On the 617, I was trying to do it right, got a new tensioner and spring, but I can't for the life of me get the old bolt off that holds the spring and plunger in. Is it possible to reuse the housing and just replace the spring and plunger? Couldn't find much info about it.

Or, is it possible to buy a new bolt?

Annoyingly, it looks like other retailers are selling the same tensioner I bought on here but WITH the bolt...

-Rog

Is this on a 617 turbo or NA? They use different tensioners.

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'79 240D

Turbo. What's the difference, anyway?

-Rog

I'll answer your second question if you answer mine

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'79 240D

I thought I did...?

Anyway, I'm guessing the N/A ones come with a new bolt and the turbo ones don't, just from my searching turning up people wanting to reuse their old one. No definitive answers though.

-Rog

Well, after some heat and penetrating oil I finally got it out. It's not in the best shape, but it'll do for now. Still wondering about getting a new bolt...

-Rog

Oops, my bad. Shouldn't try to type and talk on the phone at the same time.

The NA version relies more on oil pressure to maintain tension. The plunger is retractable. Its internals are completely different. The NA version is replaced as a unit if it fails, and it must be primed with oil prior to installation.

The turbo version relies on the spring for initial positioning of the plunger, which is non-retractable. The tensioner body is mounted first. Then the plunger is inserted, followed by the spring, and finally the plug. For removal, you take the plug off first to relieve tension, then remove the body from the block. You should not have much difficulty loosening the plug with the tensioner firmly mounted in place.

I don't think that new tensioners come with new plugs.

The plunger must be re-set any time the tensioner comes off, and it should be done even if just the spring is replaced. The only way to do that, since the plunger is not retractable, is to pull the whole thing. You don't need a new tensioner if the plunger is not damaged, just the spring and maybe a new seal for the plug. Either way, the plug has to come off the tensioner and the tensioner has to come off the block.

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'79 240D

On the NA 617 Timing Chain Tensioner you can remove the End Cap and get the Sping and the Plunger out from that end.

On the Turbo 617 you can do the same but can only remove the Spring. The Plunger has a round spring type ring in a groove. The Ring expands into 1 way grooves on the inside diameter of the Timing Chaing Tensioner Housing. That means the only way the Plunger can go is inwards. You cannot compress the Plunger back out the way it came in; or at least you are not supposed to.
If you are changing the large Timing Chain Tensioner Rail on the Turbo 617 you need to remove the whole Housing in order to get at the Plunger and pull it out.

See post #7 for a diagram.
Timing Chain -Seized?

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84 300D, 82 Volvo 244Gl Diesel

I see. Looks like I may have screwed up installing the tensioner then... I couldn't get it closer than 1/2" to the block, so I'm guessing the plunger needs to be backed out. Is that possible? I really should quit using DG's guides, they tend to be unhelpful on the most crucial steps...

-Rog

EDIT: Never mind, I understand now. You can pull the plunger all the way out one way and reinsert it in the back to start over. That would be hell if it went in but would never come out.

BTW, is it normal for the plunger and the rod on the tensioning rail to not meet perfectly centered? In other words, the old plunger has a worn area that's offset to one side rather than right in the middle.

Yes, you can retract it, but not by pushing it back. You remove the cap, then the entire housing (2 small bolts, 1 nut on exhaust manifold), remove the spring, then push the plunger thru and return it to the other side (outside).

Check your spring real close. Mine was worn ~1/2 thru, similar to other photos I saw here. I need to buy another spring ($6 here). I am in the middle of working on this (began as oil chain tensioner replacement).

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

I don't think it is unusual for the two to meet a little off center. It's likely that the contact surface on the rail is worn as well. The rail is alloy, and somewhat softer. Worth thinking about replacing if it has excessive wiggle when the tensioner is out. You want to avoid creating a condition where the plunger can slide out past the rail contact.

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'79 240D

I'll just call it good for now then. The main thing was replacing the chain, which was keeping me up at night. Went much smoother than trying to figure out that dumb tensioner, and the chain was the part that I thought was going to be hairy. None of it was making noise, but I was rebuilding the front end after a crash, so I figured it would be as easy as it gets to do it now with everything out. Plus I don't have any record of it being done (270k miles).

On to the next project...

-Rog