Manual
 

I recommend going to the MBUSA site and ordering the factory CD's for the 126 chassis. Best $27 I've spent on my cars. It even includes the owners manual! The manuals are a little hard to find. I think you have to go to "literature", "vintage" to find them.

in a leakdown you just pressurize each cylinder and measure how long it takes for each to lose pressure, i think. i have never personally done one. i dont think it requires turning the engine over.

a simple one in which you just look for the source of the leaks could be done by pressurizing each cyl and see if air escapes from the intanke or exhaust.

tom w

Do the leak down test
 

With compression as low as the numbers your reading, you should definitely be able to hear air leaking in the crank case or intake/exhaust if you hook an air source up to each cylinder in turn. I performed the same test on mine before I tore it down. If I recall correctly the lowest cylinder had around 230 psi and I could definitely hear air through the oil fill. In this case, it correctly identified the rings as the culprit. This test doesn't take long, and is very informative.
BB

and if the probelm happened to be worn intake cam lobe, the leakdown might be nil on that cylinder.

which would be very good as a cam can be changed with the head on.

tom w

Just when I got resigned to the idea of "Off with her head!", it occurs to me that once the head bolts come off, I have no chance to do a leakdown and thus really see what the problem is. So I want to pursue the leakdown. My greatest fear is to have the head and valves done, button her up and have the same smoking issue.

So, I have the rockers off, can I do a leakdown with the rockers off? Seems like it may actually be easier, knowing that the valves will be as closed as they're gonna get. And how do I find TDC on 2-5. One's easy, but then it's 70deg for each past that correct? Right now I've got the cam marks and the pointer down below on TDC.

Thanks again for the continued help.

One more quick thing before I go to bed....

What in the world are those bolts holding the head on? I suppose a special wrench is in my future, but where would I find such a thing? Thanks.

Its a twelve pointed bit, called a "tripple square" if memory serves. I got a set of three from my local Auto Zoo when I pulled my head.

Hey Sailor, did you pull the head on your 300d? If so, or even if not and you may know, how'd you get the head over the cam sprocket? Did you tie it up to the hood or something hanging overhead? Also, how was the part about removing the cam sprocket? I've heard that woodruff key can shoot in all directions when popped off, including down the abyss. Scares the crap out of me, although that could be the only reason I'd need to pull the engine out and do a complete rebuild. Yikes.

stuff the abyss with rags. tie the chain to the sprocket and tighten it up and tie it off to itself so it cannot slip on any of the sprockets.

cam lobes look good?

tom w

Hey Tom, thanks, yeah cam lobes look good--definitely no unusual grounding. I didn't measure it, but touch and look inspection looks good.

Do you think I should try a leakdown? The rockers are off, and I'm at TDC on 1. I'd hate to get the head rebuilt and get the car back on the road only to find out my smoking problem hasn't been fixed. If I do a leakdown and find that it's pistons or rings, I think I'll just keep going and pull the engine. What do you think? Thanks again.

Do you have the equipment needed to do a leak-down test?

I was thinking of doing just to the point of being able to hear where the air is leaking, so I thought I would need an adapter to get an npt into the injector hole and a regulator on my compressor. Since my compression on the low cylinder is so low, I thought it's be painfully obvious where the air was leaking without alot of work or special equipment. What do you think?

I take it this car is not your daily driver. :)

Nope, got a spare Camry for now. But if this work gets this car to a point where it's not smoking and running good, then out with the Camry.

i think your plan sounds ....sound. the very low cylinder should leak a lot either down or up or both. any significant leakage down is a bad sign.

if you do end up pulling the moror, then there is another whole range of optins to explore from a good used motor to a fully rebuilt exchange motor.

good luck.

tom w