The N/A Maintenance FAQ

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Supramania Contributor
Authorized Seller
Feb 26, 2006
Well, I guess since the maintenance section took way too much space in the N/A Upgrade FAQ, I decided to post up a completely different topic. In this thread I'll post up every single maintenance-type reference I've found on these forums and possibly others, so it's easy to find help instead of looking through tons of threads with the Search Function. This is a thread I've linked to in the N/A Upgrade FAQ so people get the hint that maintenance is key to having a decent/running N/A. The general rule of thumb for me when posting up these references is I'll link you to it if it's not on these forums, and if it's on these forums I'll just put it in a quotation box (unless there's too much information, then I'll just leave it as a clickable link).

Table of Contents:
Post 1 - General References
Post 2 - Engine Break-In Tips/Information
Post 3 - Engine Rebuild Tips/Information

You have no idea how many people skip this stage in an attempt to make their car faster. On a car that is easily over 15 years old, with possibly no idea of what the previous owner did, it's important to make sure the parts work before you modify the car. Modifying the car to make more power on parts that were probably already going to fail is going to cause a huge amount of problems. Here are a few nice quotes for you:

Nick M said:
There is very little wrong with this car as intended from the factory. The only thing is all of you that have gotten your hands on them. Those of you in this category know who you are, and those who are not know who you meat heads are.
SupraCentral said:
However I still stand by my statement that 99 times out of 100, the weak link in the MKIII is the owner.
There are tons of sayings which bash MK3 owners (which are similar to those ones above) and the thing is, it's true in most cases. The sad fact is, the problem is the owner, not the car.

Also, Here's some information of the whole Regular vs Plus vs Premium debate (gas).

Gives good information for stock applications on whether to use regular, plus, premium or whatever. The consensus is just to use 87 octane unless you have advanced your timing, or have done Intake/Headers/Exhaust in which you should use 89 octane, as a member reported that he started hearing a knock after he started running a OBX header on his car with 87 octane. 91 octane is usually completely unnecessary unless you are running really high compression, or highly advanced timing, or something drastic.

Well, there's some much info on this I won't even post it here, and instead, I'll give you a VERY useful link on the common Maintenance Required. Here is also a big list of guides on how to do a lot of things to your car, such as checking codes, etc.

Here is a link to the Toyota Service Repair Manual (TSRM). This has everything you'll need to do the maintenance, provided you look in the right places, etc.

Here's a basic maintenance schedule to follow.

Nick M said:
As the almighty oil change is constantly a hot topic around here,::dead horse::

here is the maintenance schedule from Toyota. It will be suprising for some. This is from the 91 repair manual. If I had a TSB stating it superscedes the old information, I would give it.

7MGE oil and filter every 12 months
7MGTE oil 5000 miles or 6 months
7MGTE filter 10,000 miles or 12 months

In your oweners manual it would state a different rate for "harsh conditions". The repair manual has defined that for us.

  1. Towing a trailer, camper, or with a pickup topper
  2. Repeated short trips less than 5 miles below FREEZING
  3. Extensive idiling or low speed driving for long distances
  4. Dusty, rough, muddy, or salty roads

Except for the expected contamination from the last item, the others are due to excessive blowby created in those conditions. Boosting is not listed, as the engine is very hot, and you are in and out of load, unlike pulling a trailer, which we don't do anyway. When the engine heats up, the addititves put in at the refinery work to keep the oil clean and free of varnish and acid.

If you are doing this, the schedule changes to,
7MGE 6 months oil and fitler
7MGTE 2500 miles oil
7MGTE 5000 miles filter.

edit: now go read jetjock, adjuster, and jdub's oil and filter quality threads
Here's some comments on Rod Knock and such.

Supracentral said:
General Rod Knock Info:

Diagnosing Engine Noises can be the most difficult thing a mechanic can do. Misdiagnosis is the norm rather than the exception.

I almost laugh when people open up and say it's a "rod knock" for every noise from fuel pump rattle to rocker arm tap.

My personal favorite was a customer of mine who insisted he had a rod knock when in fact a bulge in one of his tires was hitting a shock absorber.

You might not have enough money to send your kid to college after you spend it fixing an audio illusion. On the other hand you may spend dozens of hours and hundreds of dollars replacing parts in an engine that is truly shot.

First thing you need to do is spend 20 bucks for a cheap stethoscope at the auto parts store or if you are going to do this a lot get the electronic ones from Steelman for about $120.

But, possessing human nature, you will convince yourself that a hose stuck in your uneducated ear will do just as well. No sense in arguing with you that the whole idea is to be able to discern infinitesimal changes in direction and intensity that require the use of two somewhat experienced ears AND the right tools.

So stick your dumb ol' hose in your stupid ol' ear and we'll start with some clues.

Remember that diagnosis of engine noises is nothing more than splitting possibilities down to only one

First off, eliminate all of the accessories like the alternator, power steering pump, A. C. compressor and vacuum pump by removing the belts one at a time. If the noise is gone, of course the problem is a belt driven accessory. If the naughty noise is still there you should be able to hear it more clearly by not having the accessories whirring away.

If the engine has a carburetor instead of fuel injection it probably has a mechanical fuel pump mounted to the engine. Before the engine gets too hot, put your hand on it. If it is making a noise you should be able to feel it.

Try to track the noise down with the stethoscope tip or the end of the hose suckered onto the engine surface, sealing the end. Spend a full ten minutes putting the hose all over the engine, not just where it is loudest. Try to envision the parts moving inside the engine. You are training your ear, not just listening, so don't get in a big rush except to be sure that the engine doesn't overheat. A trained ear can tell you which piston is slapping or which rocker arm is clacking from outside the engine so if you come out from under the car proudly saying, "it's the bottom end" get your dumb-ass back under there until you can tell me it's coming from the oil pump or the 3rd piston back on the driver's side or the flywheel or the camshaft.

Rod knocks are loudest at higher speeds (over 2500 RPM) Feathering the gas pedal may result in a distinctive back rattle between 2500 and 3500 RPMs.

Bad rod knocks may double knock if enough rod bearing material has been worn away allowing the piston to whack the cylinder head in addition to the big end of the connecting rod banging on the crankshaft rod journal. It will sound like a hard metallic knock (rod) with an alternating and somewhat muffled aluminum (piston) klock sound.

Wrist pin knock in modern engines is very rare today but is a favorite for the misdiagnosticians.

Determining which cylinder contains the noisy parts may be aided by shorting out the plug wires one by one with a common low voltage test light. Now you won't get the bulb to light up but it is a convenient way to short the cylinders without getting zapped or damaging the ignition coil.

Attach the alligator clip to a convenient ground, away from fuel system components, and pierce the wire boots at the coilpack or distributor end of the wire.

If the noise is changed when the plug wire is shorted to ground, you can figure that the problem is in the reciprocating bottom end parts. (piston, wrist pin, connecting rod or connecting rod bearing)

The reason the sound changes is that when you short the cylinder plug wire you are stopping the combustion chamber explosions that are slamming the piston downward making the inside of the big end of the connecting rod bang against it's connecting rod journal. Or in the case of piston slap, no explosion changes how the piston is shoved hard sideways against the cylinder wall.

If you get a change in the sound when you short a cylinder out it may become moot as to what the problem is because the oil pan and cylinder head must be removed to correct the problem.

[Generally speaking, an engine with damage to reciprocating parts (pistons, rings, connecting rods, wrist pins or rod bearings) and more than 70 thousand miles is not cost effective or risk free enough to attempt to repair. Replacing a crankshaft, for example while the rest of the engine has 70k perfectly maintained miles on it is risky enough but whatever killed the crank has scored the rings and packed the lifters with debris and smoked the piston pin bosses etc. You need to find out why things went bad to start with. Engines don't just fail. There are reasons for the failures.]

If the sound doesn't change, look at parts other than the reciprocating ones. In many cases of rod-knock or piston slap, more than one is banging so even if you eliminate the noise from one rod the other one will still be a-banging away with a different, more singular tone.

Commentary on rod knock after a HG swap

I've seen dozens, no probably HUNDREDS of cars develop rod knock after a head gasket repair.

The common (incorrect) assumption is that the new head gasket provided higher compression and the additional force on the worn out old bearings cause a failure. In a word, bullshit.

What the real cause is, 99.9999% of the time is coolant in the oil. Now before you go and discount this, understand a few things:

Many tests have shown that as little as 0.04% (400 PPM) water in lubricating oil can cut the fatigue life of bearings by as much as 48%.

Moisture is generally referred to as a chemical contaminant when suspended in lubricating oils. Its destructive effects in bearing applications can reach or exceed that of particle contamination, depending on various conditions.

Water may cling to metal surfaces or even form a thin film around solid contaminants such as silica particles. But by far the most damage is done when 'etching' occurs.

Water etching is a common type of corrosion occurring on bearing surfaces and their raceways. This corrosion is caused primarily by the generation of hydrogen sulfide and sulfuric acid from water-induced lubricant degradation. Yes, you read that right water (and anti-freeze) when mixed with oil and heated inside an engine combine to form acid. This eats away the soft surfaces of your bearings in no time.

(Ever notice that a Supra with a BHG for any length of time will have rust in the coolant? - Guess what - the coolant has become acidic by mixing with the exhaust gasses that are getting into the water jacket!)

Remeber your bearings are never supposed to "touch" anything but oil. The bearings ride on a very thin layer of oil. Once there is some etching, the oil pressure drops (since the etching has provided the oil with a place to go other than where it is supposed to be) and eventually the bearing touches the rotating surface. After that it's all over.

Did you do your head gasket replacement with the motor out of the car? Did you drain 100% of the coolant from the motor before you removed the head? Did you pull the oil pan while changing the gasket? If your answer to any or all of these is no, I'll bet coolant contamination in the oil was the culprit.


Supramania Contributor
Authorized Seller
Feb 26, 2006
If you have a new engine, here are some helpful tips.

Reg Riemer said:
The following are a few notes on break in and other new engine tips.

Do not rev your engine over 3000 rpm. Many new engine owners blow the long term life of their new piston rings within the first 1500 miles, I mean miles not Kms. The only thing that needs to break in on your engine are the rings! The rest of it could be run on the Dyno at 7000 rpm 5 minutes after it is first started. Piston rings need time to bed in to the new block surface. If you go more than 3000 or 3500 Max you will not get the correct bed in pattern. Very Key. When on the highway do not drive at same speeds, don't rev the motor over 3250 rpm and also don't lug it to much. The best thing is small changes in speed, 80,100,105,110,75,80, etc. basically just don't use the cruise control on the hiway and you will get a great break in.

Head retorque will not be needed. Your engine has racing-spec head bolts and the factory torque spec's are not to be used.
Your spec is 70 ft/lbs.

Things to do, I have noted things that must be done and things that are optional:

Be sure you have the cooling system all up to speed:

*New rad cap {a must do}
*New clutch fan {a must do}
*New or Serviced Rad {a must do}
*New Toyota thermostat {a must do}
*New Toyota rad hoses, replace as necessary

Make sure exhaust system is up to speed:

*Remove Cat's from down pipe by installing a straight pipe {a must do}
*Or replace the Cat's with single High Flow or factory new ones {optional}
*Clean all engine parts to be put on the new engine long block {optional}
*Install new spark plugs {a must do}
*Check resistance on plug wires {a must do}
*Replace clutch disc {a must do} its the old pay me now or pay me later rule. When the engine is out it is out anyway, never put in a worn clutch disc, anything less than 80 % left is not worth your time.
*Have turbo inspected by turbo shop.

Oil and oil changes:

*Only use Toyota Ceramic oil filter on the engine at all times. This is the best filter on the market.
*Use Esso Ultra 10-30 oil for break in. Esso oils have proven to work well in 7M turbo and 2JZ twin turbo engines.
*Change the oil after the first 500 kms to new Esso Ultra 10-30.
*After this change the oil every 2000 km's.
*When the engine has 10,000 km's you can use Esso 100% synthetic 10-30, or 5-30, 15-50 is good in the hot summer months. The Esso 100% synthetic will not burn through your engine as may of the other brands do. The club has compiled a lot of documented facts about oils that work and don't. I'm not telling you to use the Esso products because someone said they were good or some sales man said they would do this or that. The Esso oils have proven themselves over and over again. As has the Ford gear oil for the Diff's in the Supras and Redlines synthetic MTL for the 5 & 6 spd trans.

This should see you to a good new engine.
Contrary to the standard break in process (which is to baby the car until 1000 miles or so), you might be able to break your car in a different/better way, which is covered in this link.

Decide which way you want to break your car in :)


Supramania Contributor
Authorized Seller
Feb 26, 2006
If you decide maintenance isn't enough and want to do a rebuild, here's some information for you.

p5150 said:

This is intended to serve as a guide and to share the lessons that I've learned through the thousands of dollars I've spent. If you plan on rebuilding your 7M, please consider what I have to say. This isn't an all-inclusive guide or "everything you need to know". This is only intended to be supplemental information. You still need to familiarize yourself with basic engine maintenance techniques available in any Haynes or Chilton's manual. See also


When selecting your machine shop, look at their operation. It would be in your best interests to select the machine shop that has the cleanest setup and the newest, most accurate equipment. Many machine shops cannot correctly machine components for our engines.

The 7MGTE oil system is a high-flow, low-pressure system. At idle, the stock specification from toyota for oil pressure is 4.3psi. Yes, I said 4.3 psi, NOT 43 PSI! From the factory, the 7MGTE has rod clearances of .0008 to .0021, total thrust washer clearance of .002 to .009 (thats the clearances of both sides added together) and crank main bearing clearances of .0012 to .0019.

Check your oil pump drive shaft clearances:

Also -ensure your camshafts have the correct clearance. .0014-.0028 for the number 1 and .0010-.0037 for the rest of the journals.

Clearances too large will contribute to low oil pressure.

In additon, you should keep in mind that with such tight clearances it is possible for the measurements to change significantly with a change in temperature. If you take home your crankshaft, pistons, etc and re-measure them in your 0 degree garage, the measurements will probably change from the climate controlled readings of the machine shop. (And vice versa) Keep everything the same temperature for the whole process.

And, keep in mind that your mic might read different than your machinist - compare notes. Bring your mic in to check it out.

Many machine shops feel that it is necessary to make the clearances larger on these motors for "high performance" applications because thats what they do for the V8's. This, quite simply, is not the case. I learned this when I lost my first motor. Clearances that are too large will lead to a significantly lower oil pressure at idle and take out your bearings.

So, with that being said, BUILD THE ENGINE TIGHT. And always, I repeat always double check ALL measurements for yourself with a micrometer. Check your crankshaft, rods, piston bore, etc. etc. Dont trust the machinist to make sure that they are all correct. You will have a lot of time and money in this - dont let it go to waste.


Any reputable machine shop will wait until they have the pistons before they bore the block. If they want to bore the block before they have the pistons walk away with your engine because they are RETARDED!!

If you coat the pistons with any type of thermal barrier, consider the fact that they might not expand as intended from the manufacturer. Add .001 of clearance if you moly-coated the skirts.

HKS used to sell 85.5mm pistons - which are actually quite larger than the stock bore. I would limit any custom piston size to that.


Ensure that the rear timing cover is bolted to the block when you mill the top. If it isnt, your head will be held up by it and not seal correctly against the block surface.

Ensure that your machine shop gets it smooth. The first block I had done still had pits in it. My machinist insisted it would be "fine". Fuck him. Ill talk more about surfacing for your head gasket later.

A good machine shop will paint the block exterior, and ensure that all of the oil and coolant passages are clean upon the delivery of the block. If they are full of rust and debris when you blow out your oil passages before assembly, be sure to bring it up to your machinist.

CLEAN OUT THAT ENGINE!!!! Keep it clean - your oil passages should be spotless before assembly. Get a drip pan under your engine block while it is on the stand and blow it out with WD-40, air, with a final rinse of engine oil. Remove the piston oil squirters and ensure that they arent stuck open for some unknown reason. Ensure that they are clean and move freely. They have a check valve in them that shouldnt allow oil past at lower psi. Once you get the block clean, reinstall and torque to specs.

Check your oil filter housing. There are two relief valves in the housing - one bypasses oil to the oil cooler and the other bypasses oil in the event that the filter clogs. Ensure they are clean and installed in the correct DIRECTION.

Tap out all of the bolt holes and follow up the tap with a gun bore brush. You will make things easier on yourself.
And always, always cover it up when you're done for the day. Avoid dust-kicking drafts in your work area at all times. A trash bag with the little yellow handles that sinch it up works well.

CLEAN YOUR CRANKSHAFT OIL PASSAGES - same as above. If your crankshaft has a groove worn in the ends from the oil seal, you can purchase a repair sleeve that will fit right over the end.


Measure and set your ring-end gaps.

Use plenty of moly-based lube on your bearings during assembly.

I dislike plastigauge, my personal belief is that a good set of mics are far more accurate. However, plastigauge can be a good indicator of where you stand with your clearances - just dont rely on it.

Use ARP hardware - the new main stud kits have been changed. (The Supra community can thank me for that.) The old kits used to hit the pickup tube for the oil pump. Be wary if you have picked up an old kit.

Get a quality torque wrench.


The first thing you should do, before doing ANYTHING to the head you plan on rebuilding, it have it inspected and cleaned by a competent machinist. But be wary! I once had a machinist bead blast my journal surfaces He thought that bearings were supposed to go in there.

A mild street port will do the engine well. You dont have to go overboard and can finish the job in less than a week, part time. should give you a good tutorial on basic head porting. It really isnt that hard as long as you keep it simple and just gasket match the manifold to the head, smooth out the casting flash and the valve seat ridges. DO NOT PORT MATCH THE EXHAUST MANIFOLD TO THE HEAD. Opening up the exhaust ports on the head removes the reversion dam and will cause you to lose torque because the manifold will no longer scavenge the head. If you doubt me, search.

Camshafts from the 7M will oftentimes have a gouged appearance to them. They are fine, and you will be hard pressed to find a set that arent the same way anywhere else. The "gouging" or "scoring" is caused by aluminum buildup from the head. Dont polish them unless they are extremely rough. Polishing the aluminum off will only make your clearances larger in the head and contribute to oil pressure loss. The aluminum will only build up again over time.

In my opinion, aftermarket valvetrains with stronger springs are a waste of time. These engines werent made to rev anyway. A stock valve system is adequate, but gains can certainly be seen through larger valves. Ive heard of people fitting 2jz valves into these heads as a cheap solution - youll have to research that one on your own.

Schneider racing cams does a good job at regrinds.

Some people fit NA cams into the turbo block for gains on the bottom end. A dyno was floating around where somebody changed out one for the other and you can clearly see that NA cams peak at a lower rpm. Sure, this is great for under 350hp supras, but if you are going for big numbers with a big turbo keep the stock, turbo cams or order some performance regrinds from Schneider.

Set the valve lash (+.002 over TSRM) at about .010 on the intake and .012 on the exhaust for initial break in. Valves tend to seat a little bit - this will give the valves room to seat without sticking open.

You can get replacement valve shims from toyota for $$$$$$ or you can go to your local machine shop and get them $$. If your machine shop doesnt stock them look around more. I get mine from a machine shop for 3 bucks a piece.

Check the exhaust manifold bolt holes and helicoil if necessary.


This topic has been beaten to death. Here is my opinion from my experience:

Different head gaskets will yield different compression ratios from your engine. You need to consider all parameters when selecting a head gasket. Get an online compression calculator that considers engine bore, stroke, piston deck height, piston dish volume, head volume, head gasket thickness, head gasket bore. Yes, you actually need to measure these things. This is one of the most important things you will do. 1mm thickness change in a HG can change your compression dramatically. An 83mm bore hg compared to an 86mm bore hg can do the same thing. The bottom line is this: YOU NEED TO KNOW WHAT YOUR COMPRESSION RATIO WILL BE. Dont be a dumbass, figure it out so you wont run 20 psi on 9:1 when you think its 8.4:1. Also, you dont want to be stuck with a 7.5:1 slug that you thought had stock compression.

You can re-use an HKS MHG. Just spray it thouroughly with that copper spray from napa. This will fill in the irregularities from a standard machining. It is not necessary to lap the head when you use this stuff.


HKS recommends an RA of something like 15? microns or less. Dont quote me on that exact figure but its close. No machine shop will be able to accomplish that without some really advanced equipment. IMO, a copper head gasket would work well, but I have yet to use one. Some people have used the permatex brake quiet instead of the copper spray. I know it sounds goofy, but supposedly it works.


Use ARP studs. No, they dont clamp more than the bolts, they provide a more well-distributed torque. With bolts it is possible to read 80ft/lbs with a torque wrench and not have the appropriate clamping force because junk was in the threads of the block.

You DID remember to machine the front timing cover with the block, RIGHT?


Do not break in an engine with synthetic oil. It is too slick. Manufacturers do not design their rings to be broken in on synthetic and they will not seat correctly. Use dino oil for the first 1000 miles. Change it after the first test drive, 50, 500, and to synthetic at 1000. (Just my method, do what you like) Drive it hard.

Good luck.
And here's an add-on to that:

Adjuster said:
If you re-use any MHG, make sure you clean it first with brake cleaner. (Takes off all the hylomar/rubber etc.) Generally that stuff tends to degrade over time. My Greddy MHG did not have any from the start.

I've found the Brake Quiet to be very effective on these bare gaskets to seal up all the smaller scratches and stuff. No leaks yet, and it's been done 4 times to this Greddy gasket.. still no leaks...

Last time around, we did machine the right bore into the gasket by clamping it between the block and the tourqe plate. I can't say enough how important the tourqe plate proved to be. It changed the bore by 4k in places.. That is quite a bit, and would take alot of ring wear to seal up, if it would seal up at all.
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