your motor for zero deck clearance and say 10.5:1 compression. As the all aluminum engine warms up your deck clearance will increase by about .010 and your compression ratio will drop by a corresponding amount. You can see this in the valve lash settings on an all aluminum combination - my aluminum head stuff will grow by about .009 cold to hot - the all alloy stuff needs to be near zero lash cold.