Tricky crank no-start problem

[DonaldFoss]

[mention]80stech [/mention] Thanks for the clarification. On the lapping, that’s interesting and worth bearing in mind. I did as advised by my dad and a Toyota mechanic in the family, I’d only done SBC valves on iron heads before. Lapping was supposed to fix whatever grooving was there. I’m doing the valves myself as part of the adventure. When I told my dad about the leaking, he told me to put them on the engine anyway and they’d probably fix themselves. I should have tested the valves before doing anything to them.

I’m 54 and yes, I still go to my dad for advice with mechanical stuff, any type of mechanical stuff. He’s forgotten more than I’ll ever know, and he doesn’t seem to forget anything. My brother was a F16 crew chief and airplane mechanic. Me? I was great at cross threading things. Maybe that’s why I did electrical engineering and computer science.

Given the cost of good valves, and money I already spent, I might just buy another head off ebay, put a second head gasket on and try that. They were around $330 last I looked. If I like the new-to-me head, assuming everything is working, I’ll get it decked and port both sides again.

This intake is a stock M54 attached via 7mm bolts versus the studs that are stock to a M54 engine. I like bolts better, less likely to drop into the intake or anywhere else. Personal preference I guess since I shake and drop things too easily to deal with.

I did the spark gap test tonight. Since it’s just me I used a 4k camera and reviewed footage after each test. I’m not certain about the markings on the device, they didn’t line up with my calipers so I measured out manually 10mm, then 15 and 20mm from the tip of the electrode. I got consistent spark over 4 strokes at 10mm, 15mm and 20mm. One time it arced to the turbo, about 5 inches away, so I put a piece of wood in front of the turbo to prevent it from happening again.I think the coils are ok. I was really about to order some supposedly higher energy coils for forced induction too, but from what I recall, 15mm is recommended minimum spark gap length for forced induction, and this exceeds that spec.

I’d like to have a Trillium induction unit that would measure voltage too, but they’re a little pricey and wouldn’t be here for a few days anyway.

When reviewing the INPA guide for removing Vanos, there was a handy quick test for timing. If you turn the crank until the first lobes on both intake and exhaust and pointing inwards to the #1 spark plug recess, and you have the cam holders installed on the back of the cams, the holders on the intake side should be flat or less than 1mm high at highest level, and the exhaust side should be flat. If this is true and you have the intake/exhaust cam on the correct sides, BMW says timing is within spec. If it’s not raining for a while tomorrow, I’ll pull the valve covers off and check this.

I loosened and cracked open the downpipe from the turbo to see if that made any difference from the exhaust puffing sound. Not really. This doesn’t eliminate exhaust totally, but almost.

[80stech]

Your dad was kinda right, in fact that's what the machine shop will tell you when you can see light through the valves that have "cut" seats, the burr wears off pretty quick and then you still have a nice sharp edge on the seat, usually doesn't work that way for lapping it's usually only getting worse. I just noticed that you do some Arduino as well I had a pretty neat setup with one Arduino taking readings in the E-box linked to another on the dash with 2 OLED screens but don't use it much any more. I also made a pretty cool Arduino based fuel pressure gauge

Are you sure that your spark tester isn't marked off in thousands of volts? mine measures roughly 20mm at 30,000 volts. A really big problem with these coils is actually the spark plug boot, if you squeeze the end and can see any cracks it's a problem.

[DonaldFoss]

It might have been thousands of volts. I measured the millimeters with calipers and marked it myself. I assume there is a constant relationship between length of the spark and voltage.

On Arduino, I have it reading 6 sensors, running a RESTful interface and web socket interface, and I have a React app running that loads off the web server on the WiFi router. WiFi router is a net gear with a custom rom. It can connect to any other WiFi like my phone or my house. I could put a SIM card in a USB dongle but why bother when my phone is in hotspot mode at all times. I mainly use the Arduino for data acquisition. The react app by default polls the Arduino 20x per second and updates the 14” touchscreen mounted to the dash vertically using the stereo mounts to the 75mm VESA mounts on the monitor. It also sets up DS2 from the ECU and streams that, storing it in a document database in the back of the car. It can display any data and graph from DS2, OBD2, or whatever comes across CANBus/RS485. It can send CAN messages too but I don’t do that much anymore. I found it amusing to see the steering wheel angle changing in real time, but it’s not useful in real life. It can also connect to the Arduino via web socket but the refresh rate is too high for the display with that, the browser gets overloaded. I also have an external USB GPS/Glosnass/whatever else. It has a daemon I talk to for coordinates, direction, speed, etc. it integrates into Linux too.

It is a KDE interface and can play music, videos, whatever else. Google maps in the browser works with the USB GPS module.

I like playing with stuff and exploring what I can do. I started programming in C in 1983, so coding the Arduino didn’t bother me at all.

[DonaldFoss]

Update: timing!

For those who posited timing as the issue, bravo! I don’t know if this is the smoking gun, but it makes sense, even why I had in the throttle body a couple weeks ago.

As some suspected, the intake timing is off. I followed the BMW guide from INPA to check if the timing and the exhaust was correct, but not intake. It’s weird because the paint marks on the cam from when I did it, and the person before me, still lined up, but it was clearly off.


This is a delta angle reading. The engine at the back of the head and the top of the spark plug ports is 32 degrees. The block on the exhaust cam is 0.1 degree off. The intake is off by 5.1 degrees.

The cam block holder is allowed to be up to 1.0mm high on the end. Mine is 7.46mm high.

I’m going to look at the timing instructions in INPA and perform that procedure.

The reason the timing is probably off is because when installing the engine, I used a 500 lb ratchet strap to angle the engine at 32 degrees to line it up with the transmission and everything. The ratchet strap broke and the engine flopped to the left against the side of the engine bay. I pulled the engine back out, inspected it and didn’t find any damage. I then used a 3,333 lb ratchet strap to angle the engine and stuck it in. I didn’t take the engine apart and that has bitten me. C'est la vie…

[DonaldFoss]

The gap on the intake cam block, on the right. I couldn’t get a pic showing the calipers, I didn’t have enough hands.

The Einfahrt and Ausfahrt sides were correct. It rained too much today to retime it, and tomorrow doesn’t look much better. Plus I need to go to my parents and pretend I’m a small appliance repairman.

[DonaldFoss]

[mention]80stech [/mention] [mention]andrewwynn [/mention] Either of you or anytime else seen where an M54 head won't hold timing? I do the BMW timing procedure in ISTA, put the head faceplate special tool on, torque the bolts to 5 then 20 Nm, rotate crank by hand 2X, then try to put blocks back on the end of the cams, and it's off again, intake by 2.3 degrees this time, exhaust by 0.3 degrees. Did this 3 times.

I left it in time and checked compression, and it's 145 on cylinder 1, with a 90% loss on the leak down test. Still crank no start, although some of the injectors leaked, so I'm fixing that now but it doesn't even try to start.

I'm seriously thinking about buying a used head with all the valves in it.

[andrewwynn]

I've only done the m62. Are you having an issue with the vanos not clocked correctly m62 only has one per bank but it there was never sooid feedback that I had the vanos set to the "start" position. Not sure what else could repeatedly throw off timing.

With m62 two things I remember was 1: special tool to put in place of the chain tensioner while setting timing. (and turn the engine 720° while doing)

2: after chain tight, snug but not tight the cam bolts and do another 720° to remove any backlash between sprocket and cam.

[80stech]

The timing procedure is to get the chain on the right tooth of the gear, If it's a hair off that's OK. Check the valves at TDC (use a stick in the spark plug hole) exhaust and make sure the exhaust has just closed and intake is just opening turning engine over bay hand in proper direction.
If compression is 140 to 150 with 4 strokes on all cylinders then compression is not the problem.

How are you doing with this??

[80stech]

Any updates ??

[DonaldFoss]

Couple things: when checking the timing with a couple cranks, use the air pressure in the oil banjo connector to simulate oil pressure. If not, it thinks the lack of pressure is a signal and can adjust the intake angle. One I put the vamps controller back on and used 3 bar of air pressure, the timing held.

The root cause of all my problems seems to be my oil pump. I installed a Seems Legit pump and tensioner during the rebuild. The rings are never getting enough oil to seal, and no seal means no combustion.

I’m not saying anything bad about the Seems Legit oil pump-it seems to be a solid unit. It could be the O-ring on the pickup or other things. There is virtually no oil in the oil filter and no oil squirts if I crank it with the oil send sensor disconnected. With the car outside and no room in the garage, It’s been too hot outside to pull the engine again and tear it down in the garage even though I have AC in the garage.

Having oil pressure should be on the crank/no start guide.

I’ll update here for tribal knowledge sake once I get it to make oil pressure.