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Valvetrain Help needed M103
I am rebuilding a 1990 300E M103 engine and I just put my new cam in and started putting the rest of the head together. When the head was taken out, I had a valve job and the head was resurfaced. Along with my new cam, I got new 3.0mm ball sockets, and new lifters but kept the stock rockers. Now I have a clearance problem. When I go to tighten the rocker arms down, the valve springs start to compress and thus the valve starts to open. I am positive that I am on the flat part of the cam so the valve springs are not supposed to be compressed at all. I tried putting the old ball sockets in and the problem wasn't as bad but it was still there. What do I do now? Is there an easy solution or am I going to have to shave some metal off of the ball sockets. As far as I know, there are only 3.0mm and 3.5mm ball sockets available and I already have the 3.0mm. Thanks to anyone who can give me some help.
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George Carstens |
#2
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The shims that go into the rocker arm prior to installing the hydraulic compensators are available in 3 different thicknesses.
There is a special tool that uses a dial micrometer to measure the preload of the rocker arm, this is the only good way to know if they are set properly. Gilly ps In Fastlanes catalog, they are found in engine mechanical, "valve adjsut shims", then are called what I believe the correct name is "Thrust elements". They are available in 2.2mm, 1.8mm, and 1.5mm
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Click here to see the items I have up for auction at EBay Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold) |
#3
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So what do I do...do I disgard the "ball sockets" that I have right now and use these shims instead?
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George Carstens |
#4
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right well now that I have actually thought about it....sorry for my last post. So how do I figure out which shims are the right ones without the tool. Is there any clearance in between the rocker arm and ball socket that I could measure? Thanks for all of your help!
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George Carstens |
#5
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The adjustment can be made using either the different thickness ball socket (on the end of the valve stem) OR by using the different thrust element. Since you are at the thinnest ball socket (3.0mm) and are still too thick, you obviously need a thinner thrust element. Going by memory, there are marks on the thrust element to help identify their thickness. The thinnest one has one "dot" in the middle of it on top, you can see it by looking at the top of the rocker arm, the top of the thrust element is exposed. This is the most common when the engine leaves the factory. Many people assume the "dot" is an oil hole, it is not, it's an ID mark. I believe the next thickness up has 2 ID dots, and the thickest one has 3 dots. If you at the thinnest thrust element and the thinnest ball socket, you may need to either have the valve job done over using new valve seats installed, or replace the head.
Gilly
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Click here to see the items I have up for auction at EBay Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold) |
#6
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I don't know how to check the adjustment without the tool.
It makes more sense to me if i think about it that the factory would make it so the thicker shim would be installed, not the thinnest, so that if a valve job is done that there will be room to adjust it. Possibly I have the order mixed up, maybe the "one dot" thrust element is the thickest. You can't measure clearance like a mechanical lifter. What is in the rocker you can think of as a hydraulic "lifter" for a pushrod engine, it has a preload, not a clearance. But not alot. It shouldn't be pressing down and actually moving the valve, the compensator should be pressing in. I'll try to remember to look tomorrow to see what the ID marks are on the thick and thin shims. Gilly
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Click here to see the items I have up for auction at EBay Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold) |
#7
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I measured the shims that were in there from the factory and they came out to 1.8mm. So I went ahead and ordered the 1.5mm ones. The thinner shim should give me the clearance I need. Hopefully it will be enough preload not to have noisy valves but not too much to open the valve. Thanks for all your help. If there is anything else that you could recommend...I am still open to suggestions. Do you know how much one of those tools costs? Thanks
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George Carstens |
#8
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George:
I think i found the tool. I'm having trouble with this website, can't get everything to load: http://www.********.com/sirtools/tools_benz.html Go there, I think what you need is M 0025, $65, which if it's correct seems like a deal to me. Plus you'll need a metric dial indicator, probbaly with a 2" extension or so. (or a fractional inch dial idicator if you want to do the conversions) Gilly
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Click here to see the items I have up for auction at EBay Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold) |
#9
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George:
Got it to all load and got an image up of it. Yeah, that's the tool and looks like it comes with the extension for the dial indicator too. Gilly
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Click here to see the items I have up for auction at EBay Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold) |
#10
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George
I didn't write down the part numbers, but the shims are identified like this: NO ID mark=.9mm 1 ID mark=1.8mm 2 ID marks= 2.2mm There is no shim with 3 marks like I thought there was. The ball sockets as far as I know have no kind of ID marks Gilly
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Click here to see the items I have up for auction at EBay Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold) |
#11
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Are the marks just punches on the top of the shim?
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George Carstens |
#12
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Yep, like someone just knocked it with a center punch. As I said, the 1.8 with just a single mark is the most common, you can see the marks by just removing the valve cover. it looks like an oil hole or something, but it's the ID mark. It's right in the center of the shim.
Gilly
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Click here to see the items I have up for auction at EBay Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold) |
#13
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Ok well I got the tool. Now, could you explain to me how to use it? When my machinst did my valve job, he did not shave metal off of the top of the valves, so now I have to disassemble the head and shave metal off of the valves that are too long. I am using the thinest shim and I am still compressing opening the valves when they are supposed to be closed. How much preload am I supposed to have on a 1990 300E motor and how do I use the tool to measure it? Thanks for all your help!
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George Carstens |
#14
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The thinnest shim has no mark on top, no punch mark. It's smooth.
There are also 2 different thickness inserts that fit on top of the valve stem (the part the ball fits in to). Did your tool come with the extension for a dial indicator, and do you have a dial indicator? Gilly
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Click here to see the items I have up for auction at EBay Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold) |
#15
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I have the thinnest inserts and the thinnest ball sockets already. The tool did come with an extension and I do have a dial indicator.
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George Carstens |
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