Hi all,

I am adjusting the valves on my 82' 300D (123.133) for the first time tomorrow, and I have a few lingering questions that my research hasn't answered:

-When using the feeler gauge, how much resistance should I shoot for? Some say a lot, some say a little, and the FSM doesn't specify.

-My valve cover is quite dirty and I don't think degreaser alone will cut it. Could I wire wheel it to clean it up? I haven't cleaned a lot of aluminum, so I'm concerned that's too rough.

-While I'm in there, what should I be checking? Timing chain stretch, overall condition, anything else?

-Any 'tricks' for a good valve cover seal? I purchased a new gasket.

Thanks in advance!

I am adjusting the valves on my 82' 300D (123.133) for the first time tomorrow, and I have a few lingering questions that my research hasn't answered:

-When using the feeler gauge, how much resistance should I shoot for? Some say a lot, some say a little, and the FSM doesn't specify.

This is hard to explain. You shouldn't have to force the feeler in. It should glide in and out with the slightest resistance. IF it's too loose, you'll be able to get the slightly larger feeler in (which is no good). Basically, if you can fit either the next size up or next size down, you've got more adjusting to do.

-My valve cover is quite dirty and I don't think degreaser alone will cut it. Could I wire wheel it to clean it up? I haven't cleaned a lot of aluminum, so I'm concerned that's too rough.

Is this purely an aesthetic question? I've only ever used simple green.

-While I'm in there, what should I be checking? Timing chain stretch, overall condition, anything else?

Timing stretch is good to look at. In general, just get eyes on stuff. The more you're in there, the more familiar you'll become with a certain baseline.

-Any 'tricks' for a good valve cover seal? I purchased a new gasket.

People really seem to struggle here and I have no idea why.
Put the gasket on, make sure it's seated properly, torque to spec. And if you can, buy the MBZ brand gasket -the quality is readily apparent.

__________________
1981 240D 4sp manual. Ivory White.

Thanks for the quick reply Shern.

Valve cover cleaning: Yes, purely aesthetic. On my power steering reservoir cover, I wire wheeled and clear coated it and it came out nice. I'd like to do the same here, but don't want to damage anything. If nothing else, I'll just wipe it down.

Gasket: yeah, I've been reading lots of threads with people struggling with this. I'll take my time and should be fine.

Always consider the “availability heuristic.”

For every report you read of someone struggling with RTV, dental floss, leaking corners, there are a dozen others who had no issues whatsoever and thus, don’t post about it.

It can be a little intimidating at first, but once you’ve done it, it’s really a non-event and actually a fun bit of DIY!

One thing I don’t see come up very often (something I figured out by accident), is that the valve caps are not perfectly flat. When I’m setting clearances, I rotate each valve until I find the tightest spot, then set clearance to that point. You’ll sometimes read of people making an adjustment and then getting in there a week later and finding a few that are still too tight. I think it’s usually because of this. It’s a minor thing and nothing to fret over if you’re feeling overwhelmed. It wasn’t until my 3rd attempt (granted, within a week) until I noticed this.

Good luck, and enjoy yourself!

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1981 240D 4sp manual. Ivory White.

Great tip! I have never heard of that, seems like an easy thing to overlook. I start tomorrow afternoon, I may be back questions, thanks!

Shern is correct. The valve cover gaskets are usually not problematic, actually the opposite, they are one of the best designs out there. Definitely rotate the valve to find the tightest/least clearance and adjust on that position. On the loose side of the spec is better when adjusting valves.

Don't overthink this, just don't confuse the intakes and exhausts and you'll be fine. Make a drawing to prevent confusing the two.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Careful when tightening down the valve cover. Doesn’t need to be torqued down like mad. Looser is probably better. You can distort the cover of ya bear paw it

Having a set of bent 14mm wrenches is the best way to be successful.
aside from that, the weather is usually the hardest part of the job.
If you take a break, throw a clean rag over the valves, go in and have a beer, then go back and finish.

wear leather gloves when loosening the jam nuts, your knuckles will thank you.

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1977 240D auto w/OM616.916 engine
2005 Matrix 5spd
2006 Prius

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