Author Topic: Finding local mechanic?  (Read 230 times)

Sonch

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Finding local mechanic?
« on: 22 September 2020, 06:22 PM »
This may be the wrong place for this, but looking for a good mechanic in the Detroit/Ann Arbor area. Do we help with that kind of networking here?

I’ve been enjoying fixing various mechanical/electrical items (window regulator, antenna, etc) but now it sounds like I have a valve train issue and I’m not ABOUT to go digging. Totally out of my depth I was thoroughly intimidated by the four page discussion I read on the topic here!  :-[ Issue is ticking in upper engine in exact sync with rpms.

So anyway...we know people in this area or is it sacrilege to ask in a mechanical forum? lol

Randys01

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Re: Finding local mechanic?
« Reply #1 on: 24 September 2020, 12:58 AM »

I'm on the other side of the world. Others will surely respond to your local request..and it is absolutely fine to ask about preferred suppliers....
You might see it prudent to introduce yourself and your car a little more. For instance, I'm probably the author of the that 4 page dissitation you are trying to swallow..........
The point is, the answer to your question depends largely on what year/variant W116 you have.

Sonch

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Re: Finding local mechanic?
« Reply #2 on: 24 September 2020, 05:33 AM »
Thanks Randy, very uplifting (*ahem*). You were indeed one of the authors and authorities on what I reading.

I have a 1979 450 SEL. She’s a beaut with low miles 62k and very clean. Hard to imagine there being too much of the sludge issue. The audible engine tick is fairly light but very consistent and continuous and perfectly married to rpms. Coming from upper right

Randys01

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Re: Finding local mechanic?
« Reply #3 on: 27 September 2020, 04:12 AM »
So it's clean,,low mileage and a later hydraulic valve lifter variant.
One or 2 light ticks and the low mileage suggests that you do not have a valve guide issue but you probably have a tappet clearance issue. Notwithstanding the modest mileage, time is time so don't discount the sludge issue after 40 years.
 If you can confidently consolidate the suspect noise to one bank or the other then that's a great start.
When you say upper right can I presume you mean in Mercedes speak...the lh or the rh cambox.?..ie when seated at the wheel..left cam or right cam box?
Whichever you mean, the procedure is much  the same.
Warm the engine but not hot.
Pull the offending cam box.
Remove  all the plugs.
Remove fuel pump relay
Remove coil lead
Crank the motor and finish off by hand rotation to bring each of the cylinders to top dead centre on the compression stroke. observe the cam lobes for each  cyl should be equi distant pointing upwards at "10 to 2".
Using a torch inspect spark plug hole to make sure you can see top of piston and ensure you are damn close to TDC.
Once satisfied see if you can get a feeler gauge of any value...005 of an inch min between the cam lobe base and the rocker arm pad.
What we are looking for is any valve for which the valve lifter has not fully pressurised and closed out any gap. You can be reasonably strident in trying to get the feeler in.
As you work your way along the bank,getting each cyl to TDC -give the engine a good crank..............this is to ensure that the lifters remain pressurised as you work your way thru them.
And yes it gets messy...and it's slow work.
So there are 8 valves to check.  Now this process  may identify a suspected gap or lash. If you should be so lucky, then the valve lifter is the likely culprit.more than likely it has swallowed some goo and will not bleed properly or pump up.
Let's just get to this point and see how you go. If you identify the culprit..good-oh. Put it all back together unless you have time and resource to leave the it open for further work.
The process I have described is not in any service manual.
W/shop procedure is to throw the lot out and replace.
Our initial endeavour  is to try and  isolate the offender. This little routine does not yet require any specaal tools or parts.
Of course, if you have plenty of money a you can swap all 8 out with doing any testing.
anyway give it a go and report in.


 

TJ 450

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Re: Finding local mechanic?
« Reply #4 on: 27 September 2020, 07:55 AM »
With the M117, just in case, I’d be pulling the valve covers and checking the oil supply to the cam lobes/ bearings. The plastic fittings are known to become brittle and work loose leading to oil supply issues. Worst case it can lead to worn lobes and seizure of the cams/ bearings. These are cheap and easily replaced.

Beyond that, you could replace (or have replaced) the noisy lifter and set it with the go-no-go gauge.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Sonch

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Re: Finding local mechanic?
« Reply #5 on: 27 September 2020, 08:03 AM »
Thanks guys. How risky is it to drive until I get to this?

Randys01

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Re: Finding local mechanic?
« Reply #6 on: 28 September 2020, 01:16 AM »
What Tim is suggesting is of course good housekeeping whilst you are on a specific issue. One or 2 ticks is nothing until you can get to it.
Of course replacing the noisy lifer is all very well once you've identified it/them. It's finding the needle in the haystack  that's the trick.

Randys01

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Re: Finding local mechanic?
« Reply #7 on: 28 September 2020, 11:53 PM »
Foot note: the rigamarole I have described presumes you don't have a Go no go gauge. If you do then of course it's a lot simpler BUT be aware that the gauge will not tell you if a lifter is a tad weak. It will only tell you that the lifter is shimmed within range. Trying to get a feeler gauge in will alert you to  a weak lifter.
 Sooner or later you will need the gauge. Be aware that MB altered the value of the valve lifter in the late 70's. Logic says your 79 lifters should be set to the new value. Now there is a lot of unsettled argument as to whether later go no go gauges were calibrated to reflect the new values. it is unclear whether new gauges from say Pelican Parts are calibrated to the newer value.??
yes..it is a riddle!.but there is a way out of the maze.
.we can come to that later.