Pushrod guide plate problem...
Thread Starter
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Pushrod guide plate problem...
I have a set of 3/8" push rod guide plates on an engine that has 3/8" stock, not hardened (I assume) pushrods.
The push rods keep wearing out/through the guide plates. I just pulled the valve cover today to replace a cover gasket and was shoked to find that the rods are well on there way to wearing through a 2nd set of guides. (!) There is absolutely NO discernable wear to the pushrods at all. I don't get it.
Flat tapped cam, 113 heads, Summit Racing Guides, and NON self-aligning, stock rockers.
I thought thatthe need for hardened pushrods was b/c the rods would wear out...not the guide plates. Non-hardened rods will wear out guide plates?
The push rods keep wearing out/through the guide plates. I just pulled the valve cover today to replace a cover gasket and was shoked to find that the rods are well on there way to wearing through a 2nd set of guides. (!) There is absolutely NO discernable wear to the pushrods at all. I don't get it.
Flat tapped cam, 113 heads, Summit Racing Guides, and NON self-aligning, stock rockers.
I thought thatthe need for hardened pushrods was b/c the rods would wear out...not the guide plates. Non-hardened rods will wear out guide plates?
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
Pictures?
I've had ARP guide plates with Moroso hardened pushrods and nothing of that sort occuring.
Sounds like some serious alignment issues but hard to say anything without seeing it.
I've had ARP guide plates with Moroso hardened pushrods and nothing of that sort occuring.
Sounds like some serious alignment issues but hard to say anything without seeing it.
Thread Starter
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
10-4. I guess that is probably the logical thing to do. Here are pics, for anyone who is interested...
Cam is not 'high lift'. It is a comp, flat tappet. 210/218, and something like .450 lift. Springs are stock '90 vette springs.
I don't know what do do, other than throw another set of guides pushrods in it. I was under the impression that using non-hardened pushrods, w/guide plates would cause PUSH ROD wear. Not guide plate wear. I don't get it. Guide plates are "Engine Pro" brand.
Cam is not 'high lift'. It is a comp, flat tappet. 210/218, and something like .450 lift. Springs are stock '90 vette springs.
I don't know what do do, other than throw another set of guides pushrods in it. I was under the impression that using non-hardened pushrods, w/guide plates would cause PUSH ROD wear. Not guide plate wear. I don't get it. Guide plates are "Engine Pro" brand.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
1) Buy some good hardened guide plates.
2) What is the diameter of your rods? It doesn't look like there is much clearance between the rod and the plate. This might be contributing to your problem.
3) If your rods are not wearing and are still straight (roll them on a glass surface to test) then keep using them and just get the correct guide plates.
Check out this post...the pisture at the end. Look at the rod on the left side of the picture....looks litke much more clearance than what you have.
http://forums.corvetteforum.com/c4-t...-question.html
2) What is the diameter of your rods? It doesn't look like there is much clearance between the rod and the plate. This might be contributing to your problem.
3) If your rods are not wearing and are still straight (roll them on a glass surface to test) then keep using them and just get the correct guide plates.
Check out this post...the pisture at the end. Look at the rod on the left side of the picture....looks litke much more clearance than what you have.
http://forums.corvetteforum.com/c4-t...-question.html
Last edited by John A. Marker; Jun 22, 2010 at 07:58 PM.
Race Director
Joined: Jun 2009
Posts: 10,428
Likes: 9
From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
Perhaps Im missing something here. But why run the guide plates at all??
Stock rockers, flat tappet cam, not super excessive valvesprings.. why are the guide plates needed is it because of the heads? It would seem the stock rockers are fighting the plates while trying to find where they want to run.
honestly just curious.
Stock rockers, flat tappet cam, not super excessive valvesprings.. why are the guide plates needed is it because of the heads? It would seem the stock rockers are fighting the plates while trying to find where they want to run.
honestly just curious.
Last edited by Bondami; Jun 22, 2010 at 08:14 PM.
Race Director
Joined: Apr 2003
Posts: 17,698
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From: moraga ca
As mentioned, get some good quality guideplates and your problem will be solved. To answer why guideplates are needed, without guideplates, the hole in the head that the pushrod goes through provides no lateral stability for the pushrod. Without guideplates or self aligning rocker arms, the pushrods would push the rockers at an angle and the rockers would fall off the tip of the valve which would result in a "kaboom" type noise that would require $$$ to repair.
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Thread Starter
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
1) Buy some good hardened guide plates.
2) What is the diameter of your rods? It doesn't look like there is much clearance between the rod and the plate. This might be contributing to your problem.
3) If your rods are not wearing and are still straight (roll them on a glass surface to test) then keep using them and just get the correct guide plates.
Check out this post...the pisture at the end. Look at the rod on the left side of the picture....looks litke much more clearance than what you have.
http://forums.corvetteforum.com/c4-t...-question.html
2) What is the diameter of your rods? It doesn't look like there is much clearance between the rod and the plate. This might be contributing to your problem.
3) If your rods are not wearing and are still straight (roll them on a glass surface to test) then keep using them and just get the correct guide plates.
Check out this post...the pisture at the end. Look at the rod on the left side of the picture....looks litke much more clearance than what you have.
http://forums.corvetteforum.com/c4-t...-question.html
Thanks for reading and looking.
Last edited by Tom400CFI; Jun 23, 2010 at 12:23 PM.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
I am assuming that the 5/18 is a typo. So you are putting a 5/16 rod into a guide plate manufactured for 5/16" rods. I just checked out Jeg's and that is how they advertise the plates. So I would have to guess that there is clearance (however small) between the plate and the rods.
I have to believe that the plates you have were not processed properly during the hardening process or lower grade materials were used. You should not be wearing the side of the plates. Go with a name brand guide plate.
Here is a picture of a push rod in the guide plates on my AFR heads. You will note the broken screw in stud!! Damn...happened on the road. These plates came with the heads and have about 40,000 miles on them. I had to go to a shorter rod with my LPE 74211 roller cam and roller lifters. But the old rods showed no signs of wear.
These plates have Air Flow Research (AFR) stamped into the plate, although they may have been made by another company for them.
I have to believe that the plates you have were not processed properly during the hardening process or lower grade materials were used. You should not be wearing the side of the plates. Go with a name brand guide plate.
Here is a picture of a push rod in the guide plates on my AFR heads. You will note the broken screw in stud!! Damn...happened on the road. These plates came with the heads and have about 40,000 miles on them. I had to go to a shorter rod with my LPE 74211 roller cam and roller lifters. But the old rods showed no signs of wear.
These plates have Air Flow Research (AFR) stamped into the plate, although they may have been made by another company for them.
Race Director
Joined: Jun 2009
Posts: 10,428
Likes: 9
From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
As mentioned, get some good quality guideplates and your problem will be solved. To answer why guideplates are needed, without guideplates, the hole in the head that the pushrod goes through provides no lateral stability for the pushrod. Without guideplates or self aligning rocker arms, the pushrods would push the rockers at an angle and the rockers would fall off the tip of the valve which would result in a "kaboom" type noise that would require $$$ to repair.
(so thanks for answering what appeared to be a very dumb question with class
. )
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
Interesting and disappointed, I have Summit full roller rockers from when they were made by scorpion and they work great. I wouldn't have expected this quality from Summit brand parts.
Are the pushrods that are wearing the guide plates being pressed on at all by the heads? I know on some stock heads some clearancing is required and maybe that is why you have some guide plate wear going on...?
Are the pushrods that are wearing the guide plates being pressed on at all by the heads? I know on some stock heads some clearancing is required and maybe that is why you have some guide plate wear going on...?
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
I have a set of 3/8" push rod guide plates on an engine that has 3/8" stock, not hardened (I assume) pushrods.
The push rods keep wearing out/through the guide plates. I just pulled the valve cover today to replace a cover gasket and was shoked to find that the rods are well on there way to wearing through a 2nd set of guides. (!) There is absolutely NO discernable wear to the pushrods at all. I don't get it.
Flat tapped cam, 113 heads, Summit Racing Guides, and NON self-aligning, stock rockers.
I thought thatthe need for hardened pushrods was b/c the rods would wear out...not the guide plates. Non-hardened rods will wear out guide plates?
The push rods keep wearing out/through the guide plates. I just pulled the valve cover today to replace a cover gasket and was shoked to find that the rods are well on there way to wearing through a 2nd set of guides. (!) There is absolutely NO discernable wear to the pushrods at all. I don't get it.
Flat tapped cam, 113 heads, Summit Racing Guides, and NON self-aligning, stock rockers.
I thought thatthe need for hardened pushrods was b/c the rods would wear out...not the guide plates. Non-hardened rods will wear out guide plates?
Also, 3/8", not 5/16"?
Jake
Last edited by JAKE; Jun 24, 2010 at 01:55 PM.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
I would first check that there are no self-aligning tabs on the rockers and no "indents" worn into their tips.
If the rockers look ok, get a set of CC hardened push rods & guide plates.
If the rockers look ok, get a set of CC hardened push rods & guide plates.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
The stock lifter to pushrod & rocker to valve stem setup is messed up because the valve stem centerline is wider than the lifter's centerline. This is more noticeable with the higher ratio lifters that will tend to sit more off on the sides of some of the valve stems.
Use an adjustable guide plates to make the rockers line up with the valve stems: http://www.summitracing.com/parts/AFR-6104/?rtype=10
or
pickup some offset rockers: (example not the correct fit): http://www.summitracing.com/parts/CRO-72801X1-8/
or
Pick up a set of stamped self aligning rockers and call it a day. The ones below were from a stock '89:http://shop.advanceautoparts.com/web...1_900494043___
Use an adjustable guide plates to make the rockers line up with the valve stems: http://www.summitracing.com/parts/AFR-6104/?rtype=10
or
pickup some offset rockers: (example not the correct fit): http://www.summitracing.com/parts/CRO-72801X1-8/
or
Pick up a set of stamped self aligning rockers and call it a day. The ones below were from a stock '89:http://shop.advanceautoparts.com/web...1_900494043___
Thread Starter
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Interesting and disappointed, I have Summit full roller rockers from when they were made by scorpion and they work great. I wouldn't have expected this quality from Summit brand parts.
Are the pushrods that are wearing the guide plates being pressed on at all by the heads? I know on some stock heads some clearancing is required and maybe that is why you have some guide plate wear going on...?
Are the pushrods that are wearing the guide plates being pressed on at all by the heads? I know on some stock heads some clearancing is required and maybe that is why you have some guide plate wear going on...?
2. The heads don't touch the push rods. The rod-hole is ample size and then some, for each push rod.
Thread Starter
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Yeah. I should not need any of that w/my combo of very basic parts. I have a set of COMP guides on the way, and a set oc COMP hardened pushrods. I'll give that a whirl. If that doesn't work for some strange reason, I'll get some self aligning rockers.
Melting Slicks
Joined: Jan 2009
Posts: 3,482
Likes: 195
From: folsom california
I can't really see the style head you have from the posted pictures; but, I have a 350 out of an 86 or 87 CHP car; the heads themselves have very narrow slots where the push rods pass through; these are, in effect, the guide plates for that partcular engine; adding aftermarket guideplates to this style head could cause the type problem you're experiencing.
