M42 running VERY loud (video), low oil pressure light is on

[Vivek]

So I overheated my old engine and replaced it with a newer m42. I did an m20 flywheel/clutch swap, most gaskets (upper/lower oil pan, upper/lower intake, oil filter housing and O ring, valve cover) except the head and profile. I checked all the upper pan bolts and they're good and tight. I replaced the timing chain tensioner because the timing chain had just started to make noise (got the engine from a good friend). Cam gears look brand new. Didn't touch the guides.

So here's my problem. I start it up and it idles fine but I've run it for less than a minute total because it's loud as hell and I don't want to risk damaging anything in this engine that I've put so much work into. I hope the link below works, it's loud as fuck. My oil pressure light comes on and stays on. My guess is that the chain tensioner isn't getting oil so it isn't adequately tensioning the chain. A couple of the plug wires (3&4) weren't fully connected but that made no difference once I fixed it. Any help would be greatly appreciated
Vivek

http://youtu.be/CuXx-4TR_0g

[kwill22]

Sounds like he chain tensioner isn't working. Do you have an oil pressure tester? Made sure you didn't block any passages when you replaced the gaskets?

[bmwman91]

Did you check out / replace the oil pressure check valve that lives in the timing case? Parts 5-8.

http://www.realoem.com/bmw/showparts.do?model=AF93&mospid=47305&btnr=11_0504&hg=11&fg=30

If that is missing or seized, that would cause your issues. The original part was superseded with a different design because the original one would get stuck open.

[Vivek]

Sounds like he chain tensioner isn't working. Do you have an oil pressure tester? Made sure you didn't block any passages when you replaced the gaskets?

I don't believe I did. I was cafeul on the upper oil pan gasket. The oil filter housing I didn't put any extra care into but I did it on a stand so my feeling is that I didn't mess it up. It would be leaking if the gasket was pinched or moved, right? Ill check that out, I'm not home right now.

Did you check out / replace the oil pressure check valve that lives in the timing case? Parts 5-8.

http://www.realoem.com/bmw/showparts.do?model=AF93&mospid=47305&btnr=11_0504&hg=11&fg=30

If that is missing or seized, that would cause your issues. The original part was superseded with a different design because the original one would get stuck open.

It was off a car that ran fine, but the timing chain had just started to make noise. Could that have been the issue? It was driven for a couple days after it started to make the noise. Cam gears literally look brand new (ill upload a pic). Cold compression was above 180psi on all four. But the engine sat dry for a few months. Does this sound like the valve could have failed, and is it hard to replace?

[roguetoaster]

Did you replace the gasket on the oil pickup tube? Was the tensioner installed extended or compressed?

You could visually check to see if the top end is getting oil.

[Vivek]

Oil pick up as in under (or above I guess) the upper oil pan? I didn't touch that. I put the tensioner in uncompressed/extended.

[Vivek]

How would I visually check the top end for oil, pull the valve cover? Or should I be able to see it though the oil cap hole? Sorry for all the questions, this is my first time swapping an engine so I'm a total noob when it comes to this stuff.

[kwill22]

Take the valve cover off and see if everything is covered in oil like it should be

[Todd Black 88]

Not sure on the m42, but you can see oil flinging around on my s14 with the cap off.

[Todd Black 88]

I would pull the fuel pump relay, put the battery on a charger, and turn the car over with the starter untill you build oil pressure. Never start a dry motor without first confirming adequate oil pressure.

[bmwm42]

You should see oil flinging with the cap off my guess is either your oil pressure relief valve is stuck...or your tensioner is shit

[Vivek]

I would pull the fuel pump relay, put the battery on a charger, and turn the car over with the starter untill you build oil pressure. Never start a dry motor without first confirming adequate oil pressure.

Can I do this without risking damaging anything? How long should I be able to do that without burning up the starter? I'm thinking I should find a way to accurately meter the oil pressure first, unless maybe it just needs to be turned over for a while for it to build up, but I don't think that's normal.

[roguetoaster]

Can I do this without risking damaging anything? How long should I be able to do that without burning up the starter? I'm thinking I should find a way to accurately meter the oil pressure first, unless maybe it just needs to be turned over for a while for it to build up, but I don't think that's normal.

Yep, keep your cranks under 30 seconds each, with 15 seconds being an ideal maximum. Clearly you need to let the starter cool at some point, use your best judgement and you will be okay.

The only easy place to check oil pressure with a gauge would be at the oil pressure sensor.

You could also pull your tensioner back out and just see if there is anything odd about it, broken spring, etc.

[bmwman91]

If the oil pressure light is in, then it seems unlikely to be the tensioner. Letting things sit for a while is surprisingly hard on an engine. As has been recommended, you really need to check your oil pressure. Low pressure will make the thing super noisy like an old diesel. And kill the engine. Not the best.

My bet is on the pressure check valve in the timing case being stuck or having a busted spring.

[Vivek]

If the oil pressure light is in, then it seems unlikely to be the tensioner. Letting things sit for a while is surprisingly hard on an engine. As has been recommended, you really need to check your oil pressure. Low pressure will make the thing super noisy like an old diesel. And kill the engine. Not the best.

My bet is on the pressure check valve in the timing case being stuck or having a busted spring.

Okay thanks. So it looks like the noise is definitely the timing chain, and that my oil pressure has something to do with it. Ill see if I can find a way to test the pressure. Cranking it with the starter should read more than probably 5psi, right? I'm gonna be out for a few days but ill look into replacing my check valve when I get back.

Edit: and I was just reading that I have to pull the upper oil pan to replace the check valve. dammit please someone tell me there's an easier way.