Feeler gauge confusion - PeachParts Mercedes-Benz Forum

toddyvol · #1 05-18-2010, 10:26 AM

I for some reason find myself confused on which is the correct feeler gauge for the exhaust valve on my 1982 300D Turbo.

I know is is suppose to be .35mm

My feeler gauge options are:

One feeler gauge says...014/.356mm or gauge #2 says....012/.305mm

Which is correct?

The picture below says .012 which would be wrong? Wouldn't that equal .30mm?

okyoureabeast · #2 05-18-2010, 10:35 AM

You're mixing inches and millimeters

Just ignore the inches and use the millimeter markings.

Use the .356mm feeler gauge for exhaust and the .105mm (or whatever it is) for the intake. Remember it's better to be slightly loose than slightly tight.

toddyvol · #3 05-18-2010, 10:38 AM

Quote:

Originally Posted by okyoureabeast

You're mixing inches and millimeters

Just ignore the inches and use the millimeter markings.

Use the .356mm feeler gauge for exhaust and the .105mm (or whatever it is) for the intake. Remember it's better to be slightly loose than slightly tight.

My intake gauge says .004/.102mm

okyoureabeast · #4 05-18-2010, 10:54 AM

Quote:

Originally Posted by toddyvol

My intake gauge says .004/.102mm

Yup that's what mine says too. I just forgot what the gauge actually says and threw some nonsensical number out.

Shawn T. W. · #5 05-18-2010, 11:10 AM

Also remember that there are different values if engine in cold compared to hot . . . I prefer to do them after it has sat all night.

ah-kay · #6 05-18-2010, 12:15 PM

The picture seems to be wrong.

0.012" x 25.4 = 0.3048mm. Use the gauge closest to 0.35mm.

charmalu · #7 05-18-2010, 12:26 PM

Diesel Giant has a good pictorial showing the gauge to use.

http://www.dieselgiant.com/valveadjustment.htm

I have the same set of gauges he shows craftsman #40811. there is no gauge exactly .10mm. the .004in is .102mm so it`s close.

there is no gauge exactly .35mm. the .102in is .305mm. that would be closer to the .30mm the none turbo eng uses for the exhaust .

the .356mm is .014in and would be closer to the turbo exhaust.

Usually by the time I get the nuts tightened down, Iam off anyway, takes me about 4 times to get it right. so maybe using the next size larger I would be on the money.

I just did my 80 240 yesterday for the first time and realized the exhaust is different between the turbo and NA.

Charlie

Diesel911 · #8 05-18-2010, 01:14 PM

Or, you could get an only mm Feeler Gauge set if you can find one.

The Valves need to be adjusted but it is not and adjustment the needs extreme precision. A few thousands of a mm will not make a practical difference.

HuskyMan · #9 05-18-2010, 01:21 PM

I think the dealership or fast lane may have a certified set of OEM Mercedes metric feeler gauges for sale. you might check and see if they have them.

toddyvol · #10 05-18-2010, 02:20 PM

Valve adjustment completed. I made my wrenches and suspected one of my welds wasn't very good before I started, sure enough it snapped. So I had to grind the old weld off and re-weld the wrench that snapped. I guess that's what I get for being lazy.

The previous owner had stated that the valves had been adjusted in February or about 2,000 miles ago. I found that all were pretty close except #1, #2, #3, and # 10.

#8 and #9 were dead on .35mm.

Car does seem to run a tad smoother. I'm amazed at how much power or torque this car has. Seems like the valve adjustment bumped it up a notch. I'm also mpg fanatic so I'll be watching to see if that has increased. I was getting about 21mpg around town before the adjustment with zero interstate driving.