[Supras] Whipping noise, throttle control, stock fuel piping

Mon Feb 4 22:29:35 CST 2008

Jeff, Rocky:

    Thanks for the responses.  What happened to other postings?

    The stuck lifter or bucket idea occurred to me as well, which is 
really scary from a standpoint of throwing shims.  If that were to be 
the case, I would expect at least some detectable misfire because a 
valve is being held at least partially open during at least the start of 
combustion.  If it is a stuck bucket or valve stem, combustion force 
could slam the valve closed, carrying the bucket and shim with it.  
Also, it is very loud, and can easily be heard from 50 feet away with 
the car in the garage and the garage door open during initial warmup.  
Before the new '65 GTO I had a '59 Chevy 348 which made the same type of 
noise, but it was unchanging and was not as loud.  It turned out to be a 
loose bolt in the water pump pulley, which was stamped and formed such 
that two thicknesses of sheet metal existed at the flat portion where it 
bolted onto the pump.  The V-belt was located to the rear of the pulley 
face loading the face off center, so the sheet metal sections "cracked" 
against each other every revolution.  I would have expected (more?) spot 
welds, but there were not any. 

    The present sound is much louder than a spark jumping and is 
definitely mechanical in nature.  One action I will take is to listen 
with the stethoscope, and will also listen to intake side cam cover 
noises at the oil filler with the rod and diaphragm removed.  One thing 
I've learned is that the inside of the engine is normally a very noisy 
place, listening at the oil filler, putting the bare stethoscope hose 
into the hose from the oil filler to the crankcase and listening the 
same way at the dipstick tube.  For sanity (?) I did the same thing with 
my 2003 Maxima (55K miles, good condition) with the 24 valve chain 
engine, and it was just as noisy. 

    We have more snow on the ground now after taking the Supra out for 
one glorious day yesterday.  It had sat for two weeks, not without 
battery charging and attention to minor details.  I do have one major 
problem which cannot be solved, however:  My (second) other half got 
sick to her stomach.  She is not accustomed to being pushed back in the 
seat, need to shift gears, or the power which the car now develops.  She 
lived all of her life in NY, and never drove.  She will drive our 4 
cylinder Camry locally, but in the 10 years we know each other, highways 
are still scary to her.  Logic does not prevail:  Older Federal and 
State roads with businesses and traffic lights are not as safe as the NJ 
Turnpike is, yet she will stay with the older roads because the speed 
limits are only 45 or 50.  Well, the same thing happens if I play the 
organ too loud and the subwoofer shakes the house at 16 Hz.  Never had a 
sheet rock nail pop in 25 years of doing that.  Makes me think of taking 
my ex-wife's father out in the Firebird years ago.  He shook visibly 
when getting out of the car.  At the time I thought that was great fun, 
but now, I realize it was probably cruel.  It's been in storage needing 
restoration since my second wife and I met. 

    On the positive side, I am learning how to cope with the "negative 
resistance" characteristic of throttle vs. turbo boost, and can now 
handle starting from a stop in first gear with boost limited by throttle 
on a "dynamic" basis.  Breaking loose in second gear strangely is more 
difficult because it is unpredictable, and everything happens faster due 
to increased speed.  Well, May is coming, and hopefully so is the first 
Novice day at Pocono. 

    One more item of possible interest:  The stock fuel piping just 
barely starts to become inadequate with a genuine Walbro pump at about 
18 PSI boost with 550cc injectors, a 57 trim CT26, and 45 PSI static 
fuel pressure.  Can describe how I know if anyone is interested.

    Thanks for the ideas.

    Bernie

Speedtoys wrote:
> Cam noise is 1/2 of engine rpm.   Stuck lifter?
>
>
> Got brakes?
> ======
> 25hrs or one season with one pad set is possible.  Save money and pit 
> time, compromise nothing.  Ask how.
> TXT or Tone: 8414546712 at txt.att.net
> http://www.speedtoys.com
>
>
> On Feb 4, 2008, at 3:28 PM, "berniek at technicaldevelop.com" 
> <berniek at technicaldevelop.com> wrote:
>
>> Hmm..  The group has not seemed this dead in a long time.  Is the server
>> down?
>>
>>
>> Anyway, my '91 (550cc, Lex, Walbro, upgraded IC, 3" exhaust) makes a
>> very loud repetitive cracking sound from someplace near the front of the
>> engine on cold startup.  It sounds almost like an amplified arc, or
>> cracking of a whip when I listen under the hood.  Most times it occurs
>> at random, but if I speed up the idle slightly, it occurs at times in
>> sync with what appears to be every other revolution of the engine (i.e.,
>> 4 stroke style).  The sound must be outside the engine, since it sounds
>> like a cracking whip.  It appeared after about 600 miles on a refreshed
>> JDM.  One thing I need to do is check the harmonic balancer bolt.  I did
>> not tighten it all the way to the spec, as the pipe used on the breaker
>> bar began to bend.  Could it be the balancer moving torsionally on the
>> crankshaft against the woodruff key? Strangely, once warmed up it is
>> fine.  The stock pistons are fitted loose, and I do have cold piston
>> slap as well, expected.  But this noise is far more "in your face"
>> regarding high frequency content, not muffled or damped by the block 
>> walls.
>>
>>
>> BernieK
>>
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>
>