I was driving down the road and all of a sudden the car lost power and then it started ticking. I reduced speed, pulled over and popped the hood open and I could hear the ticking comming from the TPI base. I knew it wasn't a pushrod and I could hear it backfiring so I drove to work. I later cranked the engine and reved it up as suggested by a fellow worker to free up any stuck lifters and the ticking stopped. The assumption is that it was a stuck lifter.
These lifters are brand new but they get stuck like that? My oil pressure is 50psi at hwy speed and about 35psi at idle and I use Havoline 10w30 synthetic blend.
My question is would changing to a different oil prevent this, or what else can I do to keep this from happening again. Also are there other issues I need to look into?

-Ozzy

 

I'd look somewhere else first. Maybe at the EGR or exhaust. Maybe the rockers are not adjusted correctly. You did check the lifter bores for binding and burrs and any other problems right?

 

Not really, the engine is running fine now. I see what you are saying about the EGR, but once I revved the engine (to 4k) several times it just quit making the noise. I could actually feel the ticking on the accelerator pedal too so I knew it was firing back into the plenum.

 

Well, I spoke too soon. The damn thing is still acting up. I used a screwdriver to listen for the ticking and it is comming from the lifter valley. The engine feels like it is stumblimg when revved up and it idles crappy and shakes the whole car. I looked at the spark plug wires, listened for the injectors firing, recheck timing, all checks out good. I have no SES light comming on so there are no codes and therefore no EGR trouble (EGR w/diagnostic switch).
The engine started to act up a few miles down the road after doing a WOT run. I still think it's a bad lifter. Any suggestions before I pull the whole top end off?

-Ozzy

 

Did you pull the valve cover to make sure that its not just a loose rocker nut???

 

I had the same thing with my engine. It WAS one of the lifters. It would tick the loudest when I first started the car. After a few minutes it would get quiter or go away.

 

I haven't had time to do much with it since I work shifts (days & nights). I can't really get into the engine now because I am taking the car on Friday (16th) to the paint shop and it'll be there for a month. but when I get it back I need to tackle this first thing. I am planning on taking the whole intake off and check the lifters. Those are brand new Crane Cams OE hyd roller lifters I just put in a few months back. We'll find out when we get it all apart in a few weeks.

Mine now just ticks at idle hot or cold. It stops when revved but it feels like a rev limmiter is holding it back, although it will rev to red line but like it is running low on fuel or when spark plugs are arching. None of those are the problem though.

-Ozzy

 

Ahh...ok....

But I would still definately check the rocker arm nuts first before you go pulling the intake...

If the clicking was only when you first started the car I would say that the lifter just needs to pump up, but since it is all the time I think theres a good possibility that it could be a loose rocker arm nut. The same thing happened to me a few days after I did my cam swap in May. The car ran good for a little bit and then all of a sudden I could hear clicking and the car had NO power. I got home and pulled the valve cover. Sure enough one of the rocker arms was real loose so I re-lashed that valve. The same nut kept on coming loose on me so I used double nuts on that one rocker arm until I got some Crane Posi-Locks and haven't had a problem since.

 

I agree with 82camaroZ28. If it is happening all the time I would definitely pull the valve cover and check the rockers. It could still be a lifter that has collapsed.

 

Great guys, I got the same response from a mechanic friend here at work. I'll check that out.

-Ozzy

 

Who needs a mechanic when you got TGO? You had your answer in the first response.

 

You got a point there, thanks.

 

Well. I know it's been a while but finally got around to tearing the engine appart. It was in the paint shop for a month then it's been sitting on the driveway.
I started pulling things off and when I got the base off this is what I found:

http://home.earthlink.net/~tokrah/images/pushrod-1.jpg
http://home.earthlink.net/~tokrah/images/pushrod-2.jpg

I should have known better than to put the used pushrods back in. I haven't pulled the passenger side valve cover to see if it damaged the rocker (Alum. R.R.). We'll see tomorrow.

-Ozzy

 

Ouch...yeah, that'll do it...

 

Got the valve cover off and it just keeps getting worse.

http://home.earthlink.net/~tokrah/images/rocker-1.jpg
http://home.earthlink.net/~tokrah/images/rocker-2.jpg

Those are GMPP LT4 studs. The machine shop put them in and I wonder if they were overtorqued or if it was just metal failure. The Scorpion Rockers did not get messed up, that's a good thing.

-Ozzy

 

To me, it looks as though you have a coil bind issue or the pushrod slot is too small causing the pushrod to bind.

 

The spring seats were machined down for the new springs and were checked at the shop for bind and for clearance on the seals. The machinist used the cam specs to check all that stuff. The pushrod slots were enlarged too as you can see on the second picture.

 

I could see that the slots were enlarged but not if it was enough. Also if the pushrod length is off a little I would think could cause the slot size to be more critical.

 

There was enough clearance, I remember checking them when I was setting the lifter preload. But the pushrod lenght was a little off. I have ordered an adjustable pushrod lenght checker to get the right lenght before I order the new pushrods.

-Ozzy

 

Any comments on the apparent rust in the last linked photo? (Also shows up a little in the other photo from the top.)

Fractography really shouldn't be conducted long-distance, but if I had to make a guess, it would be that that stud was overtorqued. That is suggested by the fracture pattern (1st rule of fractography - don't put the broken pieces back together - that destroys evidence), and rust. If you could get a picture of the bottom of the stud, that might help.

If in fact overtorque is the cause, I'd suspect all of your rocker studs.

 

I don't really think it was rust, although in the picture it might seem that way I did not notice any when I inspected it. What you might see here is oil. Here is the side-by-side shot:



The surface look loke it was a clean break or snap, and nothing to indicate there was a crack. This is just my best guesstimation.
BTW, all studs are going to get replaced with new ARP ones.

-Ozzy

 

Well, as I said, long-distance diagnosis is always dangerous. But, still has a torsion look to it.

 

I totally missed that! It looks really bad on the bottom rocker shot.
Five7kid, what do you think about the pushrod broken on the bottom half? Thats what led me to suspect something was binding.

 

That's what I first thought, too. I expected to see self-aligning rockers and guide plates.

Most likely the pushrod was a victim - after the rocker got off kilter, the pushrod bound & snapped.

Another long-distance guess, though. I'd love to get those parts under a microscope.

 

Remember that the pushrod that got bent was the intake, but the stud that broke was the exhaust. Very odd. What could have done that to the pushrod if it wasn't binding? (not rulling out binding yet)
Also the stud part left in the head is no good anymore cause I had to drill it to get it out.

-Ozzy

 

Ah, I did miss that.

In that case, the broken exhaust rocker probably got in the way of the intake rocker that was still trying to do its job.