to the best of my knowledge, 1.5

Bill

 

original #5 exhaust lifter

When the pushrod first left, I replaced all the roller lifters and all the pushrods. The pushrod that left was not bent - I could probably have reused it, but didn't. I matched the new pushrods to the old ones and they were the same length - same with the lifters. I did not replace the rockers. What I did find interesting is that when I pulled the original lifters, two of them had broken keepers. I found one keeper lying in the valley

 

1.5 is what the build sheet for the zz4 says and that is what I ordered and what I got matched to what was in the engine.

 

The method I settled on was to start with #1 and work my way down #3, #5 and #7. as soon as saw the #1 rocker move I would place my hand on the rocker and have my friend tick the starter. I could feel the rocker move with each tick of the starter. I could feel it go up and I could feel it go down. When I felt no movement from the tick of the starter, I assumed I was on the base circle. It was my thought that as long as there was no visible movement and I could not "feel" any movement, I was on the base circle. In looking at pictures of a cam, I could discern no distinction between any part of the base circle - as long as I hadn't started up or down the ramp. After setting all the valve on one side of the engine I went back and rotated the engine a number of times - making sure the lifters were pumped up. I then ticked the engine over for each cylinder , watching the rockers open and close - the same method I used to set them initially. When I felt they were on the base circle I jiggled the rocker arm and tried rotating the push rod.

Just want to help with this and not flame you for your hard work at this. But without being there to witness the method it is very difficult to say that is accurate or acceptable. It's mainly because no one else does it like that. Though there are plenty of ways to verify the lifter is on the base circle I have never known it to be done like that.

My shop manual for 1974 says to find TDC on #1 cylinders while both those valves are closed and therefore on "base circle". Now you need to be sure #1cyl vlvs are closed because #6 cylinders is also at TDC when the timing tab mark says 0. Next the manual states exh #3, exh #4, exh #8, intk #2, intk#5, intk #7 are all on base circle at this point and can be adjusted. To adj the rest of the vlvs you just have to rotate the motor 1 full turn back to reading 0 degrees on the timing tab which now puts #6 cylinders TDC but w/vlvs shut (on base circle).

Myself I like just to work the cylinders as pairs as I know at TDC and every 90 degrees of crank rotation there are 2 cylinders at TDC with only 1 cylinder having the valves closed and lifters on the base circle. I guess I've just gotten used to the sbc firing order and am convinced the cylinder ready to fire at TDC has to have both valves closed and both lifters have to be on the base circle.

Something that may help to make a few drawings of the cam lobes and crank rotation and you may be able to see how the crank turns twice for each time the cam & lobes turn. Then follow the crank throws to see how every 90 degrees there are 2 pistons at TDC.

Finally if you need a close look at the cam lopes you can buy USB cameras (endoscope) for your laptop with LED lights on the end. I found one eBay $15 and it works as a poor man's bore scope. I guess what I'm saying is we anxiously await to see/hear what you're cam lobes look like.

Hope this helps and good luck.

 

It seems reading LS1tech GM had a questionable lifter supplier for a few years. I have read of stock lifters failing on LS1tech so I am not shocked to hear about a lifter problem.

http://ls1tech.com/forums/generation...ad-lifter.html


http://ls1tech.com/forums/generation...rior-ls7s.html
see post 29 in the above link.

I believe LS non link bar lifters work in a roller SBC block but I would verify with a good shop or manufacturer.
http://ls1tech.com/forums/small-bloc...gen-i-sbc.html
http://ls1tech.com/forums/lt1-lt4-mo...t1-lifter.html

A good discussion on LS lifters:
http://ls1tech.com/forums/generation...s-welcome.html

I would also call Straub as he is a Morel distributor (most vendors get their Morel lifters from Straub) and a long time SBC/BBC engine builder about setting up the valve train. If I had a ZZ4 needing a cam, the LT4 hotcam is a nice upgrade with OEM reliability. http://www.straubtechnologies.com/

 

I gotta be stupid..How does valve adjustment affect wiping a cam or a lifter or anything else?....You can adjust them three way...the RIGHT amount of preload, TOO MUCH preload and a valve will not close and the engine will skip, TOO LITTLE preload and it will tick like a SOB. None of these translate into a mechanical failure in my mind. Teach me some more...


And again, what am I missing ... are those pictures of the lifters from THIS engine currently? If so, why has not the cam been checked NOW? Either by looking at it or simply putting a dial indicator to ascertain travel?

 

I gotta be stupid..How does valve adjustment affect wiping a cam or a lifter or anything else?....You can adjust them three way...the RIGHT amount of preload, TOO MUCH preload and a valve will not close and the engine will skip, TOO LITTLE preload and it will tick like a SOB. None of these translate into a mechanical failure in my mind. Teach me some more...

Easy tiger, I'm a amateur here just like you and don't have a Spintron Valve Train Analyzer to prove every detail. But let's try and look at to loose first. If pre-load was set while lifter was on a ramp of the cam lobe then very possible slop can occur between the p-rod and lifter/rocker arm and transferred to the valve stem tip. If you can't see how that could hurt metal parts at say 5,000rpm then I'm out here.
Next over tightening the preload collapses and bottoms out the little piston inside the lifter which the starts to hold the valve open. For intake valve that allows exhaust gas back up the intake manifold or for exhaust valve blows mixture out into the exhaust manifold. But worse case the valve is opened so far that when the cam lobe approaches peak the spring retainer hits the valve seal/guide boss.

Now trying to research the cause of this over the Internet is kinda fruitless. Better to just find all the damage and repair. Hey I've wiped lobes before and sometimes learning the hard way is more effective.

Hope this helps.

 

Cardo0


My nickname is MR Easy Tiger....


I understand all you are saying but what I'm saying if a lifter is misadjusted either way, tight or loose, how in the world does the OP not hear it with his ears [loose] of feel it with his fanny [tight skip]?


Either way...how, within reason, does either adjustment break stuff? Of course I'm not saying 4 turns too tight or loose but how could you even mess it up that much?


Back in the old days, we put clips over the rocker arms and adjusted the valves while the car was RUNNING! [Tick stop and 1/2 a turn]


If I'm wrong...completely not too old to learn from those smarter than me...

 

Listening for the lifter click or tick is something I try to discourage for a new novice but I have to say it is proven method. I just don't trust my own ears enough let alone all the variables in the parts and their condition to recommend or use it. Actually I used to totally oppose setting pre-load by sound but the Chevy Power Manual describes it so I have forced myself to live with it and listen to those that use it. But I still can imagine multitudes of new enthusiasts with wiped lobes using that method and I have witnessed posts revealing that.

We have consider a new enthusiast really doesn't know what to expect or listen for. Once the engine is running the sound of a performance cam is now proof everything is okay though it may not. And now the situation may be the cam (or lifters) are bad enough to break more parts.

Will one more thing since you bought up 1/2 turn pre-load is I used to be a 1/2 turn or less pre-load but discovered that takes away some vlv lift compared to one full turn which is giving up some power. The argument for smaller preloads is it minimizes holding the valve open if you over rev your motor and float the valves. To me that's kinda like expecting failure. Well I use a rev limiter anyways so I'll take the power instead of security.

Hope this can make sense rather than nonsense.

Good night.

 

First, I would like to thank everyone who has given my problem some thought and has offered insights and suggestions. On the first occasion, the #5 exhaust valve's rocker arm came off its pushrod. This happened while the engine was idling. I replaced all pushrods and all lifters. I have revisited my posts here when I first asked for advice - the initial incidence happened in June of 2015. I drove the car the rest of the summer with no issue. At the start of this driving season I started chasing annoying exhaust leaks. After I had all of them fixed, I still had a ticking noise. I tracked this down to the #6 intake lifter. It had excessive lash. It was then that I decided I had an issue with the rocker nuts - as first suggested by tuxnharley last June 6, 2015. I bought ARP Locking rocker nuts. I installed them in August of this year. After I had adjusted the lash on all 16 valves I had no noises from the valve train and the engine had never felt stronger or quieter. Less than 300 miles later the #5 exhaust valve rocker stud shears off. I was idling at a stop light.
I have trouble believing that the cam lobe went flat and that was the cause of the initial rocker arm coming off the pushrod. The #5 rocker arm seem to have full range of motion when the engine was being turned over. I spent a great deal of time setting the lash this last time. I adjusted them. I would think if the lobe were worn to the point that it was the cause of the issue that the rocker would not have full range of motion.
What may or may not be broken at this point is not as important to me as is the initial cause of the rocker coming off of the pushrod in June of 2015. I keep coming back to an oil issue.
I intend to replace the rocker stud. Get a new rocker ball. Put a hole in an old valve cover I have over the #5 rocker and restart the engine and see if I have oil coming through the pushrod at a rate equal to the other rockers.

 

...or you can get some clips like I show in post #4

Bill

 

I bought a set of those plugs nearly 20 years ago when I had the original 327 rebuilt. I tossed them out a couple of months ago when I went through my garage, getting rid of stuff I hadn't used in years, in preparation to moving to a smaller place.

 

Oil volume may be an issue, but if oil is puddled in the corner drain depressions and you already replaced the lifters and pushrod, the problem likely is something else.

The rocker ball and rocker arm socket wear is a concern. The rocker arms are case hardened. Once the surface wear penetrates a few thousands, the rocker should be replaced. Wear in the rocker socket or ball can be due to oil starvation or poor startup lubrication. Wear through the hard surface, on startup or over time, and the bearing is shot.

GM may have had a batch of poorly hardened rocker arms, and it is far too late to identify a supplier problem and warranty claim.

New rocker arms, or upgraded roller trunion and tip arms, should be installed.

 

After I have replaced the #5 exhaust rocker stud and sourced a new rocker ball and rocker arm, I intend to observe the oil flow through # 5. I worry I have some casting/machining crap somewhere in the oil passage that supplies the #5.

If, however, the oil volume looks good, I will replace all the lifters and install roller tip rockers.

I intend to take all my broken parts of the #5 and the rocker and rocker ball from #1 (which looks ok to me) to a machinist I know and get his opinion

 

Oil feed starts from the lifter oil galleries, to the lifters. The oil port at each lifter bore is the only isolated oil passage that you have not replaced.

You replaced the other oil control and channeling parts: the lifters and pushrods. I assume all pushrods were blown out to clean, with a confirmation see through inspection.

If block casting flash or debris is a concern borrow a oil pump priming tool and pump oil to inspect flow to the lifter bore with only the suspect lifter removed, and a lifter on the opposite bank removed. Watch and gage the oil flow (eyeball flow volume). Compare the flow to a lifter bore on the opposite bank and oil gallery. If the flow is the same, the problem is not an oil passage in the block.

If there is a flow difference, rod and brush the oil passage feeding the suspect lifter bore. Look for debris and feel for rough flash catching a pipe cleaner. Do a second oil prime flow test and look for improvement.

Check valve lift at the suspect cylinder with a vernier caliper or dial indicator at the retainer. Measure closed and open height. Intake lift should be the same, same for exhaust lift, for all cylinders. A difference will confirm a worn cam lobe.

Do this before buttoning up the lifter valley. Rule out a problem you will cover up.

My concern is if one rocker arm has wear, the others have hidden wear. If you want to test oil flow at the #5 rocker, ok, but replace all the rocker arms.

 

In post #22 you picture a lifter. The recessed area in the center of the lifter body is where the lifter picks up its oil. If that recessed area is not exposed to your oil galley the lifter will starve for oil. It would also not adjust. If it is adjusting it has oil flow. You can install the lifter and measure its travel and determine if the recessed area is exposed to the lifter galley for oil feed.

 

You raised an interesting point about the push rods. I know I bought some assembly lube when I installed the new lifters and push rods. It is possible I plugged something at some point with the assembly lube.

Still, I think there is some commonality between the #5 exhaust valve rocker coming off its pushrod first (before I had any involvement) and then after all the lifters and all the pushrods were replaced (where I was totally responsible), the #5 exhaust valve rocker stud snaps off and the #5 rocker ball is worn away.

I like your idea for comparing one oil galley to a different one on the other side. It will make for a nice winter project

 

Verify you don't have any coil bind on the #5 cylinder adding extra load to your valve train. Also verify the valve is operating freely and not sticking in the valve guide again adding load to the valve train. Something is goofy or your #5 would be working like the other 7 cylinders. The only way I know to verify the valve in a good engine without pulling the head would be to use the rope trick. Insert enough rope into the spark plug hole so when you rotate the piston up by hand the rope keeps your valve from falling out as you pull the valve keepers off. Then you could inspect the valve movement and inspect the valve spring and make sure it matches the specs on your engine.
This trick in your case is better than using air in the cylinder because you would be able to feel the valve movement without pressure being on it if you lower the piston just a little bit and then raise the piston when you are ready to re install the valve spring.
Something is off or it would still be on the road. Just a couple ideas and I hope they are not off base.

 

I am wondering if maybe the #5 rocker stud had been damaged some how - bent, fatigued, cracked, etc - when the rocker and push rod came loose the first time, and then failed subsequently after all of the other work.

If I am reading and understanding all of this correctly (?) all of the damage has been confined to the #5 rocker area, correct?

Are we just chasing a phantom here which all dates back to the original problem?

IF (big if) I am understanding all of this correctly and if it were my engine, I'd be mighty tempted to just replace that #5 stud, rocker, lifter, push rod etc, put it all back together, and run it for a while.

Easy for me to say 'tho - I know!

 

Don't know if you have solved your problem yet but I thought I would pass on this information from Comp cams:

"Rocker arm clearance must be checked at several places. It is very common with higher lift cams to have the rocker arm contact the rocker stud when the valve is in the full open position. Be certain to check this, as lack of proper clearance will cause broken studs, broken pushrods or worn-out camshaft."

"The clearance between the rocker arm and the valve spring retainer must also be checked. This problem will be more pronounced when the valve is closed. The retainer is most likely to contact the underside of the rocker arm right in the center. Be sure to maintain at least 0.030" clearance at this point. Pushrod clearance must also be checked, especially when using higher ratio rocker arms. The pushrod seat in the rocker is moved toward the stud in this case, so it must be checked at several different lift points for contact with the cylinder head or guide plate."

How did obtain this pearl of knowledge? From the school of hard knocks! As they say 'Been there, done that and got the T-shirt. But I broke about 5 or 6 pushrods before I read the instructions.

Good luck with your problem.

CJ