Aluminum Head Do's and Dont's
Thread Starter
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Aluminum Head Do's and Dont's
I am very new to aluminum heads. I have never built and engine before using aluminum heads, and I want to research this before I get into the project.
What are some big DO'S and some big DONT'S when working with aluminum heads on an iron block?
I did do some searching, but found a lot of conflicting info, and I want to get it straight.
Basically the project is:
1973 405 (400 Bored +.020)
Aluminum Vortec Heads
Speed Pro Dish Pistons
10.1:1 CR
Roller Retrofit
Crane 119661 Roller Cam
I do know about the steam holes, and I will make sure they are drilled before the heads go on. I will also be enlarging the temp sender port to match the stock sender for my car.
What I am looking for are tips from guys that have used aluminum heads before, as far as sealing, bolts, anti-seizing, anything to keep threaded holes safe and clean. I plan on painting the heads to match the block so the outsides will be protected.
Thanks guys.
What are some big DO'S and some big DONT'S when working with aluminum heads on an iron block?
I did do some searching, but found a lot of conflicting info, and I want to get it straight.
Basically the project is:
1973 405 (400 Bored +.020)
Aluminum Vortec Heads
Speed Pro Dish Pistons
10.1:1 CR
Roller Retrofit
Crane 119661 Roller Cam
I do know about the steam holes, and I will make sure they are drilled before the heads go on. I will also be enlarging the temp sender port to match the stock sender for my car.
What I am looking for are tips from guys that have used aluminum heads before, as far as sealing, bolts, anti-seizing, anything to keep threaded holes safe and clean. I plan on painting the heads to match the block so the outsides will be protected.
Thanks guys.
Drifting
Joined: Feb 2005
Posts: 1,738
Likes: 2
From: San diego ca
Always use anti-sieze on bolts and sparkplugs that thread into or through an aluminum head... thread sealant is ok too for those bolts that go into the water jacket.
Never use just water for coolant lest your heads corrode (distilled might be ok I'm unsure)
be very careful about cross threading - it doesnt hurt to chase the threads first time you get ready to bolt to the head to be sure.
A sacrificial anode in the radiator is a good idea.
Make sure to use a head gasket intended for aluminum heads
Never use just water for coolant lest your heads corrode (distilled might be ok I'm unsure)
be very careful about cross threading - it doesnt hurt to chase the threads first time you get ready to bolt to the head to be sure.
A sacrificial anode in the radiator is a good idea.
Make sure to use a head gasket intended for aluminum heads
Le Mans Master
Joined: Sep 2000
Posts: 9,078
Likes: 7
From: DFW TX
Cruise-In VII Veteran
St. Jude Donor '07
Couple of tips from me.
I seemed to have better luck with Orange coolant. Green will try to find it's way out around the aluminum intake runners. Not sure why, but I had problems and the vendor told me to switch and it worked.
Also blow out all holes. If there is any liquid in any of the bolt holes, when you tighten the bolts down you will crack the head or strip the threads.
Used locking header bolts. The anti-sieze will let the bolt work out with it.
Simple Green is a no-no on aluminum heads, it will oxidate them fast.
Hope this helps.
I seemed to have better luck with Orange coolant. Green will try to find it's way out around the aluminum intake runners. Not sure why, but I had problems and the vendor told me to switch and it worked.
Also blow out all holes. If there is any liquid in any of the bolt holes, when you tighten the bolts down you will crack the head or strip the threads.
Used locking header bolts. The anti-sieze will let the bolt work out with it.
Simple Green is a no-no on aluminum heads, it will oxidate them fast.
Hope this helps.
Racer
Joined: Jul 2007
Posts: 444
Likes: 0
From: Roselle IL
couple things I learned:
- Don't use steel shim head gaskets
- BBC: Be sure that bolts in pushrod guides are sealed
don't use RTV on head bolts, use thread sealant or permatex 2a (side note: I have seen several posts on other boards about ARP thread sealant failing in head bolt applications)
- You must use hardened washers under you head bolts
- You must use hardened shims under your valve springs
- If you do valvle lash cold, you subtract .006, not .002 like for iron.
- Don't use steel shim head gaskets
- BBC: Be sure that bolts in pushrod guides are sealed
don't use RTV on head bolts, use thread sealant or permatex 2a (side note: I have seen several posts on other boards about ARP thread sealant failing in head bolt applications)
- You must use hardened washers under you head bolts
- You must use hardened shims under your valve springs
- If you do valvle lash cold, you subtract .006, not .002 like for iron.
Thread Starter
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Safety Car
Joined: Dec 2005
Posts: 4,270
Likes: 20
From: Central Michigan
Yep, exactly. You'd probably be OK if you bolted on your intake/headers and left them, but if you plan on intake swaps or run into situations where you need to remove the headers to get at another part of the car(I've had to do this several times), the constant tightening of the bolts can take it's toll on the cast aluminum threads.
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Thread Starter
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Well I was thinking of using an aluminum specific self etching primer, and using a high temp engine enamel that I use to paint all my engines. If it comes off or starts to flake while it's still on the engine stand I'll strip it all off and leave the raw aluminum look.
Instructor
Joined: Dec 2007
Posts: 184
Likes: 0
From: Crystal Lake IL
A sacrificial anode is a piece of metal that is highly reactive and will hopefully react with corrosive chemicals before they do any damage to your heads. They're very common in marine applications...I'm not too sure about non-marine applications. Just know the basics of what it is.
Drifting
Joined: Oct 2004
Posts: 1,496
Likes: 1
From: Lafayette Louisiana
A sacrificial anode is a piece of metal that is highly reactive and will hopefully react with corrosive chemicals before they do any damage to your heads. They're very common in marine applications...I'm not too sure about non-marine applications. Just know the basics of what it is.
Le Mans Master
Joined: Apr 2005
Posts: 6,360
Likes: 429
From: Seattle Area WA
I think one of the most important tips is to use the correct coated, or Stainless Steel Faced Head Gasket to prevent Galvanic corrosion between the heads and block.
Header studs are nice as opposed to bolts to reduce wear on the threaded holes.
BTW, are you using the Patriot Heads, they are the only cheap aluminum head I can think of.
Header studs are nice as opposed to bolts to reduce wear on the threaded holes.
BTW, are you using the Patriot Heads, they are the only cheap aluminum head I can think of.
Thread Starter
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I think one of the most important tips is to use the correct coated, or Stainless Steel Faced Head Gasket to prevent Galvanic corrosion between the heads and block.
Header studs are nice as opposed to bolts to reduce wear on the threaded holes.
BTW, are you using the Patriot Heads, they are the only cheap aluminum head I can think of.
Header studs are nice as opposed to bolts to reduce wear on the threaded holes.
BTW, are you using the Patriot Heads, they are the only cheap aluminum head I can think of.
No the heads I am using are PBM. I know they are not American made, but I am getting them NEW, shipped, and loaded, for about $700.
Do you happen to know the part number for the head gaskets I will want for a 400, and aluminum heads? Maybe stock thickness?
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
The issue with corrosion is the same as with alu radiators. There was a thread about this some time ago. Dewitt stated that you only needed to use sterilised water without minerals that act as electolytes.
Pro
Joined: Mar 2008
Posts: 716
Likes: 1
From: Albuquerque New Mexico
What intake manifold will you be using? If your using the GM Vortec Heads many will say that you can bolt the older style intake right up to them. This is true - you can physically bolt it up but I wouldn't cause the ports don't line up well at all and will hinder the flow. The Vortec style manifolds are specifically designed for those heads for a good reason. May not apply but thought I'd throw it out there. One other thing you can expect is a small amount of improved handling due to the reduced weight and also for a wider smile when you're staring at your engine compartment. Have fun. 
Thread Starter
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
What intake manifold will you be using? If your using the GM Vortec Heads many will say that you can bolt the older style intake right up to them. This is true - you can physically bolt it up but I wouldn't cause the ports don't line up well at all and will hinder the flow. The Vortec style manifolds are specifically designed for those heads for a good reason. May not apply but thought I'd throw it out there. One other thing you can expect is a small amount of improved handling due to the reduced weight and also for a wider smile when you're staring at your engine compartment. Have fun.
Yeah I am getting a Vortec specific manifold, and since I have an L88 hood and lots more room I'll be getting an Air Gap version.
Pro
Joined: Mar 2008
Posts: 716
Likes: 1
From: Albuquerque New Mexico
Sounds good - that's what I did. I almost bolted up my old style RPM air-gap manifold onto my fast-burn vortecs (cause they said I could) and when I saw how poorly it aligned I decided to buy the vortec air-gap dual-plane manifold. Are these heads the "fast-burn" type. If so you may want to do some research on timing your engine cause due to the excellent efficiency of the cumbustion chamber design they do not require as much total timing.
Pro
Joined: Mar 2008
Posts: 716
Likes: 1
From: Albuquerque New Mexico
Sounds good - that's what I did. I almost bolted up my old style RPM air-gap manifold onto my fast-burn vortecs (cause they said I could) and when I saw how poorly it aligned I decided to buy the vortec air-gap dual-plane manifold. Are these heads the "fast-burn" type. If so you may want to do some research on timing your engine cause due to the excellent efficiency of the cumbustion chamber design they do not require as much total timing.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
if you deck it. Iron/aluminum, with steam holes, .039 thick, 4.200 bore,
9.0cc volume. FPP-1014. www.competitionproducts.com
9.0cc volume. FPP-1014. www.competitionproducts.com