Is this normal? (Pushrods/Guideplates/Rockers)
Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,961
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From: Sealy Texas
Cruise-In III Veteran
Is this normal? (Pushrods/Guideplates/Rockers)
See the linked video I made: (caution, it's a little over 2 megs!)
Rocker Movement
These are L98 Corvette late-model D-port heads that I purchased from a forum member a few years ago that I've finally gotten around to putting on my motor; those are the stock guideplates which have roughly 3/8" openings, and I have 5/16" pushrods on the way that are .100" longer (used a length checker to find that I needed longer pushrods.) The rockers are just stamped steel roller-tip 1.6:1 rockers..
As you can see, there's about 1/16" clearance between the guideplate and pushrod (this is just a stock pushrod that I used for testing purposes.)
Is this normal, or do I need guideplates with less tolerance so they don't move side-to-side so much? It seems like they'd rattle around in the guideplate but I'm not sure. :confused:
[Modified by Ken73, 8:16 PM 2/11/2003]
Rocker Movement
These are L98 Corvette late-model D-port heads that I purchased from a forum member a few years ago that I've finally gotten around to putting on my motor; those are the stock guideplates which have roughly 3/8" openings, and I have 5/16" pushrods on the way that are .100" longer (used a length checker to find that I needed longer pushrods.) The rockers are just stamped steel roller-tip 1.6:1 rockers..
As you can see, there's about 1/16" clearance between the guideplate and pushrod (this is just a stock pushrod that I used for testing purposes.)
Is this normal, or do I need guideplates with less tolerance so they don't move side-to-side so much? It seems like they'd rattle around in the guideplate but I'm not sure. :confused:
[Modified by Ken73, 8:16 PM 2/11/2003]
Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,961
Likes: 1
From: Sealy Texas
Cruise-In III Veteran
Re: Is this normal? (danno85)
Yup. I confirmed it in the "Chevrolet Power" book I have. Here's the quote:
So, I guess I'll be getting a new set of guide plates! :rolleyes:
The pushrod guideplates installed on H.O. cylinder heads are for self-aligning production rocker arms. These rail type rocker arms have guides that center the rocker tip on the valve stem; consequently the pushrod guideplates are not hardened. If you install any other type of rocker arm (including old-style production rockers without aligning guides,) hardened pushrod guideplates should be substituted
Burning Brakes
Joined: Nov 2001
Posts: 1,189
Likes: 2
From: Austin TX
Re: Is this normal? (Ken73)
That's interesting becaue I didn't know that any heads for self-aligning
rocker arms even had guide plates. That explains the wide gap though
because you don't want "two" alignment mechanisms. The guide plates
in this case must just be to hold the pushrods "close by" while the rocker
arms are off.
Dan
rocker arms even had guide plates. That explains the wide gap though
because you don't want "two" alignment mechanisms. The guide plates
in this case must just be to hold the pushrods "close by" while the rocker
arms are off.
Dan
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: Is this normal? (Ken73)
Besides being for 3/8ths inch push rods, those guide plates are for the "Bowtie" aluminum heads. Those heads have the exhaust valve guides .050 offset, further from the intake guides, than any production head. I haven't contacted Chevy, yet, but I need a set. The yahoo that built my engine made the same mistake, in reverse. Would you want to get rid of those? Good luck, and...
RACE ON!!!
RACE ON!!!
Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,961
Likes: 1
From: Sealy Texas
Cruise-In III Veteran
Re: Is this normal? (CFI-EFI)
Besides being for 3/8ths inch push rods, those guide plates are for the "Bowtie" aluminum heads. Those heads have the exhaust valve guides .050 offset, further from the intake guides, than any production head. I haven't contacted Chevy, yet, but I need a set. The yahoo that built my engine made the same mistake, in reverse. Would you want to get rid of those? Good luck, and...
RACE ON!!!
RACE ON!!!
If you want these guide plates, you're welcome to them - give me $5 + the cost of shipping (to make it worth my while.) I bought new Comp Cams ones last night for $17 at the local race shop......
Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,961
Likes: 1
From: Sealy Texas
Cruise-In III Veteran
Re: Is this normal? (gkull)
What kind of media player do i have to download to see your movie. I run across that type from time time.
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Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: Is this normal? (Ken73)
If you want these guide plates, you're welcome to them - give me $5 + the cost of shipping (to make it worth my while.) I bought new Comp Cams ones last night for $17 at the local race shop......
Your "Cheverolet Power" book must be later than mine. Mine is dated 1988. I have never heard of "hardened" or not, guide plates. Only that hardened push rods must be used with guide plates. And that non guide plate engines have non hardened push rods. My book makes the distinction between normal and Bowtie guide plates by the identifying "05" stamped into them. I will e-mail you tomorrow with my address and make arrangements to pay you. Thanks, and...
RACE ON!!!
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
Re: Is this normal? (danno85)
That's interesting becaue I didn't know that any heads for self-aligning
rocker arms even had guide plates. That explains the wide gap though
because you don't want "two" alignment mechanisms. The guide plates
in this case must just be to hold the pushrods "close by" while the rocker
arms are off.
Dan
rocker arms even had guide plates. That explains the wide gap though
because you don't want "two" alignment mechanisms. The guide plates
in this case must just be to hold the pushrods "close by" while the rocker
arms are off.
Dan
Is this normal, or do I need guideplates with less tolerance so they don't move side-to-side so much? It seems like they'd rattle around in the guideplate but I'm not sure. :confused:
Thread Starter
Melting Slicks
Joined: Aug 2000
Posts: 2,961
Likes: 1
From: Sealy Texas
Cruise-In III Veteran
Re: Is this normal? (h rocks)
Pushrod length checkers. Set the rocker on and get the roller tip set on the valve stem so it wipes across the entire face properly. I've got 1.6:1 stamped-steel roller tips.
Burning Brakes
Joined: Oct 2001
Posts: 1,146
Likes: 0
From: Milford NH
Re: Is this normal? (gkull)
What kind of media player do i have to download to see your movie. I run across that type from time time.
http://www.apple.com/quicktime/download/
Safety Car
Joined: Apr 1999
Posts: 4,623
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From: Ohio
Re: Is this normal? (Ken73)
Did you use a spring for checking hydraulic valve lifter rockers? The reason I ask is that I thought I needed them too once upon a time. Got BAD info from guys that only had solid lifter experience while checking them with the heads on the motor.