Need advice on chasing down a rattle on my m20.

[digger]

i made some shims with the febi shafts so the plugs fit nice and tight, at the other end i sanded them down so they weren't too tight lol

[gnmzl]

Yeah, I've heard the same stories about the febis, the ones I used were Ruville, just dug up the receipts. As stated, they looked legit aside of that length issue. Holes and retaining slots were spot on. Well, I guess we'll find out soon enough, really hope this endeavor will help someone in the future.

[whodwho]

...
Genuine were listed as NLA. I don't know if that's still the case now.
...

They are available again and oil pumps as well, now I just need a new dash to come back available 8^(

[digger]

i bought some OE ones a couple months back, they come without end plugs

[D.Martijn]

i bought some OE ones a couple months back, they come without end plugs

Yes, When I did a cylinder head rebuild, I found another/newer part number as the first time I tried ordering the rockers shafts they were NLA. Also no end plugs included.
11331264533 is NLA
11331274975 is available

[digger]

just need to by the correct plugs for the genuine shafts

[gnmzl]

Hello everyone and thanks for the latest input - it had helped.

I got laid off just after my last post on this topic, so working on chasing this down was put off naturally.
After squaring stuff out, Wednesday evening was the night of truth.
Whoever says you need to disconnect the water radiator to remove the cam while head/engine is in the car, send them this pic.



I resorted to trying this, because I failed to find a suitable container to capture the coolant. Thought we had one in the shop, but it went missing.
What I had to do is, besides the obvious removal of clutch fan, fan shroud, cam sprocket etc. was remove the coolant hose clamp located on the frame rail intake side, remove the inner fender (early models have this protruding into the engine bay lower inner fender) and make sure the jeesus bolt doesn't jam up against the fins. I used a plastic bottle cap, tight enough to stay on there while turning the crank and shallow enough to allow for a 22mm wrench to fit onto the bolt.
In my case, the 16" SPAL was in the way, but thankfully upon initial install, I made my life easy with some simple brackets and these handy wing nuts.




These shot portrait better how much room I had to play with




Just enough, so I went ahead and started removing the rocker shafts.
Intake side one was REALLY hard to remove. Like, so hard, I had to take my time and remove it in a total of 4 hours, being careful not to mar the head casting in any way.
Very much worth mentioning is on one of my previous attempts to fix that issue I found that it was twisted to the side, resulting in the key allowing it to move forward from it's originally intended position in the head. Keep this in mind for later in that post
It was really difficult at times, given the limited space and leverage I had. In the end, it came off and so did the exhaust side shaft (so much easier), followed by the cam itself.

Needless to say, the culprit was found, I'll let the pictures do the talking for me. Below are the cam lobes and the corresponding rocker arm above them.








Sure, all of the rockers have some sort of weird wear pattern. But that number 3 exhaust rocker ...... never seen anything like that wear patter.

So, now the only thing left not inspected are the shafts.
Previously I stated the following:

...As stated, they looked legit aside of that length issue. Holes and retaining slots were spot on. Well, I guess we'll find out soon enough, really hope this endeavor will help someone in the future.

This statement is wrong.



Pictures don't really show it well, but the holes are not perfectly matched and neither are the rocker positions. True, the misalignment is small enough to not cause any issues.
Granted they stay in place and not rotate or slide about.

Here is my thoughts on what happened, please feel free to correct me if you think I'm daydreaming and have a more serious problem:

Since the intake valves were kissing the pistons ever so slightly, the pressure from that event goes into the rocker pivot point and that is the rocker shaft. The intake shaft get slightly bent (hence the difficult removal) and also rotated and slid forward. Combined with the slightly misaligned oil holes on the shaft, this leads to not enough oil pressure for the spray bar on top of the cam. Oil starvation occurs and all rockers and cam lobes suffer damage. Exhaust rocker on number 3 suffers the most for some reason, assuming my valve lash adjustment was out of spec on this one, and it causes the clatter.

So ... ok, cause of weird rattle found. Now I need to make sure it never happens again.
By chance, a brand new set of IE HD rocker arms is sitting in my closet. It was a deal you can't say no, so I grabbed them about a year ago.
A set of OEM rocker shafts is also in my closet, thanks to you gents - ordered one as soon as I saw the comments they were again available.
Now what i think doing is:

- Polish the pads on the new set of rocker arms.
- Talk to a reputable machinist to see if the cam is salvageable.
- If cam is kaputt, buy a new one and have the lobes polished as well, or polish them myself (I'll have a spear cam to train on lol )

I wonder how to make sure I get oil flow to the correct places before that.
How stupid is the idea of removing the timing belt and spark plug and give it a few r3vs via starter? In theory shouldn't do harm, but it seems to me like a stupid idea and genius at the same time.

Your input will be greatly appreciated.

Moral of story: walks like a duck, talks like a duck, chances are it is a duck.

[digger]

Some of the rockers are totally rooted. What brand are they ?

what oil do you use?

[gnmzl]

Those are Ireland Engineering HD rockers. Oil was Motul 300V Competition 15w50.

[digger]

I’d say either lack of lubrication maybe sprayer bar clogged or substandard pad material

[gnmzl]

Possibly, last time I checked the spray/drip bar it was ok. It was a brand new oem unit upon installation.
Talked to a guy, he said better to not polish a cam. Odd, I've seen machines advertised to do just that.
What about the idea to remove the timing belt and spark plugs, a few seconds cranking the starter and see if oil comes out the correct places on the head, as is without cam and rocker now. Just to make sure oil gets to the head.

[digger]

you need everything in the head assembled (rocker shafts, cam, rockers etc) to test the oil system and therefore you need the timing belt connected as well if you rotate the engine. instead of cranking the engine you could also spin the oil pump with a 6mm hex (remove the cover on the intake side) and drill and slowly rotate the engine by hand

your cam is probably toast short of a regrind but i wouldnt do anything to a new one. the IE rockers could probably benefit from a polish as they are very differnt to OE finish but that needs to be done professionally so that eveything is square and the finish isnt too smooth.

[gnmzl]

I get what you mean. Thanks for the input. Next update will be well after the holiday season.

[gnmzl]

Happy New Year everyone.

Let's continue this ordeal.
I need advice on some topics.

1. This one is for digger:
I called around and talked to a reputable guy involved in rally racing teams around here and he says there isn't such a place in our country that can salvage the camshaft or polish the rocker pads. My question is - what is meant by "don't make the finish too smooth" Is that possible?

2. I am contemplating on getting a different cam. Here is the camsheet of the dbilas unit that was in the engine, the one from the above pictures.



It is a bit different than advertised in their catalog, difference being max lift is supposed to be 11.5 and valve lift 2.8 but according to the camsheet it's 11.1 and 2.6 respectively.

https://dbilas-shop.com/motor-ventiltrieb/sportnockenwellen/bmw/2-0-2-7-6-zyl.-12v-m20/neue-nockenwellen/1198/bmw-2-0-2-7-6-zyl.-12v-m20/sportnockenwelle?c=15814

I'd say I trust the camsheet, since the cam was bought through a re-seller and they may have had the older cam version in stock or just misadvertised the one in stock. Not sure, but I would trust the camsheet that came with the cam. Thoughts on that?

The cam I am currently eyeballing is the catcams 291

http://www.catcams.com/products/camshafts/datasheet.aspx?ENGINE_id=111&CAMSETUP_id=2464&Language=english

The way I see it, please correct me if I'm wrong:
The catcams cam will sacrifice a bit lift at TDC, which in turn will reduce the possibility of another valve-piston contact. In the same time it has more max lift, which should compensate for the smaller lift at TDC. The bigger lobe separation will give me a slightly better idle.
What I can't figure out is how it would affect the powercurve. Dynosheet prior to rocker failure:



3. What about adding an oil additive - currently I'm eyeballing the Liqui Moly Molygen Motor Protect product. It's supposed to create a thin "deformable" layer on the engine rotating surfaces. Anyone have any experience with that and/or comments?

https://www.trodo.com/engine-oil-additive-liqui-moly-molygen-motor-protect

Your input is greatly appreciated!

[digger]

Happy New Year everyone.

Let's continue this ordeal.
I need advice on some topics.

1. This one is for digger:
I called around and talked to a reputable guy involved in rally racing teams around here and he says there isn't such a place in our country that can salvage the camshaft or polish the rocker pads. My question is - what is meant by "don't make the finish too smooth" Is that possible?

2. I am contemplating on getting a different cam. Here is the camsheet of the dbilas unit that was in the engine, the one from the above pictures.

It is a bit different than advertised in their catalog, difference being max lift is supposed to be 11.5 and valve lift 2.8 but according to the camsheet it's 11.1 and 2.6 respectively.

https://dbilas-shop.com/motor-ventiltrieb/sportnockenwellen/bmw/2-0-2-7-6-zyl.-12v-m20/neue-nockenwellen/1198/bmw-2-0-2-7-6-zyl.-12v-m20/sportnockenwelle?c=15814

I'd say I trust the camsheet, since the cam was bought through a re-seller and they may have had the older cam version in stock or just misadvertised the one in stock. Not sure, but I would trust the camsheet that came with the cam. Thoughts on that?

The cam I am currently eyeballing is the catcams 291

http://www.catcams.com/products/camshafts/datasheet.aspx?ENGINE_id=111&CAMSETUP_id=2464&Language=english

The way I see it, please correct me if I'm wrong:
The catcams cam will sacrifice a bit lift at TDC, which in turn will reduce the possibility of another valve-piston contact. In the same time it has more max lift, which should compensate for the smaller lift at TDC. The bigger lobe separation will give me a slightly better idle.
What I can't figure out is how it would affect the powercurve. Dynosheet prior to rocker failure:


3. What about adding an oil additive - currently I'm eyeballing the Liqui Moly Molygen Motor Protect product. It's supposed to create a thin "deformable" layer on the engine rotating surfaces. Anyone have any experience with that and/or comments?

https://www.trodo.com/engine-oil-additive-liqui-moly-molygen-motor-protect

Your input is greatly appreciated!

It seems to be recommended to have a bit of texture to retain some oil but not so rough that it causes wear. Most seem to be a nice ground finish but not polished to a mirror.

Web cams do hard rewelded cams and they used to do MM cams not sure if it’s still the case. I would imagine it would be easier, less risky and cheaper to get a new cam. You could at least enquire and see if they could repair and replicate. It looks pretty exy but that’s for a full weld job, not a repair which might be cheaper.

http://www.webcamshafts.com/pages_vehicles/automobile/bmw/1945.html

Before you buy a cam you want to verify the P to V. I’m not a fan of getting a compromised cam because of P to V issues. That’s what I did years ago and have regretted it.

That 292 dbilas cam on paper looks good. Sometimes it’s misleading when you plot it out I’ve seen occasions where it’s a lot different so you never can be sure without plotting it with dial indicator and a degree wheel of sorts.

I would get a Schrick 288 or the same DB292 as what you have over the cat cams if you have the P to V. the catcams LSA is too wide and there are other differences in the ramp design that mean the torque should be better with schrick/dbilas.

The catcams wider LSA may idle and have better fuel economy but give up a bunch of midrange and bottom end. It might peak slightly higher but will likely have less under the curve IMO

Before you scrap that cam (if that’s what you decide) if you sent it to me I can add to by database on measurements and update the thread, i will pay shipping obviously.

You just need to buy an oil that works to start with, e.g. if the Moly additive was any good/worthwhile it would be in their base oil. Sometimes for breakin an additive can work as you only want it around temporarily but any additive you need to repeat should be in the regular oil.

Torque curve looks good, though AFR sub 3500 could be improved out which will partially help the dip at 2900rpm.