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Question for the guys with knowledge on valve adjustments. Motor in question is a S54 from my M3.
Im in the process of resembling my engine and I was just about to put the valve cover back on when I decided to do a valve adjustment. Happy I did because a few were out of spec. But the issue I am having is the second to last valve I was doing (valve 11 on exhaust side) has a huge space between follower and cam. I put in the largest shim in the kit 2.60mm and its far from passing.
So my question is what could cause such a large gap?
The head was just refreshed at machine shop. im thinking the cam follower (rocker arm) for that valve is worn.
Any info will be much appreciated!

Thanks
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Refreshed, please expound.

Did the machine shop do a valve job?
If so, was "installed height" observed?

Piece of debris between the seat and the valve?

I got bit hard once on a e30 m3 when I was a new BMW technician. Doing a major service and adjusting the valves. A piece of carbon must have dislodged. It needed a huge shim, unlike the others. So I put it in.

Started the car, and that valve bent. Because something held the valve slightly open and I adjusted incorrectly as a result.

Try to look at the seat/valve interface.
 

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Thanks for the response!

The head shop did do a valve job. New seats and seals with a few bent valves replaced due to previous owners lack of maintenance. Head checked out perfect and all the valves seemed closed when I inspected prior to assembly. I’d hate to tear this whole thing back down lol.

I will see if I can somehow measure the springs to see if they are in fact closed on that cylinder.

Any idea if it’s possible to remove a rocker without removing the actual cam? I’ve got the timing set perfect would hate to have to redo it.

Thanks


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I had a visit of a car from another shop that had a recent valve adjustment. They forgot to slide one of the finger followers back into place on cyl. #5 intake. The cam was acting directly onto the top of the valve cap/spring/hat. Naturally the shim was missing.
We didn't want to yank the head. We spent an extraordinary amount of time replacing the seat/spring/hat/keepers with some home made tools. Albeit we didn't have to take anything else apart. Not sure if I'd go that route again.
The follower was okay, as it was off to the side doing nothing. Luckily he came in in a very few miles and the cam lobe was just fine.

I think verifying the height of the tops of the valves/springs is a great place to start. You've got to find out why that one wants a gigantic shim....
About the only thing you can do is buy a cheap vernier caliper and use the part that pushes out of the back. Measure down to a common spot (spring seat (?) steel seat under the spring) for a few and compare the measurement against the maleficent one. Measure the back of the caliper against the shim cup down to the seat, if...you can.

Let us know your findings.
 

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Thank you for the response!

Saturday I went ahead and called the dealer and ordered a follower as I really thought/hoped this was the issue. It’s coming from PA and I’m in south Florida so it won’t arrive till Wednesday ish. So when I came home today I decided I’d take a better look to see if I can figure this out and confirm my theory.

I was definitely wrong in thinking follower. As I uncovered the engine I kneeled down to the height of the head and just glanced at the height of the springs between #11 and 12 valve since the cams are point straight up they should be at the same height since they theoretically are closed. Well #11 is definitely sitting a little lower than 12. Take a look at the photos I snapped when I tried peeking into the valve from the exhaust.

#11 valve is open on the exhaust side.
I can’t visibly see anything (carbon/debris)keeping the valve from closing.
I’m going to ask my girlfriend to record the opening into that valve from the exhaust as I turn the engine over to see if maybe the valve is bent.

Good progress but I believe this head may need to be disassembled and removed again. Or at least cams out. Fingers crossed I’ll report back with any new findings or hopefully with a resolution!





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Something is indeed holding that valve open. Looks like a bit of crust or carbon on the valve shaft. Can you move the piston down and then lever or actuate the valve while observing it with your scope? That is the scummiest valve I've ever seen after a valve job!!!
 

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Discussion Starter #7
Something is indeed holding that valve open. Looks like a bit of crust or carbon on the valve shaft. Can you move the piston down and then lever or actuate the valve while observing it with your scope? That is the scummiest valve I've ever seen after a valve job!!!
What is the scumminess you are referring to?
(I am a Noob to engine reassembly/building so would like to learn what things to look out for)
Any suggestions on how to manually actuate the valve? Will I be needing to purchase a specialty tool?
I’m going to take a wild guess and say any tool to actuate the valve will require me to take the exhaust cam off to operate it

I have a funny feeling that this head is coming off again shortly!

Thanks


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Can't be 100% sure from the photo but it looks like it's hanging open.
The goo is likely assembly lube leftover from assembly. No harm, no foul.
Looking carefully at the last photo, you can clearly see the cleaner (shinier) portion of the valve stem at/near the top of the valve stem, where it goes into the valve guide.

That's one of the working parts of the valve. That's the part that goes up/down inside the valve guide. Hence the different color from normal wear and constant rubbing. The part below it is a different color as it has NO contact with anything.

A Guess...: That valve guide is too tight and/or has a burr in it from finish honing of the guide. It's also possible that the top of the valve nicked off a very fine piece of the bronze guide and it's hanging up the valve?

Now what are your options?

You could rotate the engine so that the piston was say 1/3=1/2 way down in THAT bore/cylinder and the can (close) but not acting on the valve. Get a lever (usually a "U" shaped hook with a lever as found with amazon head disassembly tools) and work that valve (take the shim out and place it in a safe place away from the "work".) up/down and see if it frees up?
So lets hypothesize you're successful: Are you confident that the valve/valve guide has enough clearance? Will it hang up at the worst possible moment when the engine's running and it hits the piston??? Tough call.

Alternately you can remove the head, disassemble and remove all the valve springs. Then with two pieces of 2x4 under each end move the valves up/down and feel the valve guides and the clearance each one has. Do some, many, one have too tight of a clearance? Correct the issue.

In all likelihood if....the others are fine it's a burr. But it MUST come out and one needs to be sure that it didn't really scuff up the inside of the valve guide (the valve itself is likely fine as they're VERY hard) and alter the inside surface.

One does NOT want a valve to hang open at just the wrong moment. Broken off tulips of valves wreaking havoc inside a combustion chamber is a very ugly thing. I've seen it countless times.

Notice I didn't say your machine shop [email protected]&ed up. But something isn't right, now it's time to be like Sherlock Holmes and find out why. For that valve and check the others.

Lastly, do you own a strong AA maglight? Can you see both valve springs? Are they both good?
Is the amount of protrusion of the valve tip into the hat the same as another valve. Use an easy one like #1 or #2 as a gauge. Slide the finger follower out of the way, remove the shim and look at the top. Then compare it to your problem child.

Good luck!
 

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Discussion Starter #10
Were you able to get in there and make some observations?
MrMCar thank you for all your knowledge so far!
I am beyond thankful!

I was going back in forth in my mind yesterday.
Luckily the head shop is literally around the corner from my office.
I went over there and had a chat with the owner and he was as stumped as I was.
So since no matter what I do or what I find id still have the head shop resolve the problem so I can have the peace of mind that It was done right and nothing from me trying repair it will pop up and get me in the back later down the road.
I have decided to take the head off and give it back to the shop to have them figure out what is wrong and resolve it.

But as I was driving home last night something popped in my mind and I think I know what really had happened.
They day the head was going on the block I had to run out to pick up a family member from the airport.
I was working with a friend of mine on the engine and I left him to keep pushing forward while I went to the airport to pick up my family. So when I returned my friend was telling me about how when he was fastening down the exhaust cam he had an issue with the very last cap on the exhaust side ( #11 & #12) he said as he was taking down the cam cap nuts the last cap would not go down all the way. He described it as if the cap was hitting one of the guides (that's on either side of the receiving end of each cap) and wouldn't let it go down all the way. So he said he took off all the cam caps on the exhaust side made some sort of adjustment on the cam im guessing, and when he retightened it down it was fine.

So in my mind it clicked. What I believe happened is when he was initially setting the exhaust cam down he didn't have it oriented close enough to TDC and when he took the the exhaust cam down it was trying to open the valve while the piston was at the top of the cylinder which most likely bent the valve on 11 and probably 12 also.
I believe that would explain why the cap wasn't going down all the way.

Hopefully the shop confirms my theory.

Heres another question for you.
How do I go about getting the cam to go down as evenly as possible when fastening the caps?
I want to avoid running into this issue again. Intake cam is fine because I was the one who did it and noticed no issues when installing. But since I will need to be removing both cams I want to try to install them I guess neater then the last install would be best way to put it.

Thank you again for all your help!!

Morris,
 

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Well good sleuthing and I'd believe your assessment is correct. As a generality (many years of experience here) we never install the cams with the engine @ TDC. Seems counter-intuitive, but we usually have the engine a few degrees BTDC. This way the piston tops are slightly down. Slowly walk the cam caps down (we have the tool) 1/4 of a turn at a time and evenly so that the cam doesn't bend. (It does, believe me) Then we get the cams to TIME with the bridging tool and use a dial indicator set on piston #1 to obtain true TDC with the bottom end.

Go through the complex timing procedure, rotate the engine 4 times (two complete cycles) and then install the VANOS and repeat the rotation. Checking with the tool to be sure timing is 100%.
 
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