How do u tight'n guide plates?
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Burning Brakes
Joined: Oct 2000
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From: Palatine
How do u tight'n guide plates?
I have stock 624 heads. Is there supposed to be movement/play with the guide plates on the head studs ? I dont understand how they would be tightend down without using a seperate nut under the roller rocker.
Race Director
Joined: Sep 2000
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From: The Top of Utah
The 624 iron heads have the push rod guide cast in. You may have to elongate the slot to prevent the push rod from hitting on the end of the slot. Especially with a higher lift cam or higher ratio rockers.
The 624 heads have pressed in rocker studs. You don't (can't) use guide plates with pressed in studs. The heads have to be converted to screw in studs to use guide plates. If you have changed the cam, and especially the valve springs, or plan to rev the engine significantly higher, you will need screw in studs, anyhow. Increased stresses on the studs will cause them to pull out of the heads. And THAT will ruin your day.
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The 624 heads have pressed in rocker studs. You don't (can't) use guide plates with pressed in studs. The heads have to be converted to screw in studs to use guide plates. If you have changed the cam, and especially the valve springs, or plan to rev the engine significantly higher, you will need screw in studs, anyhow. Increased stresses on the studs will cause them to pull out of the heads. And THAT will ruin your day.
RACE ON!!!
Safety Car
Joined: Feb 1999
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From: Fountain Hills AZ
Originally Posted by CFI-EFI
The 624 iron heads have the push rod guide cast in. You may have to elongate the slot to prevent the push rod from hitting on the end of the slot. Especially with a higher lift cam or higher ratio rockers.
The 624 heads have pressed in rocker studs. You don't (can't) use guide plates with pressed in studs. The heads have to be converted to screw in studs to use guide plates. If you have changed the cam, and especially the valve springs, or plan to rev the engine significantly higher, you will need screw in studs, anyhow. Increased stresses on the studs will cause them to pull out of the heads. And THAT will ruin your day.
RACE ON!!!
The 624 heads have pressed in rocker studs. You don't (can't) use guide plates with pressed in studs. The heads have to be converted to screw in studs to use guide plates. If you have changed the cam, and especially the valve springs, or plan to rev the engine significantly higher, you will need screw in studs, anyhow. Increased stresses on the studs will cause them to pull out of the heads. And THAT will ruin your day.
RACE ON!!!
It sounds like you're trying to install guideplates on heads that haven't been modified for them. Besides tapping and drilling for screw in studs, the bosses need to be milled down to compensate for the thickness of the guideplates. To answer your original question, the guideplates are held in place by the hex head of the screw in studs.
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From: The Top of Utah
And as an additional note. If you convert to screw in studs and use guide plates, you need to grind away and totally eliminate the stock "cast in" push rod guides. Of the three possible ways of guiding the push rods, no more than ONE should be incorporated in a given engine.
Of course if you are not going to stiffer springs, a wilder cam, or higher rpms, you may be OK with the press in studs, in which case you don't need (or even want) the guide plates.
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Last edited by CFI-EFI; Sep 20, 2004 at 10:37 AM.
Thread Starter
Burning Brakes
Joined: Oct 2000
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From: Palatine
Thanks for the answers. My next Question:
I installed the 268H comp cam kit. Im also installing some older 1.5 roller rockers. Its a mild street setup. The pushrods I have are 5/16 erson performance, the warning sticker on the box says the rods are to be used with guide plates only.
? Is that just on there to gurantee better life out of any pushrod? Can I use them without guide plates? Or should I put my old pushers back in.
I installed the 268H comp cam kit. Im also installing some older 1.5 roller rockers. Its a mild street setup. The pushrods I have are 5/16 erson performance, the warning sticker on the box says the rods are to be used with guide plates only.
? Is that just on there to gurantee better life out of any pushrod? Can I use them without guide plates? Or should I put my old pushers back in.
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
I don't understand the warning. *I* don't see the problem of using them without guide plates. But rather than lead you astray, I suggest you check with Erson or a machine shop for a clarification. Guide plates NEED hardened push rods, I don't know why you can't go the other way.
RACE ON!!!
RACE ON!!!
