Top end noise

[Jaysin]

First of all I want to say this site is killer. I just got a 95 Monte Z34 FOR FREE from one of my buddies. While he was driving it the water pump went out and it overheated. He just parked it and bought a new car. After 6-8 months of sitting he told me if I could fix it then I could have it. Well, I tow it home and replace the water pump. When I get it started a metallic noise comes from the cam carrier area. I can only explain it as a "clacking" sound. Expecting the worst I pull the UIM and cam carriers out. The cams and lifters (don't know what else to call them) look perfect. The ends of the valve stems and springs look good as well. There is oil pooled up on the head and cam carrier so I can only assume that it's getting oil up there. The only thing I found "wrong" was the PCV line (?) disconnected from the LIM. THat would account for the oil in the intake. So the big question is..... What else could be making that noise? Thanx for any info!

[pepsi_coke]

Fuel injectors?

[Jaysin]

Think louder. My injectors are dirty though. I'm thinking of asking if a Chevy restoration shop down the road can clean 'em up.

[DreX]

That doesnt sound good. If the car overheated 2 much the heads are in risk of failure, also the block. Its possible that a bearing wear out. Injectors dont make noise as far I know.

Change the oil and isnpect if there is any metal chunks. I also heard that if the engine has been sitting for a long period the lifters tend to get discharged and makes a peculiar noise. The will go with the time.

I use Mobil 1 Synt 5W30 and Fram X2 Filters, K&N are good 2.

Dre

[Jaysin]

I hope for the lifter bleed down option. If the heads are had I'm just gonna cry...

[Juglenaut]

After overheating and then let to sit for about 8months it is possible for a few springs to be impacted enough to a point where some of the valves float, also possible for the lifters to be impacted as well, this will cause excessive lash as they are not adjustible so replacement is the only option.

You could be hearing valve noise from an impacted spring, or valve lash. You may need to rebuild the heads.

By impacted I mean that the Lbs of a spring closed, mid, and full height seat may be so to speak impacted at the point where the spring was last moved to at the time of a overheat shut down.

[PlatinumZ34]

Injectors dont make noise as far I know.

You obviously don't drive an LQ1 ... If you have the original injectors as i did, they will be extremely loud, it sounds exactly like a worn cam.

Are you sure its the top end??? could be piston slap...

[Jaysin]

Thanx for all the input everyone! A few more questions though.... Is there a tell-tale sign of worn cams/ lifters and/or vlvs or do I need to pull and inspect everything. Like I said, the cam and lifters LOOK good. The heads remain on the engine as of now. WHat does a head rebuild kit cost?

[SappySE107]

Actually, injectors are gonna make noise in every motor. Ok, how bad was it overheated? Have you ran the engine for more thna 15 minutes since you fixed the water pump? I am hoping you put fresh fluids in it before you ran it. Depending on how long and bad it overheated, it could just be the lifters are bled down. Oil in the intake is from the PCV system...its a piece of shit from hell but its so critical that you can't just bypass it either. A catchcan is pretty much required on this motor to be 100% oil free on the intake side. Most likely its the oil control under the lower intake along with a bad PCV sucking in oil. I have the same issue and just add oil often at the moment.

Back to the noise. After doing a timing belt job, its normal for the engine to make some unusual noises for a good 5-10 minutes. Not always but it can and has happened to me quite a few times. Im gonna guess that if it were bearings, you would be knocking, not ticking. It would also be the bottom end, no bearings up top. Now if the cam carriers warped its gonna be interesting.

[Anonymous]

Im gonna guess that if it were bearings, you would be knocking, not ticking.

Actually it does sound more like a ticking. It is really loud, and kinda sounds like the lifters on a cold, but 500 times louder, and a bit deeper, but not much.

[SappySE107]

How long have you ran the motor?

[Anonymous]

With the bearings, I ran the car for about 15 minutes to get it to a friend's house, and about a half hour after this to get it back to my house. I took it to 4000rpm once, at about 80% throttle, to see if it felt normal. It did, but I didn't know what the noise was. I learned later it was the bearing. Other than that, I kept the rpm below 2,000rpm on the way home. THis driving shitholed my crankshaft. Wish I would have known at the time that is was a bearing, but oh well.

I don't know if you were asking time running on my new motor or old one. My new motor has about 9,000 FLAWLESS miles, and fast ones too

[SappySE107]

Oops, i thought you were the guy that started the thread. Overheating isn't going to automatically throw a bearing. Carl has overheated his 3 times now to almost 300 degrees, if not over. He even melted spark plugs. This is why I am thinking its just the lifters bled down from sitting, and the clattering is just the lifters being empty of oil and pumping up horribly.

[Jaysin]

Once I got the car running the longest it ran was 5 min... I didn't want to cause any internal damage so I shut it off. Thats when I decided to pull the engines top end apart. How long does it normally take for the lifters to pressurize? Anything special I can do to help it along?

I hope to have this car up and going within a month. Taxes will help alot. WHile I have it torn this far apart I am going to go ahead and do the timing belt, upper and lower intake manifold gaskets, plugs and wires, and clean it up under the hood. I also figured I would take the heads off and bring them in to do springs, guides, and seals. It probably needs cleaned due to a pretty nasty carbon build up in the intake/ exhaust ports. What does that normally cost?
Thanx for all the help again!!