timing chain tensioner won't screw in

[bobthebuilder]

I've been thinking about this and given what I see in the hole and what a bottom tap looks like, I have doubts that the tensioner will screw in all the way. The bottom tap will do its job but it won't go to the very bottom against the boss. (Why is that boss there anyway???). So, I have some options: 1) Invest $35 in a bottom tap and hope it works. Maybe I can force the tensioner in the last thread or so enough to tighten down and seal. This option retains the threads. 2) Force the tensioner in now. If it strips out, have I lost anything? Can a machine shop repair stripped out threads - weld in some aluminum and re-tap and retain the oil passage near the front? 3) bite the bullet and pull the head and take it in for repair. It's about $100 for minimal parts (head gasket, head bolts, valve cover gasket). All those parts were just replaced with the top end rebuild and the engine only run for about 30 minutes. But, head bolts stretch and gaskets compress.

I wouldn't mind #3 except I just had the thing apart for the top end rebuild and I know what a pain in the rear it will be to do it again, and the time I don't have to do it. Another thought is how to remove the boss without metal chunks falling inside. If the boss were gone, I could continue tapping through. I don't recall - with the valve cover off, can you reach down inside and touch the hole where the tensioner comes through? Might be possible to catch the boss parts as they are filed off through the tensioner hole.

Anyone have thoughts or other suggestions?

Thanks everyone.

[toxicavenger]

Can you buy a bolt with the same diameter/threads as the tensioner and screw it in to clean the threads out? Then coat it down with some lubricant like white lithium grease to make it a smooth run in.

[bobthebuilder]

Unfortunately not. I could definitely feel the tap sort of cutting threads, not cleaning threads like a chaser, which is basically a bolt with a leading cutter on the threads to clean. I had another idea today - pull the valve cover and see if I can reach down to the opening enough to pack a rag below the opening so I can file the boss off and catch the metal filings. If I can remove the boss, my tap will likely continue down its path and finish cutting threads. I don't see a need for the boss. It appears to be nothing more than a stop for the tensioner, which isn't needed as you can only screw it in so far until it torques down against the head.

[bmtastic]

Like I said , I used a TAP 22 X 1.5 to clean the thread . I used it all the way in and out , till it went smooth . Then I used engine Oil for the inside of the thread . Make sure ure tensioner's thread is smooth / clean as Well .

[Finding41]

I wrote the red part first then when I was looking for pictures I came up wit the answer.
Your engine has turned a bit and hte chain is tight on thea side. So when you put the tensioner in it can't go because the other side of the chain is loose.
Here is how to fix it.
Get a socket that fits onto the drive shaft and turn it clockwise. Keep tension on it and the tensioner should go in easily because that side of the chain will now be loose. If you pull the spark plugs out the engine will turn easier.

Note the Vasoline holding the spring and plastic plunger together to get it back in the hole.
Have fun!



Bob. Are you putting the small bolt in the tensioner before installing?
If so Stop!
It should go in as long as you have the ratcheting extension piece all the way in. (Like in the picture you posted.)
You can take the valve cover off and get to that area... kind of. It's tight.
You may be able to get a small (1/2") vacuum hose in there. Attach it to your regular vac and away you go. Put the rag underneath too. (Tie a string to the rag.)
When I was playing around trying to get the timing right on my rebuild I would take the 12 mm bolt with spring and plunger out of the tensioner. Then use a piece of coat hanger to get to the part on the tensioner to get the plunger back in. Look in the thread I did called: rebuild my 2.3T
I have a bunch of pictures and descriptions of how not to do it and how to do it after you did it wrong first...

[bobthebuilder]

Marty/Finding41 - boy I sure wish it was that easy. Not so in my case. My chain already had slack on the back side - I can move the guide in and out about 1/2" with a screwdriver. It is a great suggestion and not something I had thought of.

But, I do have good news to report. I resigned myself to the fact that I could muscle the tap in and hope for the best, and worst case, I'd have to pull the head back off. So tonight I ran the tap in till tight, turned it 1/4 turn, backed it out, cleaned out the hole, and repeated a bunch of times. Nothing bad happened - seemed to still be cutting threads. Then, I felt the tightness back off slightly and I knew I had gone past that boss that seemed to be in the way. After that, I could turn the tap fairly easily for a couple of turns and I knew I had cut the threads all the way. I probably dropped a few little pieces of aluminum down around the crank and chain as it went through the back side, but hopefully, once the engine is running, I can let it warm up, then drain the oil. Maybe do a second oil change for good measure to get the bits out. I have not changed the oil yet anyway since the top end rebuild and there may well be some coolant in the oil from when the head gasket blew. I've only had it running a total of 20 minutes or since since the rebuild, and had an oil change or two on the list of things still to do anyway.

Last significant thing to do is replace the coolant diverter valve on the firewall. Looks like a bit of a bear to get to, but since I bought that cable operated hose clamp tool, jobs like this are much easier to do.

Will post again when I have the 9-5 running again and hopefully not leaking!

Thanks Saabworld forum. Couldn't have done the top end and this tensioner repair without you.

[Finding41]

To make it a bit easier to get to the heater valve thing unbolt the electrical plug box above it and pull the whole wire harness towards the pass side. Use a bungee cord to hold it over until you have the valve done.
Note: Now is the time to change the vacuum lines while your in there...
Good luck.

[bobthebuilder]

Got about five feet of vacuum hose sitting here! I've already replaced several that were deteriorated and expect I'll find more!

[Burnsside42]

FYI - if you have an old tensioner you can make your own thread chaser. I've done this and keep one in my tool box for when this happens. It's easier to operate too since it's made to fit in that location ;-) Silly Saab's.

[bobthebuilder]

Thought I was good to go this week - put it all together and actually start driving this car. Well, I've got a new issue with this chain tensioner. Somehow as I was cleaning the threads with a tap, I fed the tap in at an angle, i.e., not perpendicular to the head. I don't know how that could happen as the tap should have been following the old threads for the most part. Here's a couple pictures showing the problem - it's about a 1/16" gap at the bottom of the tensioner where it seats on the head/washer. I have the tensioner a little beyond finger tight - snugged it in with a socket wrench. It is not torqued to spec. I'm not so sure torquing to spec is going to take up that gap.

I am not sure where to go from here. I'm thinking I'm going to have to either pull the head and see if the place that machined the head can weld in some aluminum and retap, or pull a head off a donor at the junkyard (several to choose from right now...) and hopefully not have to machine that head.

Anyone have suggestions? I know there is oil pressure behind that sealing washer, so we're not talking about some sort of caulk/filler. I don't think two washers would flatten out either.