First time Aluminum block questions
#3159915
07/16/23 11:36 AM
07/16/23 11:36 AM
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Joined: Aug 2009
Posts: 304 Portland, Oregon
Digger73
OP
enthusiast
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OP
enthusiast
Joined: Aug 2009
Posts: 304
Portland, Oregon
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Hello all. I am building my first aluminum block big block engine. I have built iron block engines with aluminum heads in the past. I have always ran the iron blocks on the run stand up to operating temp. Then I allow the engine to cool over night and retorque the heads. What I don't know is this. Are there any considerations like this for the aluminum block? Like do I need to retorque the mains? Any first fire up tips pre and post would be greatly appreciated. Thank you, Digger73 (Mike)
Last edited by Digger73; 07/16/23 11:42 AM.
I live with fear everyday but, sometimes she lets me race!
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Re: First time Aluminum block questions
[Re: rickraw]
#3159940
07/16/23 01:25 PM
07/16/23 01:25 PM
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Joined: Feb 2005
Posts: 20,197 PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,197
PA.
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I haven’t retorqued a head in 47 years of racing and engine building
1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27
Livin and lovin life one day at a time
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Re: First time Aluminum block questions
[Re: pittsburghracer]
#3159947
07/16/23 01:49 PM
07/16/23 01:49 PM
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Joined: Sep 2003
Posts: 19,591 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,591
north of coder
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I haven’t retorqued a head in 47 years of racing and engine building what head gaskets are you using John ? MLS, factory shim, composition type, or all of the above ?
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Re: First time Aluminum block questions
[Re: moparx]
#3159951
07/16/23 01:57 PM
07/16/23 01:57 PM
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Joined: Feb 2005
Posts: 20,197 PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,197
PA.
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I haven’t retorqued a head in 47 years of racing and engine building what head gaskets are you using John ? MLS, factory shim, composition type, or all of the above ? 1008, 1009, 1039, I forget the marine gasket number, and big and small block Cometic Gaskets.
1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27
Livin and lovin life one day at a time
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Re: First time Aluminum block questions
[Re: dvw]
#3159958
07/16/23 02:16 PM
07/16/23 02:16 PM
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Joined: Feb 2005
Posts: 20,197 PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,197
PA.
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I retorque all my stuff during the build itself. Torque as normal. Then after setting 15 minutes or so crack each fastener loose. Then tighten to spec in one pull. You'll be amazed how much further the fastener rotates from the original posistion. Then send it. no need to fire it first. Dave Koffel taught me this trick. Doug Exactly but that’s not what he’s talking about. Retorque on an engine stand is common practice but not after firing up the engine. I usually do it the next morning
1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27
Livin and lovin life one day at a time
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Re: First time Aluminum block questions
[Re: pittsburghracer]
#3159970
07/16/23 02:35 PM
07/16/23 02:35 PM
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Joined: Mar 2003
Posts: 2,524 PA
moparacer
master
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master
Joined: Mar 2003
Posts: 2,524
PA
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I haven’t retorqued a head in 47 years of racing and engine building Same here.
67 Barracuda street/bracket car 11.27-119 68 Dart 502 BB 8.70s-152 414 cid SB Dragster 7.65-174
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Re: First time Aluminum block questions
[Re: pittsburghracer]
#3159985
07/16/23 04:03 PM
07/16/23 04:03 PM
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Joined: Aug 2003
Posts: 43,292 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,292
Bend,OR USA
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I haven’t retorqued a head in 47 years of racing and engine building I may have retorrque one or two after taking them off the engine dyno just to see if any moved or loosened on iron blocks, none did. Aluminum expands 8 times as much as regular cast iron. I do recheck the torque readings after doing both heads while assembling them, I use oil or ARP lube on all the threads and under the heads of the bolts and on the head bolt washers also, I use the lower factory torque specs. based on hearing Tom Hoover state at one of the old Mopar Drag seminars that the upper spec is for dry bolts, fasteners and the lower spec. is for oil, lube, on the threads
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: First time Aluminum block questions
[Re: Cab_Burge]
#3160000
07/16/23 05:08 PM
07/16/23 05:08 PM
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Joined: Aug 2009
Posts: 304 Portland, Oregon
Digger73
OP
enthusiast
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OP
enthusiast
Joined: Aug 2009
Posts: 304
Portland, Oregon
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Thank you all for your answers. This is just my first experience with an aluminum block and just wanted to see if there were differences I needed to know about. I have always backed the head fasteners off after torqueing the heads and hitting straight to the torque final value. When I started using aluminum heads I run the engine(s) on the run stand to temp. Then let the engine(s) cool over night and check the heads torque again. This all sets my mind at ease that I might be doing something right. Digger73 (Mike)
I live with fear everyday but, sometimes she lets me race!
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Re: First time Aluminum block questions
[Re: pittsburghracer]
#3160595
07/18/23 02:13 PM
07/18/23 02:13 PM
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Joined: Sep 2003
Posts: 19,591 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,591
north of coder
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I haven’t retorqued a head in 47 years of racing and engine building what head gaskets are you using John ? MLS, factory shim, composition type, or all of the above ? 1008, 1009, 1039, I forget the marine gasket number, and big and small block Cometic Gaskets. thank you sir.
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Re: First time Aluminum block questions
[Re: moparx]
#3160795
07/18/23 10:38 PM
07/18/23 10:38 PM
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Joined: Aug 2003
Posts: 4,696 On the parachute mount
n20mstr
master
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master
Joined: Aug 2003
Posts: 4,696
On the parachute mount
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the most important thing i would say , is get used to the way temp effects the valve lash. AMbient from 90 to 40 will tighten it a lot . Expect to see .010 or less at 70 because it will grow a lot at 180* engine temp. When building these engines in my basement in the winter , i set the lash at .008 in 50-60 degree temps. THe best thing is to get the engine uo to temp you will run it at, Check the lash on one int and exh, Let the engine cool overnight , then measure it again. Take not of the ambient temp and you have your "growth" factor .
....BAD A$$ STREET CAR.....
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