Guideplates
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Guideplates (Epyon127)
It looks like all the L98s with #113 heads (i.e. '88-'91) came with non-hardened guide plates.
If your engine has screw-in studs you can simply remove the studs and install guide plates, assuming the studs are threaded down far enough.
On an engine with pressed-in studs, like early L98s, it would be best to remove the heads to machine the stud holes for screw-in studs.
If your engine has screw-in studs you can simply remove the studs and install guide plates, assuming the studs are threaded down far enough.
On an engine with pressed-in studs, like early L98s, it would be best to remove the heads to machine the stud holes for screw-in studs.
Instructor
Joined: May 2003
Posts: 180
Likes: 0
From: Indiana
Re: Guideplates (Epyon127)
I just recently added Comp Cams hardened guideplates and pushrods to my 93 LT1 in order to use a set of non-self aligning roller rocker arms. The rocker studs were plenty long enough to support the thickness of the guideplates and there's no reason to remove the heads for this job.
The only thing I would add to what 65Z01 said is that it looks like the LT1's were built with a head gasket that extended into the lifter valley with "guide" holes for the pushrods. This seems to have replaced the non-hardened guideplates GM used as an assembly aid on L98's. Do not use the non-hardened (OEM) guideplates as a real guideplate, they weren't intended to be actual guideplates once the self aligning rockers are installed. Also, do not use guideplates at all if self aligning rockers are used as the two don't mix, but you knew that aready didn't you. :)
Al. :cheers: :seeya
The only thing I would add to what 65Z01 said is that it looks like the LT1's were built with a head gasket that extended into the lifter valley with "guide" holes for the pushrods. This seems to have replaced the non-hardened guideplates GM used as an assembly aid on L98's. Do not use the non-hardened (OEM) guideplates as a real guideplate, they weren't intended to be actual guideplates once the self aligning rockers are installed. Also, do not use guideplates at all if self aligning rockers are used as the two don't mix, but you knew that aready didn't you. :)
Al. :cheers: :seeya
Drifting
Joined: Jul 1999
Posts: 1,337
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From: Brighton, MI
Re: Guideplates (Al R)
OK, now I need to learn something. I am putting together an engine I didn't take apart. I installed a set of Comp Cams guide plates under the studs, mainly because they were in the box of parts and I assumed they were used. You say not to use them if you have self-aligning rockers. I am using crane roller 1.6 rockers. Are those "self-aligning", and I should therefore take the guideplates out? BTW, haven't put the heads on the motor yet.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Guideplates (Jeff Hickman)
The self-aligning rockers have a small ear on either side of the tip that rides on the valve end.
In the case of roller tips, the ears stick down on either side below the roller to keep the roller centered over the valve stem tip.
I suspect the Crane RRs are self-aligning, in which case you need to pull the studs and remove the guide plates to avoid binding problems. You might check the Crane web site to see if they even offer an non self-aligning RR.
You only want to use ONE alignment method for your rockers!
In the case of roller tips, the ears stick down on either side below the roller to keep the roller centered over the valve stem tip.
I suspect the Crane RRs are self-aligning, in which case you need to pull the studs and remove the guide plates to avoid binding problems. You might check the Crane web site to see if they even offer an non self-aligning RR.
You only want to use ONE alignment method for your rockers!
