SOLVED: Yet another 1.7 "clattering" investigation NOW WITH VIDEO, What to look for? Options

[jrmdir]

Hello:

I'm still trying to sort numerous suspect items related to idle, mixture and hesitation in this recently acquired car but the "valve?" noise is driving me crazy while I work on various adjustments.

I've adjusted the valves at least three times and believe there is no excess clearance but it seems to have gotten louder recently so I'm going back under to check things out - and this time plan to take the rocker arms off to check for new looseness or anything weird that would throw the feeler gauge measurement off.

I've read about possible valve seat detachment - is there a way to check for this short of removing the heads?

Anything else I should look for? What are the chances of rod knock instead of valvetrain?

Notes: Mileage unknown. Car sat for 3+ years and of course the seller claimed "ran well when parked" LOL! Compression is good when warmed up, not so good in #1 and #3 when cold. No blue smoke. Hard to tell but the loudest noise seems to be #2 but that's just a guess.

Thanks!

Ron

[rjames]

As my chance you have hydraulic lifters? If so, they must be adjusted to a different spec and can take awhile to quiet down (fill up with oil), especially if the car has been sitting for a long time.

[Shivers]

Years back I purchased a set of P n C’ s that at idle clacked like crazy. What do you have

[jrmdir]

Thanks rJames - I'll check. With the rocker arms off should I be able to pull the lifters out with a magnet? Or is more disassembly needed?

Also, Shivers, what are P n Cs? A brand of Hyd lifters?

Thanks again,

Ron

[BeatNavy]

With the rocker arms off you need to pull the pushrods out of the tubes. Then you can retrieve the lifters out of each bore with a magnet. Keep the pushrods and lifters in order, oriented properly, and clean. If they are hydraulic you probably should go back to solid, although maybe someone can confirm that it won't mess up valve geometry.

It helps to put each cylinder at TDC as you remove the rocker assembly. At TDC the valve springs will be relaxed and you won't have rocker arm parts flying across the garage.

P&C = pistons and cylinders. If you didn't build this engine I wouldn't expect you to know which ones you had.

I've never had a dropped valve seat or heard one AFAIK. You may want to read valve adjustment procedures again, or ask questions. It's not necessarily easy or obvious for first (or third) timers.

Good luck.

[jrmdir]

Thanks for the helpful details BeatNavy. (The P n C confusion was a Doh! moment (IMG:style_emoticons/default/smile.gif)

I'm going to check this thoroughly even though I'll be shocked to find hydraulics - this car is nothing if not bone stock original (looking.) Except for the Monza exhaust one of the POs added way back when. Which is the next noise source to go, but it doesn't exactly fit with someone investing in quieter lifters.

I'll report back.

Thanks again.

Ron

[914werke]

that shouldnt be necessasry, a hydro setup will use 1 piece steel pushrods & rocker shaft spacers rather than the tipped alum. Push Rods's and springs used on the parts that are OE on the /4.

[JFG]

are you 100% sure it's the motor?

I asked because mine has a rattle. the heat exchanger cover is loose on the pipes.

[jrmdir]

Update.....

First, thanks for the suggestion JFG, I wish that was it but my car has no HEs and the noise is definitely rev related and sounds just like valves or something worse like piston slap.

So, I did some more investigating and decided that before I take things apart I'm going to do another - hopefully more precise - adjustment. Got half way through it today and did find some extra clearance but no smoking guns so far. I'm thinking of getting a new feeler gauge for reference and also perhaps temporarily setting them all too tight just to see if things quiet down so I can rule out more serious sources.

Oh, 914werke - thanks a lot for the "tip" about the pushrod tips. As seen in the first photo I believe that is the aluminum tipped OE version you were talking about? So no hydraulic lifter mystery to solve!

The only thing I noticed that didn't look right is that on 1 and 2 intake valves, the adjusting screw is off center from the valve stem. See photo 2. I can push the rockers to the left to line them up so it seems as if another aluminum spacer like those seen in Photo 3 would do the trick if added to the right of the rocker. If in fact that's worth correcting.

Thanks again. More updates to follow.

Ron

[jrmdir]

EDIT: Started a new thread with the videos below: http://www.914world.com/bbs2/index.php?showtopic=355079


Update as promised - and not any good news yet.

In order to try to rule out misadjustment as the cause, I meticulously re-adjusted and double checked. And cranked it down just a bit to .005" just to be sure.

When I next started the engine (1st video) I thought I'd hit pay dirt because it was as quiet as I've heard it. Yeah!

BUT, within a few minutes the clatter came back with a vengeance - videos 2 and 3.

I focused on cylinder 2 as that seems to be the loudest corner but it's hard to tell. FWIW, I unplugged that injector but did not notice any real change. Also when cranking without starting there doesn't seem to be any mechanical noise.

Any help with diagnosis and next steps would be much appreciated.

Ron

Video 1: Cold Start https://youtu.be/5XBiv7zarvw
Video 2: Warmed up & noisy https://www.youtube.com/watch?v=JFfPNDZkSnk
Video 3: More noise https://www.youtube.com/watch?v=9fOrGUK6wZs

[914sgofast2]

Make certain each pushrod is centered in the middle of the lifter when you adjust the values. I had a somewhat similar issue and discovered that one of the pushrods had become dislodged from the center of the lifter when I was adjusting the valves.

A worse case scenario would be that you(1) have a valve seat coming loose; or (2) have the oil pump shaft migrating out of its bore in the oil pump and hitting the heads of the rivets that hold the timing gear to the camshaft (I had that happen to my 1.7 liter.)

[jrmdir]

Don't know how I missed this in my prior investigations but I recently came back from a few weeks in the d-Jet tuning maze and decided to take another look. This time I was able to get my stethoscope against the base of all of the pushrod tubes and #1 came up the winner with nocking noise of the same cadence.

In no time I had the tube and rod out and found the problem. A little bit of dent removal and the noise is gone! Who knew the clearance between rod and tube was that tight?

Anyway, thanks for the input and for the advice to not always assume the worst.

Ron