Club Cobra - What is your experience with aluminum engine blocks?

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What is your experience with aluminum engine blocks?

I am going to replace my current 289 HI-PO with a 331 stroker. One option on the list uses an aluminum block. The car will see some occasional road course, auto cross, and drag strip action, but will be mostly street driven in a spirited manner (95%). I am wondering how viable an aluminum block will be for my relatively low performance needs (375-400HP) from a durability standpoint. My current PRO reasons are weight savings and overall car balance, and extra cooling ability the aluminum offers. One big CON is the high cost of admission for the alum block. So, is this worth it or should I stick with the iron block. The rest of the motor is Edelbrock Performer RPM Air-Gap intake, AFR 165-COMP heads, Aviad road race oil pan, headers, forged steel crank, H-Beam rods, and forged pistons when the size is determined. Thanks for any help and insight you can provide.

At that power level, stock Ford blocks are primarily used. The weight difference is 60# in an 8.2" block. Not much. For the nearly $2k difference, you could get lightweight pistons with short lightweight pins, and internally balance your crank. Maybe add a lightweight flywheel (like the 18# Quartermaster clutch from Levy's). A lightweight crank could save 10#.

If you were going to use a Dart block anyway (around $2600 prepped I believe), you may want to spring for the extra $1200 for the aluminum.

At that power level, are you using a hydraulic roller or a mild solid flat tappet cam?

I've raced many things with both iron and alum blocks--If weight savings and car balance is primary--balance the lbs vs cost per pound against other areas that you can achieve weight reduction--smaller radiator/oil cooler/plumbing--brake system components--lighter exhaust system--suspension/steering system,etc. You can make the power level your looking for with a four cylinder so consider your needs/wants carefully---or DO IT ALL!!!!

Jerry

I have a Ford RDI M-6010-F302 #810 Aluminum Siamese Block (New) that I am willing to sell for $3,895.00

Allan

Heavy duty, light weight alternative to cast iron
356-T7 aluminum block with 4-bolt, steel billet main caps
Iron sleeves, bore range 4.000”-4.155”
Siamese cylinder bores, 5.200” long
Finished main bearing bore for 2.248” journal diameter
Uses common OD cam bearings, part number M-6261-J351/R351.
Weighs approximately 100 lbs.

"What is your experience with aluminum engine blocks? "

I've touched one before. :D

The weight savings of smaller CI blocks is not as large as many would imagine. If a true copy of the iron block it would be even lighter but they do improve strength beyond the iron blocks. The Alum. blocks are built stronger and the extra mass offsets some of the savings. The big advantage IMO is the ability to repair if damaged in addition to the WOW factor, strength and so on.

Just for the record, Flatlander lists 8.2" Dart aluminum Dart blocks for $3669.

Quote:

Ford Aluminum Blocks

Dart puts Ford racers in front with our first Aluminum blocks designed just for Fords. Working with leading Ford racers and engine builders, we designed the Race Series small-blocks to solve the shortcomings of production-type blocks used in high-performance and competition applications.

Dart blocks for Fords are produced on dedicated tooling and machined on state-of-the-art CNC equipment. We added the features that Ford racers need to build powerful and reliable engines. Take a close look and you’ll see why Fords fly with Dart!

• Premium alloy: Dart aluminum blocks are cast from virgin 355-T6 aerospace alloy for superior strength and integrity.

• Siamesed cylinders: Standard 4.00" or 4.125" cylinders can be safely bored to 4.165" diameter. Ductile iron sleeves and extra-thick walls prevent cracking and produce excellent ring seal.

• Scalloped water jackets increase coolant flow around cylinder barrels to prevent detonation, extend engine life and produce consistent cylinder temperatures.

• Four deck heights: 8.200" (302), 8.700" (stroker 302), 9.200" (351C) and 9.500" (351W) allow displacements up to 450ci. Short-deck versions fit under stock hoods while tall-deck versions are ideal for big-inch engines.

• Steel four-bolt main bearing caps are standard. Three center caps have splayed outer bolts for maximum strength; rear cap uses standard onepiece seal.

• Two main bearing diameters: 302 (2.249") or 351C (2.749") allow choice of small or large journal crankshaft.

• Stock components make Dart blocks a direct replacement for most production small-blocks. Provisions for stock motor mounts, accessory drives, smog pumps, starter brackets, oil pans and pumps.

• Upgraded oiling system has a complete stocktype system plus a low-restriction priority main oiling system with front and rear external oil pump feeds.

• Dual crossovers allow oil flow to be metered with restrictors for roller lifter cams and/or roller rocker arms to reduce oil flow and windage.

• Reinforced head bolt bosses are blind tapped to prevent leaks and produce accurate torque readings. Extra-thick decks prevent head gasket leaks.

• Standard camshaft and camshaft drive can be used.

• Precision CNC machining ensures consistent high quality and eliminates expensive “blueprinting.”

As part of complete weight loss program, an aluminum block is a key part, saving 60#. To really take advantage you would also use a lightweight crank (10-15#), lightweight rods, pins, and pistons (2-3#), small diameter damper (2-3#), lightweight clutch/flywheel (20-30#), and maybe some additional lightening machining. You can probably get close to 80-100# weight reduction, most of it off the front wheels.

Alan,
Please tll me about the tires on your FIA. I want to go to racing tires on my FIA (ERA) and yours look like they work well (from our pictures). From the Goodyear dealer web sites it appears that there are at least 2 options for the Eagles that fit a Cobra.
Thanks,
Pat

Pat,

I use the standard Goodyear "Cobra" tires from Roger Kraus http://www.rogerkrausracing.com/contact.html

They are the rain tire with groves, I have 3000 miles on them almost all track time. They will be good for another 200 miles. I might try the Bluestreaks on the next round.

Allan