Isky adjustable pushrod guide plates
Thread Starter
Joined: Mar 2006
Posts: 4,668
Likes: 5
From: Central Kentucky
Isky adjustable pushrod guide plates Okay I got a set of New Isky adjustable guide plates dirt cheap (almost free) and I have some questions.
I currently have GMPP guide plates and if you look at the slots, there is a slight wear mark are on the two outer edges. The inner edges hardly even show a blemish. This kind of leads me to believe that the the guide plate slots need to be slightly further apart to more balance the contact the PR makes on both edges of the slot.
Measuring the Isky plate (never ground or modded) with the two halves slid tightly into each other, the Isky slots are .013" further apart than the slots on GMPP guide plate. Even looking at the rockers on the head, it appears that the slots should be slightly further apart.
With all that said, it seems like grinding or shortening the Isky guide plates is possibly not needed. If anything, they might work right out of the package and probably have better alignment than the GMPP guide plates.
What are you guys finding is the standard install procedure for the Isky guide plates? Anybod finding the need to grind them to shorten them? Is anybody having to lengthen them? They look good to me right out of the package fitted together tightly.
I currently have GMPP guide plates and if you look at the slots, there is a slight wear mark are on the two outer edges. The inner edges hardly even show a blemish. This kind of leads me to believe that the the guide plate slots need to be slightly further apart to more balance the contact the PR makes on both edges of the slot.
Measuring the Isky plate (never ground or modded) with the two halves slid tightly into each other, the Isky slots are .013" further apart than the slots on GMPP guide plate. Even looking at the rockers on the head, it appears that the slots should be slightly further apart.
With all that said, it seems like grinding or shortening the Isky guide plates is possibly not needed. If anything, they might work right out of the package and probably have better alignment than the GMPP guide plates.
What are you guys finding is the standard install procedure for the Isky guide plates? Anybod finding the need to grind them to shorten them? Is anybody having to lengthen them? They look good to me right out of the package fitted together tightly.
Are you sure you couldn't correct the alignment issues with the GM plates by loosening the rocker stud, recentering the plates, then tightening them down? You're supposed to do that anyway...
TECH Apprentice
Joined: Dec 2008
Posts: 372
Likes: 1
From: Kinston North Carolina
I have the isky adjustable ones on my LT1 and they fit as good as any ive seen. On other motors somtimes i would have to take them to the belt sander to shorten the legs a little or knotch them to clear the head bolts. Other than that i think they are the way to go if you want perfect alighnment.
You should be looking at where the roller tip makes contact on the valve stem. That is what is important. Not where the pushrod rubs the guide plate. That is not important. That's how it works.
Thread Starter
Joined: Mar 2006
Posts: 4,668
Likes: 5
From: Central Kentucky
Wow what a PITA to install these guide plates. Four hours later and only the driver side done I will completely admit the roller to valve alignment is a great deal better than what I had with the GMPP guide plates.
As many on the board have said, the GMPP guide plates are not really that great, I am now a believer. With the Isky's, the roller is very close to dead center on the valve +/- maybe 1/32" or so on maybe two rockers. I will guess that the rollers with the GMPP guide plates were off a generous 3/32" on four rockers. Yeah I had to use the mirror to get those back rockers just like Speed did.
It seemed like cylinders one and three wanted wider guide plate spacing than three and five. I really though that seemed wierd. I also had to grind the slots deeper because the the PR was making contact just like I did on the other guide plates.
After I had them all installed and I ran the motor, I had to go back in and dial in three rockers a bit better. For the other side of the motor, I will run the motor before I weld the plates to ensure the fit is spot on. That will definitely speed the process up.
The rockers just look much better overall and the rollers are contacting the valves much better than before.
As many on the board have said, the GMPP guide plates are not really that great, I am now a believer. With the Isky's, the roller is very close to dead center on the valve +/- maybe 1/32" or so on maybe two rockers. I will guess that the rollers with the GMPP guide plates were off a generous 3/32" on four rockers. Yeah I had to use the mirror to get those back rockers just like Speed did.
It seemed like cylinders one and three wanted wider guide plate spacing than three and five. I really though that seemed wierd. I also had to grind the slots deeper because the the PR was making contact just like I did on the other guide plates.
After I had them all installed and I ran the motor, I had to go back in and dial in three rockers a bit better. For the other side of the motor, I will run the motor before I weld the plates to ensure the fit is spot on. That will definitely speed the process up.
The rockers just look much better overall and the rollers are contacting the valves much better than before.
TECH Veteran
Joined: Apr 2008
Posts: 4,985
Likes: 112
wrd
I have the ISKY's. yes some had to be ground down. You want the RR dead nuts on the valve tip and these ISKY's let you do that. The GGPP ones I have found wear with hardened PR...which is what you need to run with hardened plates like the ISKY's
FWIW I like the Trick Flo .080 wall PR
I have the ISKY's. yes some had to be ground down. You want the RR dead nuts on the valve tip and these ISKY's let you do that. The GGPP ones I have found wear with hardened PR...which is what you need to run with hardened plates like the ISKY's
FWIW I like the Trick Flo .080 wall PR
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Thread Starter
Joined: Mar 2006
Posts: 4,668
Likes: 5
From: Central Kentucky
I am going to go back and dial those two back in later on to get them dead center. I am planning on reusing my existing Comp chromeoly PRs which I think are .080" too.
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