I've got those chain tensioner blues

[zakthor]

Hi All,

I was tempted to post this to the parts alias, but the problem and discussion seem better suited to the 930 alias.

Found the cause of the awful grovelling and banging that comes from my car when its cold. I thought it was lose metal in the muffler but its not...

Banging and thumping is coming from the left timing cover.

This is a '79 turbo that doesn't have pressure fed tensioners.

Mech checked on line, those kits cost a lot more than they used to - >$900 - where last I checked (in 1999) they were lots less.

Wondering if I could/should save a bunch by putting together a package here?

Or should I just get a couple of slip-prevention collars?

Until the covers are off we won't know the true damage but given the slapping its gunna be a grind fest. Good idea to upgrade to pressure fed while we're in there?

So... I know the parts are out there. What all do I need to upgrade the 930 to pressure fed tensioners?

left chain cover (930-105-063-01-OEM)
right chain cover (930-105-064-02-OEM)
2 pressure fed tensioners
oil feed lines
sprocket wheel spacers
timing chains (master link?)
hollow bolt
gaskets
bunch of nylocks

Pricing it out seems I can save a bunch if I can find used tensioners, then finding those chain covers.

Seem reasonable? Am I missing something?

Cars going under the knife on the 3rd so I need the parts soon.

Thanks,
Eric

[AFD660]

You'll probably save money finding all the parts but I dont think anybody is going to part out their tensioner kit from a running 911/930. You might be able to find them on a wrecked one but who knows what kind of condition they are in... I was lucky enough to have mine come with the kit already installed when I bought my 930. Might just have to take the hit with buying the whole kit if you need it that soon... Good luck...

[zakthor]

What is the difference between carrera and 930 kit? I thought they were the same.

[A930Rocket]

Have you looked here at Pelican and Verte x Automotive in Fl?

[AFD660]

Im sure it is the same kid... lol.. sorry for the confusion.

[jwasbury]

Are you doing this yourself or paying a shop?

1st place for you to save is by doing yourself rather than paying a shop.

Please check the condition of the idler arm bores and the shafts that they pivot on. According to some, the older style arms are as much to blame for chain tension problems as the tensioner units themselves. The newer style arms have a larger bearing surface and do not require the spacers.

I changed mine out during my rebuild, and found that the old arms were badly scored in the bores. One of the pivot shafts was also very scored and had to be replaced. The idler arm on that side was actually binding on its shaft because of the severity of the wear.

[zakthor]

Originally Posted by jwasbury

Are you doing this yourself or paying a shop?

1st place for you to save is by doing yourself rather than paying a shop.

Look at this response in 29 minutes:

WTB: Carrera Oil Fed Tensioner Kit or Pieces

I'm paying a shop. I'd honestly love to do this myself but I don't think I have time right now to bone up on everything I'd need to know. I found the pelican guide, but it sounds advanced to me. (Set timing?)

At this point in this cars short ownership some DIY would make the wife very happy.

Any mechanically able folks in the seattle area that would supervise? I've got a grill... great nw beer?

[mark houghton]

Originally Posted by zakthor

Look at this response in 29 minutes:

WTB: Carrera Oil Fed Tensioner Kit or Pieces

I'm paying a shop. I'd honestly love to do this myself but I don't think I have time right now to bone up on everything I'd need to know. I found the pelican guide, but it sounds advanced to me. (Set timing?)

At this point in this cars short ownership some DIY would make the wife very happy.

Any mechanically able folks in the seattle area that would supervise? I've got a grill... great nw beer?

Wise to have a shop do it it you're not up to speed on the process. Really not that difficult, but get the valve timing wrong and you could have a catastrophe on your hands (BTDT once, and only once, many moons ago with my 911T when I over-confident and stupid...can you say young with still raging hormones?). Bent a $75 sodium filled exhaust valve when the piston kissed it, and had to go through all the trouble to pull the head and replace the guide as well.

For some reason I thought that all 930's had pressure fed tensioners. If not, what year did they become standard?

[bleachii]

Not sure when they became standard but I know my '79 had them installed after the car reached the US dealer but before the original owner picked up the car from the dealer. It entered the States late Dec of '79 so maybe they started using the updated tensioner in '86?

[jwasbury]

Originally Posted by mark houghton

For some reason I thought that all 930's had pressure fed tensioners. If not, what year did they become standard?

If I have my 911 development history correct, the pressure fed tensioners arrived in 1984, when the 911 Carrera arrived (superceding the 911SC). I think the pressure fed tensioners are sometimes referred to as "carrera" tensioners. I suspect that the 930 got them at the same time, but who knows.

One factoid that I also seem to recall is that prior to introduction of the pressure-fed tensioner, the 930 had different and supposedly superior mechanical tensionsers vs. the 911.

[zakthor]

Originally Posted by mark houghton

Wise to have a shop do it it you're not up to speed on the process

Yeah after a fitful night's sleep I also think its a good idea for the Most Excellent Mechanic to lay his hands on it. Since there's grinding he'll be a better judge of what needs to be done. Also he'll be better able to eyeball the oil leaks.

I think I'm better off getting comfortable and geared up for easier jobs (bleed brakes, remove intercooler, how to jack up the car) before I get involved with something like this.

Maybe my wife will get me the projects book for my birthday...

[equality72521]

A guy has a set of Stomski race tensioners in the classified for $65 shipped.

FS: Stomski Racing solid tensioners $65

[Rob 930]

Just so you know, it's not univerally accepted that the pressure fed tensioners are necessarily "better." Not only do they sometimes fail too, but the external oil lines and fittings that feed them have also been known to leak or fail, which can cause a fire. I'm not necessarily suggesting you go back to non-pressure-fed tensioner, but be aware that there are pros who build engines without them and swear by it. I think that the statistics for longevity of the latest and greatest non-pressure-fed tensioners are pretty impressive. It used to be that people would add an aftermarket collar to the tensioner plunger to prevent total collapse (but would allow an impending failure to be detectable by ear). This might be an option for you too. If I had a very original early 930, I would absolutely go back to the non-pressure-fed tensioners to preserve the originality of the appearance, and to avoid having to slice and dice the sheet metal pan behind the engine to accommodate the tensioner oil lines.

Rob

P.S. Just saw you're in Bellevue. I'm in Redmond. PM me if you want to talk.

[zakthor]

Originally Posted by Rob 930

Just so you know, it's not univerally accepted that the pressure fed tensioners are necessarily "better." Not only do they sometimes fail too, but the external oil lines and fittings that feed them have also been known to leak or fail, which can cause a fire. I'm not necessarily suggesting you go back to non-pressure-fed tensioner, but be aware that there are pros who build engines without them and swear by it. I think that the statistics for longevity of the latest and greatest non-pressure-fed tensioners are pretty impressive. It used to be that people would add an aftermarket collar to the tensioner plunger to prevent total collapse (but would allow an impending failure to be detectable by ear). This might be an option for you too.

Thanks for the feedback Rob.

Could be, I've read that too. Really won't know what the damage is until its opened. For all I know there's already a collar in there saving my bacon.

From my reading of threads and books the problems reported with the earlier setup were:
- idler arm binding (fixed with newer idler arms with wider bushing in 1980)
- ramps destructing
- spring collapse in tensioner

There is discussion of fatigue cracks in the oil feed lines but I'd not heard of catastrophic failure. Or Fire! I had these in my sc and it was reassuring to see them. And Buyers asked for them by name. Never really read about them before though. Now I see that pressure fed tensioner isn't that interesting, I'd want to know that the idle arm bushings were updated too.

I've found some relavant links:

Jerry Woods Chain Tensioner Mod

Shops that don't recommend Carrera Tensioner Update?

Originally Posted by Rob 930

If I had a very original early 930, I would absolutely go back to the non-pressure-fed tensioners to preserve the originality of the appearance, and to avoid having to slice and dice the sheet metal pan behind the engine to accommodate the tensioner oil lines.

Don't remember reading anything about snipping the pan.

Given I've got all the pieces for the new setup, and something bad happened already, I think it makes sense to go forward.

[garibaldi]

Youre taking a big chance there Im sorry to say. Aside from the fact that you can skip timing and all that stuff when the tensioners fail, the motor really should come apart and needs to be flushed. That grinding noise you heard, that sounds like someone using an old muffled chain winch insie your motor is actually just that, the chains dragging along the ramps and case casting. Its grinding it up, its ground it up. Do yourself a favor, pull off your oil filter, cut off the outer metal shell, pull the filter element out, carefully put off the end caps that hold the folds together, and spread out the filter element like your reading the dead sea scrolls and look at how much filings are in the filter. Thats whats passing through your motor now, its going through the pump, through the mains, through the spray bars, etc. You really cannot rely on the filter to catch it all, they bypass half the time, so the filter doesnt do as much as you think. The only way to really be safe, is to pull the motor apart, inspect and replace the bearings, pull all of the case plugs and clean the **** out of everything. I had the same thing happen to mine and I actually had a pressure fed tensioner fail on me. Even those can go bad, the little check valve in them can go and they collapse just liek the old hydraulic ones do. It can be a mess. Ive seen it a handful of times back when I was working on porsches. Didt mean to ruin your day. But check the filter at least so you can see if there is debris in there. Chances are there is, esp if you have been hearing that noise

[zakthor]

Uh. To what extent do you mean "motor apart"... bearings? You mean the ones in the muffler?

Not driving car until it goes to mech, but now it sounds like I should prepare myself for a bit of a porsche vacation.

What do you mean "big chance"? If there's damage its already done, right? Or that pressure fed is itself a problem.

I took the filter apart about 800 miles ago and there was nothing in it. At least no sparkly bits.

Case is aluminum so I guess there'd be no filings clinging to the drain plug.

[garibaldi]

yep, the muffler bearings hahah. I had a similar issue on my 77 911 turbo 3.0 I had pressure fed tensioners. For a few weeks id start the car and while it was waerming up, id hear this faint chain like grinding noise that would come and go. I chased my tail on it for ages trying to pinpoint it. turns out it was one of the tensioners check valve. It wasnt able to pump up all the way. None the less, there was a ton of grindings in my case. the filter had plenty of it too, you could just spread the pleats and see it in there. Point is , that that stuff obv gets pumped through the motor, and it can clog up your cam bars, wedge into passages, and if it gets sent into a bearing, it will jsut embedd itself in the babbit and make a new home. It can get ugly, and theres only one way to get it all out. Or you just keep your fingers crossed and just replace the muffler bearings, those are easier, they take about a half hour and are only about $20 hahaha. Unless you got lucky and there hasnt been any damage yet. Keep you fingers crossed and just check out that stuff. The filter is the easiest to go by, but you have to actually cut it open and pull apart the element, you cant just peek in the holes on the face, you wont see anything there. Good luck!, I was just sharing my past experience with a similar situation

[zakthor]

Originally Posted by garibaldi

yep, the muffler bearings hahah. I had a similar issue on my 77 911 turbo 3.0 I had pressure fed tensioners. For a few weeks id start the car and while it was waerming up, id hear this faint chain like grinding noise that would come and go. I chased my tail on it for ages trying to pinpoint it. turns out it was one of the tensioners check valve. It wasnt able to pump up all the way. None the less, there was a ton of grindings in my case. the filter had plenty of it too, you could just spread the pleats and see it in there. Point is , that that stuff obv gets pumped through the motor, and it can clog up your cam bars, wedge into passages, and if it gets sent into a bearing, it will jsut embedd itself in the babbit and make a new home. It can get ugly, and theres only one way to get it all out.

It sounds like exactly the same problem. How did your story end? You took the entire motor apart down to the crank bearings? That is a full rebuild?

[zakthor]

Question: will oil analysis tell me what I need to know? Or are we only worried about the larger bits?

[garibaldi]

Honestly, I left it. I couldnt deal with it. Before that I had already plled the motor apart twice after a full rebuild first time due to some hack machine work (before I knew any better or was doing that work myself) and faulty bearings after I had gotten it together, then again when I had a set of camshafts fail and chewed up the lobes after 2k miles. I was cooked mentally. i replaced the tensioners and kept monitoring the filter, but every time, it had a lot of debris in it. In a perfect world, I would have taken it apart and rebuilt it for the third time, but I had no patience nor money to go through that. I knew it was all through the motor, the filter, the galleys, the coolers etc. its a mess, its basically shards of aluminum floating around the motor. It will bite into the main and rod bearings, pass through the oil pump gears, the whole nine. Despite what most people think, an oil filter doesnt catch everything and filter 100% of the oil, theres this littel thing called a bypass on the oil paths that runs open pretty much all the time so not 100% of the oil pumping through the motor gets filtered. Plus the source of the debris is in the case, and it settles down at the pickup , so it gets sucked right into the pump and passed along from there. That screen on the pickup snorkel is only there to stop the REALLY big pieces of crap lol. At that point I had almost 150k miles on it and it was on its last leg and I had too much other stuff going on. Needless to say , i wound up becoming a machinist and built race engines about a year after, but its that cobblers shoes scenario. it still ran ok, but im sure the bearings had some stuff in them, and maybe the journals were scored up a bit, but hey whats a littel extra oil clearance right lol? The motor was tired.

But to answer your question, yes, if that is what has happened and you have stuff thats been ground off the case, the motor should really be gone through soup to nuts if you want to rest 99%