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Farintosh 06-30-2012 04:10 PM

Please help! Engine thumping/bouncing.
Hello E30 gurus,

Ran into some trouble with my E30 and am completely stumped, any help would be greatly appreciated.

First some background info. I bought my first E30 325iC and changed the timing belt 2 months ago as a precaution. All was well until just last week when I started to hear a thumping on my way home then a grinding. Took it all apart to find the camshaft gear had worked and the dowel pin was no long snug. I changed both parts and now there is no grinding or whining but the entire engine still bounces significantly when the car idles. If necessary I can post a video of the engine running. I adjusted the valves during the timing belt change and they were fine, so I don't think that's the problem. Wondering if its something as simple as new spark plugs, but I'd love a second opinion before I open it all up again.

Tempted to take the car into a professional and get there opinion, anyone come to mind? I live just north of Markham. Is the dealership viable or should I find a private shop/individual?

Thanks for your time!


Ceeker 06-30-2012 04:31 PM

sounds like you skipped a tooth on the timing gear. I would tear it down and recheck the timing marks to make sure your belt is on properly. Seeing that you changed the belt and running fine I will assume you did the 2 full cranks of the engine manually to make sure the marks lined up before reassembly? since your dowel pin came loose I suspect something skipped and your engine timing is off. got back to square one. Surest way to make sure everything is good.

DR.ZED 07-02-2012 04:16 PM

I've done this before. 1 tooth off on a timing chain.

The Firebird was supposed to make 360+RWHP ended up making 267 RW when we tuned in on the dyno. Darn thing ran fine though, you would never know!

My bet is that you're more than 1 tooth off. Don't mess around too much if you're that far off the engine is an interference engine you could mash the valves.

Ceeker 07-02-2012 06:57 PM

I heard the motor; idle didn't drop when I pulled #5 spark plug. He might have a couple problems. told him to start with easiest to hardest task. First figure out electrical. might be running like shit because he's on 5 cyl. it was rapping pretty loud in the center. Told him to remove the valve cover and inspect and readjust his valves. then go from there.
I suspect his timing is off but when you have 2 or 3 issues it is difficult to assess. Process of elimination.

richie_s999 07-03-2012 07:25 AM

if your looking for a professional opinion in Markham check Bavarian Motors. If your looking to travel a bit your other option is Stance Factory in Ajax.

Farintosh 07-03-2012 04:05 PM

Thanks for all the responses. Here's a video to confirm any suspicions you may have had:

Hard to tell from the video how much the engine is bouncing. I'm currently going down the checklist Ceeker generously laid out for me. Found that there is current right from the distributor cap pin to the spark plug, not sure whether the problem lies within the rotor the pin or possible withing the valve train. Taking a look tomorrow.

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