well, i have a clacking noise still. i believe its valvetrain. i hooked up the timing light to it. the clacking pulses at what appears to be the same speed as the timing light's flash. according to some manuals i read, that indicated a 90% chance of the problem being in the top end. well, i don't know but let me tell you what its not.... it's not the lfiters, not the pushrods.

i have gm guideplates and pro mag 1.6 NSA rockers.
the big hint i can give you is that the car clacks louder when cold and then quiets itself down when the motor warms up. it still clacks when warm, but much quieter. the motor has .005" piston to wall clearance with je pistons so it should not be slapping much at cold idle, and it better not be slapping at all during warm idle. the car drives fine and hauls *** (3/4 throttle a few times). can't hear the clacking at all when driving, or when under the hood when you give it gas. I'm stumped. plain stumped. what kind of clacking gets quieter when it warms up, but does not go away?
Under the stethescope, the noise sounds the same about everywhere you put it. whether it be the block, the valve cover, intake, oil pan, etc. it's a little more noisy from the passenger side valve cover than anything else, but still the same clacking. you can really hear it from under the car, but when you put the stehescope on the oil pan, it's not really any louder than anywhere else i put it. i really doubt it's the bottom end and hoping its not. i can't find the problem????
i could swear its the pushrods in the guideplates, but thats abnormally loud for pushrods hitting guideplates. the pushords do have light scuffs on them but who knows. ???

 

The last time I heard a clack (not to confused with a tick or a knock) was valves kissing the pistons. Did you check your piston to valve clearance with those 11.4:1 pistons?

 

no, but that shouldn't be an issue according to bret. the pistons are a -5cc relief. the block is zero decked and the heads are 56.6 CC (58 cc lt1's milled .010) the cam is right around .600. the car has been driven 80 miles already for short here and there test runs over the past few weeks. wouldn't that have hurt somethig by now?

 

I believe Rob is right, your problem is valve interference. But not neccesarily valves to pistons. Could be spring bind as well. It could and usually does show up later than the amount of running you did so far. You should measure valve travel that is required to touch the piston and while you're at it, check for coil bind or interference with the rocker.

And BTW, Pro Mags are extremely noisey.

Last thing, does your pistons have valve reliefs on one side of the piston? Where the pistons installed correctly?

 

i wouldn't think the coils bottoming out is possible. the springs are comp beehives bret bauer sold me with his cam as a kit. the pistons are -5cc relief. reliefs are only on one side, and they are installed correctly.
i know pro mags are noisy, but they shouldn't clack like that. now whats this deal with coil bind with the rocker arm? the coils themselves should be more than fine since bret sold me this package. he obviously knows what he was doing. They were all installed to height by a machine shop. how do i measure valve travel that is required for it to hit the piston? thanks for actual good info. please give more!

 

anybody know how i can test this?

 

I would think it be more like the rockers or perhaps the lifters/lifter bores are worn.(or something to that effect) If the valves were hitting the pistons by now they'ed be bent especailly since the car has been driven with the problem.

b.t.w.-is it possible to get a quiet valvetrain with .600 lift ?

 

You would bring the piston to TDC, put a light spring on the valve and measure the travel of the valve with a dial indicator.

 

i don't think i have a valve spring compressor capable of getting these off. the motor is only 2k miles of it's complete refreshening. it's not the lifters. I've tried two different sets. the lifters were all tight in the bore. no play whatsoever that i could find. the rockers i bought used. they seem to be good. ?? what about coil bind on the rocker? i could have sworn when we turned the motor over by hand the first time i heard something that sounded like binding. it was only two or three times, but we never found what the noise was. this was before the motor went in the car. so basically i need to do something before i wear out a spring or something worse??
I know the valvetrain is supposed to be noisy, but this is a clack. much louder than any normal noise. the sound is much like solid lifters. problem being i don't have solid lifters....

 

When I installed used rockers on my 94 Stang it had a clacking type noise , but it went away when I put new adjustable R/R's on. lol
As for what I meant about the lifters was that with oil on them for install you my not feel any play but with a load it changes how it rides in the bore.

 

I'd really like to focus on spring bind and things close to it. i did hear that sound i described when turning it over by hand. the cam was supposed to be .598 but it ended up being .603. i told the machine shop to clearance it for .598. is this going to matter? would simply switching to 1.5 rr's solve this?

 

What about the possibility of the rockers hitting the valve covers? Do you have clearanced stock valve covers with the Pro Mags?

You can visually check and measure for spring bind or even the possibility of the spring retainers hitting the valve seals.

 

all of my diagnosing attempts have been done with valve covers off, obviously leaving that out of the pitcture. I'd like to eliminate all stupid little things, like lifters, valve adjustment, installation, etc. the only thing i can think of right now is to try and buy new rockers. would that make any difference if the shop only clearanced the stuff for .598 and it's actually .603? the springs are new and setup for the cam. all installed to height. I'm assuming it was all done correctly by the machine shop. I'm just curious, how could the rocker arm effect the spring and how it works, other than pushing it down farther with a higher ratio rocker arm?? this is frustrating me. I've been waiting for parts all summer and now i've been trying to get rid of this tick for the past 3-4 weeks. very frustrating. thanks

 

Assuming things are "done correctly" and not actually checking them is not going to eliminate any possibilities. Make sure your rockers are not contacting the retainers.

 

It still sounds like a valve lash problem to me. If lash isn't right they will CLACK.....and when the motor warms up, lash tightens up a little as well, making the CLACK become a clack.