View Full Version : Rocker arms wont stay adjusted???


f-body
09-15-2005, 02:02:00 PM
Ok Comp Cam 280 w/.480 lift hydraulic cam, 882 casting heads with 2.02/1.60 valves screw in studs and guide plates (heads came factory with this stuff), Competition producs valve springs, retainers and locks, brand new stock type rocker arm nuts from NAPA. I drive 7 miles to work and they are out of adjustment.
WHY? This is the same same combo I ran before I had a fresh valve job done, replaced valve springs, I adjusted valves using stock nuts and they clattered after driving for a day, now its worse. I drive to work ok at about 3500 plus rpms and I get here and the rockers are loose??
I know poly locks but then I need to get tall valve covers since I have the factory 74 Z28 aluminum valve covers with the little dripers inside and they do not have enough clearance for poly locks. And good tall aluminum valve covers are $100-200 or higher if you want the really nice GM ones. Any reason why? will poly locks solve the problem?

Joekool
09-15-2005, 03:41:00 PM
Did you torque the rocker studs before you assembled the head? If they is not a enough torque they can back off slightly which will cause the valve train to come out of adjustment. Most heads call for 45 to 65 ft/lbs for the rocker stud to head torque. If the studs are torqued and not backing out then you could either have a bad lifter(s) or chitty adjusting nuts. If the adjusting nuts are backing off you should beable to tell, if less threads are exsposed on the stud then when you adjusted the valvetrain then the nuts are backing themselves off. Mabey count the number of threads exposed on a few of the rocker studs and then drive the car. Pull the valve cover off and see if the same number of threads are still visable, if not then they are backing off.

Mwilson
09-15-2005, 07:20:00 PM
The cam isn't wearing down real fast is it?

Marv D
09-15-2005, 08:15:00 PM
You best pull the oil filter and cut it open. New rocker nuts, and if the studs were torqued,,, no other explaination but the cam is going away in a HURRY. Get to the bottom of it before you circulate any more trash through the motor.

night rider
09-16-2005, 02:49:00 AM
Did your new rocker stud nuts come with new grooved lock balls. (should be 16 nuts, and 16 "spacer" looking things with a flat side and a rounded side)

Also did you install the lock balls with the flat side up?

I seen this happen before, if the grooved lock balls wear then it can let the rocker nut back off.

If that ain't the prob, and your rocker studs are torqued down and not pulling the threads out of the head, then I hate to say it, but it sounds like 1 of the 2 bad lifters or cam going flat.

f-body
09-16-2005, 01:59:00 PM
Brand new nuts from NAPA, I only used the same grooved ball that ride on the rockers all nice and cleaned when assembled.
I Checked the screw in studs they were not and still are not loose.

Car runs fine even with the noisy rockers so I doubt its the cam going bad. I could drop the filter to find out just to be sure. Freds has Havoline filters for $1.99 I bough all they had just in case when I freshened up the bearings. Wouldn't it run bad if the cam was flat. A friend had a cam go bad in his 81 with a 229 V6 and it was popping back through the carb, still ran crappy but kept popping out the carb. He changed the cam and the engine went on for as long as I could remember.
From others experience what does it run like when the cam goes flat??
I will pull the filter and cut it open just to be sure.
The Chevrolet race valve covers with the raised " Chevrolet" name on them are over $200 ouch. I will look at the circle track store this weekend for an inexpensive alternative or maybe the swap meet in Arlington Ballpark next week September 23,24 and 25.

O'reileys had Mr. Gasket Ploy locks that will work on stock and roller rockers for $35.00 in stock. Then I am back to the valve cover problem again.

Mwilson
09-16-2005, 04:40:00 PM
It will run fine until the lobe is almost gone

CorkyE
09-16-2005, 10:00:00 PM
Are the rockers actually loose? Do you have Rhoads lifters or some other bleed down type? These will not sound noisy until the oil warms up and viscosity lowers. At that point they will clack like mechanical lifter. I actually like mine... Other than that you better do what Marv said - cut the filter and check. I don't think poly locks are the answer at this point, keep us informed.

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79 Z28 Bought new, honeymoon ride, same wife, same car.

merlin007
09-18-2005, 07:38:00 PM
i had a bbc run "fine" with the number one intake lobe completely gone!!!!!!!!!!!

check your oil/filter. its cheap, quick, and easy piece of mind.

f-body
09-20-2005, 04:00:00 AM
Ok here is how it went. I started this engine for about 15-20 minutes getting it to run and break in the new bearings. Changed the oil. Drive the car for a few days having to adust lifters every other day.
Now to where we are now

Ok removed oil filter and the oil in the filter had some material in it, nothing bad looks like stuff you would find after initial start up on a rebuild. I mean there was almost nothing there. I cut the filter open and almost nothing in the filter. I even strained the oil from the filter.
I also drained the oil from the pan and strained it, it had nothing in the oil.
So any little stuff that I found was caught in the filter.

Now adjust lifters with engine running using little oil clips on rocker arms to keep oil splash to a minumum. So I back off rockers until they click then retighten until they stop clicking and tighten 1/2 turn. I did each cylinder then turn the car off install second nut on rocker arm stud so I now have two nuts on each stud. I kept stoping the engine to keep from any more oil from getting on the headers. My last non running adjustment was way to tight.
So I get the valves adjusted install second set of nuts, reinstall valve covers let engine cool so I can clean all the extra oil off the engine and headers spray engine with cleaner, rinse engine.
Ok ready for a test drive. take car down the road all is well. Car feels stronger too. Drive a few miles, engine feels good. Drive some more pull over, wait for no cars, put tranny in low step on brake rev up to almost 3000 rpm(3500stall) let off brake car takes off nice just squats and goes. 1st to 2nd Shift at 5800 rpm, shift at 5500rpm into 3rd. Drive a little more pull in driveway, get out of car open hood listen to guess what??? rocker amrs clatering away AGAIN!!!!!!!!!AAAAAUUUUUUUUUUGGGGGGGGG!!!!!!!!WTF!!!!
Still don't think its the cam. Its running to well to be bad and there is no material in the oil to show cam wear. I am woundering if the engine is knocking from maybe a rod bearing. I guess the nuts could have backed off. Well it was almost midnight so i pulled the camaro back in the barn and will be driving my 89 Nissan pickup with 195,000 miles to work tomorrow because my car wont work right.
I will check the oil tomorrow to see if its bad and might pull the filter to see if the oil in the filter is bad and look for material.
I will check the rocker amrs first to see how loose they are and if the second set of nuts backed off. I might just fire it up with the valve covers off to see if its one or a few that are backing off.

I am thinking its a nice high speed run to see if I can blow the dam thing just for fun I am really sick of this. This will be the last time for this budget crap, next time its all new and all good stuff. Same for automatics I am going to a Richmond 5 or 6 speed from now on. Visa Loves me ALOT!!! Sorry really pissed because the car club is going to the track this weekend and because of all this and a few little things I probably wont be going. I guess I could take my truck just for fun.



[This message has been edited by f-body (edited September 20, 2005).]

Mwilson
09-20-2005, 10:17:00 AM
How big are your valve springs? I had a problem with rocker spring interference and It took me 6 mos. to figure it out but they were hitting with the valve closed just barely , I ended up ordering 100thous. longer pushrods and no more problems, if you think you have a rod knocking remove the plug wires one by one and if its a rod it should stop as soon as the plug loses fire on that cyclinder.

tomsti
09-20-2005, 12:04:00 PM
I don't think .480 lift should be too big for stock rockers. However by chance are they not being able to rock 100% back and forth and are hitting the studs? I would imagine you should start to see some wear on the inside of the slot where the stud goes through the rocker.

Mwilson
09-20-2005, 01:30:00 PM
Mine were hitting the retainers with a lunati .515 lift cam.

[This message has been edited by Mwilson (edited September 20, 2005).]

f-body
09-20-2005, 02:11:00 PM
Same cam, same heads, same engine, same rocker arms, new valve springs. Same combination I ran years ago when I had this engine in my Z28.

AJ_72
09-20-2005, 03:34:00 PM
Try getting new nuts and balls and try it again. (That just sounds bad.)

The balls wear into the rocker. If you don't match them to the original rocker they'll keep wearing with a different one.

And new nuts just because they're lock nuts and once you cycle them too many times (more than once) they're junk.

If anything, use the old nuts as a jam nut on the new ones. You'll have plenty of room for two nuts on one stud.

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350CID, Vortec 062 heads, Magnum 280, Performer Intake, Holley 650 DP, 3.42 rear w/ Auburn posi, 2600 Stall/TC
"Things are more like they are now than they ever were before."
Former U.S. President Dwight D. Eisenhower

rustbucket79
09-20-2005, 09:57:00 PM
If you have one (or more) rocker stud with more threads exposed than other ones, on the rocker that keeps having to be adjusted, you have a cam failing.

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
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tomsti
09-20-2005, 11:49:00 PM
I just took a look at one of the 280 hydraulic cams in the Comp Cams website. The gross lift for the cam I looked at was .520

http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=11-208-3

Does your cam card specifically give the lift you mentioned?

[This message has been edited by tomsti (edited September 20, 2005).]

GoldenOne7710
09-20-2005, 11:57:00 PM
<font face="Arial,Verdana" size="2">Originally posted by tomsti:
I just took a look at one of the 280 hydraulic cams in the Comp Cams website. The gross lift for the cam I looked at was .520

http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=11-208-3

Does your cam card specifically give the lift you mentioned?

[This message has been edited by tomsti (edited September 20, 2005).]</font>

The cam you looked up is for a big block chevy. I think we're dealing with a small block here.

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Objects In Mirror Are LOSING

[This message has been edited by GoldenOne7710 (edited September 20, 2005).]

tomsti
09-21-2005, 12:04:00 AM
Suppose so http://www.nastyz28.com/ubb/frown.gif well that would make sense...

f-body
09-21-2005, 01:14:00 AM
I kept all parts mated on the same cylinder and the rockers and the lock nuts and rocker balls all on the same studs. Labeled everything just to make sure I put it all back where it came from.

I will try pulling each plug wire one at a time to see if the rod is knocking.

I will also look for any interferance with the springs and rockers and with the rockers and studs.

f-body
09-21-2005, 01:15:00 AM
I kept all parts mated on the same cylinder and the rockers and the lock nuts and rocker balls all on the same studs. Labeled everything just to make sure I put it all back where it came from.

I will try pulling each plug wire one at a time to see if the rod is knocking.

I will also look for any interferance with the springs and rockers and with the rockers and studs.

f-body
09-22-2005, 12:13:00 AM
Well it aint the cam!!

Ever take a valve cover off? Some of the rocker arms should be in the open position and guess what drum......... roll please..........there not. All the rocker arms look like the valves are in the cosed position. Just a guess but is it possible they are bleeding down?
Lifters are $3.49 a Autozone. Felpro 1206 intake gaskets not available locally.
So the Camaro is down for a little while. Bad weather predicted this weekend anyway since Hurricane Rita will bring bad weather. At least I am east of Dallas so It should not be to bad.
When I do change them I will let you know how it goes and if it fixes the problem.

f-body
10-05-2005, 01:46:00 PM
Well it was the cam almost every high point of the lobe was worn!!!
SOB!!! Now I need to pick another cam, but my compression is to low for anything I like. Might just go with a stock 74Z28 cam also know as the GM 350hp cam .447 lift its sort of small. Just pissed at least I know what the problem was.

Mwilson
10-05-2005, 02:52:00 PM
Thats why I hate Hyd. lifters! I always run them about .001 loose myself because I'm afraid of wearing the cam out.

1981coupe400ci
10-08-2005, 04:28:00 PM
look at a lunati voodoo cam.. #60103LK or #60102LK...



[This message has been edited by 1981coupe400ci (edited October 08, 2005).]

79silverz28
03-30-2006, 01:18:19 AM
Why wouldn't you just buy the same cam and put it in again, this time maybe running the rockers a little looser?

rebski
03-30-2006, 09:10:58 AM
Did you follow correct assembly recommendation. Smear correct lube all over everything. Set lash at 0. Run engine above 1800rpm for 20mins for cam break in. Then set lash at 0 plus 1/2 turn. Screw in studs are alot harder then stock ones but will work with the stock interferance type nuts.


just some things to think about.:bowtie:

doechsle
03-30-2006, 10:10:23 AM
double check behind your machine shop on the valve spring pressures. If the bottom of your lifters are not dished out then its not a cam wear problem. All flat tappet cams pitt across the max lift area of the lobe, it from the core material loosing its softer materials but the carbon particles have worn down enough to have adaquit surface hardening. It just looks like it's failing when you see this. There are only 3 hyd lifter manf. right now, Standardyne, Hi-lift (Old Johnson) and Delphi. The delphi looks like it has a washer made to the bottom of it and is a very good lifter, the high lift is also a very good lifter. That's all the good I have to say about the 3 lifter companies.

ZS10
03-30-2006, 04:29:47 PM
Why wouldn't you just buy the same cam and put it in again, this time maybe running the rockers a little looser?
This happens to a person and they tend to shy away from Comp Cams after that. I wouldn't use one again either. I have one, only because it was replaced on warrenty.
You don't break in a cam by runnung the rockers loose, use weak springs for the first 20 min.