DF175 Adjusting Shims for Tappet Clearance

[Zuki175]

I have a 2007 DF175 nearing 800 hours. Performed a tappet clearance check and a few shims needs adjustment. This is my first time servicing the tappets so please bare with my inexperience. I followed the instructions on the Suzuki Service manual and it was quite an easy inspection. Just tedious removing many bolts.

The question I have is which size shim should I use since the replacement shim thickness in millimeter alternates from .02 to .03 increments. See Shim I.D. No. chart in attached photo for reference. What I need is an in between shim thickness from what's available on the chart.


I'll use a 2.50 mm shim (existing shim) as an example for my calculation.

Tappet Clearance for DF175 (cold engine)
Inlet: 0.23 - 0.27 mm (0.009 - 0.011 in)
Exhaust: 0.30 - 0.34 mm (0.012 - 0.013 in)


i.e. A = B + (C - 0.32mm) for Exhaust side A [ Shim Thickness in mm for replacement] = B [2.50 Existing Shim] + (C [feeler gauge measurement] - 0.32mm)

A = 2.50mm + (0.28-0.32)

A = 2.50mm + (-0.04mm)

A = 2.46mm Shim needed for replacement

I only have a choice of 2.45mm or 2.48mm shim. Which size shim do I use, smaller or bigger?


My Tappet Clearance numbers:

Exhaust Inlet

E1 .28mm / .28mm I1 .23mm / .23mm
E2 .30mm / .30mm I2 .25mm / .25mm
E3 .30mm / .30mm I3 .25mm / .25mm
E4 .29mm / .29mm I4 .25mm / .28mm




image_1224.jpg

[artdf175]

Your example is the one right down the middle
I would approach it slightly different what is the range and then what is the closest to the middle of the range
.28 - .30 is -.02 28-.34 -.06 2.50 -. 02 = -.248 2.50 -.06 = 2.44
so the adjustment falls within 2.44-2.48
a 2.48 gets to the outside of the range
a 2.45 gets you closed to the middle and .only .01mm off a perfect number
hope that helps
Art

[Harper]

I'd always opt for the slightly wider clearance within the accepted range, especially on exhaust valves. Which in the case of your example would be the 2.45 shim.

And with your numbers, I would adjust all four exhaust clearances, and adjust just #1&4 on the intakes.

[Zuki175]

Thank you both for your input. That was helpful.

[redlowrey]

If it was my engine I would be putting the cam cover back on the engine. The good thing is you had clearance, you are a thou down on minimum clearance, remember the clearance increases when the engine is hot, not like a cast iron engine where the clearance will diminish when the engine is hot.

[Zuki175]

If it was my engine I would be putting the cam cover back on the engine. The good thing is you had clearance, you are a thou down on minimum clearance, remember the clearance increases when the engine is hot, not like a cast iron engine where the clearance will diminish when the engine is hot.

I immediately put everything back in place with the cowling and the motor cover for protection from the element. I try to be meticulous in caring for the motor. But thanks for the heads up on that.

If I understood you correctly, I should replace the shim that will get me closer to the upper end of the tappet clearance (cold engine)? For an example, aim toward 0.27 for Inlet and 0.34 for the Exhaust? I was thinking of just settling for a shim that gets me closests to the middle range.

I ordered the Tappet Holder from boats.net. I'll remove the shims to take notes on the shim size. Then I'll do a final calculation on which shim I should order for the tappets that needs adjusting. I'll check back here to pick your brains before I order the shims from boats.net.

[Zuki175]

Does the interior look clean for about 800 hours of use? This is my first time opening up the cam cover.

[Harper]

Looks good.

[wilbur1]

ZUKI 175 what did the tool cost.? If I may ask.

[Zuki175]

About $170.00 from boats.net. Lowest price for a new part from what I was able to find on the internet.

[redlowrey]

The next job to prepare your self for will be removing the inlet manifold and replacing the plastic butter flies before they break and end up in the combustion chamber.

[Zuki175]

The next job to prepare your self for will be removing the inlet manifold and replacing the plastic butter flies before they break and end up in the combustion chamber.

What timing, I was thinking the same thing after reading a few write ups about the butterflies breaking. I was looking up the parts number and was not able to find it on the manifold diagram. Do you know the part number for replacement butterflies? Are they also made of plastic or did Suzuki upgrade it to a better material?

[Harper]

You can't get the butterflies by themselves, as far as I know. You have to replace the whole manifold.

[Moonlighter]

Wasnt it just the pins that hold the butterflies in place that was the problem?

Some loctite would probbaly sort it out??

[Zuki175]

What was causing the butterflies to break apart? Were the pins getting loose and causing the butterflies to smash against the opening?