Valve adjustment on the fence.

[TheCafeKid]

And would it hurt to drop them one and a half? Say a 2.8 to a 2.65?? To much?

 

[Steve]

And would it hurt to drop them one and a half? Say a 2.8 to a 2.65?? To much?

If your clearance was exactly 0.03mm (the minimum) and you changed ONE shim size, your new clearance would be 0.08 mm (the maximum), so why would you want to change more than one size? If it takes more than one shim size to bring it into range, that means that the valve was never closing, so I would suspect burned valves, too. :shock:


.

 

[TheCafeKid]

AHh ok see that was confusing me. Almight Steve..answer me this...Im tight at 04 all across my intake ( couldnt find a set of feelers that go to 03 anywhere so i bought these from Z1) My number 3 exhaust is tight at 04... Cyl one is kewl to 05 and the rest will go to 06. Drop one across the board on the intake and one on the number 3 ex right?

 

[TheCafeKid]

Ok i think i figured out my confusion. IS THIS RIGHT?

Say i have a clearance of .03 and the shim is a 2.75. Changing the shim to a 2.70 adds the .05mm of clearance i need to get back to spec correct?

 

[Steve]

OK, shuffle time. :shock:

On the intake side, try moving shim #1 to #2 or #4 to #3. You might end up doing both of them anyway, but do one and measure it. See if your clearance is between .08 and .09. If so, your clearance before was between .03 and .04. Leave it at the larger one. Go ahead and do the other side, too, and check the clearance again. You do not have any 2.70 shims that you can put in intakes 1&4, so it looks like you will have to buy them, but you can put the 2.65 from Exhaust #4 in to verify. Since that is two sizes smaller, you should end up with .05 too much clearance on intakes 1&4. This will verify whether you need a 2.65 or a 2.70 in those locations.

On the exhaust side, again, you don't have any 2.70 shims to check #3, so take the 2.65 from #4, put it in #3 and see if you have .05 too much clearance. If you do, they you will need a 2.70, for sure.

If all that works out, it looks like IN 1 will move to IN 2, IN 4 will move to IN 3, two new 2.70 shims will go in IN 1&4. You will put a third new 2.70 shim in EX 3.

Total shopping list, assuming the measurements work as they should: three 2.70 shims.


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[TheCafeKid]

Ok was already in the process of that when you posted. Unfortunately, my smallest (2.65) did nothing to change one of the 2.75's i replaced. However i have a pretty good range of them here all the way to 2.5 that i snaked out of a head i bought. Forgive me again, but when runing the feeler gauge, if it WONT go under the lobe, its too tight right? I have at 04 it going about half way in, does it need to pass all the way thru?

 

[TheCafeKid]

Looks like i have run into the same problem as Kurt.
My exhaust side is fine. My intake side might be F-ed. DAMNIT

 

[robertob]

AND someone please explain to me why the BOOK says measure with the lobe up rather than flat?

Lobe UP/away from the shim is the most accurate way.

BUT, lobe at 90 degrees to the shim is also acceptable.

The factory has you do it that way on some of them so that you don't have to turn the motor as many times.

 

[49er]

Ok was already in the process of that when you posted. Unfortunately, my smallest (2.65) did nothing to change one of the 2.75's i replaced. However i have a pretty good range of them here all the way to 2.5 that i snaked out of a head i bought. Forgive me again, but when runing the feeler gauge, if it WONT go under the lobe, its too tight right? I have at 04 it going about half way in, does it need to pass all the way thru?

TCK, it is good practise to measure the existing shims with a vernier to confirm that they are as marked. I have found incorrectly marked shims when measuring up X shims at a breakers yard. Of the 40 odd shims I measured, 3 had incorrect sizes stamped on them. I'm sure that they hadn't been ground, as they all had the grey oxide surface commonly seen on these shims. Most ground shims aren't marked with their size anyway, so you have to measure them!
You should be able to lightly force the feeler blade between the lob and bucket. On high mileage 8 valve engines, you will find that the feeler will be tighter on one side of the blade (width wise). This is because the lobes wear slightly tapered due to the camshafts flexing under high rpms. The 16 valve engines have more cam bearing support so aren't as prone to this problem.

 

[TheCafeKid]

Oh ive had the calipers out the whole time for that very reason! Thanks for the help tho bro. I have relegated myself to the fact that the whole intake side is just that Far out. Ive examined the valves from what i can see and i dont see any scorching or pitting so im hoping that this didnt cook em. Its totally odd ball that the exhaust side were all in spec, but the intake was up to four sizes out.

 

[Nessism]

Lobe UP/away from the shim is the most accurate way.

BUT, lobe at 90 degrees to the shim is also acceptable.

The factory has you do it that way on some of them so that you don't have to turn the motor as many times.

Actually Robert, with the factory cam position both valves adjacent to each other will be on the base circle thus neither valve spring will be pushing on the cam. This position is ideal since the cam will be in the most neutral position as opposed to having one valve pushing on the cam and skewing it in the journal clearance.

Might be a situation of splitting hairs but considering the clearance is so tight, it's hard to justify going against the factory method.

 

[BassCliff]

Lobe positions

Lobe positions

Its totally odd ball that the exhaust side were all in spec, but the intake was up to four sizes out.

Mr. TCK,

Forgive me for asking the obvious. After you replace a shim, do you spin the engine a few times to make sure it's properly seated in the bucket before you re-measure? To go down 4 sizes (i.e. 2.8mm to 2.6mm) with a shim seems excessive.

Here is a view of the #1 exhaust lobe when properly positioned (pointing forward) to measure the clearances for exhaust #1 and #2.

Position #4 exhaust lobe in the same manner to measure both #3 and #4 exhaust clearances.

Here is a view of the #4 intake lobe position used to measure clearances for intakes #3 and #4.

Position #1 intake lobe in the same way (pointing up) to measure #1 and #2 intake clearances.

This picture shows the relative positions of all lobes when checking clearances (looking from the right side of the motor).

Basically, when checking exhaust clearances, point the outside lobe forward and measure both on that side. And when checking intake clearances, point the outside lobe up and measure both on that side.

Now I'll shut up before I display any more of my ignorance. I'm just relaying what I've learned from the Suzuki Shop Manual and my experience.

Thank you for your indulgence,

BassCliff

 

[Colin Green]

Mr. TCK,

Forgive me for asking the obvious. After you replace a shim, do you spin the engine a few times to make sure it's properly seated in the bucket before you re-measure? To go down 4 sizes (i.e. 2.8mm to 2.6mm) with a shim seems excessive.

Here is a view of the #1 exhaust lobe when properly positioned (pointing forward) to measure the clearances for exhaust #1 and #2.

Position #4 exhaust lobe in the same manner to measure both #3 and #4 exhaust clearances.

Here is a view of the #4 intake lobe position used to measure clearances for intakes #3 and #4.

Position #1 intake lobe in the same way (pointing up) to measure #1 and #2 intake clearances.

This picture shows the relative positions of all lobes when checking clearances (looking from the right side of the motor).

Basically, when checking exhaust clearances, point the outside lobe forward and measure both on that side. And when checking intake clearances, point the outside lobe up and measure both on that side.

Now I'll shut up before I display any more of my ignorance. I'm just relaying what I've learned from the Suzuki Shop Manual and my experience.

Thank you for your indulgence,

BassCliff

Thank you BassCliff.

Just what I needed.

 

[Road_Clam]

I for one, never understood the reasoning behind the factory specified position of the cam lobe in relation to the tappet for the purpose of adjusting the valves. One would think that rotating the cam lobe exactly 180 degrees away from the tappet would yield the minimum lobe base circle, but there must be a specific reason Suzuki want's the lobe at to odd placement angle....

 

[Guest]

I for one, never understood the reasoning behind the factory specified position of the cam lobe in relation to the tappet for the purpose of adjusting the valves. One would think that rotating the cam lobe exactly 180 degrees away from the tappet would yield the minimum lobe base circle, but there must be a specific reason Suzuki wants the lobe at to odd placement angle....

Their method puts the cams in a more "neutral" position. Putting each cam lobe 180 degrees from the tappet will sometimes leave other lobes pushing down on tappets, which can skew or "bend" the cam shaft and give you false readings.

 

[tkent02]

The spec for the cam clearance in the cam journal is .025mm - .053mm

If the cam lobe on the adjacent cylinder is down at the time, it will raise the cam by this distance, severely skewing your shim clearance measurement. Doing it the way Suzuki intended gives an accurate and repeatable result.