Schabelmj

i just finished a valve clearance adjustment on my 87 targa, and noticed an rpm- synched clicking on either cylinder #2 or #3. I rechecked intake clearances, and they are fine - clicking still present. Before I drain oil and check exhaust clearances, I'd like to see if this sounds familiar and is due to too tight or too loose clearances.

Car has 73k miles - and didn't experience valve guide wear out.

Thanks for the advice!

tyro

You've done a valve adjust before?

The feel is rather tight, I wouldn't describe it as a "light drag" at all.

rusnak

It's hard to know how the valves were adjusted from the description. If it's not really bad, then I think I'd drive it a while, maybe do a few tanks of Techron, then do another oil change and valve adjustment just to get some use out of the oil. You might get away with re-using the valve cover gaskets, or maybe just change the lower ones.

dshepp806

I wouldn't call it "light" either......

my first go produced clearances that were a bit loose,...subsequently providing the associated sounds...........

I'd recheck......

Doyle

Schabelmj

Ok - perhaps too loose. Yes, have done this before, and must have been lucky first time through. That sound is clearly new.

My approach was to open the adjustment, seat the shim tool, tighten the set screw until there was drag, and then tighten the nut to lock the set screw, while checking the shim movement to make sure the set screw didn't tighten. Apologies for mangling all of the names of the parts. I went with the guidance that it is better to be too loose than too tight, but this clicking indicates I was too liberal.


I'll open it back up and check back. Better safe than sorry.

Schabelmj

By the way, there are only 5 minutes on the oil and valve cover gaskets. Engine never got to temp - as it was obvious that it wasn't right. I'll reuse the gaskets, and try to recover the feesh oil. Lot's of other things done as well as part of this years annual maintanence (plugs, distro cap and rotor, filters, cv boots, replaced leaking tube and seals to oil pressure sending unit which meant muffler removal/polish/gaskets and a healthy underside clean throughout, etc.), but those items all check out.

dshepp806

Yes: better "loose than tight"!!!!!!!!!!!! Do give a good check of the arms, pads, etc... and such, to ensure all is mechanically sound.....

YES,..that "drag" is a learned thing,...I usually let my P-wrench do it, as he's done far more than I ever will and "knows" the "feel"....he's far better than I will ever be...STILL, something that can be learned by a lowly EE, such as myself...mechanical stuff can be humbling to me, at times....I want it damned near perfect, (at anything I do......) ...to quantify by "feel" is an inviting quantification.....I'd prefer to measure it somehow (accurately)....not feel,...not degrees of turn,....but GAP...........in anycase,...so goes the "feel"....you'll get it right....

BEST!

Doyle

dshepp806

Do check out the threads on changing out the pressure sending unit...if not done correctly, one can really make a mess........

Make sure she's dry up top (the standard 3 points up top)...

Doyle

dshepp806

Never mind (sorry),..I see you've "gone thru" the sending unit...

Schabelmj

Indeed - didn't touch the sending unit - just replaced the oil line (with the silly metal to rubber to metal interface that is prone to leaks...mine was) that feeds thr sending unit. That's a job...since it required removal of rusty muffler bolts.

whalebird

I would add that, when the covers are off and your checking the valve lash: check the position of the rocker shafts. Aside of a lenghty description, the search function here will reveal how this is done. It's easy really, and is easy to adjust if need be given some simple tools. This should be a part of every valve adjust.

ivangene

I'm pretty sure I will get mine closer next time, I bet I was a little on the loose side but its running fine and any noise is fairly uniform across the motor -

I do wonder in your description - why did you loosen each one up?

"My approach was to open the adjustment"

I found that several valves didnt need any adjustment and in fact they were "just right" which helped me develope "the feel" for the drag on the tool......which also prompted me to go back and re-do a couple that I had already done....I would also re-check every one after you are "done" before buttoning it up

(then let the kids put the rest together )

syzygy

you shouldn't have to drain the oil. Just use ramps or similar on the driver's side and allow time for any oil to drain out. You could also just drain the sump and leave the oil tank.

rusnak

WB, when time permits, I woulf appreciate your take on checking the rockers and adjusting them. I think this is worth knowing and benefitting from.

whalebird

Rus, I searched for a DIY on this with no good references. I may need to dig further. This is an easy check to perform and also to adjust. If one knows what to feel for, it can be done with your fingers and not even having to "look" at it.
The rocker should wobble back and forth around the area of the rocker shaft located in the middle of the shaft. Meaning the rocker should be centered on the shaft. The deception here is that the shaft "bosses" in the cam tower are thicker on one side of the rocker, but the thick boss is on the opposite end of the shaft on the other bank of cylinders. In short, the rocker shaft is rear-centric on one side of the engine, and forward centric on the other side albeit the shaft is divided evenly by the rocker itself. I don't recall which bank is which.
To relocate a shaft that has migrated in either direction is pretty simple. The worst part is getting the required allen wrench to fit the binder bolt. I have a garden variety allen wrench of the correct size(5mm, maybe 6) that I cut short at the bend to fit in the tight quarters of the binder bolt. The binder can be loosened and the rocker can be relocated forward or rearward then tightened with the said allen.
Snafu #1: the cylinder being observed must be at TDC before the rocker can be moved, otherwise the cam has it loaded with valve spring pressure. Thats one reason this is good practice during a valve adjust.
Snafu#2: the binder bolt is not loosening/tightening without turning the entire rocker shaft. For this, the binder has an allen wrench provision at it's opposite end for countering...requireing another short allen wrench.
My disclaimer: My info here is from memory and it's been a while since I've been inside one of these motors, thus my intentional lack of details. Details like when do you know the shaft is centered? IIRC, the end of the shaft should be flush with the exterior of the short/thin boss in the cam tower. Tool selection may be open for debate, also which end do you loosen, and which do you counter upon (it's not hard to tell). So, I would encourage anyone in audience of this post to seek another reference, or maybe someone with better working knowledge will clarify. Ed, you just did this on the 3.4,no? A Bentley manual may help, though I never used one. The FSM will be the last word.
Shifted rocker shafts are not uncommon, but not an everyday occurrence either. I have had numerous cars that had this situation, and a 930 that altogether dropped a rocker. One indicator of a loose/migrated shaft is an oil leak in the area of the head/cam housing union - or the area above the heat exchanger around the oil return tubes. There may also be an audible ticking for extreme cases.
For me, this was always a part of a valve adjustment, and I would happily return any shifting rocker shafts for no charge to the customer. It's very easy, and may prevent major top end damage, win/win/win for the mechanic/car/customer.
I hope others will post to clarify my abstract here. I have to imagine this is covered in other threads and I will search. I'll post a link if I find one.