Hey Guys,

I've finally had the common coolant leak coming from my timing cover on my 89 460. I pulled everything apart to fix it and decided to replace the timing set since the truck has 225k on it and there was significant slop in the chain. I had to fool around with the timing gears a bit to line the crank and cam marks up but finally got it done. After I put everything back together and fired the truck up it ran like trash for a minute then died. I cranked it a few times but couldn't get it started back up. I'm worried I somehow got the crank turned a full revolution before I lined up the marks so I was at TDC on the exhaust stroke instead of the compression stroke. Does this sound like the mistake I made? If so, did I damage the valves? I'm not sure if this is an interference engine or not. Any help is much appreciated!

 

This is not an interference engine so no damage to valves.

TDC is always TDC to the crank, it is the cam that decides if it is the exhaust or compression stroke, so that is not your problem. When you are 180 out, that refers to the distributor, not the crank, so I would check to see if your distributor is stabbed correctly before you tear this all back down.

 

Jas88,


I'm relieved to know that I haven't damaged the valves on this thing and what you are saying does make sense. So as long as the crank mark is at 12 o'clock and the cam mark is at 6 o'clock and are aligned then there is no way the timing of the crank and cam is off? I didn't even touch the dizzy when I did this job so I'm a bit confused on how the dizzy is 180 degrees out.

 

Yes that is correct. I only brought up the distributor b/c you were referring to being 180 out (being on exhaust stroke instead of compression) which is only applicable when stabbing the distributor.

 

Well I finally got a chance to work on this again and I'm stumped. I wanted to make sure everything was timed correctly so I pulled #1 spark plug, found TDC on compression stroke with the finger over the hole technique and made sure rotor was pointing to #1 wire and everything checks out. Timing mark is even at 0 on harmonic balancer. Truck will start but idles rough and eventually dies like it floods out. Will not start again and smells like its running really rich. I will check it with my timing light tomorrow if I can get it started again. Anyone got any ideas on this?

 

Cam or valve timing is way above my pay grade but iirc a quick and dirty test is check that when #1 cylinder is at TDC compression, the mark on damper "0" TDC, the #6 cylinder ex. and in. valves will also be in overlap if it is correctly phased, roll the damper back and forth with a breaker and should see them closing/opening right at TDC on the damper.

 

This concerns me. What exactly does this mean? Lining up the marks should be pretty straight forward.

 

I used the harmonic balancer bolt to turn the crank to get it at 12 o'clock. Because I didn't use an impact wrench I couldn't get the bolt to back out. I ended up rocking the crank back and forth before I got the bolt out. This is what I meant when I said "fooling around". Anyhow, I thought I was certain I had both marks lined up before I buttoned everything up. In fact, I remember stepping back to eye everything in to make sure. Obviously I did something wrong though. Even if I was off a tooth or two would it cause my issue? It seems like there is a timing set that has 3 different marks for advancing or retarding. At this point its looking like I'm going to have to tear everything back down... Damn

 

You could pull the right side (passenger) valve cover to see if both valves are closed and push rods are loose when you are at #1 TDC.

 

Well Guys I finally took some time to work on the truck again and tore everything back down. Apparently, when I made sure I had my marks lined up the first time I did this I was ****-eyed! It turns out I was one tooth off. See photo. Anyhow, I got everything lined up right this time and the ol truck is running again. So for you guys wondering what difference it would make if you are just a tooth off? The answer is it won't run at least not on an EFI engine.

 

Wow I always wondered that. Glad you got it figured out.