My newly ported-polished-tuned-1.6 lifter etc - engine began to make valve train noise this autumn, after about 3000 miles since I put it together.
I thought, must be a lifter or cam issue... Not fun...

Anyhow, I just came in from the garage, I have opened up the top and at a first glance, I cant see any damage besides normal wear ?!

One of the lifters however was very loose, just as if the adjustment screw have opened a bit.

As I see now the only thing to do is to go through each of the pushrods and lifters and take a closer look at them to rule out any wear, any idea what can have happened here ?

The lifter of the pushrod which was very loose was not compressed at all and the valve in closed position, engine pulled fine, it just made some noise, no metal found in oil etc..

Picture of the cam and lifters. No shocking news here. The adjustment must have come loose.
Is there any good way to prevent this ? Locknuts above the adjustment nuts ?

I'm betting the studs backed out of the head. Did you use permanent lock-tite on the rocker studs? I bought my second Fiero for a sweet deal because the previous owner thought he blew the motor after he did a full performance build. Pulled the valve covers and a few of the studs had backed out and the rockers had twisted off the valves completely.

Also, you should be using either a break in oil, or a oil with a high ZDDP content, like diesel oil. The EPA changed the regulations last year and motor oils no longer have the Zinc content they used to and people are wiping cam lobes out like crazy now. I switched to Shell Rotella for this reason.

I went out again and checked that the studs were ok, and they had not moved, but I will locktite them anyway when putting things together.'

I found the error:

On the bottom of the pushrod there was a small metal shrapnel, and when removing the rocker and rod I found that the
loose pushrod was "mushroomed" on the side that points to the rocker arm, look at the picz below:

What causes this ?

[This message has been edited by kjelle69 (edited 12-13-2009).]

If I had to guess, I'd say the valve springs are experiencing coil bind. Maybe the valves were adjusted too tight, or the valve springs can't handle the lift.

Do the valve springs have wear marks where the coils are rubbing against each other? Also, which camshaft and valve springs are you using?

Standard Camshaft, Comp Cams 1.6 roller rockers, comp cams pushrods, Fiero store Performance valve spring set.
Also all valves are new, the standards valves from Fiero store.

I have machined down the spring seats in the heads to comply for the extra lift.

Maybe safest to go to 1.52 roller rockers and a new set of pushrods.

I will check the springs for binding marks. I will also check all the other lifters / pushrods.

[This message has been edited by kjelle69 (edited 12-13-2009).]

Hi kjelle, I would like to offer my input here. First, when you go to order your new push rods, ask if they are available in Chrome Moly steel. Also, 1.6 rockers may be giving you a little too much lift. A trick I learned from my old friend Nunzi The Pontiac Expert from Brooklyn N.Y. is to take the nuts one at a time, place them on a flat steel surface and give them a rap on top with a hammer. This makes them tight on the top giving a better bite on the studs. Or, you can put in a set of poly-locks. These nuts have a allen screw on top which when tightened hold very tight to the stud. I had these on my 428 Pontiac Catalina wagon. They never loosened, even at 6,000 rpm. I must point out one observation I made while viewing your pics, you did not de-burr the block ? If you look around the lifter boss area and all along the lifter valley area, you see all that casting flash. That should have been ground off prior to reassembly, as this is a open invitation to a crack developing. By doing this you give the oil a much less restricted path back to the crankcase. One other thing here, if you do change the rockers, I would get the full roller rockers. This will decrease friction at the pivot point on the rocker and free up a little more horse power. The other gent told about ZDDP in the oil, he is 100% correct ! I stocked up on Shell Rotella 15W40 before they changed the formula. It is still a great oil. If you have roller lifters in your engine, then this is not a critical issue. If you have flat tappets, you need ZDDP ! These are only suggestions to you. I hope I have shed some light on your problem. Best of luck to you ! Ernie

Apparently you only had that issue on one pushrod? that is the impression I got. you may just have gotten a defective pushrod.
if that is the case, you will need to replace the whole set, as you can;t trust any of them. (also, a clogged pushrod will do that, no oil flow to the tip, and that likely also damaged your rocker. ALWAYS inspect your pushrods, wash them with alchohol or acetone and visually look thru them to be sure they are clear.)
just to be sure, if you use the stock rocker studs, with the fine thread you need to do the 1.5 turns on stock, and about 1.3 - 1.4 on the 1.6 ratio to get the proper lifter preload. if you installed the course thread sbc studs, the preload is .75 turns stock or .7 of a turn on a 1.6 ratio.

As a side note, I am not too thrilled with the wear on your cam. in that 1st pic the leftmost one with the shine looks good, the next 2 going left look like there is some galling on the surface, a properly broken in cam will shine like a mirror on the contact point. you can get some zinc oil additives you can add that will help even at this point, ot get the shell rotella turbo diesel oil, usually available in a marine supplier. (older marine diesels are not emissions restricted, and require a high zinc content)

I have used some Break in paste from the start and at each oil swap used the Mopar ZDDP additive Black plastic bottle, cant remember the name. Maybe I'll go for a set 1.52 roller rockers instead to lighten up the stress a bit. Also a new set of pushrods, is there any recommended place where I can get better quality pushrods ?

To be honest, the apparent difference in performance was not that big anyway, I dont think that 1.52 lifters will drain too much performance...

[This message has been edited by kjelle69 (edited 12-14-2009).]

I agree with the spirng bind suggestion from above
I wrecked a few cams before discovering: Sping Install Height
1.710" is the hieght for most Fiero 60dV6 aftermarket springs
my heads needed machining - not all do.
only way to know is to measure from the spring seat to the retainer bottom
not easy to do with the spring in the way tho....maybe get scrap cut to size, as a measuring stick

the rocker nut does NOT "back off". the cam is wrecked, and the lifter is now sitting lower, probably has bowl shaped wear on it. and a ledge, which makes it hard to remove.

No no, Pyrthian, I removed the lifter, it has no damage at all, neither does the cam lobe.
I have machined the heads to spec myself, with the correct measurments.
I even have a table of the result .

I am still thinking of changing back rockers to rollers 1.52 to be absolutely sure.


Before Machining:




After Machining of the Spring seats.

[This message has been edited by kjelle69 (edited 12-14-2009).]

wow - nice work!
the spring install height is often overlooked - and always my first thought when this happens - being I went thru it a few times.

When going through the ISH I can see that it actually is the Cyl 5 Exhaust that has the lowest tolerances, and this is the one that has the worn out pushrod...
You say 1.710" but in a earlier post you said:

"something to make sure of: spring install height. you need to measure from the base of the spring to the bottom of the retainer. make sure you have 1.70" or whatever that is in metric. if you have less than that - there is a chance the spring will bind when compressed. and - if it binds - it will wreck soemthing - most likely your camshaft."

So I machined them down to 1.70" or close. but the one failing seems to be the one that is 1.6988" Crazy how close to spec..... Do you think that the problem might have damaged the same lifter internally.

The ISH - Lift on that one is 0,5458" And the lift with 1.6 rockers will be: 0,437 That leave us with 0,1088 until binding. Ok, If the lifter was adjusted too tight ?! Still the dampening in the lifter should take up the binding force, it should not be bottomed out there...

I dont have the mojo to take apart the heads again and machine them down any further, I will get a set of 1.52 lifter, I am sure they will fit fine, and I hope that it does not affect the performance too much in a negative manner....

[This message has been edited by kjelle69 (edited 12-14-2009).]

the ideal answer is to check packaging of the springs - it should be labeled somewhere.
I have seen 1.7 & 1.71
not sure if this is a rounding/tolerance problem - but 105# @ 1.71 is what my crane cams springs were spec'd for, and I think these are the same springs sold by the Fiero Store.

I am a bit to close to spec it seems, what do you think of going back to 1.52 rockers that will surely clear all spec doubts...right ?

quote Originally posted by kjelle69: I am a bit to close to spec it seems, what do you think of going back to 1.52 rockers that will surely clear all spec doubts...right ?

hard to say - 0.01" - 0.02" is not alot. just cleaning the retainers/keepers can get you that, or lapping that valve.
but - putting the 1.6 on the intake valves, and the 1.52 on the exhaust has been done as well

Hey ! Good idea ! I will definitely do that ! :-D

Just came in from the garage again, removed all lifters, rods and rockers, everything looks just ok. Not even visible wear in the rocker that was connected to the faulty rod.

looking back at the pics
looks like the pushrod was not getting oil thru it, and it wore itself out rubbing un-lubricated against the rocker
perhaps it had a clog inside the pushrod or the lifter
it clearly not gonna flow oil looking at the last pic - like the ball at the end just collapsed on itself
and, I would expect that rocker received some damage/scoring as well.

and - also - curious about the prting job - looks like the "shark fin" was removed on 2 of the ports?

I must check to see if I find any clogging.
Shark fin is not totally grinded away, but its surface is smoothed and i made them somewhat sharper.

Like in this picture: