How to - Re-Shim Cams

Due to fitting different cams I had to re-shim them. This guide should give an idea of what is involved and how to go about it.

Tools/Consumables Required:

10mm Socket

Ratchet for Socket

Torque Wrench (20nm range)

30mm Spanner

Small screwdriver

0-1" Micrometer (Or 0-25mm if you prefer metric)

Imperial Feeler Gauges - A good range is required with individual feelers. I had 0.0015" then 0.002" to 0.025" individually.

Assembly Lube (You can just use clean oil as per the manual if you wish)

Loctite 5922 (Sealant for the front cam journal bearing)

Wipes (I went through quite a few)

Gloves (if you want to keep your hands oil free)

Paper - To write sizes down on

Pen - To write with

Permenant Marker - To mark shims.

Note1: This guide assumes you have half a clue what you are doing. I won't be turning it into a laymans guide for the safety of your engine. This is an engine critical job and must be done properly and carefully. Anyone attempting this must be competent with using a torque wrench, a micrometer and feeler gauges. Ham fisted use of any of the equipment could lead to a badly running engine or worse.

Note2: Cleanliness is next to godliness when it comes to the insides of your engine. You must make sure that everything you use is as clean as possible. Dust won't be too much of a concern but certainly don't leave your engine open to the elements overnight or anything like that. If any larger debris gets into the head and you don't notice you will cause damage to your engine. I'm personally going to be doing an oil change after a few 100 miles just to clean out any dust and crap that may have gathered in the head/block/cooling system etc even though I have covered everything anytime I have been leaving it. I probably don't have to but I would rather be safe than sorry.

I won't be covering removing the timing belt etc, this is already covered in a couple of the other guides so I didn't see any need to repeat it. This guide will begin with the timing belt off, the cam pulleys off and the cam covers off.

So this is where we will be starting...

The first thing you want to do is measure the current clearances. Firstly rotate the cam using the 30mm spanner so that cam lobes 1 & 2 are pointing upwards. If you look at the above picture you will see that 1 & 2 are pointing upwards on the intake side. Be careful not to damage the head while doing this, the cams will be very tight and quite jerky to turn. Using the feelers measure the gap between the shim and the underside of the cam. The following picture was measuring one of the exhaust side gaps but the principle is exactly the same. Work your way through the feelers till you find the one that fits the snuggest and write this size down along with the corresponding shim number.

Do exactly the same for the 2nd shim gap and then rotate the cam so that lobes 3 & 4 are uppermost. The manual says to measure different ones at different locations at different rotation points on the cam, I found that doing it the above way saved lots of confusion and only added a few minutes of time to the job at hand.

I had the following results...

Intake1 0.009

Intake2 0.009

Intake3 0.007

Intake4 0.007

Intake5 0.008

Intake6 0.008

Intake7 0.008

Intake8 0.007

Intake9 0.008

Intake10 0.008

Intake11 0.006

Intake12 0.008

Then simply do the same on the Exhaust side. My results:

Exhaust1 0.010

Exhaust2 0.011

Exhaust3 0.010

Exhaust4 0.010

Exhaust5 0.010

Exhaust6 0.011

Exhaust7 0.010

Exhaust8 0.010

Exhaust9 0.011

Exhaust10 0.011

Exhaust11 0.010

Exhaust12 0.010

The stock gaps are:

Intake - 0.006" to 0.010"

Exhaust - 0.010" to 0.014"

According to the stock limits my cams are fine but most cam manufacturers will specify their own gap tolerances. In my case the limits were 0.010" intake and 0.012" exhaust. This meant that I needed to re-shim everything. Thankfully a little juggling helped out but we will get to that later.

Ok, now that we know the current gaps the decision has to be made as to whether re-shimming is required. In my case it was so the cams had to come out. The front journal caps are removed first and entirely, no need to loosen them off in any order. Once the bolts are loosened the cap may need some leavering to get it off of the seal, I used a large taped up screwdriver resting on a small block of wood to do this. Thankfully there is a tab on the caps for doing just that. The rest of the caps are loosened uniformly and in an order. The following picture shows the order of loosening. Simply loosen each bolt 1 turn then move onto the next until the cam is free. Pay attention to this step here, if you don't do it properly you can quite easily snap your cam. Be patient and don't try to get ahead of yourself.

Once the bearing caps are off gently remove the cams. The cam seals will be in place, I would recommend replacing these but it's up to yourself. Put the cams somewhere safe and dirt free. Leave the oil on them as that will make for a good lubricant when they are going back in. The following picture shows the exhaust cam out and the intake cam free.

Now you need to remove shims from the buckets. Firstly you need to mark all the shims so that you know which one goes where. Simply give the tops of the shims a wipe and then mark either "I" or "E" followed by the valve number. The buckets are notched to give access to the shims with a small screwdriver. You need to be fairly gentle removing them as oil will be holding them in place. It can get a little tricky, for some I just pulled the bucket out to get it out. Always place the buckets back in the same location that they came from. I'm not sure on the tolerances of the buckets so I was always careful of what ones went where.

Once all the shims are out you want to measure them using the micrometer.

Mark the size of the shim next to the corresponding gap that you wrote down earlier...

Intake1 0.009 - 0.1100

Intake2 0.009 - 0.1110

Intake3 0.007 - 0.1100

Intake4 0.007 - 0.1130

Intake5 0.008 - 0.1140

Intake6 0.008 - 0.1090

Intake7 0.008 - 0.1080

Intake8 0.007 - 0.1110

Intake9 0.008 - 0.1095

Intake10 0.008 - 0.1110

Intake11 0.006 - 0.1120

Intake12 0.008 - 0.1125

Exhaust1 0.010 - 0.1120

Exhaust2 0.011 - 0.1095

Exhaust3 0.010 - 0.1100

Exhaust4 0.010 - 0.1100

Exhaust5 0.010 - 0.1130

Exhaust6 0.011 - 0.1130

Exhaust7 0.010 - 0.1110

Exhaust8 0.010 - 0.1100

Exhaust9 0.011 - 0.1130

Exhaust10 0.011 - 0.1100

Exhaust11 0.010 - 0.1125

Exhaust12 0.010 - 0.1135

From the above you can work out the sizes of shim that you require. The most important thing to remember here is that in order to increase the gap you need to decrease the shim size. It's very easy to get confused and end up buying a larger shim when you actually require a smaller one. In this instance I need a 0.010" gap on the intake and a 0.012" gap on the exhaust

Intake1 0.009 - 0.1100 - (-0.001) 0.109" required

Intake2 0.009 - 0.1110 - (-0.001) 0.110" required

Intake3 0.007 - 0.1100 - (-0.003) 0.107" required

Intake4 0.007 - 0.1130 - (-0.003) 0.110" required

Intake5 0.008 - 0.1140 - (-0.002) 0.112" required

Intake6 0.008 - 0.1090 - (-0.002) 0.107" required

Intake7 0.008 - 0.1080 - (-0.002) 0.106" required

Intake8 0.007 - 0.1110 - (-0.003) 0.108" required

Intake9 0.008 - 0.1095 - (-0.002) 0.1075" required

Intake10 0.008 - 0.1110 - (-0.002) 0.109" required

Intake11 0.006 - 0.1120 - (-0.004) 0.108" required

Intake12 0.008 - 0.1125 - (-0.002) 0.1105" required

Exhaust1 0.010 - 0.1120 - (-0.002) 0.110" required

Exhaust2 0.011 - 0.1095 - (-0.001) 0.1085" required

Exhaust3 0.010 - 0.1100 - (-0.002) 0.109" required

Exhaust4 0.010 - 0.1100 - (-0.002) 0.108" required

Exhaust5 0.010 - 0.1130 - (-0.002) 0.111" required

Exhaust6 0.011 - 0.1130 - (-0.001) 0.112" required

Exhaust7 0.010 - 0.1110 - (-0.002) 0.109" required

Exhaust8 0.010 - 0.1100 - (-0.002) 0.108" required

Exhaust9 0.011 - 0.1130 - (-0.001) 0.112" required

Exhaust10 0.011 - 0.1100 - (-0.001) 0.109" required

Exhaust11 0.010 - 0.1125 - (-0.002) 0.1105" required

Exhaust12 0.010 - 0.1135 - (-0.002) 0.1115" required

The shims come in 0.002" increments and I was told by Dude to always work to the larger tolerance so where an exact size can't be found you need to drop to the closest LOWER size. From the above you can see that the following is required...

0.106 1

0.107 3

0.108 5

0.109 5

0.110 5

0.111 2

0.112 3

Obviously we don't want to buy all new shims (they are £10 each) so we need to try and make the most of what we currently have, which are....

108 1

109 3

110 6

111 4

112 4

113 5

114 1

When ordering shims they come in 0.002" increments. It was recommended to me by Dude that I work to the larger end of the limits so when a size isn't available, ie 0.107", the next size down is ordered, ie 0.106". Taking the above into account the following would need to be ordered (thankfully I had a spare head with more shims to make use of so I only needed a few)...

0.106 x 4

0.108 x 6

The shims of use that we currently have are:

0.108 x 1

0.109 x 3

0.110 x 5

0.111 x 2

0.112 x 3

TBC

Once you have all the shims they need to be laid out into size, check them again with the micrometer then lay them out...

From here, lay out each am individually from the piles so that they are ready to go. Be sure to check and double check here.

Once you are completely happy simply place them into the corresponding buckets. Make sure that the buckets freely rotate in the bores, it should be really easy to rotate them. If it isn't, take them out and check them they may be corroded. If they are they need replaced and you may need to resize that shim.

I then placed the cam in position and put some assembly lube on the journals. Once you are happy with everything it's time to start tightening it down. I followed the manual which for the TT you are told to put the no.3 and no.7 caps in place till they are touching the head. The cams also need to be rotated to the correct orientaton before tightening. On the Intake its around 3 o clock and on the exhaust it's around 11 o clock. I tightened them down to just above the head and then put the no.1 bearing in place. Put the cam seal in place (I recommend new). A light line of loctite is required round the outer edge of the bearings (see the manual) just to make a perfect seal. It's now time to follow the manual for the tightening proceedure. The order is as follows..

The same as with the loosening this needs to be done uniformly. One turn at a time on each bolt in the order above to get a uniform tightening. The bolts are torqued to 20nm (14lbs). I set my torque wrench at 10NM and did them all up to that (not at once, over numerous passes) and then did them all up to 20NM just to be sure it was uniform.

And you're done. Now simply check the gaps with the feelers using the same method as described earlier. If you have done everything correctly it will be bang on

Excellent post Scott. This is a definite how to guide...

I have a few questions.

1. You said the gap/clearance you required for the new cams was 0.010" Intake and 0.012" Exhaust.

Did your cams come with a range or was it that specified value? If it was a range, how did you decide what value to aim for?

2. All your new shims were purchased from Toyota correct? I assume you dont get sort of universal ones?

Maybe a more general question,

I have heard of ppl using the shim under bucket on the 2JZ head (using Nissan shims, I think?). Is there some reason for this or advantage?

Thanks..

Excellent post Scott. This is a definite how to guide...

 

I have a few questions.

 

1. You said the gap/clearance you required for the new cams was 0.010" Intake and 0.012" Exhaust.

Did your cams come with a range or was it that specified value? If it was a range, how did you decide what value to aim for?

 

2. All your new shims were purchased from Toyota correct? I assume you dont get sort of universal ones?

 

Maybe a more general question,

 

I have heard of ppl using the shim under bucket on the 2JZ head (using Nissan shims, I think?). Is there some reason for this or advantage?

 

Thanks..

1. The manufacturer just gave a fixed value of 10 and 12 thou. The standard limits are +/- 2 thou but after speaking to Dude he said to aim towards the higher end, giving more of a gap, rather than the lower end. A little more clearance is better than being tight. From that I took my limits to be 10-11 thou and 12-13 thou. I tried to hit the figures spot on and for the most part I managed it. Only one or 2 have drifted out.

2. I bought them all from Toyota yes. I don't know if universal ones can be purchased but I personally wouldn't take the risk. If I still worked in the Machine Shop I would have simply made my own or ground down the ones I have. If you are grinding down any shims make sure you grind the bucket side though. I'm pretty sure they will be case hardened and you dont want to get underneath that as the cam will wear down the shim if the hardening is lost.

3. The only reason I can think of the shim under buckets being a preference would be when running serious RPM. I could be completely wrong but I imagine there might be a slight worry of the shim flying out and causing damage. With serious RPM the clearance stroke of the cam might be slightly faster than the upstroke of the valve. This would possibly leave a gap that the shim could fly out between causing damage. Even if that theory is totally wrong if you can find out why people run shimless buckets I would guess it to be the same reasoning. At my level I personally wouldn't worry about it.

HTH

1. The manufacturer just gave a fixed value of 10 and 12 thou. The standard limits are +/- 2 thou but after speaking to Dude he said to aim towards the higher end, giving more of a gap, rather than the lower end. A little more clearance is better than being tight. From that I took my limits to be 10-11 thou and 12-13 thou. I tried to hit the figures spot on and for the most part I managed it. Only one or 2 have drifted out.

 

2. I bought them all from Toyota yes. I don't know if universal ones can be purchased but I personally wouldn't take the risk. If I still worked in the Machine Shop I would have simply made my own or ground down the ones I have. If you are grinding down any shims make sure you grind the bucket side though. I'm pretty sure they will be case hardened and you dont want to get underneath that as the cam will wear down the shim if the hardening is lost.

 

3. The only reason I can think of the shim under buckets being a preference would be when running serious RPM. I could be completely wrong but I imagine there might be a slight worry of the shim flying out and causing damage. With serious RPM the clearance stroke of the cam might be slightly faster than the upstroke of the valve. This would possibly leave a gap that the shim could fly out between causing damage. Even if that theory is totally wrong if you can find out why people run shimless buckets I would guess it to be the same reasoning. At my level I personally wouldn't worry about it.

 

HTH

Thanks Scott...

1. Understand your theory.

2. For something as impt as shims I would stick to Mr T's parts as well.

3. I remember my 4AGE 20V had the shim under bucket design, that engine revved to 8200rpm in stock form, so that theory could check out!

To change the Shims, is it necessary to take the cams out, when i did mine i used this method. But im sure i found a special tool somewhere that pushed the valve down to slide it out. Im planning on checking mine in few months and wondered if there was a easier option.

To change the Shims, is it necessary to take the cams out, when i did mine i used this method. But im sure i found a special tool somewhere that pushed the valve down to slide it out. Im planning on checking mine in few months and wondered if there was a easier option.

It is possible but it looks like a footery nightmare. It might be OK if the head was on the bench but in place on the car I honestly wouldn't fancy it.

Guess i take risks lol, i cant see the shim going far or into the engine holes. Just think for the less mechanically minded people who dont fancy taking the cams out be a easier option, How often do you think the shims should be checked scott?

Guess i take risks lol, i cant see the shim going far or into the engine holes. Just think for the less mechanically minded people who dont fancy taking the cams out be a easier option, How often do you think the shims should be checked scott?

The trouble is going to be getting the rear shims out though, you would need to be my height with a spine of titanium to pull it off with minimal fuss.

I'm not sure bud. There will be a schedule from Toyota though. I personally have never checked the clearance, the only reason I re-shimmed the head was to get the best out of the cams and to make sure I wasn't taking any risks.

To be honest the best bet would be to do this job when you are changing the timing belt. The belt is off anyway so the job is relatively straight forward from there... as above.

The trouble is going to be getting the rear shims out though, you would need to be my height with a spine of titanium to pull it off with minimal fuss.QUOTE]

 

Being my height i can do them sitting in the engine bay

I reckon its easier to take the cams off to remove the shims, instead of fiddling around under them..Not going to save you much time doing it with the cams in place.

This is awesome mate!!! Thanks for this!!!

Good post Scott

Can you translate from inches into mm?

Snarfed for the tech FAQs after a passive aggressive snipe from Scott

Good post Scott

 

Can you translate from inches into mm?

Yeah, multiply by 25.4

Snarfed for the tech FAQs after a passive aggressive snipe from Scott

To be fair I didn't realise it had as much response as it did lol. Selective memory at its best I guess

There are a few different ways of doing this, even the Toyota manuals confusingly list two ways of removing the cams, but this is one of them and it's a good one. I've used it myself

A couple of useful additional things:

1) If you are initially checking the shim clearances to see if anything needs changing, chances are you haven't dismantled the front of the engine, so the cam gears are still on and connected to the crank pulley. In this case, undo the spark plugs but leave them in situ, so when you rotate the cams you aren't also fighting the compression of one or two cylinders at the same time.

2) You can gently tap the #1 cam caps at the top, alternating towards and away from the front of the engine, to crack them off. Use something wooden or plastic. It's less scary than levering them.