Toyota Nation Forum banner

1 - 19 of 19 Posts

·
Registered
1997 Corolla
Joined
·
3,568 Posts
Discussion Starter #1 (Edited)
This is a Do-It-Yourself guide to replacing the valve stem oil seals on the 7A-FE or 4A-FE engine found on 7th generation Corollas. It assumes that you already have the camshafts off and have removed the shims and buckets from each valve.

Since you have to remove the camshafts to do this, it makes sense to do this while doing other maintenance such as changing the timing belt and adjusting the valve clearances.

Why:
New oil seals allow a tiny amount of oil to slip down between the valve stem and valve guide to keep it lubricated. When the oil seals get old they will allow too much oil to leak down into the valve guides. This will cause excessive oil consumption and carbon build up in the cylinders and on the valves.

Tools:
Lisle 36050 Valve Keeper Remover & Installation Kit
This is the tool that allows you to remove and install the valve spring retainer and keepers without removing the cylinder head. There is not enough space to fit an overhead valve spring compressor. The Lisle 36200 tool will not work because it only contains the larger tools, and the remover tool is too large.

Valve Stem Seal Pliers
Various brands that all look similar. This makes pulling the oil seals easier. You might be able to use some needle nose pliers, but you risk damaging the valve stem if the needle nose pliers slip while using them. The dedicated valve stem seal pliers fit straight down over the valve stem to minimize the chance of nicking the valve stem or the cylinder head surface where the buckets slide.

Tools to hold the valves up while the valve spring retainers are removed
There are 2 methods:
(1) air compressor with hose fitting for the spark plug hole to pressurize the cylinder
(2) a narrow rope to fit down the spark plug hole to fill the cylinder, then turn the engine by hand to compress the piston onto the rope to hold the valves in place.

The merits of these methods can be debated. I've never used the compressed air method, so I have to plead ignorance, but I have read about others that have used this method on other engines many times without failure.

A 11mm deep 6-point socket or something similar
This is used to press the new oil seals into place. It may be possible to press the seals into place with your fingers, but the idea is to only apply force on the outer part of the seal, so the inner part doesn't get damaged.

3/16" heat shrink tubing
This is placed over the top of the valve stem to protect the oil seal lip as it slides over the top of the valve stem and the lock grooves (for the keepers). The oil seal kits by Fel-Pro supposedly contain a thin plastic sleeve that serves the same purpose. The valve stem diameter is about 5.97mm, so a plastic straw or similar item that fits snugly on the valve stem would also work. The heat shrink tubing can be heated to shrink it until it fits snugly on the valve stem.

An L-shaped pick tool
I used this to clean some of the old seal material off the valve guide and to confirm that the seals were fully seated.

Toothpick
To clean some sludge from around the valve guide without scratching the valve stem.

Rags or paper towels
Put these over the oil passages and other areas of the cylinder head to prevent the keepers from accidentally falling and getting lost. Also, put them over the camshaft bearing surface near the valve you're working on to prevent accidentally scratching the surface with the oil seal pliers.

Parts:
8 Exhaust Seals, Toyota part 90913-02089
8 Intake seals, Toyota part 90913-02090

Various other aftermarket kits are available, such as Fel-Pro. These kits should include the 8 intake and 8 exhaust oil seals. Seals can be made of various materials, so you need to do a little research to insure you are getting quality seals if you go with an aftermarket brand.

Whether to use aftermarket or OEM seals is another area of debate. Some will say that Viton aftermarket seals are superior to Toyota seals.

Lisle 36050 Valve Keeper Remover & Installation Kit:
This is what's in the kit.

These parts are used to remove the keepers and spring retainer. The small one fit our engines correctly. They are magnetic, so when you press down on the retainer it pulls the keepers up, then you can remove the retainer and spring to get at the seal.

These parts are used to reinstall the spring retainer and keepers. The protrusion on the tool is spring loaded, so as you press down on the retainer the protrusion is pressed in by the valve stem and keepers, then as the outer part of the tool compresses the retainer and valve spring underneath it, at a certain point the spring action pops the keepers down into place, so you just lift the tool off and you're done. The large one worked better than the small one.


Procedure:
The valves need to be held in place when doing this. There are two methods to do this. One method is to insert rope into the spark plug hole with the piston down, then rotate the crankshaft to compress the rope into the valves above, then brace the wrench on the crankshaft bolt to prevent the piston from moving. This is the method I used.

The second method is to use an air compressor to fill the cylinder with compressed air to hold the valves in place. I used the rope method because I didn't have the correct hose attachment to screw into the spark plug hole. The downsides of the rope method is it was hard to thread the rope down into the cylinder. It also can carry dirt from the spark plug tubes down into the cylinder. It doesn't always fill the cylinder evenly, so a couple times a valve wasn't held firmly and I had to pull some of the rope out and recompress the rope.

If I had to do it again, I think I'd get the hose attachment for the air compressor. The downside to this method is if you lose power or the compressor breaks in the middle of the job the valves will fall into the cylinder. I wouldn't want to have to walk away in the middle of the procedure and rely on the compressor continually working as air leaks out, but you can do one valve at a time if you feel like doing a little at a time.

With either of these methods, you work on one cylinder at a time, then move to the next cylinder.

I had to use a wood skewer to push the rope down into the cylinder. This is a 3/16 inch thick nylon/polyester rope.

I used a 1/4 inch thick blue nylon rope for two cylinders. Both types of rope took several minutes to string about 12 feet of rope into the cylinder. I wonder if there is some type of rope that would be easier to string down into the cylinder.

Then I turned the crankshaft until I felt the rope was tight in the cylinder and then braced the ratchet. (I had my strut removed in this picture because I was doing multiple projects at once.)

There are two ways to remove the keepers with the tool. The first is to just use your body weight to press down on the tool until you hear the keeper pop into the tool.
The other way is to tap the tool with a hammer, and this compresses the spring just enough for the keepers to pop out.
Here is the retainer and keepers in the magnetic tool after removing them. Use the smaller removal tool in the kit.

Each valve has two keepers that look like this. The ridge fits into a circular groove on the valve stem.

The two keepers fit in the spring retainer like this. When they are installed on the valve stem, the upward force of the spring on the retainer keeps the keepers squeezed between the valve stem and retainer, and the keepers prevent the retainer from moving upward. The hole in the retainer is narrower on the bottom which doesn't allow it to slide up past the keepers.

Lift the valve spring out and put it with the retainer and keepers.

Now use the valve stem seal pliers tool to pull the seals off the valve stems.

I put a small piece of a plastic straw over the end of the valve stem so if the pliers slipped I wouldn't (hopefully) nick the valve stem.

It is kind of tricky squeezing the pliers tightly while gently trying to pull upward. When the oil seal does pop off, the pliers go up quickly but recoil downward, so it's a good idea to put a rag or something over the adjacent camshaft bearing surface to protect it just in case the pliers hit it.

Every one of the exhaust valve seals had a small piece of rubber break off around the valve guide which I was able to extract with a small pick


I didn't have the same problem with the intake seals, but I did find a bit of sludge around most of the intake valve stems by the valve guide. I loosened and cleaned this with a toothpick or wooden skewer.


Before installing the new oil seal, You might want to clean the valve stem and make sure there are not any burrs that could rip the new seal apart. I don't think a burr would develop naturally, but if you accidentally hit it with pliers while trying to remove the old seal this is possible, or possibly someone changed the oil seals before and damaged it. I didn't check my valve stems to carefully, but they appeared to be fine.

Use the heat shrink tubing (or similar) to protect the new seals as they slide over the valve stem where the groove for the keeper is. Heating one end of the heat shrink tubing will make it slightly cone-shaped.

The Toyota exhaust seals are grey on the outside and are black on the top rubber part.

The Toyota intake seals are brown/gold colored on the outside and are grey on the top rubber part. The intake seals also have "NOK" printed on the top.

Put a few drops of oil on the seal lip, seal interior, tubing and valve stem before pushing the seal down.

You can press the seal down most of the way by hand. I used a 6-point, 11mm deep socket to press the seals down completely. That size only applied force to the edge of the seal without damaging the rubber inner seal. The exhaust seals seemed to snap down and then snap down a little farther, while the intake seals were more of a single snap into place then went down a little bit more. I used this pick tool to feel how far the seal was seated into place.

By removing two valve springs at a time you can compare the new seal to the old seal to be sure the new seal is pressed fully into place. You could feel how much space is between the bottom edge of the seals and the cylinder head. It's just a few millimeters.

After the new seal is in place, put the valve spring back in position, then put the retainer and keepers in place on top of the spring, then use the bigger installation tool to press it into place. The keepers should stay in the retainer like this before you place the tool on top.

As you press down with the tool you want the valve stem to be centered between the keepers. When it's pressed down far enough you will hear a slight click as the keepers get pressed into place.
Slowly lift the tool. If it worked correctly the keepers will be in position a millimeter or two below the top to the valve stem like this.

I didn't try using a hammer to do this. I just used my body weight to slowly press down until I heard the keepers snap back into place. The only problem arose when the valve wasn't held firmly in place by the rope. In this case, the keepers would only go halfway down. The problem was really only if the valve stem moved about a centimeter. If it just moved a few millimeters I was still able to get the keepers to snap into place.

If it didn't work, the keepers might be only halfway pressed down, or only one of them will be in the proper position. If this happens reposition the keepers and retainer and try again. Just be careful not to lose a keeper if there is any tension in the spring.

Twice, on two different valves, I had to lower the piston slightly, pull some rope out of the cylinder and recompress the rope, and this worked well enough the get the keepers installed. I held the valve in place with some string wrapped around the valve stem groove while I did this.


I give this Lisle tool a big thumbs up. It worked great once I realized that the valves need to be held firmly in place by the rope in the cylinder. If I had used the air compressor to hold the valves I think it would have worked almost perfectly.
 

·
Mr Mojo Risin'
1993 Corolla DX
Joined
·
579 Posts
Very nice! Luckily my Corolla doesn't have this issue but if I ever need to do this I can now :thumbsup:
 

·
イリジウム
Joined
·
11,832 Posts
Great writeup!

You have much better luck than I did installing the keepers with that tool. Removal was very easy and quick however. I prefer the lever type tool for compressing the springs. And when installing, the lever type tool will allow you to space out the keepers if desired. Also, lightly tap the valve stem afterwards with a hammer to make sure the keepers are indeed seated.

I dip the seals in oil and place them using the seal plier. Then measure the installed height with a caliper, comparing with prior readings.

The intake seals are usually made of a cheaper rubber. That's why for $14 a set I'd just use Fel-Pro premium set. You want all Viton rubber.
 

·
Registered
1997 Corolla
Joined
·
3,568 Posts
Discussion Starter #8
You have much better luck than I did installing the keepers with that tool. Removal was very easy and quick however. I prefer the lever type tool for compressing the springs. And when installing, the lever type tool will allow you to space out the keepers if desired. Also, lightly tap the valve stem afterwards with a hammer to make sure the keepers are indeed seated.
I first tried to use the smaller installer tool without much success. Only installed one that way. I figured the smaller removal tool was the correct size, so the smaller installer should also work. When I switched to using the bigger one things got easier. That and realizing if the rope was compressing and allowing the valve to drop a little it wasn't working. On the valves that I could feel were held up tightly the installation was quick like in the short video I posted.

Another factor might be pressing down at the correct angle and being able to get your body weight onto the tool.

Which method did you use to hold the valves up?

I dip the seals in oil and place them using the seal plier. Then measure the installed height with a caliper, comparing with prior readings.
Sounds a bit more accurate than my method, although I'm 99% sure I got them on correctly. Maybe just a wooden pencil or dowel with a mark on it could be used to judge how far down the seals need to be...top of valve stem to top of oil seal.

Did you notice an improvement in oil consumption?
 

·
Premium Member
1994 Corolla DX
Joined
·
4,153 Posts
The depth-gauge tail?

Yeah must be it! Even that seems like a tight fit.

DrZ, I've been thinking more about what you said about the OE intake seals being rubber and the exhaust seals being viton. I see how people are promoting using viton for all seals but look at the ones you picked off your engine. The rubber intake seals are not nearly as bad as the viton exhaust seals. So in my mind there's no point in upgrading the intake seals since the exhaust seals will be the first to degrade anyhow due to the brutal heat. I think you sticking with OE seals is just as well, which you already knew but I just now rationalized. :)
 

·
Registered
Joined
·
804 Posts
THIS type of sticky is what makes TN such an amazing resource.

I'm a spoiled dummy who never had a dad to start me out puttering around on cars.

But let me review a sticky like this just ONE time, and it's like I'm an expert, just like those other guys..!!!

STELLAR WRITE-UP...!!!!

^_^
 

·
イリジウム
Joined
·
11,832 Posts
The fail-safe rope method.
Which method did you use to hold the valves up?
Yes.
Did you notice an improvement in oil consumption?
Exactly! There was one or two seals that I thought I lightly hammered seated, but the gauge told me that was not the case. Some reported feeling the "click", well you guys are doing much better than I did.
The depth-gauge tail?
Yes, the intake stems see the cooler intake air. Exhaust stems see thousands of degrees of exhaust gas. It's clearly a personal preference, but I'd still Viton the intakes.
So in my mind there's no point in upgrading the intake seals since the exhaust seals will be the first to degrade anyhow due to the brutal heat.
 

·
Senior TN Member
Porsche
Joined
·
7,508 Posts
Got a link to a lever type compressor that works with the head installed on the block?
Here's one on Amazon - https://www.amazon.com/CTA-Tools-2235-Overhead-Compressor/dp/B0035533LU
Or ebay - http://www.ebay.com/itm/Automotive-Engine-Overhead-Valve-Spring-Remover-Installer-Compressor-Tool-Set-/311734577353



I made my own head-off compressor about 20-years ago to rebuild my VFR750 and still use it to this day. Most of the time, the job starts with blown headgasket, so might as well do valves while I'm there.

 

·
Senior TN Member
Porsche
Joined
·
7,508 Posts
Yes, the intake stems see the cooler intake air. Exhaust stems see thousands of degrees of exhaust gas. It's clearly a personal preference, but I'd still Viton the intakes.
Hence the usage of sodium-filled exhaust valves on demanding applications such as forced-induction. Also beryllium seats really help as they conduct heat away from the valves significantly faster than steel. Really helpful when you've got aggressive cams that leave the exhaust-valves on the seat for very little time.
 

·
Registered
1997 Corolla
Joined
·
3,568 Posts
Discussion Starter #17
DannoXYZ, that's a nice lever tool. Has anyone used it on this head (7A-FE or 4A-FE)? I'd hate to find that it doesn't fit quite right, but it does look like it's probably compatible with most heads similar to ours. I'd guess it takes some getting used to the first time just like the tool I used.

About using the depth-gauge tail on the caliper, if the valve isn't held tight by the rope, then it could move and throw off the measurement. I guess you could just make sure the valve was pulled up all the way. I used my pick tool to judge the depth from the bottom of the seal to the cylinder head which didn't depend on the valve staying still, but this method didn't give me a hard number to use. I had to simply compare by feel the newly installed seal to the old seal. Maybe something shaped like my L-shaped pick but a little thicker would have worked better for me. But really, the seals seemed to snap into place and if they weren't seated completely it'd probably be obvious using any of these methods.

DrZ, I've been thinking more about what you said about the OE intake seals being rubber and the exhaust seals being viton. I see how people are promoting using viton for all seals but look at the ones you picked off your engine. The rubber intake seals are not nearly as bad as the viton exhaust seals. So in my mind there's no point in upgrading the intake seals since the exhaust seals will be the first to degrade anyhow due to the brutal heat. I think you sticking with OE seals is just as well, which you already knew but I just now rationalized. :)
I used the term "rubber" in the general sense. Viton is rubber. It's just a special rubber that withstands more heat than other rubbers. I'm not sure what Toyota uses for the intake and exhaust seals. I just played it safe and went with Toyota seals.

I'll have to take a closer look at the old seals and see how worn out they look. I'll try to take some pictures if there is anything significant to report.
 

·
Premium Member
1994 Corolla DX
Joined
·
4,153 Posts
I would imagine you could measure with the caliper depth gauge from the cylinder head surface below the seal to the top of the seal, hence removing the valve from the equation?
 

·
Registered
1997 Corolla
Joined
·
3,568 Posts
Discussion Starter #19
Perhaps. I was thinking the width of the caliper wouldn't fit down into the cylindrical area there.
 
1 - 19 of 19 Posts
Top