brian, when doing the t-chain job you should/have to.. make a mark on the crank pulley right?

If I remember correctly there is something in place at the bottom of the crank sprocket that will prevent the chain from moving away from it far enough for it to jump a tooth. The vacuum pump spring mechanism is what probably caused the chain to "pull" down into the engine on that side. If you were able to pull the chain back into position on the cam (overcoming the vacuum pump mechanism) then you are probably ok. Let me suggest that you tie wrap the chain to the cam sprocket before you go much further.

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Jim

I seem to recall the same thing from Sixto's comments. But, he seems to have rotated the crankshaft without the chain moving.........

If you are careful and don't allow the takeup man to screwup, you don't need any marks. The new chain just follows the old one.

But, you really need three people.

One to turn the crank.

One to feed the new chain and keep it on the camshaft.

One to keep tension on the old chain as it comes off the crankshaft.


I have not done any chains personally. And, I'm not attempting it without two competant helpers. The risk of FUBAR is too great.

My memory was correct. I have attached a pic showing the tab that prevents the chain from moving on the crank sprocket. All you need to do is overcome the vacuum pump spring pressure on the actuator to pull the chain back up to the camshaft sprocket and make the ends meet.
I'm glad I take pics of just about everything I do.

Disregard the orientation of the picture. With the engine in the car the tab is at the bottom.

I have always done this job by myself but I always use alot of tie wraps.

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Jim

How in the hell do you do that?

Who keeps tension on the outbound chain?

Do you make 50 trips down to the crankshaft and rotate it 10 degrees at a time........and then move the tie wraps on the camshaft..........seems like a virtual impossibility do to it safely by yourself???

Here are pics of where the marks are on the cam gear, and where the plastic circle is at the crank pulley (I don't see any other marks on it). They are basically in the same spot as when the old chain was in. So now how can I tell if I skipped a tooth on the cam sprocket? I still am kind of confused about the setup of this engine. I wish I had a diagram of how the chain is routed.

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87 300D - Running on Veggie oil; 260,000 plus miles; Original #14 head

brian.

i was just asking since when i adjusted my valves i noticed the chain looked new compared to others i had seen in the same milage area as mine(vacuum pump is new also).. back to the topic

Here's the crank pulley mark.

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87 300D - Running on Veggie oil; 260,000 plus miles; Original #14 head

I'm sorry - I thought you were talking about a 617 engine. I would suspect that the engine you are working on is the same as the 617 in regards to the pin that prevents the chain from jumping at the crankshaft spkt. Can you find the TDC marks on the crank? Is it at TDC on #1 piston? If you are at TDC at the crank on #1 cylinder then the cam position looks good.

Brian I DO use ALOT of tie wraps during this procedure. I tie wrap the chain to the cam spkt (always start at TDC) and cut the chain between the ties. I roll the engine over and put more tie wraps in, cut the old ones and continue this procedure until the new chain is all the way in. I do have the tensioner out when I am doing this and have never had any problems during it this way. I typically have the car on the lift a little bit off the ground where it is not as much trouble getting under it to roll it over.

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Jim

We need a photo of the crank damper from the top. There is a small steel bracket........barely visible.......that determines the crank timing. Without this photo, we don't have a clue where the crank is.

The bracket is sitting about 10 degrees clockwise from TDC. It's almost impossible to see on this engine and requires you to look in from the passenger side of the engine on an angle.

How to you maintain tension on the chain as it comes up and out from the crankshaft?

That's pretty much what I ended up doing, but for some reason it didn't line up with the other section of chain, which is why I was concerned that the chain had come off the crank. I still don't exactly know what happened. All I know is I ended up taking the chain off the cam and letting it go into the engine a couple of inches (still had a hold of the end) which for some reason allowed me to pull the opposite end of the chain to where it needed to be, I was then able to pull really hard on the tensioned side and get it back on the cam and get it to meet up with the other side of the chain. But what I am worried about is that with me taking the chain off the cam in order to do this, that I might not have gotten it back to the proper teeth on the cam sprocket.

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87 300D - Running on Veggie oil; 260,000 plus miles; Original #14 head

Brian I looked for a pic of it with the tie wraps but I don't seem to have one of those. I must be too busy to be able to hold the camera. Anyway, both sides (accross the cut) of the chain are tie wrapped to the spkt so the cam spkt is pulling the old chain out. Next time I do one I will take pics of it. You go slow using this procedure but it is accurate.

Jmana you are going to have to try to find your TDC indicator on the crank. If it is lined up and the cam marks are lined up then nothing has moved. Other than tie wrapping the chain to the spkt do this before you do anything else.

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Jim

Oh, OK I think I see it. The pics not real good because it's hard to get a camera in there, but I'll try to describe it's position. I see the lines stamped on the pulley, and then I see a "20". The bracket is as far away from the first line, to the left of the line, as the 20 is from the first line.

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87 300D - Running on Veggie oil; 260,000 plus miles; Original #14 head