Metallic Rattle 2-3k rpm

[SteelGreyM]

I feel like this tune has been the common denominator in the past 3-4 blown head gaskets I've seen here. Does it code off the knock sensors or something?

I was going to make a post about this and I think I still will. I don’t believe it turns off knock sensors. In fact he had me scan my car with bmw logger and it revealed my knock sensors were bad which he then recommended I replace. I replaced the sensors and confirmed they were working (no code) before installing my tune.

I’ll be sure to make a post about these suspicions...

[Darbshaw]

Here are the compression test results, my understanding from this is that my issues are running deeper than just the head gasket.


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Also another thing I noticed when doing the compression test is that there was an extremely weird squishing sound? Like wringing out clothes or something. I’ve never done this test before so I am unaware of what normal sound is supposed to be.

Along with that cylinder 3 and 6 started to occasionally produce some steam intermittently when turning over. I assume this was due to a true head gasket leak or something of that sort making it’s way in there


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[t3ddftw]

I had a rattle at this RPM range in my first M3 and it was worn gasket rings between section 1 and section 2, but YMMV.

[SteelGreyM]

Also another thing I noticed when doing the compression test is that there was an extremely weird squishing sound? Like wringing out clothes or something. I’ve never done this test before so I am unaware of what normal sound is supposed to be.

Along with that cylinder 3 and 6 started to occasionally produce some steam intermittently when turning over. I assume this was due to a true head gasket leak or something of that sort making it’s way in there


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Sorry to hear about all this. Next step here would be a leak down test to confirm where exactly you are losing compression.

Additionally, just because you have low compression on all cyl doesn’t mean you have a blown engine. My head gasket was broken *between every single cylinder*. I’ll throw up a pic

One step at a time

[Darbshaw]

Sorry to hear about all this. Next step here would be a leak down test to confirm where exactly you are losing compression.

Additionally, just because you have low compression on all cyl doesn’t mean you have a blown engine. My head gasket was broken *between every single cylinder*. I’ll throw up a pic

One step at a time

Okay, leak down after work tomorrow hopefully. Gotta go a couple hours to get my old daily off the airport lot haha.

I’m assuming autozone will have one of those to rent as well. Anything specific to look for with the leak down?


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[SteelGreyM]

Okay, leak down after work tomorrow hopefully. Gotta go a couple hours to get my old daily off the airport lot haha.

I’m assuming autozone will have one of those to rent as well. Anything specific to look for with the leak down?


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https://www.youtube.com/watch?v=svlwuhK0IIU

50s kid is the best. So sad he stopped making videos...

You’ll need an air compressor.

Here is the kit he uses: https://www.amazon.com/OTC-5609-Cyli.../dp/B0030EVL60

Here is the harbor freight version: https://www.harborfreight.com/cylinder-leak-down-tester-62595.html[/URL]
Harbor freight is pretty hit or miss on quality on this one.

[SteelGreyM]

Any update?

[Darbshaw]

Any update?

Sorry! Haven’t had the opportunity to get the harbor freight leak down tester since I’ve been too busy during the week to grab my second car and have been trying to make the M driving as essential as possible. Been trying to stay out of the 2-3k rev range because I figure that’s where that detonation sits.

Ordered a pretty cheap and harbor freight equivalent leak down tester on amazon which was supposed to be in today but got pushed back to tomorrow. Current plan is for the leak down this weekend.

After weighing my options I’ve most definitely decided it’s still financially the best decision to stick with the M and get it fixed myself. DIY on the job is no issue for me and it’ll be a fun time pushing my limits.

I’m feeling pretty optimistic for the leak down test. As long as I’m not losing any of that compression down into the block I’m ready and good to go for a long weekend or two and a little bit of extra cash spent.
Priced out the parts for a full seal refresh kit and a valve spring compressor to change out all the seals there and get the head fresh and good to go. I believe I was looking at roughly $500 tool included and then another little bit to finally pick me up a quality torque wrench for the job.

Kinda have been tossing up the idea of doing cams while I’m in there and really going all out but that’s a big if.

At this point I’m going to get me a nice big white board for the garage and just start listing what’s needed. If we get to the point of a bottom end rebuild I’m still debating between that and just buying a used lower mileage engine to do the maintenance and swap.


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[SteelGreyM]

Sorry! Haven’t had the opportunity to get the harbor freight leak down tester since I’ve been too busy during the week to grab my second car and have been trying to make the M driving as essential as possible. Been trying to stay out of the 2-3k rev range because I figure that’s where that detonation sits.

Ordered a pretty cheap and harbor freight equivalent leak down tester on amazon which was supposed to be in today but got pushed back to tomorrow. Current plan is for the leak down this weekend.

After weighing my options I’ve most definitely decided it’s still financially the best decision to stick with the M and get it fixed myself. DIY on the job is no issue for me and it’ll be a fun time pushing my limits.

I’m feeling pretty optimistic for the leak down test. As long as I’m not losing any of that compression down into the block I’m ready and good to go for a long weekend or two and a little bit of extra cash spent.
Priced out the parts for a full seal refresh kit and a valve spring compressor to change out all the seals there and get the head fresh and good to go. I believe I was looking at roughly $500 tool included and then another little bit to finally pick me up a quality torque wrench for the job.

Kinda have been tossing up the idea of doing cams while I’m in there and really going all out but that’s a big if.

At this point I’m going to get me a nice big white board for the garage and just start listing what’s needed. If we get to the point of a bottom end rebuild I’m still debating between that and just buying a used lower mileage engine to do the maintenance and swap.


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You’ve got a good plan so far!

I ordered every brand of valve seal to compare them and none of them look like the BMW brand stuff. I’m gonna use those even though they’re ludicrously overpriced.

If you haven’t done a VANOS job yet update it with Beisan stuff. As far as timing goes get the BMW brand stuff. Aftermarket stuff has bad fitment and your timing will be off.

Change out your cam bolts while you’re there. As far as head gaskets go you can go with OE BMW which is Elring. Or you can go with cometic. Make sure you use new head bolts. Wether you go with BMW brand or ARP head studs is up to you.

https://www.fcpeuro.com/products/bmw-engine-cylinder-head-gasket-set-11127831920

If you’re going full OE this isn’t a bad kit but get BMW valve seals.

[Darbshaw]

You’ve got a good plan so far!

I ordered every brand of valve seal to compare them and none of them look like the BMW brand stuff. I’m gonna use those even though they’re ludicrously overpriced.

If you haven’t done a VANOS job yet update it with Beisan stuff. As far as timing goes get the BMW brand stuff. Aftermarket stuff has bad fitment and your timing will be off.

Change out your cam bolts while you’re there. As far as head gaskets go you can go with OE BMW which is Elring. Or you can go with cometic. Make sure you use new head bolts. Whether you go with the BMW brand or ARP head studs is up to you.

https://www.fcpeuro.com/products/bmw-engine-cylinder-head-gasket-set-11127831920

If you’re going full OE this isn’t a bad kit but get BMW valve seals.

So I actually have already done my VANOS with the full anti-rattle kit and new cam bolts and all. Did mine before the exhaust hub went and saved me from getting a new one of those! From that job, I did pick up a true BMW timing bridge as well.

As far as head bolts go, I was planning on the OE for them iirc are priced around 40-60 bucks. Although ECS lists a brand that is a fraction of that at like $20 or so. I don't think I will want to risk having to do the job again to save $40 but I am curious to see if anyone has chosen to use those head bolts.

https://www.ecstuning.com/b-ajusa-parts/cylinder-head-bolt-set/11127831862~aju/?gclid=Cj0KCQjw7sz6BRDYARIsAPHzrNJv6LuCjW0-QakyI85nYa0XIaAYk7gMgVglFMWy6fH74huOTTAGoaAaAqeOEALw_wcB

Thanks for the link to the fcp kit! I did not realize they had one available. Actually I think if I play it smart I may be able to take advantage of FCP lifetime warranty and piece and part the items for the kit since I've already ordered my valve cover and vanos gasket and such through them.
Is there any real major difference to the valve seal? I figure OE and OEM should be spot on. Theres a significant price hike when going to OEM valve seals and for 24 of them .

[SteelGreyM]

So I actually have already done my VANOS with the full anti-rattle kit and new cam bolts and all. Did mine before the exhaust hub went and saved me from getting a new one of those! From that job, I did pick up a true BMW timing bridge as well.

As far as head bolts go, I was planning on the OE for them iirc are priced around 40-60 bucks. Although ECS lists a brand that is a fraction of that at like $20 or so. I don't think I will want to risk having to do the job again to save $40 but I am curious to see if anyone has chosen to use those head bolts.

https://www.ecstuning.com/b-ajusa-parts/cylinder-head-bolt-set/11127831862~aju/?gclid=Cj0KCQjw7sz6BRDYARIsAPHzrNJv6LuCjW0-QakyI85nYa0XIaAYk7gMgVglFMWy6fH74huOTTAGoaAaAqeOEALw_wcB

Thanks for the link to the fcp kit! I did not realize they had one available. Actually I think if I play it smart I may be able to take advantage of FCP lifetime warranty and piece and part the items for the kit since I've already ordered my valve cover and vanos gasket and such through them.
Is there any real major difference to the valve seal? I figure OE and OEM should be spot on. Theres a significant price hike when going to OEM valve seals and for 24 of them .

Check out the photo I posted on the OE manufacture parts list thread. I ordered Elring, corteco, and BMW. Bmw looked very different from the others. The design looked better too with a smaller diameter hole for a better seal.

I’d go with bmw head bolts. This isn’t a spot where you want to come back to because of $100 (valve seals + head bolts)

[Darbshaw]

Now for the meat and potatoes of all of this. I got my leak down tester in today and went and took a crack at it to see what the deal is. Took me a couple of tries to get the test and positioning spot on or close enough to it. One thing I will note is that I was having an issue pinpointing the sound sometimes, although after multiple runs of the test. I think I was finally able to produce a feasible and valid one. I have a pretty mean exhaust leak at my headers to section 1 so I think I was getting a lot of sound from that and making it a pain to rightfully diagnose.

Leak Down Test
Cyl 1: 12% Leak; possibly from exhaust valves, no noticeable air coming through the oil filler cap.
Cyl 2: 50% Leak; came through Cyl 3 heavily, looking back at the compression test this was expected, no noticeable leaks from the intake or through the filler cap.
Cyl 3: 40% Leak; obviously shared through 2, again no noticeable leak through the filler cap or intake.
Cyl 4: 20% Leak; Potentially through cylinder 3 or the exhaust valves, valves make more sense in this case as 3 reported in better health than 2, again no noticeable leak in intake or oil filler cap
Cyl 5: 20% Leak; When testing this seemed through 6 but again could also have more leak in the valves, no noticeable leak through the oil filler cap.
Cyl 6: 25% Leak; Seemed as this was slightly through 5, no noticeable leak from the filler cap or intake.

I am tossing up the idea of doing this with my valve cover off that way I can perfectly guarantee that neither of the valves is open. My only thing is I don't want to risk warping my valve cover removing it while it's hot just so I can test my previous results.

Verdict
Besides the idea of potentially redoing the test with my valve cover off, all in all, I would say my results are desirable with the given situation. Looking at these along with my compression test I would say that the leak numbers seem to be fairly accurate with cylinder 1 having decently high compression (relatively that is). With the lack of any leaks coming through the oil cap, I think that the bottom end may be in good shape and I can get away with just doing the head. Although I guess my situation could change once I get it apart.


Is it normal for an engine to see uneven wear between piston/cylinders/rings etc? So with the idea that Cyl 1 is performing very well comparatively, I am almost certain I should see no issues down there. Is it safe to assume that the rest would hold true for the other 5? Or can there be uneven wear between these?

Either way, at this point the M is parked in the garage for early hibernation and disassembly will begin shortly. May even start cracking at it Monday since we have a long holiday weekend.

[SteelGreyM]

Well I’d say you’re okay. It’s time to pull the head though and have a good look for yourself.

This won’t be a month long process unless you let it go that long. You can have this done in 2-3 days if you’re a decent DIYer.

Good luck!

[Darbshaw]

Thanks! At this point I'm taking it slowly just to avoid having the costs for the repair hit me all at once. Since I'm not just buying parts, I'll have to spend a little more on tools as well so I got to break it up across a period of time.

[Darbshaw]

Since I’m looking to eventually super charge the car should I be looking into a thicker head gasket?

I’m not planning on running crazy amount of boost and not going over 400-450 wheel. But since I’m in here does anyone have any idea if this would be necessary or worthwhile?


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