[Supras] Noisy injectors and piston slap

[berniek at technicaldevelop.com]

Malik:

    First, let me wish you the best for a lifelong recovery.  I really 
feel that strides in understanding of cancer are really now being made 
on an exponentially increasing basis, even though it seems as if little 
happened in that regard for the last 40-50 years.  Depending upon the 
severity of the surgery, it may take you a little while to recover.  I 
had a heart attack in 2000, followed one week later by triple bypass 
surgery, the first one in my mother's line to benefit from newer 
technology (cardiac problems run in that side of the family).  Recovery 
took about a month to the point where I could START to resume a normal 
life, but the entire healing process took about a year.  Can't run the 
NYC marathon, but otherwise am back to normal. 


    Yes, I too am grateful for this list, this medium in which to ask 
questions, offer advice from experiences, get help (e.g., Jeff at the 
track) and learn from others.  Hope this goes on for MkIII owners for 
many years, although I'm somewhat concerned that the supply of Japanese 
engines is drying up.  Prices have almost doubled for JDM GTEs in the 
last two years. 


       Bernie


sprigmo1 wrote:
> Hell of a write-up Bernie!
> I'm sill in the middle of my rebuild and found your
> whole oil starvation issue and conclusion very
> insightful.  
> I've had Jeff help me get back on track several times
> as well.  Just goes to show how valuable the folks on
> this list are!
> My motor, head and manifolds are at the machine shop
> as we speak hopefully when my Dr. releases me to go
> 100%,(surgery to remove cancer) I can get back to it.
> Keep up the good work list!
> Malik
> --- "berniek at technicaldevelop.com"
> <berniek at technicaldevelop.com> wrote:
>
>   
>>     Hope the following is helpful to others who may
>> have concerns about 
>> engine noises. 
>>
>>
>>     In former postings I expressed concern about oil
>> starvation based 
>> upon some really rambunctious driving and noises I
>> was perhaps not aware 
>> of before when the modified JDM engine in my '91 had
>> about 100 miles on 
>> it.  Also the stock gauge with a new sender read
>> zero pressure at idle, 
>> covered in next paragraph.  Jeff Moller and Pat
>> Golder were kind enough 
>> to write back to me allaying the starvation
>> concerns, Jeff particularly 
>> in some detail.  I've had an instance before with a
>> good cornering GM 
>> rear sump car where the oil climbed the side of the
>> pan under hard 
>> cornering conditions, as evidenced by noisy
>> hydraulic lifters.  Since 
>> the Supra is a bucket and shim engine, the first
>> noise which would be 
>> heard under starvation conditions would probably be
>> connecting rod 
>> bearings, a warning which would have come too late. 
>>
>>
>>     A couple of nights ago I measured oil pressure
>> with a pressure gauge 
>> connected to a new oil filter casing (soldered in a
>> section of 1/4" 
>> copper tubing to use with hose and a good gauge) and
>> found that even 
>> with a new sender, the dashboard gauge still reads
>> low by a constant 
>> 20-25 PSI (differential pressure across the filter
>> element is probably 
>> not in excess of 2 PSI at idle with hot 5W-40 oil,
>> stating because the 
>> measurement is taken in the casing, upstream of the
>> filter media).  That 
>> and other investigation is beginning to prove that
>> noise produced by the 
>> engine does not emanate from the bottom end,
>> although the first oil 
>> analysis after 400 miles showed 43 PPM lead.  The
>> lab (Blackstone) does 
>> not analyze Antimony, important because lead based
>> babbitt contains 15% 
>> of it for hardness.  The lead may be due to wearing
>> of the soft coatings 
>> on the cam journals after tightening up the cap
>> clearance as stated 
>> informer postings.
>>
>>
>>     After installing the regular oil filter again
>> (Purolator Pure1), I 
>> again started the engine from cold (about 38F in the
>> garage) without 
>> throttle, and listened yet more with a stethoscope,
>> with both the 
>> diaphragm/rod and with just the open hose end during
>> warmup.  
>> Conclusions are as follows:
>>
>>
>>     1.  There is no noise from the main or
>> connecting rod bearings.  
>> There is no noise at all at the bottom flange of the
>> block under any 
>> condition, including teasing the throttle when
>> warmed up.  Ticking and 
>> minor rumbling noises may be heard at the front and
>> rear segments of the 
>> pan, however.  I would not trust the stethoscope
>> diaphragm/rod assembly 
>> to accurately reproduce low frequency sounds the way
>> it is built.  Of 
>> course if you remove everything but the hose, you
>> will hear every sound 
>> which is airborne.
>>
>>
>>     2.  During warmup, there is piston slap
>> particularly on one front 
>> cylinder.  #1 was the first one I honed, and may
>> have increased 
>> clearance a bit too much since the hone stones were
>> new, and spring 
>> tension was apparently too high, although it was
>> completely backed off.  
>> I used sufurized cutting oil with the stones at
>> first, but then switched 
>> to machine oil.  I recall it did measure a couple of
>> thou more than the 
>> others afterwards, but did not think much of it at
>> the time.  Literally  
>> a couple of thou does not seem like much, especially
>> when clearance 
>> ranges for stock pistons in the TSRM are considered.
>>  During warmup the 
>> oil pressure is high, opening the piston squirters
>> which probably keeps 
>> piston temperature low, as long as the oil pan feels
>> lower in 
>> temperature than about 120F-130F, the hottest one
>> can continuously 
>> touch.  The noise begins to disappear when the oil
>> pan becomes too hot 
>> to hold my hand on, and is just about entirely gone
>> when the radiator 
>> thermostat opens. 
>>
>>
>>     3.  Intake valve clearances, when last checked
>> about 120 miles ago, 
>> were a bit on the high side.  One was .011", whereas
>> .009" should be the 
>> maximum.  The exhausts were all OK below .012".  I
>> did refinish all of 
>> the caps to get journal clearances down, but now the
>> intake side has 
>> become a bit noisy.  During assembly the soft
>> coating was gone from 90% 
>> of the exhaust cam but not from the intake.  Pushing
>> the engine hard in 
>> back to back WOT runs may have removed the intake
>> coating.  We will see 
>> what the next oil analysis shows, but I'm going to
>> try to find a lab 
>> that does both Antimony and Gallium, Gallium being
>> present in most soft 
>> alloys (softer than babbitt).  It is used in Wood's
>> metal with Bismuth, 
>> used to make trick spoons that melt in hot coffee. 
>> In any event, my 
>> belief now is that the soft coating is where the
>> lead came from.  The 
>> next oil analysis will tell assuming I find a lab
>> with comprehensive 
>> enough tests. 
>>
>>
>>     4.  Noisy injectors?  The stock injectors in the
>> '90 made slight 
>> ticking sounds.  The NipponDenso 550cc low impedance
>> items in the JDM 
>> are very noisy, almost like valves with twice the
>> specified clearance.  
>> These injectors were purchased as Greddy items in
>> sealed bags and were 
>> directly installed, since there was evidence of
>> Stoddard solvent still 
>> on them (Usually used for test).  The engine idles
>> beautifully, although 
>> that is not an ironclad guarantee of all injectors
>> supplying the right 
>> amount of fuel.  That consideration not
>> withstanding, one or two 
>> injectors are unusually noisy, determined by
>> removing the diaphragm 
>> housing from the stethoscope and listening just with
>> the hose for sounds 
>> in the air.  This is not a criticism of the
>> injectors, just an 
>> observation to be understood. 
>>
>>
>>     5.  The father of all hellacious sounds in an
>> engine is the 
>> crankcase.  The Supra is no different. 
>>
>>
>>           a.  With the stethoscope earpiece hose
>> shoved into the 
>> dipstick tube, a subsonic sound at idle was
>> persistent, which 
>> theoreticially should not exist since a straight 6
>> is in both primary 
>> and secondary balance.  In other words, there should
>> be no change in 
>> crankcase volume like in inline 4 has, where a
>> vertical shaking force 
>> and a hum from the crankcase are seen at twice the
>> RPM, both due to 
>> connecting rod agularity.  The low pitched hum in
>> the Supra was very 
>> intense and became deafening as the speed was
>> raised.  There is a tiny 
>> amount of blowby, as evidenced at the topside oil
>> filler from a sudden 
>> but short WOT condition from idle while unloaded,
>> manifested as a couple 
>> of wisps of smoke.  It finally occurred to me that
>> the hum might have 
>> been from a crankshaft counterweight windage nearest
>> the dipstick tube.  
>> Otherwise, there is a great deal of clanking which
>> is evident within the 
>> crankcase, decreasing in intensity with engine
>> speed. 
>>
>>
>>        b.  Essentially the same sounds were heard at
>> the oil fill port 
>> when threading the stethoscope hose into the hose
>> behind the alternator 
>> which connects to the crankcase.  Again, the sounds,
>> aside from the 
>> subsonic eardrum breaker, are believed to be from
>> piston slap.  A 
>> borescope with a 90 degree mirror will be here
>> shortly to get a real 
>> live view of what is going on inside.  I've wanted
>> one as a toy for 
>> years.  Now is my excuse. 
>>
>>
>>     We just replaced the mule car I generally take
>> to work with a 2003 
>> Maxima with the chain V6.  It is a very smooth and
>> refined car(automatic 
>> for my wife) although it will accelerate and corner
>> to a good extent.  
>> It has 55K miles, uses no oil, and no engine noises
>> are evident when the 
>> hood is up.  But inserting the listening hose in the
>> oil filler produced 
>> sounds almost the same as the Supra.  The subsonic
>> component was there 
>> as well, but I'm not sure if the 60 degree VEE or
>> some other even firing 
>> arrangement like split crankpins (a la GM) allows it
>> to remain in 
>> secondary balance and hence, constant crankcase
>> volume. 
>>
>>
>>     In conclusion, the sounds I was first concerned
>> about regarding 
>> possible effects from oil starvation are probably
>> not due to starvation, 
>> the high oil lead content notwithstanding. 
>>
>>
>>     As always, comments would be appreciated. 
>> Thanks for the patience 
>> with my sometimes long-winded posts.
>>
>>
>>        BernieK
>>
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>>
>>     
>
>
>   Malik
>   It Ain't Eazy Being Me!!!!
>   92Trbo Supra 367whp
>   92 Supra Turbo Targa, 
> RC Engineering 560 injectors, Blitz peek hold 
>   device, Apexi Super AFC, Apexi AVC-R, HKS 
>   Timing Gears, Turbonetics CT-26 upgraded 
>   turbo, K&N FIPKE, catch can modification, 
> RPS Turbo clutch, Apexi N1 Exhaust, Paisley 
>   downpipe, Random Technology High flow 
>   CAT,  AEM UEGO Wideband 02 Unit, CSF 
>   Aluminum 52mm Race radiator, Walbro 
>   Racing Fuel Pump, Aeromotive AFPR, 
>   Horsepower Freaks 700hp custom Supra 
>   intercooler and hardpipes,  Greddy bov, HKS 
>   3000Pipe 
>
>
>
>
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