JeffC1500TBI

ok .. so I have 600km's on the new engine.. we go out tonight for a spin.. my buddy shows up with a gtech.. we tried a couple runs out in the country roads.. then we drive around for a while.. get home.. I pull in the garage.. and let it running so I could check the tranny fluid.we both get out and look at each other as we hear this tock tock tock tock sound.. pretty consistent and farly quick.. I grab a broom handle and stick it against the vavle cover on the ds .. everything sounds normal.. put it on the pass side and we could hear it pretty loud. it seemed loudest at the rear of the engine.. someone told me could be valves needing adjustment.. this is a fresh engine with brand new valves .. they are edelbrock performer 6085 heads.. is this normal for a fresh engine with 600k on it?? should I be calling the engine builder and having him readjust?? is it ok to drive it like this for a few days/???

thanks..

onebad82z

iTrader: (7)

This is NOT NORMAL..get to the engine builder as SOON as possible.Loose or misadjusted valves usually make a clatter noise,a "tock" as you describe it sounds too much like a lower end rod knock.Get your truck there as soon as possible and go easy on it the way there.There is also a good possibilty the cam could be wiped out,usually when a lobe or more goes flat,it can be mistaken for a rod knock,I have gone through both scenarios.Get it looked at soon,very soon.

Stroked-Z

Hi Jeff....man sorry to hear that.

You are pulling the engine. Hows the oil pressure? That is definetly a rod knock.

**** i really hate that **** man! Who built the motor?

SSC

Its not who built the engine, its who stuck thier foot in it before it was totally broken in.

1000 miles before you pound it!! This is why I wont build engines for anybody besides myself anymore.

Could be a rod, but probably just somthing in the valve train keep your fingers crossed.

JeffC1500TBI

with the old broom handle... we could hear it very clearly on the valve cover at the rear of the pass side.. if we put it on the head or anywhere else we couldn't hear it. as for break in.. I had it at the engine builders on the week end so he could check the engine out and he took it for a spin and pounded it pretty good and said it was good and solid..

JeffC1500TBI

ok I spoke to the engine guy.. he said a lifter might have umprimed itself? I dunno... so he said start it up and let it run and see if it comes back.. I started it this mornign and ran it for 10 mins and it didn't do it..

Vader

Jeff,

You can probably forget about the bearing theory, unless you've really got one spinning in there. Rod and main bearing noises seldom "go away" by themselves. It's very probable you have a valve train issue, but it's also good that you got the builder involved as soon as possible.

JeffC1500TBI

ok.. my buddy drove it down to the engine builder.. turns out it was the rocker arm slightly hitting the valve cover..

johnsjj2

I would have guessed a broken, or severly loose rocker arm. I had this happen, shortly after I got my engine running. I really thought it was a rod knock, but it seemed weird that I could feel the cylinder drop. The engine just went flat. It turns out I broke the rocker at the fulcrum.

JeffC1500TBI

no one is surprised at what the problem was!

anyone else ever had that happen?

SSC

I figured a loose rocker was a problem I dont see how it can be hitting the valve cover though. Ive loosend up a couple of rockers before, took 7k to do it.

BTW Sweet truck!:rockon:

Stroked-Z

I was at Luskville this year & saw that happen to an ealier Z28. When he came back from his run i thought OH SHIAT HE SPUN A ROD BEARING. Man it was knocking soo loud. Turns out a rocker studd pulled out a bit & in turn the rocker wasn't adjusted properly anymore. Thats my experience....

Only thing i dont understand is that you said it didnt do it when it was cold. And then it came back. To me this is the only thing that didnt make sense.

JeffC1500TBI

well the truth is it didn't start doing it t'ill we went out and gave her a couple gtech runs and then came back and pulled in the garage.. note: I'have been having a hard time heating it up in this weather.. I managed to get it up to about 140F that night.. preivous to that I couldn't get it above 110F

Vader

Oh!? The old "home-made stud girdle" trick, eh? It ain't too cool when the rocker covers are used as a fundamental part of a "rev-kit".

Are you sure a stud has not started to pull out, or are your's screwed studs? (The Edelbrock's come with them, don't they?)

I presumed it wasn't a bearing, and I'd rather be lucky than good any day...

86Z

iTrader: (4)

i just rebuilt my 305 myself i drove easy for about 600 miles, then i opened it up 7000 rpms, purrs like a kitten

JeffC1500TBI

apparently he's seen this before.. I'm note sure how the edelbrock heads are made but they are performer 6085 with elite valve covers.. being center bolt valve covers there's a little play to move the cover... since that night was probably the hotest I ever got the engine maybe the cover moved a little..