F14's timing set replacement thread

[Guest F14CRAZY]

My coupe's been down for a couple days. I fired it up, about to leave home, when I heard a bang from under the hood. Engine idled fine, but the charging system light was on. Turned the engine off and found that my serpentine belt tensioner/idler bracket assembly broke. One of the pulleys broke, and thus both belts came off. Good thing was that I hadn't even left the driveway yet after I added 4 pounds of air to my front tires. Back in "It's Real" we did some cutting to clear the oil pressure sensor, but I now think this was not needed, and we removed a bit too much aluminum obviously <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />. I tried Bonneville Club to find a replacement, which failed. Car-part.com showed a yard in Flint parting out L67s, so I took a trip there after school and picked another bracket up ($20). So, I'm back in business.

Anyway, none of that stuff above much applies to LN3s <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />. Padgett once told of gaining low end torque after replacement. This thread at Bonneville Club has Padge...quot; slightly. The conclusion has been reached that with as many miles are our cars can have (over 100k) the sprockets and chain loosen up enough to retard valve timing and the balance shaft (though I don't know if the balance shaft matters). Performance and perhaps smoothness should be closer to new.

I have heard of 3800 timing chains breaking, but I presume it's pretty rare and not really something to worry about. 3800s are not "interference" motors, so no real damage will occur if one ever breaks on you.

Using my commercial account with Advance...r this evening. It comes with the two sprockets and the chain. To add to this, however, I'm going to also get a new camshaft position sensor interruptor magnet. I haven't had issues before, but since I'm here, I might as well replace it. Also, I'll get a new chain tensioner. I'm not if Advance has this in stock or if they can order it, so I may have to go to NAPA. I have heard suggestions to replace the water pump, but mine's not too old, and will be reused.

The kit doesn't come with any gaskets, b...sket this time.<img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

Note: my LN3 has almost 171k miles.

This is not quite worthy of being an "it's real" thread and maybe not totally related with performance, but I will be narrating with photos. Stay tuned.

[Guest F14CRAZY]

For those that wish to follow along, page 6A5E-17 of the FSM begins with removing the "front cover", which will expose the timing set. 6A5E-19 has removal and installation of the timing set.

I've been looking at the FSM, and it seems there's more in this than I first figured <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />. Not a setback to me, though. From what it looks like, I might as well replace the timing cover seal, and perhaps the oil pan gasket. Though I've tightened it up before, it's dripping. I'll re-seal anything else that's leaking there that I can reach. With things like this, even just snugging up the bolts a little more helps close up the shrinkage of old gaskets. My parents don't like it much when I park on the cement driveway or the "approach" of the barn <img src="http://forums.aaca.org/images/graemlins/tongue.gif" alt="" />

I'm not in an awful hurry to get my coupe back in service, so I can replace whatever I see fit.

[Guest F14CRAZY]

Oh yeah, I've been getting goofy oil pressure readings on-screen, so I will be replacing the pressure sender. It's in a bad spot, behind the L67 tensioner bracket assembly.

If you wonder, below is a pic of my bracket assembly. We hacked away too much aluminum that holds the center idler (without the tensioner), and it broke off. This is an old image from "it's real" and doesn't show the hacking we did. I'm gonna see if it's really needed, and if it can be done differently without hurting its integrity. Actually, since I'm getting this far, I could actually use the L67s oil filter hardware, which puts the pressure sender horizontally instead of vertically like the LN3, and won't have to do any hacking. And, with that, I can choose to use an oil cooler (though not really necessary with synthetic oil).

[Guest F14CRAZY]

I picked up the kit from Advance and ordered the CamPS interruptor, oil pressure sender, and gasket kit. The timing kit is by SA Gear and is marked to have been made in the United States. $50.

I may tear into it today if I feel like it <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" />

[Guest F14CRAZY]

I'll switch to my real digital camera for better pix when I get into it.

I got thinking about the chain tensioner that has been mentioned before. Advance couldn't get it, nor could NAPA. I called Crippen Buick about it and his catalog said that the '88-89 tensioner is not servicable, but could get it for a '90. I went ahead and ordered the tensioner for the '90 which includes a new spring. About $20.

I earlier got a copy of the page of the parts catalog with the tensioner. It's there, and also mentioned in the FSM on page 6A5E-20. FSM doesn't say anything about it being not servicable though. Must I replace the entire engine just for a chain tensioner?

NOTE: FSM calls it a "timing chain dampner" (not a typo, on my part). Parts catalog does not have it listed as a "tensioner"

[padgett]

When fitting a new interrupter, think I'd coat with JB Weld and then snap in just to make sure it stays there.

There was something about a change in tensioners during 89 and I remember seeing advice to always use the later one reguardless of year. That may be the two different units you are seeing.

[Shelby]

If it ain't broke keep tinkering with it till it is.

[Guest F14CRAZY]

Thanks Padgett. I tore into it today but had to charge my digital camera and only got not that great Pocket PC pix. I'll retake them when I get back on it.

If you wish, right click as download thi...the timing set.

I'll get some side by side comparison pix of the new and old sprockets later. The interruptor magnet is still there but looks like its ready to break apart.

[Guest F14CRAZY]

No progress on the project. Advance doesnt have my parts yet, nor does Crippen have the tensioner.

[Guest F14CRAZY]

As I promised, PIX!

Here, this is the camshaft sprockets themselves. Top has 170k miles, bottom is fresh.

Another view, though pretty much the same.

This is the Fel Pro timing cover kit. Here we have the oil filter adapter gasket, crankshaft/timing cover seal, water pump gasket, and O rings, which I haven't figured out yet.

This, the timing cover gasket itself, also comes with the kit (obviously...)

This is the timing chain "dampener", which I call a tensioner. I wish I would have got it in the photo, but it was mentioned in some older posts...it would appear that there's a crack in the middle of the surface. As also mentioned before, this assembly is marked to have been made in france.

The oil pan gasket. I messed it up removing the timing cover, since 3 (I think) oil pan bolts go into the bottom of the cover. This is a Fel Pro "PermaDryPlus", around $33 <img src="http://forums.aaca.org/images/graemlins/shocked.gif" alt="" />. Of course, this was in stock, but the regular OEM grade gasket had to be ordered and was half the price. I went ahead and bought this. Not a better warranty, but is supposed to like not ever leak. My existing gasket is drippy anyway.

Back side of the timing cover. I cleaned it on both sides afterward. Notice the hole for the crankshaft position sensor. The bolts I used for the water pump seem to have been too long, as you can see in the middle, it poked through the cover. It's now stuck and has to be drilled/tapped. The oil pump is driven by the crankshaft and it sandwiched inside the timing cover. The vertical placement of the oil pressure sensor is bad since it interferes with the tensioner assembly. As I said, we had to hack it up, and that's why I'm doing all this <img src="http://forums.aaca.org/images/graemlins/tongue.gif" alt="" />

My glorious ride still can't escape oil and grease on the outside <img src="http://forums.aaca.org/images/graemlins/mad.gif" alt="" />. At any rate, this is looking inside the oil filter adapter. Oil filter is below, not picured. Not much to see here, but thought I'd include it.

Should have used macro mode, but this is looking into the timing cover, where the oil filter adapter mates to it.

That's about all for tonight. I'm gonna visit Lowes tomorrow to see if they have a 90 degree metric fitting to repositio the oil pressure sensor so it will be out of the way. I swore I also saw a nice drill/tap kit there before, so will check on that too.

[Guest MauiWowee]

NAPA should have a better selection of metric fittings. Try them first, Phil. <img src="http://forums.aaca.org/images/graemlins/cool.gif" alt="" />

[Guest F14CRAZY]

Thanks Maui. I was thinking of them 2nd but I'll probably go there first. See, I got thinking Lowes because when I was working on this earlier, my dad came to see my progress, and just came from Lowes, and said they ought to have it since they have tons of stuff like that. Being metric though, I'm not sure. Keep in mind my dad's a plumber, and we haven't encountered any metric plumbing (yet...)

[Guest MauiWowee]

Lowe's is good for nuts and bolts, they do have a metric section. For that kind of hardware, don't waste your time in Home Depot. If I am correct, you are looking for an elbow, and maybe bushings. Let's hope NAPA doesn't make a liar out of me, but they haven't let me down yet. <img src="http://forums.aaca.org/images/graemlins/cool.gif" alt="" />

[Guest F14CRAZY]

Yeah I was mad a while back cuz Home Depot didn't have the hardware I was looking for, and Lowes did.

[Vincent Vega]

Aren't the O-Rings for the heater tubes?

[Guest F14CRAZY]

I worked on the proijojec most of the evening and got some stuff done.

-I test fitted the timing cover and tensioner assembly to see if my oil pressure sensor will clear as I figured it would. I did pick up a metric 90 degree brass fitting from NAPA as Maui suggested (like $3). It won't work as I thought it would. It has to be pointing forward and as close to the timing cover as possible. It's almost in the way of the camshaft-PS and the harmonic balancer (BTW, they don't seem to fail). I think it'll work out though. I was originally thinking it could point backwards, but no, the tensioner is in the way (I didn't check before I envisioned it).

-I cleaned up the 17 years or so worth of grease from the oil filter adapter and mated it back with the timing cover with a new gasket. The FSM says 30 ft/lbs, but the threads started to give <img src="http://forums.aaca.org/images/graemlins/confused.gif" alt="" />. I went with 25 to be safe, and didn't feel any harm being done. If I didn't say, I decided to stick with the LN3's filter adapter.

-When I installed a new water pump two seasons ago, I think it was, I used new bolts cuz one broke on me. As pictured, it went too deep into the cover and got stuck. It broke coming out. I cut it flush and drilled/tapped. I'm new to using drills/taps mind you, and it slipped in the drill press, so my hole was not exactly where it should have been. It's not bad though, and with a tiny bit of work on the water pump hole that I've already performed, I should be okay.

-Using a ubiquous box cutter and a putty knife of sorts, I scraped the timing cover gasket off of the block. It's not easy to access, but you can get to it easier with the passenger side jacked up, front passenger wheel off, and removing the splash guard by the harmonic balancer. I accidentally bumped the balance shaft sprocket off, but not a big deal. It has timing marks.

-Not too much related, but I decided to replace the "coupler" in the supercharger. Since I have everything off like the tensioner assembly, it's easy. I removed the "nose drive" dumping the oil. I cleaned it up and removed the old coupler. I'm not sure how it works, but it's a hard plastic little wheel with peg holes and connects the drive pulley to the rotors inside. It's supposed to absorb shock from the engine. Mine wasn't exactly bad, but they should be replaced when there's enough rotational "play" in the supercharger that you can feel. If left alone, it progresses to a rattle. Many superchargers are replaced or said to be bad because of this. About a $20 from ebay (doesn't matter where it's from, but made in USA in this case, they last around 100k miles, but not available from GM). A supercharger oil change is included in this since its lost anyway. These units, with regular oil changes, can outlast the engine or the rest of the car. Well, not my engine or car, cuz it's forever <img src="http://forums.aaca.org/images/graemlins/laugh.gif" alt="" />

-I drained the engine oil in preparation for replacing the pan gasket. When I'm finished I'm going to run with conventional oil and a fresh filter for a couple hundred miles to clean 'er out, then switch back to my Mobil 1.

I want to call this like a mid-life rebuild, but I don't think its reached that point yet.

I'll take some pix again tomorrow for you guys.

[Guest F14CRAZY]

Vincent: I think you're right on the O rings

[2seater]

You could reposition the oil sender by drilling and tapping a 1/4" npt hole in some other location on the filter adapter. If you look at the filter adapter it has a common passage internally that will all show the same pressure. I tapped the rear of the adapter to pick up oil for the turbo. An alternate idea would be a fitting tapped into the oil cooler if you add one.

[Guest F14CRAZY]

I didn't think of that Hal. My bad. Good idea which I might end up having to do. I'll be finding out if my idea's gonna work pretty soon

[Guest F14CRAZY]

This afternoon I finished cleaning the oil pickup screen and the oil pan. Reinstalled the pickup screen with its new gasket (7 ft/lbs, or 84 inch/lbs). The oil pan is hanging and ready to be torqued to 10.3 ft/lbs or 124 inch/lbs.

[padgett]

From the picture that is the original 88-90 oil pressure sender that was the subject of a TSB. The replacement has a black plastic body and is shorter (see attachment).

It screws into a 1/4 NPT recess, it is not metric.

Sprockets really do not show much wear. Can just see the magnet sticking up in the one photo.