LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Pro mags hitting rocker studs

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Old 06-28-2012, 02:31 PM
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Default Pro mags hitting rocker studs

Ok so my car has maybe 5 mins of idle time on it so far, I took the valve covers off just too see how everything was going on I noticed most of the rockers are hitting the studs..

This is the setup
LE cam
Comp R lifters
Comp guide plates
ARP 7/16 stud
1.6 Pro mags
Zero decked block
Trickflow 21* heads

So anyhow, When I was assembling the motor I didn't have a PR checker tool when I got too the valve train, I grabed one of my stock ones just too see how that would fair and using a stock lifter I made solid and turning the motor all the way over, the swipe was just about dead center. So I went ahead and installed my comp 7.2 pushrods.

This is still the case, swipe is dead center on most valves, how ever on maybe a few valves it leans just a slight amount too the left.. But I still have the problem of some rockers grinding on the stud..

Any ideas?

Pro mags hitting rocker studs-yof7g.jpg
Old 06-28-2012, 02:38 PM
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If the way you are holding the rocker is how you removed it then your rockers are installed wrong. The round side of the trunion (the round shaft in the rocker body that contains the bearings) needs to be facing DOWN while the recess (pictured above) needs to be facing UP (that's how the poly lock engages).
Old 06-28-2012, 02:45 PM
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Like he said. The trunion is upside down...

The devil's in the details.
Old 06-28-2012, 02:47 PM
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Yes I know, They are all installed right.. I was just spinning the Trunion before I took the picture Witch is why it looks upside down.
Old 06-28-2012, 03:38 PM
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Huh.... You really do learn something new everyday...

If it helps at all I have no idea which way mine are facing, and it hasnt blown up yet.

Last edited by trilkb; 06-29-2012 at 02:12 PM.
Old 06-29-2012, 12:26 AM
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Any more input? really at a loss here..
Old 06-29-2012, 06:26 AM
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Can you take a pic of the studs on the heads?
Old 06-29-2012, 03:21 PM
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Pro mags hitting rocker studs-t5blj.jpg

Pro mags hitting rocker studs-1crxx.jpg

some pics of the swipe.

Pro mags hitting rocker studs-sjdku.jpg

Pro mags hitting rocker studs-lwhmf.jpg
Old 06-29-2012, 07:19 PM
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The only other thing I have seen cause this is pushrods being way too short, or bent.
Old 06-29-2012, 07:27 PM
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I got a PR tool, about a 7.4 PR is still pretty center on the valve tip, slightly lower.. heres a pic.. Should I go for some bigger pushrods?

sorry for all my shitty cellphone pics, hopefully you can see

Pro mags hitting rocker studs-hkwzb.jpg
Old 06-29-2012, 08:15 PM
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I can't see that well enough to give you advice. Here is what mine looked like two years when I was specing them for my setup. I have perfect 1/4 moons on each side of the tip. I think I ended up with 7.1" pushrods. Now, from what I see it doesn't look like you are getting much contact with the valve tip. I'm wondering if the valves are too short?

Last edited by Speedy; 06-29-2012 at 08:22 PM.
Old 06-29-2012, 09:22 PM
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I think its getting enough contact, Iv watched a valve go under full lift and its alot of lift like you would expect from my cam, there's no were on the side of the rocker tips or anything...
Old 06-29-2012, 09:28 PM
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Your geometry is incorrect. What is the part number on your pushrod guideplates? They are probably too thick.
Old 06-29-2012, 10:06 PM
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Originally Posted by jay7199
I think its getting enough contact, Iv watched a valve go under full lift and its alot of lift like you would expect from my cam, there's no were on the side of the rocker tips or anything...
No, but where the rocker is hitting might be stopping it from contacting the valve tip properly, either because of the stem or how low you have them on the stud. This shouldn't be too hard to figure out, hand turn the engine and watch what happens.
Old 06-29-2012, 11:31 PM
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I thought I used comp guide plates, I actually used the trickflow ones that came in box with my heads... I'll turn it over by hand again, but I have done before and didn't see anything wrong. Maybe I can take a video and it will help.
Old 06-30-2012, 12:13 AM
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I have AFR castings but if I remember right I was told not to use the guide plates. That the CC Mags are self aligning or something.....was 7 years ago when I built my LT1. Looks like it might be hitting the guild plate for the width of the wear pattern.
Old 06-30-2012, 06:50 AM
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The proMagnums come SA and non-SA.
Old 06-30-2012, 08:14 AM
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Originally Posted by Bigtoyz
I have AFR castings but if I remember right I was told not to use the guide plates. That the CC Mags are self aligning or something.....was 7 years ago when I built my LT1. Looks like it might be hitting the guild plate for the width of the wear pattern.
They are definitely self aligning. That's probably what his problem is.
Old 06-30-2012, 08:39 AM
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Look at the first picture the OP posted, that is NOT an SA rocker.

Now the pic Speedy posted is a SA rocker.
Old 06-30-2012, 08:52 AM
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Hope you get this figured out, I have a very similar build underway myself and would like to prevent this from happening. Good luck!


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