TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC V8 Engine Repair and Modifications
  New Posts New Posts RSS Feed - Gen 3 v8 Lifter Bank Angle?
  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.

Gen 3 v8 Lifter Bank Angle?

 Post Reply Post Reply Page  <12
Author
Message
Ken_Parkman View Drop Down
AMC Addicted
AMC Addicted


Joined: Jun/04/2009
Location: Ontario
Status: Offline
Points: 1414
Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken_Parkman Quote  Post ReplyReply Direct Link To This Post Posted: Mar/08/2021 at 7:46am
Farna, sorry, but the lifter angle is important. A change in angle will change the cam timing events; the effect doubled in crankshaft degrees.
Back to Top
bobsterfl View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Jun/18/2009
Location: Orlando, Fl
Status: Offline
Points: 120
Post Options Post Options   Thanks (0) Thanks(0)   Quote bobsterfl Quote  Post ReplyReply Direct Link To This Post Posted: Mar/08/2021 at 11:58am

According to classicoldsmobile.com


"Oldsmobile engines from 1964 onward originally used a 45 degree cam bank angle (CBA). This angle is formed by the intersection between the cam centerline and perpendicular lifter centerline. By 1968, all Olds engines were using a 39 degree CBA. In the years between, 39 degrees was used mainly on blocks found in Toronado's, and 45 degrees was being used everywhere else. The CBA also affects the pushrod hole angle in the heads.

45 degree blocks used 45 degree heads and the same for 39 degree blocks and heads. If swapping heads between 45 and 39 degree blocks, you must watch for pushrod interference at the bottom of the head. To put 45 degree heads on a (455) 39 degree block, you have to bore the push rod holes to .562" i.d. Applies to "A" heads and some "B" heads.

Angle  Lifter  Notes
 45    0.842"  All 330's.
               Non-Toro D-block 425's, B-block 400? ['65 442].
 39    0.921"  E and G block 400's, '66-7 Toronado 425's. Some '66-7
               non-Toro blocks. Late 307's?
 39    0.842"  Most Olds engines 1968 and up. [exception: late 307's?]

There's 2 kinds of 425's: Toro and Non-Toro. There's a BIG SIGNIFICANT difference:

  • The Toro 425's use .921" lifters on a so-called '39 degree' bank angle.
  • The other 425's have the common .842" lifters on the rarer 45 degree angle, as do the 330 engines.
  • 68-up engines are ALMOST entirely .842" lifters on 39 degrees. The only difference this might make is:
  • .921 lifters are more expensive- like $100 vs. $35 for .842" units, per set.
  • 45 degree cams can be more difficult to find, but any REPUTABLE supplier can supply the grind you want in the configuration you need [Mondello, Dave Smith, etc.]"
Bobsterfl
1970 BBO Javelin
390 - Torqueflight
Back to Top
6PakBee View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Charter Member

Joined: Jul/01/2007
Location: North Dakota
Status: Offline
Points: 4304
Post Options Post Options   Thanks (0) Thanks(0)   Quote 6PakBee Quote  Post ReplyReply Direct Link To This Post Posted: Mar/08/2021 at 12:44pm
Originally posted by bobsterfl bobsterfl wrote:

According to classicoldsmobile.com


"Oldsmobile engines from 1964 onward originally used a 45 degree cam bank angle (CBA). This angle is formed by the intersection between the cam centerline and perpendicular lifter centerline. By 1968, all Olds engines were using a 39 degree CBA. In the years between, 39 degrees was used mainly on blocks found in Toronado's, and 45 degrees was being used everywhere else. The CBA also affects the pushrod hole angle in the heads.

45 degree blocks used 45 degree heads and the same for 39 degree blocks and heads. If swapping heads between 45 and 39 degree blocks, you must watch for pushrod interference at the bottom of the head. To put 45 degree heads on a (455) 39 degree block, you have to bore the push rod holes to .562" i.d. Applies to "A" heads and some "B" heads.

Angle  Lifter  Notes
 45    0.842"  All 330's.
               Non-Toro D-block 425's, B-block 400? ['65 442].
 39    0.921"  E and G block 400's, '66-7 Toronado 425's. Some '66-7
               non-Toro blocks. Late 307's?
 39    0.842"  Most Olds engines 1968 and up. [exception: late 307's?]

There's 2 kinds of 425's: Toro and Non-Toro. There's a BIG SIGNIFICANT difference:

  • The Toro 425's use .921" lifters on a so-called '39 degree' bank angle.
  • The other 425's have the common .842" lifters on the rarer 45 degree angle, as do the 330 engines.
  • 68-up engines are ALMOST entirely .842" lifters on 39 degrees. The only difference this might make is:
  • .921 lifters are more expensive- like $100 vs. $35 for .842" units, per set.
  • 45 degree cams can be more difficult to find, but any REPUTABLE supplier can supply the grind you want in the configuration you need [Mondello, Dave Smith, etc.]"


I'm glad I never got into Oldsmobile.  That just gave me a headache.
Roger Gazur
1969 'B' Scheme SC/Rambler
1970 RWB 4-spd Machine
1970 Sonic Silver auto AMX

All project cars.

"Shotgunning works great for pheasants, not so great for electrical problems"

Back to Top
farna View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Moderator Lost Dealership Project

Joined: Jul/08/2007
Location: South Carolina
Status: Offline
Points: 17626
Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Mar/08/2021 at 3:04pm
Ken_Parkman -- I understand that the angle makes a difference, but if everything is designed to work together at whatever the angle is then it shouldn't matter. Using the Olds example above, you can't use a cam made for a 39 degree lifter angle in a block made for a 45 degree lifter angle. That's obvious, you have to use a cam and rocker designed for the angle being used. Pushrods and valves are likely the same -- but of course have to be the correct length and size for the application, just no special design.
Frank Swygert
Back to Top
Trader View Drop Down
AMC Addicted
AMC Addicted


Joined: May/15/2018
Location: Ontario
Status: Offline
Points: 3149
Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Mar/09/2021 at 7:48am
farna, there is formula(s) for this. You may get the timing "peak event" at the correct location but with the angles being off, the slope of crankshaft stroke vs the camshaft "stroke"/slope will be slightly different. Your approaching slope of the camshaft would have to be different then the receding slope if you were to have an even event curve to match the crankshaft event.
Very much doubt those old engines would put that much work into this type of grind. It would take a computer programmed grinder to get this correct.
The further the angles are off the bigger the difference. If your running in the 10's of a second, likely this is were it would be seen. On a street engine, likely not even noticeable.
Back to Top
Steve_P View Drop Down
AMC Addicted
AMC Addicted
Avatar
Charter Member

Joined: Jun/28/2007
Status: Offline
Points: 2512
Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve_P Quote  Post ReplyReply Direct Link To This Post Posted: Mar/09/2021 at 10:54am
Originally posted by Hurst390 Hurst390 wrote:

Originally posted by Steve_P Steve_P wrote:

Does any 90* engine not have the lifter bores at 90*?
Cylinders are 90 degree to each other. 45 degree to crank centerline.

I thought it'd be understood that I meant that the lifter bores are 90* to each other, like the cylinders- without my typing it out.  

Really weird about the Mopar lifter bores not at 90*


Back to Top
 Post Reply Post Reply Page  <12
  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 0.062 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