#1  
Old 08-17-2020, 01:54 PM
69hardtop 69hardtop is offline
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Default Valvetrain ID help

I need help identifying some of the components in my valvetrain. The background is I’m considering a cam swap, the car is a 69 GTO with the original 400/automatic/3:23 rear axle ratio. I’ve had the car over twenty years but I’ve never been happy with the way it runs. Engine was rebuilt by previous owner, he couldn’t remember much other than its thirty over with “a ram air cam”. ��
I’ve always thoughts it’s over-cammed, never will pull much more than 13” vacuum. The vacuum is steady, I have very good static compression and the car does run strong mid to higher rpms. However, no matter how much I tinker with my Cliff rebuilt carb, I can’t get it to idle very smooth and there’s no doubt I’m pouring unburned fuel out the exhaust.....I’m guessing a lot of overlap in the cam. While it sounds great at idle, it’ll burn your eyeballs out after awhile.
So, since cam is unknown, let’s start with more basic stuff. I have these nice looking roller rockers, again source/ratio unknown.....no manufacturer or ratio marked on them. Anyone know what these might be ? When I search this forum I see Harland Sharp that look about right, but I’m not positivel. Note that they’ve been clearanced on the underside to possibly clear the studs I’m guessing. They’re also at least 20-25 yrs old based on guessed engine rebuild date. Pushrod length is right at 9 1/16 ball-to-ball and lifters are 2 inch height.
I really need thoughts on this - since I don’t know the rockers/pushrods etc do I just buy all new ? I recognize cam/lifters get replaced together, but hate to also have to purchase new pushrods and rockers if not needed. Should I wait until I pull the current cam to see if it has any identification marks....or just trash can everything and buy all new
Thx in advance
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Last edited by 69hardtop; 08-17-2020 at 02:05 PM.
  #2  
Old 08-17-2020, 02:14 PM
69hardtop 69hardtop is offline
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Quote:
Originally Posted by 69hardtop View Post
I need help identifying some of the components in my valvetrain. The background is I’m considering a cam swap, the car is a 69 GTO with the original 400/automatic/3:23 rear axle ratio. I’ve had the car over twenty years but I’ve never been happy with the way it runs. Engine was rebuilt by previous owner, he couldn’t remember much other than its thirty over with “a ram air cam”. ��
I’ve always thoughts it’s over-cammed, never will pull much more than 13” vacuum. The vacuum is steady, I have very good static compression and the car does run strong mid to higher rpms. However, no matter how much I tinker with my Cliff rebuilt carb, I can’t get it to idle very smooth and there’s no doubt I’m pouring unburned fuel out the exhaust.....I’m guessing a lot of overlap in the cam. While it sounds great at idle, it’ll burn your eyeballs out after awhile.
So, since cam is unknown, let’s start with more basic stuff. I have these nice looking roller rockers, again source/ratio unknown.....no manufacturer or ratio marked on them. Anyone know what these might be ? When I search this forum I see Harland Sharp that look about right, but I’m not positivel. Note that they’ve been clearanced on the underside to possibly clear the studs I’m guessing. They’re also at least 20-25 yrs old based on guessed engine rebuild date. Pushrod length is right at 9 1/16 ball-to-ball and lifters are 2 inch height.
I really need thoughts on this - since I don’t know the rockers/pushrods etc do I just buy all new ? I recognize cam/lifters get replaced together, but hate to also have to purchase new pushrods and rockers if not needed. Should I wait until I pull the current cam to see if it has any identification marks....or just trash can everything and buy all new
Thx in advance
Updating, a fellow PYer sent me to the Harland Sharp website and pretty much confirmed they’re HS 1.5

  #3  
Old 08-17-2020, 04:00 PM
Formulas Formulas is offline
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Rocker body has a substantial rub on the stud
Guide plates good?
Weak valve springs? Possible floating

Look like bone stock pushrods

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  #4  
Old 08-17-2020, 07:01 PM
andy kelleman andy kelleman is offline
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What is your compression and your ignition timing vacuum advance or just mechanical

  #5  
Old 08-17-2020, 07:05 PM
andy kelleman andy kelleman is offline
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Iron heads?

  #6  
Old 08-17-2020, 07:15 PM
69hardtop 69hardtop is offline
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Quote:
Originally Posted by Formulas View Post
Rocker body has a substantial rub on the stud
Guide plates good?
Weak valve springs? Possible floating

Look like bone stock pushrods
Agree on pushrods (I compared to a stock set)
It looks like someone took a mini grinder to the underside of the rockers, they’re all like that. Guide plates and springs good

  #7  
Old 08-17-2020, 07:17 PM
69hardtop 69hardtop is offline
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Quote:
Originally Posted by andy kelleman View Post
Iron heads?
Stock 62 heads, no porting. Cranking compression (Warm) all in the 175-185 range. 12 initial timing, total about 36.

  #8  
Old 08-17-2020, 07:54 PM
Formulas Formulas is offline
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Cant imagine why anybody would need to take a rotary file to the inside of such a fine rocker
That's why I assumed it was wear

If your dissatisfied with the current camshaft just change it out and in doing so you can find out what you have now and go from there

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  #9  
Old 08-17-2020, 08:35 PM
tom s tom s is offline
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over the years I have seen those rockers ground like that to help get the geometry right.Seems like a crutch to me.Tom

  #10  
Old 08-17-2020, 10:38 PM
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Tim Corcoran Tim Corcoran is offline
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What's wrong with the rocker arms your currently running? After you have the new cam installed you will need to check the valve train geometry to determine the correct pushrod length. You may have a RAIV cam in there but no way to know for sure. Being your engine is a stock 69 400 your compression may be a little on the high side. If your cam has a lot of duration and that may allow it to run today's pump gas without detonation. If you put a smaller cam in there you may end up with too much dynamic compression and get some detonation that could cause damage to your engine.

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  #11  
Old 08-18-2020, 08:23 AM
69hardtop 69hardtop is offline
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Quote:
Originally Posted by Tim Corcoran View Post
What's wrong with the rocker arms your currently running? After you have the new cam installed you will need to check the valve train geometry to determine the correct pushrod length. You may have a RAIV cam in there but no way to know for sure. Being your engine is a stock 69 400 your compression may be a little on the high side. If your cam has a lot of duration and that may allow it to run today's pump gas without detonation. If you put a smaller cam in there you may end up with too much dynamic compression and get some detonation that could cause damage to your engine.
Thank you, pretty much one of my worries. If indeed my heads are original stock with 72cc I really have to think through what I want for a build

  #12  
Old 08-18-2020, 02:26 PM
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chiphead chiphead is offline
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You will need to identify the cam that is in there now. Either stamped numbers on the cam, or degree it to measure an intake and exhaust lobe. That way you know what you have in order to keep from going to small or too big when choosing the replacement. Cranking compression tells you very little by itself unless you know the cam profile.

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