86' 300E lifter noise - PeachParts Mercedes-Benz Forum

can-do · #1 06-27-2004, 10:51 AM

Greetings All,

I'm trying to clear up all the searches I've done on this problem. The engine has 195,000 and since I've owned it this engine has ticked slightly on cold start up but clears up after oil pressure comes up. Recently the ticking sound has gone to a clatter sound.
I've read all the posts on either lifter change out or camshaft lobe problems on the older model engines. Can someone clear up a few questions about all of this?
First, how can you check the lifter to ensure that this is actually the culprit? Second, can the DIY change out the lifters without any special tools? Third, does a different size shim have to be installed to account for wear or is the original o.k. to use if the lifter is changed? Fourth, if the cam lobes are indeed worn, how does one measure the wear without removing it, or will that become obvious upon visual inspection.

Any and all info will be well appreciated,

Charles

stevebfl · #2 06-27-2004, 11:43 AM

Lifter replacement doesn't require any special tools. Measuring the shim size does. There is no need to measure the cam as it is surface hardened an any noticable wear means it is in failure.

The wear that changes shim size is the wear of the valve face and seat face where the va;lve hits. This wear allows the valve to move up through the head and the lifter has to shorten to compensate, which it does. Eventually the lifter is required to work with too much compression. There is a prescribed compression of the hydraulic element which requires a special tool for measurement. I doubt many do it as there is very little of this valve wear over most engines life.

Picking bad lifters out is an experience driven success rate. That means that your best bet is to replace them all (they all have been through the same war) or locate the area of the noise with a stethescope and replace those in whatever small area you feel confident with. You may feel a real bad lifter by pressing up and down on the rocker. There should be no clearance within the force necessary to open the valve.

can-do · #3 06-27-2004, 10:04 PM

Greetings,

Just wondering if factory engines come shimmed and if not how do I measure the distance in order to install the correct shim size on the lifter? Is it measured with a feeler guage or what, and what position is the valve in when doing so?

Charles

stevebfl · #4 06-27-2004, 10:12 PM

special tool time

can-do · #5 06-27-2004, 11:20 PM

So how do you know if a lifter needs a shim or is just not holding pressure?

can-do · #6 06-29-2004, 11:30 PM

How do you deterimine whether a valve lifter is going to require a shim in addition to the lifter replacement or is fine the way it is?

Charles

samiam4 · #7 06-30-2004, 01:16 PM

Inspect lifter.

Keep the existing shim for each location inplace- regardless of if the lifter is replaced or reused. Shimming is to make-up for valve seat in-set. The lifters are machined to close-tolerances.

I think steve as pretty well said this in the previous postings.

Michael

can-do · #8 07-03-2004, 08:33 PM

I am assuming that what you are saying is that if the rocker has been shimmed, then in most likelihood it was done at the factory and should be left in place and the lifters as a best practice should just all be replaced to save myself the headache down the road? If I am missing something, please chime in.

Charles

samiam4 · #9 07-04-2004, 11:19 AM

Shimming changes are done at a valve job.

Lifters can be changed without shimming changes. Yes, if they are in your engine-leave them. Inspect rocker arms, camshaft when replacing the lifters.
The decision on to replace all or only a few is subjective and partially mileage driven. If you have one which is colapsed, then just replace it!!
My time is at a premium, so if it was my car it would get a set of lifters. I use Mercedes parts for internal work exclusively! It would have to be a large price difference to consider anything else for me. I've had problems with the others and it's not worth it for internal parts. Never got a bad engine part from mercedes *yet*.

Michael

can-do · #10 07-06-2004, 07:13 PM

Greetings All,

Finally got a day off and decided to remove the valve cover to see what the situation was with the rocker arm / lifter noise I've been hearing. I wasn't a happy camper when I removed the cover. The rear rocker arm assembly wasn't even tightened down, all four bolts were finger tight and I could raise the assembly about a quarter of an inch off the head. Pulling the bolts it seemed that there was just aluminum embeded in the threaded area. I don't think it had been helicoiled before as it was all raw aluminum. I decided to check the torque on the remaining bolts and there were probably about another three or four that were near torque spec but could tell that they were wasted as well. Now what do I do? Can I helicoil these hole myself or is it a job left to a professional? I also noticed what looked like aluminum tube inserts where the rocker assembly bolt holes meet the block. Are there tube inserts that go between the rocker assembly and the head? If anyone has done this please chime in on the procedure and tools required and well as the success rate and any other pertinant info that can get this ride back up and running.

Thanks,

Charles

samiam4 · #11 07-06-2004, 09:21 PM

I'll stick my foot in my mouth now=)

I think I've seen that in the M103 engine stuff. Yes, you can helicoil it. I'd buy the set from a machinist supply company instead of an Auto parts place. They make different tolerence tapes and different length coils. You want the 3B or maybe it's 3A standard. One being the bolt and one being the nut standard. 2A/B is looser fit.
Standard kits are either 1.5 D or 2 Diamenters in length. They make them in 1-5.0 diameters. Use grease on the tap. Go 2X as much counter clock wise for every 60 degrees to break the chips. Clean the tap fairly often.

If you don't have a good machinist supply company- go to mcmastercarr.com.

Michael

can-do · #12 07-06-2004, 10:43 PM

Greetings Mike,

I guess my real question after reading some posts was whether it required a jig set-up to ensure proper angle drilling? Then my next question is whether or not do them all or just those that wouldn't torque to spec without spinning? Have any idea on the tube spacers I found inserted between two of the bolt holes? If you have ever looked at your rocker arm and head holes where it mounts, it is over drilled to accomodate a tube insert of some sort. Just wondering if all four holes recieve them or what. The helicoils, are they metric or AS or doesn't it matter?

Charles

samiam4 · #13 07-07-2004, 07:57 PM

I'll qoute the Stu's book pg 140.

"In high mileage M103 engines, it is not uncommon for the cam bearing caps bolt threads to strip. " Remove loose bearing cap bolts and remove cap. Drill damaged thread , retap per the manufacture's instruction. Helicoil or timeserts.

I think the "tubes" you are refering to in a cylinder head are alignment guides. So, yes they should be snug to slightly loose-if we are talking about the same part.

Sorry about the class information yesterday- it was wrong. For metric threads would be 4H5H and 5H.

They use a drill template for head bolt threads in the block of older aluminum V8 engines. Most cases, it's just you being careful- remember you don't want any chips left in the engine and the hole needs to be straight. Drill size is based on material size- so for example a 8mmX1.0 or 8mmX1.25 helicoil in aluminum would be a 21/64, but ideal is 8.25 mm and 8.3 mm respectively.

Not difficult to do and most places charge $25-50 per insert. The drilling is not hard- it's just slighly bigger than the major diameter of the old threads. Then if you've got a countersink put a champher on hole. Then put the tap in a tap handle(don't try and do it free hand!). Tap away per my previous comments.

Michael

can-do · #14 07-07-2004, 08:50 PM

Greetings Mike,

So if I am buying these helicoils, what size am I looking for in this particular application? I see them sized in 8mm X 1.25 if your example was pertinent to my application. Sorry such a pain, but am trying to get correct info before buying.

Thanks,

Charles

samiam4 · #15 07-09-2004, 09:31 PM

Take the bolt out..

And measure it!!! Go to HD, Ace etc and put a nut on it! Someone here might be able to chime in on the actual size. I was guessing 8X1.25. Complete guess.

Best of luck,

Michael