[v869tr6]

I purchased a IA2 alum. block and would like input, how to deal with cam bearings, piston clearance, lifter bushings, any top secret info?

[Tom Vaught]

I would personally check with Jeff V who won the Million Dollar deal twice with an IA2 Aluminum Block. If anyone knows how to make an aluminum block live and run rounds repeatedly, he would be very high on my list.

Tom V.

[Half-Inch Stud]

Good place to post the weights, to know the difference.

[Jack Gifford]

Seems to me that Bob and Frank would provide 'most all the answers, no?

[Tom Vaught]

Yes, Both would know very well and possibly The Butlers (Rodney) who has built a lot of them.

Tom V.

[steve25]

If you can find yourself a top fuel guy to pal up to that would be a good move also.

[chiefbigb]

I talked with Jeff V some about these blocks. He has used 2 of them. The first seriese and the current version with good reaults. I'm sure he could help answer some of your questions. He did mention it is very easy to cool down and builds heat slower than iron blocks. I would think in bracket racing this is a great thing.

[v869tr6]

Thanks for all the responses, my engine builder said ask a bunch of questions.
Trying to build a Dragweek type engine that will live on the street. Really about the same as my factory block but with more camshaft.

[455firebird1969]

Originally Posted by Half-Inch Stud

Good place to post the weights, to know the difference.

My IA-IIA weighs #148 with five main caps & hardware as compared to a stock 455 block with two bolt main caps bolted in place weighing #186 on the same (old) bathroom scale.

It would be nice to see more actual info posted in this thread. There was another thread addressing valve lash adjustment changing .016" after the aluminum block warms up and expands. A cam that calls for .018" would get .002 lash cold.

[Half-Inch Stud]

Originally Posted by 455firebird1969

My IA-IIA weighs #148 with five main caps & hardware as compared to a stock 455 block with two bolt main caps bolted in place weighing #186 on the same (old) bathroom scale......

So the Aluminum block is 38 Lb lighter than the stock 455 block. Good to know.

[v869tr6]

Originally Posted by 455firebird1969

My IA-IIA weighs #148 with five main caps & hardware as compared to a stock 455 block with two bolt main caps bolted in place weighing #186 on the same (old) bathroom scale.

It would be nice to see more actual info posted in this thread. There was another thread addressing valve lash adjustment changing .016" after the aluminum block warms up and expands. A cam that calls for .018" would get .002 lash cold.

The block expanding is good info to have, thanks
Lots of little things to think about if I expect this engine to be right the first time!

[lust4speed]

It has been somewhat of a learning experience with the aluminum block. Bolts and plugs continued to loosen up through a couple dozen heat cycles with the expansion and contraction of the block, and things settling in place. Another thing I wish someone had mentioned to me that the same expansion that grows the lash also grows the cylinder length, and the pistons end up farther down in the hole at operating temp, and that dropped the actual compression ratio from where I thought we were going to be. After everything was tightened up several times and things stabilized, the block has been trouble free.

[johnta1]

You're not using aluminum rods?

[v869tr6]

Originally Posted by lust4speed

It has been somewhat of a learning experience with the aluminum block. Bolts and plugs continued to loosen up through a couple dozen heat cycles with the expansion and contraction of the block, and things settling in place. Another thing I wish someone had mentioned to me that the same expansion that grows the lash also grows the cylinder length, and the pistons end up farther down in the hole at operating temp, and that dropped the actual compression ratio from where I thought we were going to be. After everything was tightened up several times and things stabilized, the block has been trouble free.

Thanks that's the type of stuff that will help me and others building these alum blocks!

[teeraven]

I may be wrong here, but I can't imagine expansion of an AL block is a major consideration.

Look at iron vs aluminum LS engines. I've never seen things like bolts loosening up, or piston height discussed as different between the two.

Interesting topic though. I'm planning to build an all AL engine for my 67, so I'd be interested in seeing what info the experts have for us.

[seancarole]

Like othors say keep it KISS al blk hds rds happy travels

[mgarblik]

The Pontiac aluminum block from my minimal experience acts much like any other aluminum engine block. The possible reason it was posted for example that the LS aluminum blocks don't exhibit any weird behavior is because they were engineered from day 1 to be made from aluminum and last 100,000 miles +. The gaskets, and fasteners in particular are designed to be used with aluminum. Bolts are much longer and are tightened using torque angle methods for accurate stretch. They use particular type head gaskets and have very large clearance holes in the heads to allow for expansion and so forth. For our Pontiacs, I would build the engine with a little greater attention to detail in the clamping areas such as head bolts. Make sure there is plenty of clearance around the head bolts. I would think a re-torque of the heads would be mandatory. The loss gain of valve lash cold vs hot is a real thing. Our nitro engine, iron vs aluminum block shows an additional .006-.008 in lash once hot. This is not unique to the Pontiac engine. A little trivia. Current top fuel/funny car engines: They typically run ZERO valve lash cold. When you are standing in the pits watching them warm-up and they start hard and spit and sputter for the first few minutes on alcohol, it's partly due to some valves not closing all the way. As they warm, they close properly and gain the valve lash. That's why they are always lashed hot when the lash can be consistent. So those engines will gain .016-.018 in lash from start to hot.
A final note: you probably already know your mains and head fasteners will use a different torque value than an iron block. I would talk to Butler or others using the block and heads you are using to get a good number. Good luck, you will love the aluminum.

[v869tr6]

Originally Posted by mgarblik

The Pontiac aluminum block from my minimal experience acts much like any other aluminum engine block. The possible reason it was posted for example that the LS aluminum blocks don't exhibit any weird behavior is because they were engineered from day 1 to be made from aluminum and last 100,000 miles +. The gaskets, and fasteners in particular are designed to be used with aluminum. Bolts are much longer and are tightened using torque angle methods for accurate stretch. They use particular type head gaskets and have very large clearance holes in the heads to allow for expansion and so forth. For our Pontiacs, I would build the engine with a little greater attention to detail in the clamping areas such as head bolts. Make sure there is plenty of clearance around the head bolts. I would think a re-torque of the heads would be mandatory. The loss gain of valve lash cold vs hot is a real thing. Our nitro engine, iron vs aluminum block shows an additional .006-.008 in lash once hot. This is not unique to the Pontiac engine. A little trivia. Current top fuel/funny car engines: They typically run ZERO valve lash cold. When you are standing in the pits watching them warm-up and they start hard and spit and sputter for the first few minutes on alcohol, it's partly due to some valves not closing all the way. As they warm, they close properly and gain the valve lash. That's why they are always lashed hot when the lash can be consistent. So those engines will gain .016-.018 in lash from start to hot.
A final note: you probably already know your mains and head fasteners will use a different torque value than an iron block. I would talk to Butler or others using the block and heads you are using to get a good number. Good luck, you will love the aluminum.

Thank you for a very helpful post, be really cool if other keep adding input!

[torqjunki]

I can verify the lash deal. I had my cam set up for .016 lash so I could finger tighten the poly lock at zero lash and tighten the Allen screw. When I ran solid lifters on Hyd roller, I had to run negative lash cold to get close to .007 hot. It does cool quickly as well. IIRC, block is 98lbs with out main caps and 118 or so with caps. My lifter pads have been machined down for roller lifter tie bar clearance. You are supposed to be able to run corporate lifters, but I cannot verify that. Mine are not bushed, but wish they were. Use the screw in freeze plugs with flush Allen wrench hole for tightening. The ones that are set up to tighten with wrench or socket can interfere with headers. Decide what head gaskets you will use and drill decks using them as guide. Swapping to diff gaskets may require plugging and re drilling coolant holes and of course having decks cleaned up.

[92GTA]

Not to get tooooo off topic, but how many magnesium Pontiac blocks are there? Chevy had a few, and there were even aftermarket ones. Lighter and stronger than aluminum. Is there anyone today casting mag Pontiac blocks? Or would it just be a one off order for the foundry to cast mag instead of alum?