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  #1  
Old 06-23-2011, 08:45 PM
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300D motor in a crazy art car - timing/knocking sounds

So I was feeling adventurous, and I opened the upper oil pan to replace the rear main seal. While I was at it I replaced the timing chain, and then I got it running - there was one moment when I thought I'd dropped the chain, and now I'm trying to check the timing.

So it got running, and the motor stopped turning - I thought, 'crap, did I seize the motor?' and when I pulled it all out and separated the transmission, I found that the torque converter bolts had gotten loose and seized up against the plate.

So I put the engine back in - by the way, this is in a p10 stepvan, lots of room to crawl around the engine - I put it back in with a giant angle iron brace to hold the back end of the engine. I carefully set it all up again, and turning it over without the glow plugs in it sounds very smooth.

Hook up the fuel system, put in the glow plugs, and turning on the starter (glowplugs not on) it turns over pushing against the compression pretty smoothly.

So I spray some ether into the intake and it almost diesels - and it hear a knock sound, pretty much at the front cylinder. Two knocks, so not only the same one.

So I took the valve cover off, and found the notch, and looked at it - and here's my first question. When I look at the Harmonic Balancer to find the angle, I'm supposed to look at the lines on the balancer marked with angles lined up against the metalshelf, not the round hole almost behind the balancer, right?

Okay, so operating on the assumption that I was reading it correctly, I put it on zero and went around to look at the notch. And it looked off, I hear now by "18 degrees" but at the time I simply agreed it looked like "one tooth"

So I take out the spring tensioner and move the chain with a wave-motion and yes, I get exactly one link worth. I put it back to what I believe is TDC and yes, the notches seem to really line up now!



So now I turn it carefully with a breaker bar, and it seems better, the spot where it was a real hardship to turn it before (where I think the valve was hitting with the timing chain one tooth off), and it seems better - only fighting compression, never a really hard to turn spot. I turn the starter on with no glowplugs, and I don't hear the knocking - so it sounds better.

Differences: it wasn't as close to dieseling this time - the last time, when we had the timing cover off, it almost started in our face, no glowplugs. Maybe cause it had been warmed and almost started and whatnot?

Second, with the ether, I still hear some knocking sound, though not as bad.

I had carefully re-gapped the valves at the end of changing the timing chain, turning the valves through their place of smallest gap - do I need to re-do it now that I've moved the timing chain one tooth?

So: things to discuss
- Am I finding TDC correctly?
- Do I need to regap the valves?

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  #2  
Old 06-23-2011, 09:37 PM
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Have you used the 2mm movement of the number one cylinder intake valve to check anything ?
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  #3  
Old 06-24-2011, 01:19 AM
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First off, you may have damaged the engine (pistons valves cam)... that knocking you heard might have been interference. Consider yourself lucky if this engine ever runs happily.

Assuming you didn't, it sounds like you have ironed one of the problems and the crank is timed with the cam.

However, it now sounds like your injection pump timing is off. My simple 2 paragraph explanation is not going to cut it... you need to do some reading on this site and find an online manual for the 'drip timing procedure' / 'spill timing' / 'low pressure delivery method'.

Or simply read about how to install the pump. That will get the engine started if this is the problem.

oh!.... here's one. -Thank a forum member for posting it.


You do not need to re-gap the valves.





Quote:
Originally Posted by leathermang View Post
Have you used the 2mm movement of the number one cylinder intake valve to check anything ?

C'mon, G. He can do it the easy way for way... for now.
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Old 06-24-2011, 01:22 AM
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On the balancer, you line up the marks with the metal straightedge that comes before before the circle.
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  #5  
Old 06-24-2011, 03:09 AM
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Okay, some good things so far...

So it sounds as if I was finding TDC correctly, and yes, it was a tooth off. And I do not need to regap the valves.

Now, I don't hear any bad sounds when I try to start it without ether, so I was sort of hoping that the sound was because of the explosion happening. I will try to record this and post it to youtube, and you could listen to the sound and see if it seems like a real problem.

Also, I will look into fixing the injector timing - I'm reading through it now.

And I will mention, I haven't entirely spent time bleeding the injectors, because I've been mostly moving really carefully through setting it up and getting it ready to start, listening to the sounds of it as I try turning it over.
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Old 06-24-2011, 06:14 AM
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http://www.youtube.com/watch?v=W913y_1jdt4

Okay, the above youtube corresponds to the sound I'm worried about, but it also seems to correspond directly to the presence of ether - which, since I gave it a squirt before it was turning over, could have gotten directly into one cylinder. OTOH, it always sounds like the knock is from the front cylinder.

There's a second video where, with no ether, there's no knocking, or only one at the beginning.

I'm recharging the battery and going to give it another try. In other news, I have now bled the injectors and know that they have fuel, and it is almost starting. The diesel injector timing has not yet been adjusted.

While it might start now that it is close, the injectors have fuel, and the battery will soon be able to kick it over even better, the question at hand is really, "does the knock indicate engine damage?"

I see a lot of references in timing instructions to finding where it is hitting, and in a lot of them they mention a tooth being off, without necessarily mentioning any radical damage done. I have seen it mentioned that 'the engine won't run if it is more than one tooth off' which seems to indicate that a single tooth isn't the end of the world.

Thoughts?
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  #7  
Old 06-24-2011, 08:23 AM
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which engine are we dealing with?
Ether has no lubrication properties.
if you have no diesel injecting, because of air in the lines, and you spray ether into the motor, you can bend rods, and score cylinders.
try WD40 instead.
how many miles on the engine?
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  #8  
Old 06-24-2011, 08:41 AM
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Can't tell much from the video except for the fact that the engine is turning over very slowly. Should be turning over faster. Don't know if that's just a weak battery or a weak starter or what.
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  #9  
Old 06-24-2011, 11:35 AM
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Yes ,Use a bigger battery with some cranking power .I had a non turbo 5 cylinder in a 77 coupe a couple years back ,same sound when trying to start it ,the end result was low compression on 2 cylinders holding it back .Primed the cylinders first by adding a heavy oil to each hole,purge ,then replaced injectors ,it fired up but was not a health motor with the low compression problem.
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  #10  
Old 06-24-2011, 12:21 PM
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Quote:
Originally Posted by jt20 View Post
.....C'mon, G. He can do it the easy way for way... for now.
Note the thread in my signature... I do not know of any ' easy' but Accurate other methods....
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  #11  
Old 06-26-2011, 10:29 PM
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Answers to questions...

What I have is a single brand new monster (semi) battery, and I had been turning it over somewhat and maybe hadn't charged it back up. I've got a couple of fresh deep cycle batteries that might work better. It does take a LOT of power.

It's a 617.925 diesel, non turbo. I think the injection timing is off now, and haven't quite figured out how to get that fixed. I'll stop spraying diesel in, will try wd40.

What are the other tricks for getting it to prime? I have now seen diesel come out of all five injectors when turning it over with one injector cracked, so I know there is now fuel down all five lines.

I'm pretty certain there's good compression - how would I test this?

Maybe it's time for a new starter. It's somewhere in the range of a 72, and may be the original starter.

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