E30 M30B35 Nightmare

[PlebLover]

I have an M30B35 in my '89 325i. It's got a lot of problems though.
Bought the car from a guy in Arizona. It seemed like a pretty good deal, but it turned out to be too good to be true. I'll list the issues so far. (The ones I know) Maybe you guys can advise on a good route to take from here.

1. Rod knock. Currently, it's sitting until I can decide what to do because of this.
2. Constant misfire. I mean it doesn't even want to start. It backfires a lot and throws flames from the exhaust. (I know this is not a good thing) It's missing on at least two cylinders non-stop. I have replaced the Distributor cap, rotor, and all of the plug wires. The only thing I haven't replaced is the pulse sensor. That was going to be next until I realized what that knocking was.
3. Grooves on the 6th cylinder wall. I'm not entirely sure how bad this is.

I've put a lot of thought into it, but right now I'm on the fence as to whether I should just buy another engine, or if I should spend the extra cash to redo this one from top to bottom. I know I'm looking at at least $800 to rebuild it if all goes well, but if that rod knock is anything to go by, it's probably going to be a lot more.

[1987E30project]

Buy another engine. You probably can find a used one for less than 800. Save the busted one and rebuild it at your leisure.

[Ether-D]

^This. Done.


Welcome and good luck.

[navytapaul]

+1

They're cheap enough that you should just get another one and rebuild that one.

[SketchyRex]

Word up. Have a spare motor man.

[Mr. Burns]

ouch.
Killing a M30 is no easy feat, but this one may be on it's way out.

what ECU are you running and do you know which wire harness was used in the swap?

check your CPS with a known working on...otherwise I would advice to seek a replacement engine-as others have said they can be had fairly cheap...it's a matter of poping the old one out and pitching the new one in. can be done in a day with some friends and some pops.

[Jb325is]

It's very common for the injector plugs to come loose with the b35 injectory harness box because most people don't install them correctly, especially if trying to use it with a b25 harness. If your has has the injector harness cover, pop it off and push the plug onto each injector. Also check coil and distrib. cap and rotor.

[PlebLover]

Sorry about the late reply. I purchased another engine instead of trying to fix the old one. I'll probably be putting it up for sale at some point if I don't just rebuild it over time. I'm running the 179 ECU that came with the engine. (At least I will be once I get the new engine put back together and into the car. At this point, I think the only thing it needs is a valve adjustment. Compression is a little off, but still above 150 psi on every cylinder. The wiring harness is an M30 wiring harness. (At least the guy I bought the car from said it was) I'll be checking everything once the bad engine is removed from the car. I'm also putting in some coilovers and camber plates. I'm pretty excited to see how it turns out. I'm just going to go slow and make sure everything is done right. This isn't my first engine rebuild, but it's my first BMW engine rebuild. A good torque wrench and some new parts should be all I need to complete it. Thoughts?

[uturn]

Pull the water pump and inspect the impeller. I've seen it where they corroded away and caused the engine to run hot. Piece of mind for the price of a cheap gasket.

[lukeADE335i]

Yes - the water pump is definitely worth checking & replacing if not great on the new engine while the engine is out. That and the sump gasket - doing one of those once the engine is installed wouldn't be much fun.

[PlebLover]

I've already bought a replacement water pump. I was suspicious of it already when the coolant that came out of the engine was coagulated and gross. Currently, I'm working on cleaning out what's left of the old coolant. As for the sump gasket, how big of an issue is this? How common of a problem? I may need to add this to the list of things to correct.

[uturn]

Doing the sump too? Might as well do all the seals and gaskets too. Check the oil pump chain tensioner. Someone on here had their's grenade on them but caught it before any damage. Then check all the timing chain guide rails too.

[uturn]

The bolts holding the thermostat cover corrodes, order new bolts before starting work. Maybe a new thermostat too?

[PlebLover]

Still working on putting it back together. I hit a stopping point a few days ago when I realized I didn't have a replacement paper gasket for the thermostat cover. From what I've read online, isn't it acceptable to not put one in there since there is already an O-ring sitting between the thermostat and the cover? I'm not really sure where to buy one anyway. Can't seem to find one anywhere. Other than that, the rebuild is going smoothly. The bottom end is well within tolerances. The only real issue I've found is odd compression on a couple of the cylinders. 1 and 2 have excessively high compression. 200 and 180 psi respectively. All other cylinders are between 150 and 160 psi. I think all I need is a valve adjustment. I have the tools to do it, and that will be the last step before I put the engine into the car. Thoughts?

[lukeADE335i]

You can make them pretty easily - the gasket paper is available from any parts store - then just trace around the housing & use a ball peen hammer to mark out & carefully break the paper around any voids in the part (bolt holes etc.)