[T3] clacking valves mystery update

[David Yaghoubian]

Many thanks for the responses. Coincidentally when I was about to 
walk in the door to the shop Jim's list of potential valve clearance 
growth issues just came in on my phone, so we went over it and the 
other list responses together. Using Jim's list as reference, at this 
point it seems #3 and #4 could be the culprits (cam surfaces have 
ground down, or  lifters faces have ground down), as the adjusters 
and rocker stands were tight, the rocker shafts are not worn, and the 
valves and seats on cyls 3 and 4 looked perfect when they pulled the head.

Before continuing with more details, the current status is as 
follows: they swapped the EMPI rods for the Scat rods, inspected what 
they could of the lifters, test drove on the freeway, and then 
rechecked the valves this morning. Apparently the clearance stayed 
the same, so I drove it straight home from the shop and will check 
the clearance again tomorrow AM when it's dead cold. In short, they 
are stumped as to what is going on, but very helpful and themselves 
interested... alas the mystery remains!

Regarding the pushrods, the original set that was installed with the 
1776 build was in fact steel, stock length, and thus it was a steel 
rod that bent (!) on the #3 cyl. The EMPI pushrod set the shop 
replaced the originals with (and just traded for the Scat set) looks 
almost exactly the same length when we compared the sets, and 
although I didn't see the Scat set that is now installed, they were 
apparently also the same length. The EMPI rods didn't mushroom or 
shrink, so I'm doubting the pushrods are the immediate culprit of the 
bizarre clearance issue. With that said, since it's a 1776 with stock 
pushrods I've got potential geometry problems in the back of my mind now.

Re. the lifters, they were inspected with a lighted magnifier gadget 
(for lack of better terms, sorry) not a tiny cam as I thought. In 
looking at the outside #1 valve lifter closely again, it seems the 
hole at the seat has been worn so it looks oval rather than round. 
Severe wear here might explain the position of that valve adjustment 
screw, which is still almost flush with the locknut to measure .004 
gap. The bent steel outside #3 pushrod that caused the tube leak (and 
hence began this strange sequence) opposes that outside #1 valve, so 
now I've got a potential conjunction in the back of my mind as well. 
Having no concept how a steel rod could be bent, I don't know what 
the relationship could be (if any).

Just to go over the entire sequence in sum:
1) Outside #3 pushrod tube leak leads to discovery of bent steel pushrod.
2) Engine is pulled and head is removed to replace pushrod tube and 
view expected valve/seat damage... no damage found. Bent pushrod is a mystery.
3) Reinstalled engine gets new set of EMPI steel pushrods all around.
4) Oil and full-flow filter are changed (I didn't mention this 
before, but I have had Castrol 10w-30 in it the entire ~35K miles, 
but they put Castrol 20W/50 in. Pressure hasn't changed on the gauge, 
and temps are the same. Relevant?)
5) Car is test-driven, valves readjusted.
6) I drive ~30 miles, idle increases to 1500rpm, valves begin 
clacking like hell, strange smelling exhaust fumes. I discover 
stunningly huge gaps and adjust down to .004 all around. Arms and 
adj. nuts are tight.
7) I drive another ~20 miles, check valves again. #1 outside is as 
loose as before, taking up almost all of adjustment screw to get it 
to .004 again. Others are out at ~.013, so I adjust those again (and 
get really paranoid :).
8) Return it to shop, were they did the "current status" work 
described above, but we do not figure out what any of this has been 
caused by, and are in "wait and see" mode... not comforting.

Re. ZDDP, unless it has been in my Castrol 10W-30 (or the 20W-50 they 
just put in) this engine has never seen any. This is another issue I 
will be keeping in mind.

Re. studs pulling, the head was apparently tight when they removed 
it, but I'll inquire again.

Thanks again all! I'll report back soon with the next valve clearance 
readings... which I'm looking forward to and dreading simultaneously.

Dave