TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC 6 Cylinder Engine Repair and Modifications
  New Posts New Posts RSS Feed - Shaft rocker head chamber volume
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

Shaft rocker head chamber volume

 Post Reply Post Reply
Author
Message
232jav3sp View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/09/2013
Location: Texas
Status: Offline
Points: 2451
Post Options Post Options   Thanks (0) Thanks(0)   Quote 232jav3sp Quote  Post ReplyReply Direct Link To This Post Topic: Shaft rocker head chamber volume
    Posted: Nov/28/2018 at 8:57pm
I cannot find this info in my '69, or '70, technical service manuals. The '74 tsm I have gives chamber volume, but for the later hear.
Back to Top
FSJunkie View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/09/2011
Location: Flagstaff, AZ
Status: Offline
Points: 4741
Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Nov/29/2018 at 12:49am
They switched from what they called the "quench head" combustion chamber to an open chamber in (I believe) 1972. They switched back to the original quench head design in 1977. The pistons were different for each chamber too. I'm not sure what the CC of each chamber is.
1955 Packard
1966 Marlin
1972 Wagoneer
1973 Ambassador
1977 Hornet
1982 Concord D/L
1984 Eagle Limited
Back to Top
Greyhounds_AMX View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/14/2009
Location: Kansas City
Status: Offline
Points: 1268
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greyhounds_AMX Quote  Post ReplyReply Direct Link To This Post Posted: Dec/04/2018 at 6:40pm
My old Tripod site is still up, I measured a number of heads back then. That should all be here:

1968 AMX 390 w/T5
Back to Top
FSJunkie View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/09/2011
Location: Flagstaff, AZ
Status: Offline
Points: 4741
Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Dec/08/2018 at 2:23am
I think the 1982 and up 258 head is different too. The compression ratio is higher and the spark plugs are different so that usually means a different head.
1955 Packard
1966 Marlin
1972 Wagoneer
1973 Ambassador
1977 Hornet
1982 Concord D/L
1984 Eagle Limited
Back to Top
232jav3sp View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/09/2013
Location: Texas
Status: Offline
Points: 2451
Post Options Post Options   Thanks (0) Thanks(0)   Quote 232jav3sp Quote  Post ReplyReply Direct Link To This Post Posted: Dec/08/2018 at 10:23am
I ask because I've been thinking about getting a little bit more out of the 232 in my 69 American. I have a rebuildable 258 head from a 70s engine. I also  need to upgrade the valve springs so it makes more sense to spring a head i can get more out of. It will get me into a 1.6 rocker to make the most of the cam, and the ports I believe, are slightly better configuration. From memory, the valve guide bosses do not protrude as far into the port. I have considered doing a turbo, but honestly don't want to get into the expense involved in adding one. I would rather rebuild this head, do some port clean up, remove the square edges from the guide bosses, asket match, and have it decked to bring compression up to 9 to 1. Decking will depend on what my engine's compresson is, currently. I never did measure anything when I replaced the cam a year-and-a-half ago. Having to calculate it based off of cranking compression. All of it might lead to a larger cam; which I am fine with.
Back to Top
Greyhounds_AMX View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/14/2009
Location: Kansas City
Status: Offline
Points: 1268
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greyhounds_AMX Quote  Post ReplyReply Direct Link To This Post Posted: Dec/09/2018 at 7:48pm
Frank will tell you what we'd both recommend instead...

But if you're dead set on running a 70s head, go with bridged pivot. Also there's a machining detail that was left out of the production heads that was part of the original flow bench development. I'll have to dig a bit to figure that out again, but I'd think anyone running a 70's head should add that extra machining to get the most out of it.
1968 AMX 390 w/T5
Back to Top
232jav3sp View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/09/2013
Location: Texas
Status: Offline
Points: 2451
Post Options Post Options   Thanks (0) Thanks(0)   Quote 232jav3sp Quote  Post ReplyReply Direct Link To This Post Posted: Dec/09/2018 at 9:48pm
Originally posted by Greyhounds_AMX Greyhounds_AMX wrote:

Frank will tell you what we'd both recommend instead...

But if you're dead set on running a 70s head, go with bridged pivot. Also there's a machining detail that was left out of the production heads that was part of the original flow bench development. I'll have to dig a bit to figure that out again, but I'd think anyone running a 70's head should add that extra machining to get the most out of it.


It's not that I haven't considered the 4.0 head... I just don't want to spend the money on one, nor do I want to redo my exhaust downpipe to mate to the 4.0 manifold. Then there's filling the casting holes with JB, when really I would prefer to have them welded shut, but, more money. I could always call around the local wrecking yards and get prices on them. Truth be told, I don't have the gumption to go to a "you pull it" and do it myself. Craigslist has been a huge swing and miss for AMC parts in East Texas.
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.656 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or