Author Topic: Towed home tonight; guess that rattle (Read 8291 times)

blalor · « **Reply #15 on:** March 24, 2010, 08:07:24 AM »

Thanks, guys. I know a lot of this is engine disassembly 101, but I appreciate the advice. I have a line on an engine or two if it comes to that. I'd like to stay stock(ish) for the time being; no swap, stock timing, etc. I just want to drive the damn thing right now!

If you're looking for additional Monday-morning quarterbacking fodder, the issue came up after the car had been in for an alignment at a tire shop. I've already shown my lack of general engine knowledge, but I'd have thought that a problem in the bottom end (broken con-rod?) would happen after at least a bit of driving. It ran fine for my 50 mile commute, fine for the 3-mile drive from work to the shop, and then things got ugly. I'm assuming the grease-monkeys at the shop weren't hooning around the lot in front of customers. Maybe. And by "fine" I mean "obvious (to me) chain noise but otherwise normal".

Whatever. I'll know more once I get the rest of the case off and do a leak-down test. I'll probably call in some bigger guns before making any final assessments and reassembling.

DesktopDave · « **Reply #16 on:** March 24, 2010, 08:33:03 AM »

Yep, take those covers off, post more pics & ask away. No dumb questions here. Responses can sometimes be slow, but there's a lot of hands-on knowledge on the board.

I'd doubt the guys at an alignment shop would beat on the car. They might have the alignment off, but it's not that tempting...if you had a 300 HP turbo Civic with neons, CF jewelry and a 3kW system I might think twice.

Only we know how great these cars are...don't worry too much about the motor. BMW makes excellent engines...I'm still hopeful that the chain guides are disintegrating, the chain is hanging up in the front case and you'll have no engine damage at all.

It'll sort itself out and even in the worst-case scenario you'll have a like-new engine with all the updated OEM parts for a quarter the price of a clapped-out Lancer, WRX or Civic Si.

blalor · « **Reply #17 on:** March 24, 2010, 08:58:51 PM »

How far should I be able to insert a bolt for locking the flywheel? More for exploratory purposes, I tried using a 7mm allen wrench, but it's only going in about 5mm, which doesn't seem like enough.

nicknikolovski · « **Reply #18 on:** March 25, 2010, 01:18:47 AM »

Use an 8mm drill bit or just buy or hire the cam timing locking kit from someone.

And going off what flying lizard said about the crank bolt and flywheel pin. Done this for the first time on my car, the bolt came out piece of piss with just a breaker bar and socket.

blalor · « **Reply #19 on:** March 25, 2010, 04:07:53 AM »

My concern is that if I don't have enough of the drill bit into the flywheel, the flywheel will act as a guillotine when I reef on the vibe dampener bolt. 5mm doesn't seem like very much.

I'm not discarding the starter motor idea put forth by Lizard and Brendan Purcell, but I don't like the feel of it. I may go that route, but I'd like to frustrate myself to no end, first, by exhausting all other possibilities.

I woke up this morning with an idea for blocking the crank, but it requires removing the pulley and harmonic damper, first. Looking at my pictures from the other night, it appears the bolt has to come out before those can be removed, however.

I was thinking I could bolt a piece of angle iron to the hub and brace that against the frame rail. Ah, well.

flyinglizard · « **Reply #20 on:** March 25, 2010, 07:25:38 AM »

The drill bit is too hard, and will break. You should use a bolt cut to fit at least .
I dont think that this is a good idea. The starter and breaker bar is the standard tool set. A littl e heat to the head of the bolt will help a ton. Little heat, not red. You just want a small thermal difference. IMHO.

blalor · « **Reply #21 on:** March 25, 2010, 07:58:23 PM »

I bit the bullet and went with the starter motor trick for breaking the harmonic damper bolt free. Worked a treat. Sorry for doubting you, Lizard.

I'm glad I went this route, because I realize now that I was misreading the Bentley manual. It says to "hold the vibration damper hub stationary while the bolt is loosened" using a "heavy duty holding device" such as BMW special tool 11 2 150. The very next step says to lock the crankshaft at TDC with a different tool, 11 2 300. I thought that the point of locking the crankshaft was to make it possible to get that bolt off, and I couldn't have been more wrong. Sorry for confusing everyone.

Moving on, with the timing case open, I saw this:

Well, there's yer problem.

Still haven't done a leak-down test; chain's a little too wonky right now to actually turn the crankshaft and not have the chain slip on the sprockets. Hopefully tomorrow, but otherwise Saturday.

nicknikolovski · « **Reply #22 on:** March 26, 2010, 03:01:16 AM »

That's the deflection wheel. Basically just acts as like/is an idler sprocket to help move the chain along. This is the most expensive part in the timing chain system. About $120USD from Pelican Parts.

Are you okay with what parts to you need to change?

blalor · « **Reply #23 on:** March 26, 2010, 03:58:56 AM »

It's funny, I've never heard of this part failing. I've seen plenty of references to the guides disintegrating, but never the deflection wheel!

I'm changing *everything*.

The odometer reads over 182k miles and I think it'll be good insurance to replace the chain, all four sprockets, and the four guides/rails. RealOEM is a pretty invaluable resource. Now I just need to find the parts at a reasonable price.

I'm going to look closely at the water pump and possibly replace that, too (I don't know how old it is). I'll have the oil pan off next, as well. Pending the health of the head (lost some threads: http://www.flickr.com/photos/blalor/4459069316/), this should be a pretty straight-forward reassembly.

flyinglizard · « **Reply #24 on:** March 26, 2010, 07:28:05 AM »

Pull the head and lap the valves, new seals , skim it a touch.
Roll the crank down 90* a nd add about 1 in of ATF fluid on top of the pistons. If it has an even amount of oil above the pistons, overnight the rings will run another 100k.

This engine look as tho it has had dyno oil and not a lot of it. So anything is possible. If there is any cross hatch in the bores and the oil stays above the pistons , the pistons/ring will work as is. IMHO.
Synthetic oil would look like new inside.
Double check the rod bearings.
I hope that the lifters went dry, along with the idler gear, as the noise. I expect you will find the RTV in the oil pump and circuits.
You will be well on your way to having 4k$ in a 2k car. Just like my Son. We have to drive his car for at least 3 yrs. to get any back. Turbo next for it.It is just too slow for me.... Nice solid driver tho.

blalor · « **Reply #25 on:** March 26, 2010, 08:11:31 AM »

Quote from: flyinglizard;90043

This engine look as tho it has had dyno oil and not a lot of it.

Yeah, dino from birth. What makes you say it hasn't had enough, tho?

Quote from: flyinglizard;90043

Double check the rod bearings.
I hope that the lifters went dry, along with the idler gear, as the noise. I expect you will find the RTV in the oil pump and circuits.

I don't understand the significance of the RTV. The fact that there's any of this stuff on the engine says to me that it's been apart before. Do you think some of it blocked up the oil passages and starved the engine for oil? Would that be the cause of the dead deflection wheel?

Quote from: flyinglizard;90043

You will be well on your way to having 4k$ in a 2k car. Just like my Son. We have to drive his car for at least 3 yrs. to get any back. Turbo next for it.It is just too slow for me.... Nice solid driver tho.

I'm not putting anywhere near that much money into this engine.

This is no show car, either, but I think it's worth keeping around a while.

blalor · « **Reply #26 on:** March 27, 2010, 09:16:22 PM »

My future father-in-law came over this morning to help me assess the motor. He's currently rebuilding a '47 Ford Coupe and has about 50 years more experience with engines than I do. We started out with a leakdown test of cylinder 1 … and found 100% leakage. The air coming from the intake tract was pretty audible, and you could feel it blowing up the spark plug holes for the other cylinders. Since he had another couple hours to burn with me, we decided to press on and pull the head, just to see how bad it was. It's pretty bad.

That last one is of the intake valves for the #1 cylinder. And yes, the valves are "closed" there.

So.

Now I have to figure out what to do next. A friend recommended Clearwater Cylinder Head in Florida to get a replacement head, but they charge about $1,000 including shipping both ways for a refurbished head (complete w/ cams, I believe). Before I commit to buying another engine (most of the available ones right now seem to have similar miles to mine, or about 182k, so I'd still want to do the timing chain stuff), I'm going to try to get a local machine shop to look at the head and give me a quote for repairing the seats, guides if necessary, and installing new valves.

The other "interesting" thing is that it's apparent that the exhaust valves suffered a similar fate at some point in the past: there are similar divots in the pistons on the other edge, but they're coated in carbon. There's that red Permatex stuff on the head, too. I'm gonna have to go back and look a little more closely at those receipts the previous owner gave me…

BlueBMW · « **Reply #27 on:** March 27, 2010, 09:52:38 PM »

Seems like there is usually someone selling a complete motor on here or r3vlimited for around 300 to 600 bucks. Maybe that's a cheaper route for now and then you could rebuild the motor later if you choose.

Ryann · « **Reply #28 on:** March 28, 2010, 01:28:38 AM »

I second the complete, good running used M42 notion. Much cheaper than fixing your existing engine.
BMW designed the timing setup on the M42 to "last the life of the engine".. apparently a variable term, and a primary weak point (aside from the profile gasket failure) for our beloved engines.
The more I read, the more the M42 timing chain assembly appears to need as much attention as a belt driven system, only said attention is more expensive and difficult!

blalor · « **Reply #29 on:** March 28, 2010, 06:15:13 AM »

Like I said, I'm still on the fence about getting a new engine. In some ways that's the easy solution, but most of the ones I've seen listed lately have as many miles as mine; I'm wary of trading one set of problems for another. If I could find an engine with 100k to 140k for under $600, I'd be very interested. But how do I know that a 100k mile engine hasn't been thrashed harder than mine? Having a "spare" and rebuilding it in my spare time (ha!) is sort of appealing, but I don't really have space in my garage for the stuff that's in there, now.

It does seem like the timing components on the M42 are a failure point. It's not that hard to get in there (once you know what you're doing *ahem*) but the parts are pricey. Still, replacing the tensioner every 50k for $50 isn't bad, and requires no disassembly. No idea if not having to replace the other stuff until, say, 150k offsets the three belt changes you'd have to do on a non-chain engine, tho.

It's probably my lack of experience with E30s in general, but going from my '87 325is LeMon car and another '88 315is I test drove to this '91 M42 was night and day. The M42 is so quick-revving that it really make it a ton of fun. It even sounds good (although that could have been the impending chain failure…).