Author Topic: Timing Needs adjusting?? (Read 3530 times)

Gabs · « **on:** July 30, 2011, 10:29:50 PM »

Hey guys, so its been awhile since I posted, if anyone remembers, I hit a dear in my little 91 before winter. Well I've been slowly working on the car, new hood and fenders etc. All the while deciding to tear down the engine and do a poor mans rebuild. By poor man I simply mean, I don't have the money to replace the pistons, nor the knowledge to toy with the head just yet.

I did pull the intake all the way down to the lower intake manifold and removal injectors, all the while thoroughly cleaning everything I had my hands on, inside and out.

Like wise I did the same to the other side of the engine. Though my troubles are stemming from the timing of this damn engine, or there for lack of, due to my inexperience.

I replace all the guides, cam gears, crank gear etc. Now I did this twice. Unfortunately after putting all the new parts together the first time, sealing up the lower and upper timing case, I manually rotated the engine and felt that something was wrong. So I looked up what to look for in cam timing, the ruler across the back of the cam squares to make sure they're level, arrows pointing up and both #1 cam lobes kind of leaning up at/across each other, etc.

After this I did realize my error, my intake cam was a gear or two off of the exhaust cam. Could I have cause any damage to the valves from manually rotating the crank in this state?? I hope not

Just a side note, My error likely arose because I did not have the engine at TDC when replacing parts.

So after rotating the engine to TDC, I to the best of my knowledge aligned the cams and (montage here) put it all back together. Fill it with oil and with my key 1 click forward, from under the hood I engage the starter, and everything sounded fairly regular to me.

So I hop into my lovely blue cloth seat

, say a small prayer, and twist that key. Well there was an audible POP!!! from under the hood and I backed off the ignition, that being said I had my rad cap partially threaded on and a cooling system guaranteed to be full of air. So I figured the engine rotating 2 or 3 times maybe caused, what small seal that cap had, to POP.

So I crank it once more, No pop, and she roars to life, I mean literally, the engine sounded extremely loud and may have been "dieseling" on me. Though aside from the sound, it had a super strong steady idle, and appeared to be running well, just loud.

I only had it going for about a minute, but I have a feeling maybe I am still off a micro amount on one of the cams, enough to make it run loud.

Another thing, I thought it a bit risky putting the new tensioner in uncompressed, so I uncompressed it and with great 2 hand strength got it in.

Im wondering if I just hadn't run the engine long enough for it to adjust and settle everything in and get all oily. I slightly doubt it though.

Sorry for the short novel :rolleyes: I like to hear myself type haha

Gabs · « **Reply #1 on:** July 30, 2011, 11:08:00 PM »

Few pictures just for kicks

Nobody hate on me, but I also had to throw in a cellphone picture of my current daily driver and 2nd fav BMW, my Bronzit M20 E34.

DesktopDave · « **Reply #2 on:** July 31, 2011, 08:54:41 AM »

I had the same e34...an '89 5-speed. Great car, built like a tank but not as much fun as the e30, of course.

That first "pop" you heard was likely oil pressure getting to the chain tensioner and extending it. That's normal if my guess is right. Coolant shouldn't make a "pop" even if the system has a lot of air.

I'd guess you have to re-do that cam chain tensioner. It can't be put in "extended" if it has oil in it. When the mechanism is filled with oil, the chain rail cannot force it back, and won't properly de-tension. Pull it back out, pop it apart, drain the oil & re-install it compressed or empty of oil.

Then check your timing again & fire her up if everything is lined up OK.

danegel · « **Reply #3 on:** August 19, 2011, 04:26:09 PM »

Did you take any pictures during this rebuild process? I'm about to replace my tensioner and chain too.

Gabs · « **Reply #4 on:** August 22, 2011, 05:52:56 PM »

Sorry For the delay in response, I posted just before I left for vacation.

Dave, I often I ask myself which car I prefer my e34 525 or e30 318is, and I can never pick a side. I mean really, the Power to weight ratio is nearly identical between the 2 cars (14.0LB/1HP give or take). The real difference is that, the 318 handles corners at much higher speeds, being that it is 900lb or so lighter. Though the 525 still corners fairly fast, the added weight will put some serious wear on your tires or so is my experience. Where the 525 draws the tie in my mind, is that the overall comfort of the driver is better. Heated seats, Better air ducts, 10 speaker sound system, digital readout under speedo, more advanced computers (ie: clock unit), moon roof, CD ready deck and things of that nature. When it comes down to it they are equals in my mind, but serve different purpose on the road.

Anyway back to the topic at hand. The "pop" could not have been the tensioner extending, I had put the tensioner in uncompressed. I guess my question now is, Is the oil pump a mechanical mechanism that will pump when the engine is cranked over, but not started.

Reason I ask is, I cranked the motor with the key in position 1 a good couple times after putting everything back together both times, to ensure everything sounded normal.

It sounds like, because I put the tensioner in uncompressed, when I was test cranking the motor, I likely filled the uncompressed tensioner with oil thus not allowing it to de-tension properly. This sound correct?

Danegel I took very few pictures, as I dont like to wipe my hands off to use the camera

I have a few pictures of the engine with the valve cover and intake removed, and then a couple different angles of the engine with valve cover and both timing cases removed, showing the chain, guides and etc. Ill try and post them later tonight.

If your going to go about replacing the chain and tensioner, I'd highly recommend replacing all the timing components, (4 guide rails, 2 Cam Gears, Idler Gear, crank gear, tensioner, chain) as you will need to remove all of these parts anyway if you want to do the chain. Not to mention, you wont have to worry about timing parts for another 10 years atleast.

Side Note: a quick Thanks to Dave, you always seem to be the first to jump in with a response. Much Appreciated.

DesktopDave · « **Reply #5 on:** August 22, 2011, 06:54:28 PM »

Yep, oil pump is a mechanical drive directly off the crank snout. It'll pump oil at any time the crank spins. Click for the RealOEM diagram.

I'm not really sure if the tensioner would fill with oil before adjusting properly. I'm not sure it matters either way. It has a spring that would serve to pretension the chain. Maybe the chain had some slack and you heard it slapping off a guide? I'd assume that it's not much of a problem unless a cam was out of position.

That's essentially what I'm worried about. If the pop was a valve getting hit by a piston, the valve stem is bent and it will never seal effectively. Then you'll be getting fuel igniting out of the leaking valve and into one of the manifolds. I'd think that might sound loud, maybe like a diesel clacking. A compression check would let you know right away, and positively.

MikeDE · « **Reply #6 on:** August 23, 2011, 01:18:45 PM »

It will always make noise for a few seconds or so with a fresh tensioner. When I installed the tensioner and turned the motor by hand, you can see the (tensioned)chain guide moving back and forth, as the tensioner has no (oil)pressure in it unless the car has run.

My motor sat for about 6mos without being run while rebuilding, it took about 15-20 minutes of runtime for it to quiet down. It sounded like a diesel when I first had it running. Now, 750km later, it purrs like a kitten.