[Supras] Lessons from engine swap newbie

[berniek at technicaldevelop.com]

I've had the top end of my '90T apart many times, which is the way I 
discovered cam cap wear and the way to fix it.  However, now is the 
first time I've done a complete engine rebuild and assembly and swap for 
my newly acquired rust-free (Texas) '91.  Lessons learned which may be 
of use to others are as follows, hopefully helpful:


1.  The turbo spark timer gear has gear 13 teeth, an odd number with 
consequences.  When I put the engine together, I thought the spark 
timing was correct.  However, I could only advance the static timing to 
about 5 degrees  ATC after startup.   So off came everything to get to 
the timer, pulled it out and advanced it by one tooth.  Big mistake.  
The spark timing then could be varied from about 40 to 20 degrees BTC.  
When originally set to TDC during timing belt installation on the engine 
stand, I put the timer in while the engine was at TDC but apparently for 
the power stroke on cylinder 6 (opposite cylinder 1 in the firing 
order).  So again everything came off to get to the timer, and I 
advanced it by 6 teeth, splitting the difference between advancing by 
one tooth the first time (the reason why an odd number of teeth is 
important, like it had 26 teeth rather than 13).  This is OK due to the 
wasted spark system.  The engine will start and run at closed throttle 
without the AFM working.  So that time I started it, checked the spark 
timing, and set it to about 13 degrees BTC with all of the inlet 
plumbing, power steering reservoir bracket, etc.off the car.  It was 
totally weird running the engine to set the timing with no accordion 
hose, no AFM, nothing connected to the 3000 pipe and the cover off the 
timer.  There is about a one degree scatter between firing of #6 and #2 
according to the timing light. 


2.  Upgrading to a 57 trim turbo requires a large blowoff valve. The 
right angle Porsche/Saab item fits well epoxing the accordian hose 
connecting pipe into the discharge (side connection), and using a piece 
of a spare crankcase to head vent hose (the one behind the alternator) 
to make the connection to the 3000 pipe.  The hose does not have fabric 
reinforcement, so will be watched closely since I'll be running 15 PSI 
boost.  But the correct segment of it fits the application like its made 
for it.  The vacuum diaphragm hose on the valve just touches the 
accordion hose. 


3.  Adjustment of the Lexus AFM screw is easy if the AFM is turned to 
make the sensing module cover horizontal.  However, it requires 
fabrication of a new rear bracket for the AFM.  Also, I drilled and 
tapped the slotted end of the bypass screw with a #6-32 thread to pull 
it out if desired using a #6-32 as a handle to overcome O-ring 
friction.  The inside end of the screw is sealed.  Apparently Reg was 
not right in statements to almost completely close off the bypass passage. 


4.  The '91 came with an HKS air filter, which appears to be real crap 
from reports on the internet and the fact that the foam can be seen 
through.  Moreover, it is oiled, not good for the AFM sensor.  However, 
the curvature of the baseplate seems really good for straight airflow 
into the AFM.  A different element may be adapted (maybe the stock paper 
element without the restriction of the stock housing). 


5.  At the last minute I decided to upgrade to T-bolt hose clamps on the 
discharge side of the turbo, especially the one at the turbo outlet (can 
get to others quite readily).  T-Bolts do not cover very much size 
range, and I had run out of adjustment on the turbo discharge.  I had to 
make up a circular shim from 3-1/8" tubing in the junk pile here with a 
gap in it to use under the clamp.  The inside ends of the tubing shim 
were beveled with a bench grinder to not dig into the hose.  That worked 
really well. 


6.  Most upgrades to the Lexus AFM state to stretch the accordion hose 
over the outlet end.  That was disconcerting to do, since the hose 
hardens and cracks fast enough as it is.  If you can find it at a local 
junk yard, look for a Reillo oil burner and take the blast tube from it 
if of 3-1/8" diameter.  That size tubing may also be available from 
McMaster.  It fits with about .035" clearance in the outlet of the Lexus 
flowmeter.  I epoxied a piece in, and secured it more with sheet metal 
screws in holes drilled in the Lex outlet hose connection area.  You can 
shape the epoxy as it is curing to avoid a sharp transition between the 
Lex outlet bore and the inside end of the tubing.  The ID of the tubing 
is more than the Lex sensor location ID, so use of the tubing should not 
cause flow restriction (look at the inlet size of the CT-26, even a 57 
trim upgrade.  It is smaller yet).  Then, cut off the thin end of the 
accordion hose, and clamp the thick part of the hose over the tubing 
coming out of the Lex outlet.  It is just about the right size, and 
everything lengthwise winds up in the same lengthwise position as with 
the stock AFM. 


7.  I used an almost new radiator, used for about a month in my '90 
before the BHG.  During the first thermal soak, the bottom hose 
connection blew off, spewing antifreeze everywhere (bottom engine cover 
not on yet).  The radiator outlet pipe stub is smooth and may have been 
responsible.  In any event, a screw type hose clamp, tightened almost to 
the breaking point now resides there. 


8.  Many on the list will disagree with need for this.  I had cut and 
brazed an extension in the oil pickup to locate it further back in the 
pan as protection against oil starvation under acceleration up hills.  
1/2" tubing worked fine as the extension piece, fitting snugly inside 
the pickup tubing after cutting the horizontal section and deburring 
it.  The pickup was moved back one main bearing distance, and a robust 
second bracket was made up and brazed to the pickup (in addition to the 
stock brace).  Each was bolted to a piece of heat formed 1/8" thick 
steel strap under the main bearing bolt heads one location to the rear 
of the stock location, so it is very rigid.  I've had oil starvation 
before with other cars, and is apparently one reason why many say to run 
the Supra one quart high.  The oil pan baffle was cut out to accommodate 
the approximate 3" rearward location. 


9.  Be absolutely sure to connect both heater hoses before doing the 
final engine drop into the car, or disconnect the hoses at the other end 
to connect later.  I missed one (goes to the heater core at about the 
center of the firewall), and it was hellacious to install, requiring 
removal of the EGR valve and master brake cylinder (no, I do not have 
the arms of a 300 pound guy). 


10.  The EGR valve is easier to remove if the compression fitting and 
flange connected to the intake is removed.  To do so, the bolt holes for 
the flange need to be slotted on the side facing the bell housing, in 
order to allow engagement of the compression fitting.  5/16" washers 
over the slots under the nuts work fine to hold it in place later.  
Slotting was done on a metal cutting bandsaw. 


11.  The engine went together easily enough on the stand, but I left off 
the intake plenum, throttle body and all associated with it.  BIG 
mistake.  I had little  choice, however, since I used a JDM for the 
rebuild, without EGR or the same throttle body as on US models.  My wife 
would have gone nuts with two engines in the cellar (ground level, same 
as garage 40 feet away).  One was enough.  Now with the '91 block as a 
core, I can rebuild a complete engine if I decide to in the cellar 
without two taking up space at the same time. 


12.  Claims about use of a new oil pressure sender seem correct.  Now I 
get pressure readings which are about the same as those obtained with a 
piece of 1/4" copper tubing soldered into an oil filter and connected to 
good pressure gauge with a hose. 


13.  Both stock '91 mounts were broken, with rubber pulled away from the 
steel end plates,  The safety stops are apparently what protected 
against excessive engine lifting.  '98 MkIV mounts were used in engine 
installation, which appear to be two rolled or crimped halves with 
captive urethane inside.  They are the same size as mid '89 to 92 
mounts, but a locating lug on the bottom needs to b ground off.  Be VERY 
careful with these mounts if you ever need to lower the transmission to 
change the starter, etc.  Loosen the frame side nuts before lowering the 
transmission, as the mounts are very stiff and may break (conjecture, 
but I don't want to try it).

14.  '91 starters have tapped mounting holes whereas earlier ones do not 
and use nuts instead.  Much easier to change.

15:  One guy on ebay sells Denso starter solenoid replacement parts 
including contacts and the plunger and pushrod assembly with the ring 
contact.  They appear to be good quality and are cheap.  Measure your 
pushrods exactly, though, as some differ only by a millimeter or so.  
Starter brush wear does not appear to be a problem, but solenoid 
contacts are.  Alternator brushes appear to last for at least 300,000 
miles. 


16.  Be sure to engage the two fan shroud latches at the bottom, if you 
take apart both halves of the shroud. 


17.  If you have brittle connectors on the wiring harness, and a latch 
breaks off, the connector may be held together with a black tie-wrap run 
between the wires of each half to hold the connector together.  White 
tie wraps are plain nylon, and fail at low temperatures. 


18:  Although the O2 sensor is the same between '90 and '91, the 
connector harness is different starting in '91.  The later connector is 
also used in our '95 Camry, although the sensor is screwed in place.  . 


19.  There is no need to disconnect the two electric fans when replacing 
the radiator.  They will pull upwards and out, and rest on the left 
inner fender. 


20:  Just received the first item for the 3" exhaust ordered from a 
Random Technology dealer,  It was the Lipp elbow, which was said to be 
cast iron.  It is not.  Due to no magnetic properties, it is likely 300 
series stainless, maybe 303 or 304, but could also be 316 for the price 
of almost $200.  It is non-magnetic, the major consideration regarding 
material ideentification.  . 


    Enough for now.  Hope some of this was helpful.


          Bernie