Many thanks to those who have responded with suggestions about my baffling
problem. All I have received so far, I had already checked out with no
success.
I do have a further "clue" which I had neglected to mention. The more I think
about it, the more I believe it has a strong implication as to the cause of my
problem.
After each time it has been started and run for about 5-10 minutes (4 times
since the head installation), I have pulled the plugs afterwards, for
compression checks, valve adjustment and to get the points open for
regapping. Each time I have pulled them I've examined the appearance of the
electrodes. Very unusual. #'s 1, 3, and 4 all have a slightly "moist"
appearance. Only #2 has a normal gray-tan "hot" appearance. The last time I
put them back in, I replaced them in different cylinders.
The one put in #2 became the one with the normal gray-tan look, losing its
"slightly moist" look it had gotten in another cylinder.
This suggests to me that maybe I didn't do a good job of installing the head
gasket.
It's the first time I had used the Permatex "Copper Cote" (someone on the list
had touted it). The head surface was pristine, and had been checked for
"trueness". I had cleaned the block surface as best I could, it was good and
smooth. I then sprayed the Copper Cote evenly on both sides of the gasket and
on the head and block mating surfaces. I torqued the (lubricated) bolts in
the prescribed sequence, in three stages: 35 ft-lbs, 45 ft-lbs, and 50
ft-lbs. The last time I had installed a roadster head gasket was about 20
years ago, used the gasket "bare", and had no problems. Maybe I was
overzealous this time :-(.
It also suggests that *only* #2 is firing. I can't believe that's
possible--for the engine to run on one cylinder!! Maybe the others are firing
sporadically ??
I really don't want to pull the head and install a new head gasket.
I have already "pulled up" the head bolts back up to 50 ft-lbs before the last
time the engine was run.
Most, but not all, required a little additional turning to get back up to 50.
Those that didn't, I backed off a little, then pulled back to 50.
The same bad performance resulted--no apparent improvement.
Questions:
Don't my good compression check results (original "kokua" message) imply a
good head gasket?
What could be explanation of the spark plug appearance?
Could it be actually running on one cylinder? --Nah!
Any suggestions other than replacing the head gasket? Maybe backing all the
head bolts off in the reverse sequence, then retorquing back to 50?
All thoughts, recommendations, etc. are solicited.
TIA,
Dave
'68 1600
Kailua-Kona
"David R. Conrad" wrote:
> Hello List:
>
> My roadster suddenly started operating on three cylinders last July. Some
> may recall an appeal from me for advice at that time. I again thank those
> who offered opinions/suggestions. My initial diagnostics suggested a bad
> valve in #1 cylinder. That *is* what it turned out to be, a triangular
> shaped chip out of the exhaust valve of #1.
>
> Slowed down by heavy involvement in some home improvements, I finally got
> the head off and to "Akamai (meaning 'da best!) Machine" for
> reconditioning. Just after I left it with them, they closed down the shop
> for a 2-week vacation. After a few delays in getting the parts (some
> associated with the transportation delays after Sept. 11)
>
> Finally got the head back from Akamai Machine last week. Believe that
> they did an excellent job. I put the engine back together last weekend
> with high hopes that the car would run even better than before; it had been
> running well before the valve failed.
>
> I adjusted the valves to .020 (cold) and performed compression checks. I
> thought the results were quite good. "Dry" the mean value was 133 psi
> (+1, -2), very consistent for two checks, and with 10cc of oil added, the
> mean value was 145 (+/-) 3 psi.
>
> I made no changes to points and timing since it had been running well
> before the valve failure.
>
> Then I went to start it (full of confidence). Was I disappointed!
>
> Very hard to start, and when started, it ran very irregularly, with
> definite missing and occasional backfiring. It suggested that the timing
> was off. The distributor hadn't been touched!
>
> Checked the dwell, and it was 59*, higher than when I had set it, maybe
> influenced by the fact that the rpm had to be ~15k to keep it running.
> (though I thought dwell was not rpm dependent). Anyhow I reset it to 50*
> Then I tried adjusting the timing about 5* each way, advance/retard.
> Seemed to run a little better at 5* retard (that is, rotating the dist. 5*
> CCW--maybe that's advance, I don't remember).
>
> Anyhow, I've about run out of ideas and it still runs like crap.
>
> I would welcome any thoughts, and thanks in advance!!
>
> Dave
>
> '68 1600
> Kailua-Kona
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