Bent pushrod, worn guideplates, pictures attached...Need help quick.
07-09-2006, 10:41 PM
#1
Bent pushrod, worn guideplates, pictures attached...Need help quick. Well, I fixed my 5.5K RPM stumble, it was the ICM.
To celebrate I went out for a very spirited country drive. I made several 1/4 mile runs and on the way home just driving a normal 55 MPH I hear a loud banging noise.
The rev limiter is set to 6000 and the push rods I am using are Melling hardened rods that I got at Autozone when I did my LT4 spring and RR install.
I instantly knew it was somthing in the valve train. I pulled the cover and one exhaust roller rocker is cocked at an angle. Clearly what is going on here is the roller tips are running off center due to excess GM guideplate wear. This one guidplate simply was so bad the roller tip fell of the valve. I can see at least two more areas of concern that appear to have excess wear. What would cause these guide plates to do this to happen?
The rocker DID NOT come loose, after removing the RR I saw damage on the arm next to the roller tip, the guide plate is severly worn away and the tip of the valve is slightly beveled on the edges. I drove maybe 2 miles under these conditions to get it home. I also used a magnetic retriever to as many metal shavings out of the head as possible.
Here are some pix:
I smoothed out the damage on the RR, the tip spins freely:
My questions:
1. What are the chances the exhaust valve is bent?
2. What are the chances the lifter is shot.
3. If the valve is NOT bent, can I still use the valve if the tip shows slight surface blemishes? What about lash caps?
4. What exactly causes this to happen, rapid decell at high speed, other?.
5. What are the most reliable push rods that will not do this.
I really want to avoid pulling heads.
Thanks
To celebrate I went out for a very spirited country drive. I made several 1/4 mile runs and on the way home just driving a normal 55 MPH I hear a loud banging noise.
The rev limiter is set to 6000 and the push rods I am using are Melling hardened rods that I got at Autozone when I did my LT4 spring and RR install.
I instantly knew it was somthing in the valve train. I pulled the cover and one exhaust roller rocker is cocked at an angle. Clearly what is going on here is the roller tips are running off center due to excess GM guideplate wear. This one guidplate simply was so bad the roller tip fell of the valve. I can see at least two more areas of concern that appear to have excess wear. What would cause these guide plates to do this to happen?
The rocker DID NOT come loose, after removing the RR I saw damage on the arm next to the roller tip, the guide plate is severly worn away and the tip of the valve is slightly beveled on the edges. I drove maybe 2 miles under these conditions to get it home. I also used a magnetic retriever to as many metal shavings out of the head as possible.
Here are some pix:
I smoothed out the damage on the RR, the tip spins freely:
My questions:
1. What are the chances the exhaust valve is bent?
2. What are the chances the lifter is shot.
3. If the valve is NOT bent, can I still use the valve if the tip shows slight surface blemishes? What about lash caps?
4. What exactly causes this to happen, rapid decell at high speed, other?.
5. What are the most reliable push rods that will not do this.
I really want to avoid pulling heads.
Thanks
Last edited by wrd1972; 07-10-2006 at 07:38 AM.
07-09-2006, 11:20 PM
#2
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[/QUOTE]
The rev limiter is set to 6000 and the push rods I am using are Melling hardened rods that I got at Autozone when I did my LT4 spring and RR install.
4. What exactly causes this to happen, rapid decell at high speed, other?.
[/QUOTE]
i think you answerd you'r own question.if you dont want you'r pushrods to bend or break buy some good one's like some comp hi-tec
The rev limiter is set to 6000 and the push rods I am using are Melling hardened rods that I got at Autozone when I did my LT4 spring and RR install.
4. What exactly causes this to happen, rapid decell at high speed, other?.
[/QUOTE]
i think you answerd you'r own question.if you dont want you'r pushrods to bend or break buy some good one's like some comp hi-tec
07-10-2006, 01:34 AM
#3
dont know the cause prolly a rocker too loose...to the valve if the valve spring locks catch its prolly ok...also your puchrod wasnt hardened so the valves prolly ok....the pushrods are cheap mayb 40 bux for hardened ones go get some any brand..if its a brand name youve heard of its prolly better to go ahead and get them..i have my stock 94 puchrods in mine since they are hardened from the factory i pull it to 6800...gm guideplates comp pro mag rr 7/16
07-10-2006, 12:40 PM
#4
You know im having this issue right now and i havent figured out what caused my guide plate to wear like yours did there not as bad though.Im running Trick Flow one piece hardend push rods and GM guidplates like what you have there im wondering if the GM guidplates are not as hard of a material as the pushrods.I had mine slightly start to wear right at 3000 mi on my new engine when i pulled the covers off to re-adjust the valves.When did you buy your guide plates???
07-10-2006, 01:24 PM
#5
Originally Posted by roughneck427
You know im having this issue right now and i havent figured out what caused my guide plate to wear like yours did there not as bad though.Im running Trick Flow one piece hardend push rods and GM guidplates like what you have there im wondering if the GM guidplates are not as hard of a material as the pushrods.I had mine slightly start to wear right at 3000 mi on my new engine when i pulled the covers off to re-adjust the valves.When did you buy your guide plates???
I did the RR install with plates 7 months ago. By and large 14 of the plates have a tad of wear, maybe .040" or so. One plate has a bit more than that and the one like in the photo is off the scale.
Upon talking to various tech support we are leaning toward a bad rocker arm.
07-10-2006, 03:30 PM
#6
I dunno im using Harland Sharp 1.65 ratio rockers arms i cant see why to different brand of Rockers on 2 different cars are bad i bought mine about 7 months ago also when i first put them on they just didnt look like hardend metal to me like you see black oxidized plates.Im sure in another few months mine would have looked like yours.
Well update these guide plates are NOT hardend
10111771 - Pushrod Guideplate For L98 Corvette Aluminum Head & ZZZ-ZZ4 Heads (Without Self Aligning rocker arms) 10111771
PACE Price Qty
$9.95
Detailed Description
This non-hardened guideplate is used with the Corvette aluminum cylinder head assembly P/N 10185086 and 5.7-liter HO engine assembly P/N 10185072. Use with self-aligning rocker arm P/N 10089648. These guideplates should not be used when using slotted tip rockers.
Why in the hell would the make a non-hardend guidplate one spot it says to use SA rockers and in the title it says not for use with SA
Well update these guide plates are NOT hardend
10111771 - Pushrod Guideplate For L98 Corvette Aluminum Head & ZZZ-ZZ4 Heads (Without Self Aligning rocker arms) 10111771
PACE Price Qty
$9.95
Detailed Description
This non-hardened guideplate is used with the Corvette aluminum cylinder head assembly P/N 10185086 and 5.7-liter HO engine assembly P/N 10185072. Use with self-aligning rocker arm P/N 10089648. These guideplates should not be used when using slotted tip rockers.
Why in the hell would the make a non-hardend guidplate one spot it says to use SA rockers and in the title it says not for use with SA
07-10-2006, 03:47 PM
#7
Well found the correct part #14011051 i was refered to the incorrect #10111771 off another board guess i should have looked it up myself heres the right one these are hardend to tell what you have just take a file to the guide plate the file should not beable to make a file mark on it grrrrr im pissed the hardend is supposed to only have a stamp of the # 5 in it well i found a picture of both and they both have the stamp
