The stock bottom end of the Toyota Supra 7M engines is quite strong. I know
plenty examples of people running a heavily turbo charged 7M engine (both GE and
GTE) without any major problems. On this page I will explain how to get the
whole engine block apart and what you can do with it. At last I'll explain how I
rebuild the block and what I did to it.
| The first thing to do in getting the engine block ready for
a maintenance job, is removing the block from the car. Depending on your
own preferences, you can remove the engine completely with the head or
remove the head first and then the block. I chose for the last, because I
intended to replace the headgasket only and ended up doing a full engine
rebuilt. |
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The next job is something you should have done while the
engine was still in the car. The crank bolt can be so fastened, that it
seems impossible to remove it. I tried all my pneumatic impact wrenched
but none could get it loose. Then I borrowed this (picture) electronic
impact wrench. It managed to get the bolt loosened. An alternative to use
for getting it loosened is the starter. Block the bolt with a big wrench
and use the starter to brake it loose, before you remove the engine! |
| Ok, I hope I made myself clear with the main
bolt. This is really a bitch to get loosened. It took me three weeks or
something, before I finally had a wrench that was heavy enough to brake it
loose. So don't make that mistake again. I always use the starter to
remove the bolt and I have even done so with a car which had the head
already removed. You just have to reconnect the wiring loom for the
starter and use your own 'signal' wire to signal the starter with a
positive 12v signal. |
| Now the real 'disassembly' work can start. We need to remove
all accessories that are on the block. Here on the right you see the
return line tube. This tube has a restrictor in as well, which comes in
handy when the fuel pressure regulator fails. You do have to remove this
restrictor when you are upgrading the fuel pump to a 'higher flow' pump,
such as the walbro pumps. |
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At the highest point of the block, a water line is running
around it. Remove all bolts and nuts and get it away from the block |
| Now it's a good point to remove both engine mounts. Note
that the right hand engine mount (exhaust side) is bolted to the block
with only 3 bolts. The fourth bolt is already removed when you removed the
support brackets that bolt to the transmission. |
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The knock sensor(s) on the 7M are quite fragile. Remove them
carefully. There are two on the turbo engines and only one (in the middle)
on the normally aspirated engines. |
| In front of the lower timing belt front cover is a little
tube that is used for the power steering pump. Remove it by loosening the
two little bolts. |
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The newer 7M engines (89+) have an oil level sender unit in
the oil pan. This is a little floating thingy that sends out a warning
signal to the oil level light in the dash. Not all cars are equipped with
it, some have the TEMS indicators in that location in the dashboard. |
| Next to the oil level sender is the banjo bolt for the oil
return line coming from the front oil cooler. This bolt leads all oil
coming from the oil cooler back into the oil pan. |
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The power steering stay, which is located at the front right
side of the engine can be very hard to remove due to all the weather and
heating influenced. I had to use the pneumatic impact wrench to brake the
bolts loose. |
| This rubber hose coming from the oil filter bracket is the
hose delivering oil to the front mount oil cooler. A release valve leads
oil through this hose when the oil pressure build up by the oil pump
exceeds the 'release pressure'. All oil that is not needed for lubrication
will be send out to the oil cooler. |
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Removing the water pump can be a little bit difficult as the
gasket for the pump can be quite dried up. There are a shitload of bolts
and nuts to be removed for the water pump by the way. When you removed
them all, stick a big flat screwdriver near the water pump and try to
remove it from the block. |
| The sender unit for the oil pressure is on the right hand
side of the block. Remove it using an open end wrench. |
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Now remove the oil filter bracket. Again this bolt can be
quite hard to remove. I had to use the impact wrench on this one as well.
When it was loosened I could use a regular socket wrench as in the
picture. |
| You may decide for yourself what you would like to do with
the oil block-off plate in the picture here on the right. I haven't looked
to much into it's function yet, but I assume it has some function on the
NA blocks. I did remove the plate, as I tapped into the plate for putting
an oil temperature sending unit in. Behind the plate oil flows out of the
pump into the block. The perfect location for an oil temperature sender
unit. You must lookout carefully how and where you tap. There is not much
space available when you put the oil filter on the bracket. |
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| I think we have removed all gadgets from the
block. Let the real work begin now. We are going to dismantle the complete
block! |
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As you have already removed the crank bolt (main bolt), it's
an easy job to remove the crank pulley. Use a good puller, like the one in
the picture (official toyota gadget). |
| Behind the crank pulley is the front cover for the timing
belt. After you have removed this one, you can take out the timing belt
and start on removing the driving gears. The big gearwheel is for the oil
pump, the lower one down below is the crank gear wheel. Remove them both.
Get rid of the timing belt tensioner (tension wheel) as well. |
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Well, we're almost there. Time to unbolt the front plate.
Before you pull this off, notice the front plate has the exact height as
the complete engine block. So when you resurface the block (this will be
discussed later) you need to resurface the front plate as well! I forgot
to do that, so the front plate had to be send out again. Don't be as
stupid as I am! The front plate can only be pulled off when the oil pan is
off btw. But we already removed the bolts now. |
| This gearwheel comes from the other side (rear side) of the
crank. It's the ring gear, attached to the torque converter of the
automatic transmission. Here is where you unbolt the engine from the
transmission. Remove the ring gear from the crank. Notice it's not
possible to install the wheel wrong; the bolts have a special pattern
which can not be mirrored. |
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Now the time has come to cut the internals. We start with
removing the oil pan. The bolts are quite fastened and there are loads of
them, so I used (lazy as I am) the pneumatic impact wrench. |
| After you have removed all bolts, the oil pan is as fastened
to the block as before! It's glued to the engine block with gasket
sealant. To remove this, use a flat sharp knife like the one in the
picture and gently cut the whole pan loose. |
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Finally! We've reached the internals of the engine block!
You can see the crankshaft, rods, main bolts and oil pump easily. |
| Take a peak inside the oil pan. Do you see all those metal
shavings laying there. That's what you get after then years of abuse of
your engine! lol. |
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Now the front plate can be pulled of the engine block. |
| Remove the oil pump by unbolting the oil outlet from the
block and removing the two little bolts that holds the oil pump to the
block. Gently pull the oil pump out, do not damage any parts (please). |
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Now the whole crankshaft is free to reach. Remove the rod
nuts so you can take off the small caps (rod caps). These caps contain
half a bearing (rod bearing). There are six of them, for every piston /
cylinder, there is one rod cap. Organize them in such a way that you know
exactly which came from where. |
| After you've removed all rod bolt bearing caps (and the
bearings inside them), put some rubber hose over the rod bolt to protect
the cylinder wall when you push the piston (and the rod) out of the block.
The piston comes out of the block through the top (obviously as the crank
is downwards and you cannot push it through the crank). Organize the
pistons with connecting rods and nuts etc all in the same manner as you
did previously, so you know exactly which part came from where. |
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After you have pushed out all the pistons (gently, slowly
etc. etc.) you can unbolt the main bolts, that hold the main caps. The
main bolts can be very tight, I had to use the impact wrench to brake them
loose. Note that you have to use the special order as illustrated in the
TSRM. Again organizing your parts so you know exactly where they came
from, is an absolute must. Now that everything is taken of the block,
remove the oil pump drive shaft as well. This one is on the front of the
block with only one little bolt. |
| Here are all engine internal parts, nicely organized on an
old newspaper. Congratulations. You've taken the engine completely apart,
are you good enough to get it back together as well? I hope so, cause I
ain't gonna tell you how!
Joke... Let's continue. |
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| Engine block jobs
As you have probably read at the rebuilding
the head section, the engine shop can do quite some things to make
your car run smoother and faster. There are really loads and loads of
things that can be done to the main engine block, the following jobs are
common;
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Block Job 1. Honing
If you replace the piston rings, you have to hone the block. When you
have your block honed, the engine builder will grind a fine crosshatch
pattern into the holes. If you replace the piston rings without honing the
block, your engine will be burning loads of oil.
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Block Job 2. Boring
Because the piston is not only going upwards / downwards, but sideways
as well, the cylinder wall will get bend after a long time. The cylinder
will get oval, instead of straight. This can be the cause of oil burning
or lost compression. An other reason why the cylinder wall can be of poor
quality is when the engine has been laying outside for a long time, and
rust is on. In these situations you really have to re-bore the cylinder.
When re-boring, you need to hone it afterwards of course.
Another reason I can think of for re-boring the block, is getting more
power. This is generally done with NA engines, and does not really apply
to Turbo charged engines. Sure you get more power by bigger combustion chambers,
but getting the turbo pressure higher gains you much more! Keep one thing
in mind when over boring: The block will not win strength from over boring!
Block Job 3. Resurfacing
Just as the head of the engine, the block can get bent because of
excessive heat also. Of course, this doesn't happen to the block after a
couple of runs, but when you use the car day in day out for a couple of
years, the block will get bent. This is normally less than the head on our
cars, as the head is from aluminum and the block is from cast iron.
Note when resurfacing either the head or the block, you will loose more at
the outer cylinders than on the inner. Sometimes you need to compensate
this. One final thought about resurfacing: Sometimes resurfacing the block
is needed to seal the headgasket, this can be because you need a perfect
clean surface or a very flat surface. For example the HKS metal headgasket
on the 7M needs a very clean surface, otherwise it will not seal up
properly.
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IMPORTANT NOTICE
If you resurface the block, do not forget to hand in your front plate.
This plate needs to be resurfaced as well, as illustrated in the picture
on the right. If you forget about this, you have to redo the surfacing
job, just like me! The head falls over this front plate and will not seal
up when it's bigger than the block. Cutting away the gasket material is a
finishing touch, but necessary.
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Block Job 3. Piston & Rod balancing
Over the time the car is used, the pistons and rods will wear a little.
When you have taken your engine completely apart, as part of the
blueprinting process, you can balance the pistons and rods. Normally
spoken this is done individually, but if you would like to, you can do the
rod/piston combination in one go. Balancing can be done by yourself. You
need a good weighing machine or balance, and some toy to remove material
(for example a dremel).
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| On the above pictures you can see how rods were
balanced. These rods came from a four cylinder celica, not a Supra, but
the idea is the same of course. When you need to remove material from the
piston, you can do so at the inside of / under the piston. |
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Block Job 4. Crankshaft and flywheel lightening & balancing
In order to get faster acceleration, you need a better power to weight
ratio. More power or less weight. In a car you have two 'types' of weight,
one is rotational weight. This is how much weight needs to be turned
around in order to get the car moving. Rotational weight starts with the
crank and ends with the wheels and tires. Although this whole drive shaft
needs to be very strong, lightening can dramatically improve acceleration.
Loosing a kilogram on the drive train compares to loosing loads of weight
in the car. This is why lightening the crank is a good idea. After it's
lightened you need to have it rebalanced of course. Balancing a bare stock
crank is not really necessary. They come very good balanced from Toyota
and will stay so.
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Here you see a good picture of my crank. I forgot to weight
the crank before I took it to the shop, but after the job it weights 23.5
kilogram. The shop owner told me he removed about 4 kilogram. |
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Block Job 5. O ringing
Something not really common to the 7M, but it's a job that can be done
at the shop. O-ringing means placing a ring around every cylinder so that
the headgasket seals better. This ring is normally made of some good and
strong metal. I've never seen it, so if you got a picture, please
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!
Putting it back together
Well, that's about what in general is involved in getting the whole
block together, and what you normally take to the shop to have them do it.
Let's continue to check out what how I reassembled the block and where you
can put performance parts in the system.
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Well, I assume you know the drill by now. We started out
with painting the engine block. I suggest not to paint your block yellow
or green, but just use gray or silver. It's highly advisable to use a
primer first as in the picture on the left. Better to use several small
passes than drowning the block in paint. |
| The first things to put back in the engine block, assuming
you have removed them, are the oil squirters. These are only in the turbo
blocks. They spray oil on the pistons to keep them cool. According to Dean
Marcum who turbo charged an NA block, these are not needed. But put them
back or you loose oil pressure.
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Now put in the upper caps of the main bearings. As you see I
replaced all the bearings, although there were only 100.000 km on the
block. Thing is I didn't want to risk another rebuild and replacing stuff
is a cheap insurance for that. I replaced all bearings with the same size
as there was originally in. If you would like to you can measure all crank
diameters and put bearings in according to the measurements and limits in
the TSRM. When the bearings are in, install the two upper crankshaft
thrust washers. These prevent the crank from 'walking' when the clutch
force is engaged. |
| Here you see the first 'replacement' modification I did to
the block. Instead of using the regular main bolts, I used studs instead.
These studs are from ARP. If you use a stud you can put them in the block
by hand and apply the right torque with a nut. Compared to regular bolts,
this provides better force
distribution throughout the whole stud, which in turn allows you higher
torque values. I used 90 ft/lb of torque for the studs. Note that two
studs don't fit in the block. This is because of the oil pump pickup. You
can modify the oil pump, grind off the studs or put regular bolts in. I
did the last option, which I do not advice, as it's generally not a good
idea to intermix various bolts.
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After you have 'over' lubricated the newly installed
bearings and the two thrust washers you can position the crank in the
block. Do this with a friend as the crank is quite heavy and may not be
damaged by falling or something. You need two friends if you want to take
a picture! |
| Now we need to put the bearing caps on the block. The
easiest to start with is the middle cap, as this cap has the other two
thrust washers on it. Put them in place and again, over lubricate!
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Put the other side of the bearing in the cap and align it
properly. Did I tell you that you have to over lubricate the bearing with
fresh engine oil? |
| And put the bearing on the right spot. Here you can see that
I mixed the ARP main studs with regular Toyota bolts. To be fair, I didn't
realize the problems with intermixing various materials by that time. I
don't have problems with it currently and I assume I will never
have. So it's a good solution in my opinion. If you think something else,
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.
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Now if everything is in place, you can put the right torque
on the main bolts (studs). If you go with the factory bolts, stay with the
factory torque. I went as high as 90 ft/lb with the ARP studs. |
| Now we are going to put the pistons in the block. I replaced
all rod bolts with bolts and nuts from ARP. You can gently hammer out the
old bolts. If you wish to keep them in shape, hammer on the nut. If you
hammer on the bolt itself, you will kill the threads and render them
unusable. I killed all stock bolts as the ARP ones are better anyway. When
you have installed the ARP bolts you can continue with the next step.
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Now you install the piston rings on the piston. First you
put the oil ring on the lowest point. Put the two small rings on either
side of the oil ring. The compression ring number 2 is next and the top
ring is compression ring number 1. The texts or prints on the rings must
all face upwards. When the rings are on the piston, try to turn them all
around and 'feel' that the lubrication works perfect. When they are all in
place put the gap between the two compression rings 180 degrees of each
other. The two gaps of the rings holding the oil ring must go 180 degrees
and 90 degrees with the compression ring gaps. |
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Here you see another good picture on how to install the
piston rings. You stick one point in the place where the ring needs to be
seated. Then you can kinda 'turn' the ring on the piston. Make sure to
limit the scratches as much as possible. Every big scratch is oil usage
and not good! |
| Now you put the piston ring compressor on the rings. Make
sure they all fall in their place and do not get bent or broken. If you
brake one you're fucked ;)
Again lubricate as mucho as possible. Lubrication is very very
important in the survival of our species, and in the cars as well!
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Now you can put the piston in the block. This can only be
done from the top side, the side where you are going to mount the head.
I've heard people claiming to put the piston in from the oil pan, by
removing the crank, well, I do not believe that.
You can press the piston in quite easily. If needed use a small hammer to
'tap' in. Don't use excessive force. If this is needed your piston rings
are not right (like my first try when I used oversized rings on a standard
block) or one ring is not seated right. |
| And here is the piston fitted in the block. Make sure when
you tap in the piston, you're not pushing the rod to the crank and the
crank doesn't allow the piston to move more downwards. Check this by
rotating the crank a little and 'play' with the rod. It's easiest to put
the outer most pistons in first and put their bearing caps on as well,
with the nuts. Then do the cylinder 2 and 5 and last the middle two
cylinders. Turn the crank every time.
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Well, after you've put all rod bolts (holding the rod caps
and the rod bearings) on the correct torque,
you can put on the oil pump. The exact operation of the oil pump will be
covered in a separate article on this site, handling lubrication. The pump
is attached to the block with two bolts and one big nut on the lower right
in the picture, for pumping the oil into the block. |
| Put on the oil pump drive shaft. Are you still forgetting to
lubricate things?!?
The drive shaft is hold to the front of the engine block with just one
bolt.
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Now you can install the oil seals in the plates. You got a
rear plate, holding the rear oil seal and the front plate, holding two
seals. These two seals prevent oil from running out of the engine into the distribution chamber.
Tap these seals very
very gently into the plates. Use a very big socket if available or make
some wooden circles in the size of the oil seals. Tap in gently and make
sure the seal goes in straight and does not bent. |
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Put the front plate and the rear plate on the engine block. The rear plate
is sealed with one gasket, the front plate is sealed with two separate
gaskets. Be careful with the oil seals. Make sure they don't get damaged and
check if you can expect oil leakage. Fixing these locations can be a real
pain! Especially the rear oil seal.
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After the front plate is installed on the engine you can
build up the whole internals of the distribution, the gears for the
crankshaft, oil pump and the idler pulley with it's spring. |
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Now when you are absolutely sure that everything is in the engine etc., you
can put the oil pan on. This is done with liquid gasket sealant. It works a
little bit like regular glue. Put it around the engine block where the pan
needs to be sealed. It doesn't really matter if you're doing it too thick.
The remaining sealant will be pressed out and can be taken away with a
finger or something. I had some problems with the oil level sender in the
oil pan. It was only possible to get the pan on the block with the sender in
the pan. I was unable to place the sender in the pan once it was on the
block. Experiment with this BEFORE you seal up the pan with liquid gasket
filler. This applies to the 89+ engines only.
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After the oil pan is on the block, you can start with putting
all parts that came off the block back on. Here you see the oil return
line adapter. It's a block off plate for the crankcase as well. This
adapter has the restrictor in, which needs to be drilled out when you are
upgrading the fuel pump. |
| Install the water line around the block with a new gasket on
the location in the right hand picture. |
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Put the starter plate on the rear of the engine. On this
plate the starter will bolt up and the bell housing of the transmission as
well. |
| Now cut off the gasket material between the front plate and
the block. This is only necessary when you have machined the block (don't
forget the front plate).
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When you are absolutely sure everything on the block is in
place etc, you can reinstall the positioning pins. These were drilled out
so you have to replace them with new ones. They cost less than 1 dollar
for the two. Tap them in very gently with a hammer. Don't bash on the
gasket surface! |
| On the block-off plate near the oil filter mount, I tapped
the oil temperature sender. If you are going to do so as well, be
absolutely sure the oil filter still fits. My temperature sender was a
very very tight fit! Maybe an oil filter relocation kit was handy,
replacing the filters has always been a big pain! |
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After I installed most of the parts on the main block, I
screwed in all the head studs. The head studs have two different sizes of
threads, the small thread is for screwing into the engine block, the big
thread is for the nut. Check your packaging, my original packaging came
with 10 studs only. I was 4 studs too short and had to wait another 2
weeks before those arrived! |
| When you are read to put the head back on the block, you
need to fill the little gaps between the front plate and the block with
liquid sealant. |
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Put on the metal head gasket. I chose to put the 1.2mm on
the block. There was about 0.2 mm removed from my block and about 0.3 from
the head. As standard head gaskets are about 1 mm, I 'gained' 0.3 mm
compression. Well, that's about nothing I would say ;) In Holland you can
get 98 octane at all pumps, so detonation is far away. |
| Hop the head over the studs. Be very careful not to damage
the gasket surface. Do this with a friend as the head is quite heavy. The
nuts for the ARP head studs are size '14 mm'. A regular 14 mm socket (1/2
inch) does not fit. I used a 14 mm socket on 3/8 inch. An adapter to 1/2
inch was used to be able to put the socket on the torque wrench. I torqued
the head studs to 90 ft/lb. This is quite high, but well, a tight fit is a
tight fit. If you use bolts, don't go over 72 ft/lb. The ARP bolts are
size 13 mm b.t.w. |
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I installed iridium spark plugs on the engine. These only
come with 1.2 mm gaps. You have to re-gap them in order to comply with the
stock specifications (0.8 mm) I didn't do that and didn't find any
problems with it.
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Well, the block is complete, the head is on. You can now put everything
together and get the power plant in the car. Check my next story on how to get
everything back together to see how to get it back in the car.
Supra 
