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Guideplate/Pushrod clearance?

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Old 05-27-2004, 06:29 PM
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Car: 87 Iroc Z
Engine: 383ci.
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Guideplate/Pushrod clearance?

My Pro Action heads had some initial clearance problems with the pushrod and side wall of the intake port on the head. Right now the pushrod is riding on the side of the guideplate.
I plan on removing the guideplates and releaving them a bit to allow for some clearance.

If a pushrod isn't suppose to make contact with the side of the guideplate, then why do we use guideplates. Is this contact normal. Do I need to alleviate some meat from the head to allow clearance so the pushrod doesn't ride along the intake port wall? And if so how much clearance is enough?
Old 05-27-2004, 06:47 PM
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No more than a few thousandths is required for guide plates. If you alter them to provide more room, you'll defeat the purpose of having them in the first place. It is usually possible to loosen the rocker studs and slightly reposition the guide plates if necessary. Of course, you'll need to reseal the rocker studs to prevent intake leakage.
Old 05-27-2004, 06:51 PM
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So, are guideplates really needed if they're not meant to actually make contact with the pushrods? The reason I bring this up is because my valvetrain kind of sounds like a ticking lifter, but it's all over and I have pushrods riding the guideplates and/or side walls of the intake ports on pretty much all cylinders.
Old 05-27-2004, 06:57 PM
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Actually, I think I just figured it out. I'm using 1.6 Scorpion full roller rockers. I believe these are non-self aligning rockers because there is no sides along the roller tip to keep the roller tip over the valve stem, thus I need the guideplates to keep the roller in proper alignment with the valve. And in order to accomplish this, there may always be some sort of contact between the pushrods and the guideplates as they work to keep the rocker in line.
Am I correct in my assumption?
Old 05-27-2004, 06:59 PM
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Correct. If the pushrod never EVER came into contact with the guideplate, that would defeat the purpose of the guideplate.
Old 05-27-2004, 08:44 PM
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Car: '89 GMC Pickup
Engine: 383 SBC Stealth Ram
Transmission: 700R4/VIG 3200
Originally posted by Cruz'N Bruz'R
The reason I bring this up is because my valvetrain kind of sounds like a ticking lifter, but it's all over and I have pushrods riding the guideplates and/or side walls of the intake ports on pretty much all cylinders.
This is copied from an old thread on here and doesn't answer your question about side clearance but. . .

When I changed to 1.6 rockers on my TFS23° heads I had to grind the slot in the guide plates deeper for the pushrods. First, there's quite a bit of slack in the holes of the guide plates under the rockers studs and they tend to **** a bit when you tighten the first rocker stud, second, there just weren't cut deep enough.

I wasn't sure that the problem was and had installed a full set of aluminum 1.6 Comp Cams rockers. Had a lot of noise even though it seemed to run normal. I changed lifters, bought shorter pushrods, installed 7/16 rocker studs and adjusted until I was sure that wouldn't help anymore. I'd adjust one, it would get quite, start on another, and the one I just finished would start ticking again. About went nuts!

Thought maybe it was the rockers so I used a set of 1.5/1.6 Pro Magnums from my buddy. Most of the noise was gone, (the 1.5's eliminated 8 of the potential problems of course) but one 1.6 rocker was persistent. That's when I noticed it wasn't quite oiling properly either and was polishing the pushrod just slightly. I could see this on the new expensive black pushrods but couldn't see it on the standard silver hardened pushrods. I removed the guide plate, cut the slot maybe .125" deeper, put it back on and the problem was solved.

So, maybe that's part of the "ticking" you hear?

HTH
Old 05-28-2004, 05:19 AM
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Well I'm gonna dismantle the valvetrain tonight and look into this problem. SMasterson, you have a good piont, I never even thought to check the front to back play, only the side to side.

Thanks
Old 05-28-2004, 08:50 PM
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Hope it helps because it sure was frustrating for me at the time.

I didn't like the alignment from side to side on mine either and actually clearanced #1 guideplate. I ended up buying a new one to replace it because even though it looked straighter all it did was make the roller on the rocker sit off to the side of the valve tip some. I came to realize they don't sit *exactly* straight.

I changed *everything* three times and ended up using a lot shorter pushrod than I would have thought I needed. I didn't believe the TFS website when it said 7.050 because it didn't list that for Pro Magnum rockers. My block is really zero decked with a .039 head gasket and after all was said and done, 1.46 dual springs, 1.6 Pro Magnum rockers, 7.050 TFS pushrods, Comp Cams hydraulic roller lifters (850-16) did it for me. Been in there for over a year and haven't been adjusted since. Turn 7k quite often and doesn't miss a lick. (Meaning, no valve float, no ticking, just does what it's suppose to do.)

These guys on here scared me away from aluminum rockers for high milage daily street use. The Harland Sharps I had originally showed stress after only a few thousand miles. I was a chunk of change, but I feel pretty secure with the CC Pro Magnums.

Rambling again... good luck and keep working on it until you KNOW it correct.

Last edited by SMasterson; 05-28-2004 at 08:52 PM.
Old 05-29-2004, 03:16 PM
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Well, when I pulled of the valve covers there were some pushrods so tight in between the guideplates, it just wasn't right.
I pulled off every guideplate and opened up the slots a bit. I have a total of about .015" to play with on each guideplate now. I put it all back together and the ticking is still there. I'm pretty sure it's an exhaust leak now. I'm gonna get some more gaskets and double them up. Never buy cheap flowtech headers. the flanges suck.
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