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  #1  
Old 12-16-2008, 07:55 PM
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Is it worth it to buy used camshaft for my 89 300 TE

I have a 1989 300 TE that blew a head gasket, I figured what the heck I'll have the machine shop check it out to make sure everything is up to par and to do a valve job, guides, and seals. Well, I just got the call back from the shop and if turns out it needs a new cam and one lifter is bad.

I would like to know if it is worth it to buy a used camshaft and lifters

there is one on ebay http://cgi.ebay.com/ebaymotors/Mercedes-190e-300e-Camshaft-m103-engine-w201-w124-w126_W0QQcmdZViewItemQQ_trksidZp3286Q2em20Q2el1116QQitemZ120286533168QQptZMotorsQ5fCarQ5fTruckQ5fPar tsQ5fAccessories

and a few others I have found while searching used cars parts sites.

Or do I need to suck it up and and buy new?
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  #2  
Old 12-17-2008, 05:56 AM
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I have another option you can consider as well.

There are a few machine shops out there that specialize in regrinding cams.
Local to my area is Delta Cams, which has a fairly good reputation, even in the racing circles.

From what I understand, the process involves building up new material on the damaged surfaces, regrinding them to the appropriate shape, and then treating them to the correct hardness.

How they go about this, I'm not sure, but I would assume that a business that has been around for any period of time, and that is specialized in that particular industry would have at least most of their ducks in a row!


The reason I suggest this is that from the pricing I was doing when I initially found a seized cam in my 500SEC during the beginning of the refurb, I looked them up and was getting pricing around $150 for a few lobes being damaged and requiring work. If I remember correctly, they charge $25 per lobe, but I may be misremembering on that.

Best of luck, in any case!
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  #3  
Old 12-17-2008, 08:01 AM
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Using a "used" cam is a viable option.

The rocker arms should always be against the same lobe(s). That might be the tricky part.
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  #4  
Old 12-17-2008, 12:26 PM
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Hmmm, it's freezing here in Dallas, so I grabbed a coffee and thought about your predicament. Does this make sense, or did I have too much caffeine?

As Doc said, it's always recommended to keep a cam lobe and the part that rubs on it together, because they set up a particular wear pattern with each other. In this case that would be the rocker arm. So, taking off the rocker arms and putting them back in different locations could induce wear on the new rocker-arm/cam-lobe mating surfaces. The preferred used-cam swap would include the rocker arms, labeled and sorted to match the lobe that they had been riding on previously. You probably won't find that scenario unless you take the donor cam/rockers off yourself and keep them sorted.

Along the same line,, that would say that if you bought a new $400 cam, you should also buy a $600 set of rockers, so they could wear-in together. Otherwise you face the same scenario as above.

Based on that, if it were me, I would inspect the rocker arms carefully for wear on the lobe contact surface and shaft bore. If they were okay, I'd buy the used cam and slap it in. Probably the worst that would happen would be it would wear and start to tick after awhile. But the other scenario would be it's just fine; for $65 instead of $1000.

Does that sound logical?

Oh, when he said bad lifter, did he mean the hydraulic thrust element that slips in the other end of the rocker arm, or did he mean the rocker arm itself?

DG
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  #5  
Old 12-17-2008, 02:18 PM
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I fail to understand the statement "the rocker arms should always be against the same cam lobes". If you're installing a used camshaft that meets the original specs there should be no difference between it and a new camshaft. I can see where it's important to maintain the identical rocker arm orientation if it's slightly askew to the camshaft.
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  #6  
Old 12-17-2008, 02:42 PM
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Once the camshaft has been run, it is no longer identical to a new one. If you put mismatched used parts against each other, it might work, and it might wipe the lobe after the first few minutes of operation.

If you replace the camshaft with a new one, it is not necessary to replace any non-damaged lifters. Damaged lobes always imply damaged lifters.
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  #7  
Old 12-17-2008, 07:18 PM
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Matt and Fred; I think I agree with you both.
In a perfect world, when two rubbing metal parts break-in to each other, it's generally asccepted as a good idea to keep them together, and not mix-match parts during a re-assembly, even if they all appear to be fine. This would apply to main bearings, pistons, and cams/lifters, etc.

However, that being said; the 103 rocker arm/cam rubbing interface seems pretty benign; (not like a small-block Chevy lifter, rotating in a bore, and spinning on the cam lobe).
I think you could mix/match a good rocker/lobe without much danger in the 103, i.e. put a new or good used cam in with good existing rockers. But, it's not the optimal situation for guaranteed longest life of the components.
kinda like installing new main bearings without turning the crank.

I suggested this approach for this application, due to the significant cost savings, but I definitely wouldn't recommend it if he was replacing the cam on, say, a 12-cylinder, 600 HP AMG that cost mega-bucks.

It's sorta the age-old Perfectionist vs the $$ compromise scenario.

Cheers,
DG
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  #8  
Old 12-18-2008, 10:19 AM
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S-Class Guru, M.B.DOC and and everyone else who chimed in, I just wanted to say thanks (for making this more difficult). It would not be such a pain of a decision if I did not know any better to begin with, I have gone through and bought genuine parts, or ********AZ, and now that I found this sire I started buying through Fastlane, I never did the Super Parts-O-Rama stores but now this decision is a pain.

I am wondering that since the cam is as worn as it is (it seems the story's I read online never include cam and rocker replacement) that maybe the bottom end might be worse then I had thought (hoped). Between the cost of the new parts and the shops labor i am looking at $1,500 easily which is money for an older diesel to fix up.

The next thing is if it is worth it to that much into a car that I payed a little more then double that for and how much more am I willing to do (or spend) on this car. The trouble is that my Wife and I really like this one (especially my wife), the paint is decent (some chips here and there) the interior is great with the exception of the wood panel around the window controls and some idiot put a screw through the rear interior panel to hold it on. Is this car worth another paint job and dumping the money into it to basically overhaul (semi restore it)?

Last thing, If I could find a head or a complete engine I could always take the chance that the cam and rockers are good and make sure everything is disassembled and marked so it can back in the same as it came out and if I had the block to go with it I would have it on hand and ready to rebuild if the time came.
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  #9  
Old 12-18-2008, 10:26 AM
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Quote:
Originally Posted by S-Class Guru View Post
Hmmm, it's freezing here in Dallas, so I grabbed a coffee and thought about your predicament. Does this make sense, or did I have too much caffeine?
DG

Don't worry, everything you said made sense (unless I did not have enough caffeine)

Cold in Dallas? Did you get any snow recently? Last week we got enough snow to just dust over the tops of our vehicles here in South Houston, I was told that North Houston got up to 4 inches (Lucky), I have not seen snow since December of 1997 when I went back to NY (I lived there until April of 97) to get my 66 Mustang out of storage and haul it down to Florida (where I lived until 2 years ago).

No one told me that Texas could go from 70 or 80 one days and down to 40 at night sometimes.
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  #10  
Old 12-18-2008, 12:22 PM
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I would suggest fixing it and sell the car.
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  #11  
Old 12-18-2008, 12:50 PM
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i just bought and installed, do buy new rockers, I have over 2000 miles so far no issues
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  #12  
Old 12-18-2008, 01:08 PM
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DKA, no snow here in Dallas, just a tiny bit of sleet on Tuesday.
Tomorrow is predicted to be 70, so I made a golf tee time. Winter days in Texas can definitely range 50 degrees in just a few days - getting some good days in January helps make up for the summer heat. But I hate Houston in the summer - HUMIDITY.
Concerning the motor, the 103 bottom end is a tank, you just never hear of one failing it seems. As easy as it is to R&R the cam in these cars, I'd definitely take the chance on the used cam, and decent-looking used rockers/lifters. As I said, it willl give plenty of warning if it's going bad.
If it starts ticking, then you get to make decisions all over again; but if you are at all handy, you can change out a cam on one of these in a couple hours, with one hand behind your back. There are plenty of tutorials here on the forum to walk you through it.

Every time I buy a part for my old '91, I calculate how many days' payment it would be on a new MB. Usually it's waay less than a week's payment.

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  #13  
Old 12-18-2008, 06:03 PM
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S-Class, and everyone else that gave advice I just wanted to say thank you.

After I made my last post this morning I went out to clean the garage and put away all the stuff from my other German project (restoring a 65 beetle) and the same thing came to mind that S-Class mentioned on the last post, I have been so involved with tearing everything apart to get to get the head off as well as pulling everything off so I could replace the water pump and the timing chain that I completely forgot how easy it is to pull the valve cover and get cam out. Sometimes you just need to stop thinking (and stressing) about the problem and the answer just pops in there, and I was very happy to see S-Class stand by what was mentioned earlier and mention the same thing I was thinking about.

S-Class, I would love to be in some other areas of Texas such as Dallas/Ft Worth, Hill Country, Nacogdoches but my wife works in the medical field and I will just say that the pay here in Houston was just insane compared to other areas of Texas. As for the humidity, I can take Houston's fairly easy (this past summer was nasty though) considering we just came from SW Florida (the Fort Myers side of Sanibel/Captiva Bay) and the humidity just did not quit, at 2 am the humidity was torture at least here it cools of in the evening.
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  #14  
Old 12-20-2008, 06:49 PM
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My wife is a medical manager. Now that I'm retired and a lot poorer recently, maybe we should move to Houston, and she can support my car addiction - well, I can dream.

DG
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  #15  
Old 12-21-2008, 08:39 AM
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On my fist mercedes (W114 280) the fifth exhaust lobe was worn. With some sandpaper I reshaped it to a slightly smaller but smooth lobe and it ran great again. This process had to be repeated every 50K km. After 500K km the lobe was so small that performance was somewhat affected, the car would not run over 200Km/h any more.

I bought a W126 280S, and after some time the fifth exhaust lobe was worn (seems to be a m110 problem). This time a bought a used cam ($40) , cleaned all oil ducts and just put it in.

When I sold the car after 450K km the cam was still OK. Later I heard that the next two owners put another 200K km on it without problems.

Both these cars were frequently driven on the autobahn in Germany, as fast as they would go.

Rob
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