Questions about tappet stakedown and emissions equipment
 

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There's a nice little picture of the tappet guides for number 1 and 2 exhaust valves. Now I'm not afraid of doing the work but I had a few questions regarding the stakedown kit. Primarily, what are the chances I can get away with the kit and putting a head rebuild off until winter? I intend to rebuild the head (with a possible very mild port and polish job) once the first frost hits and the car gets put away for the winter but I'd love to be able to use it until then without worrying about catastrophic engine damage. It seems to run fine and pull strong (oustide of the terrible sounding clacking, of course) and I suppose I'll know a lot more once the cam is up and I can pull the tappet out of the guide and inspect the valve stems/retainers but just trying to get an idea of the risks and likliehood of it being okay for awhile once staked from people familiar with doing the job.

Also, All the directions I've seen show the cam needing to come up to install the stakedown kit but, at quick glance, it looked to me like it could be done with the cams in place. Advice on this would be appreciated. I know I should be adjusting the valves in addition to the kit but again, just trying to get it to the cold months so I can enjoy it a bit before the head work begins.

Emissions equipment. From my understanding the main cause (outside of massive over heating) for the tappet guides lifting out like this is the increased coolant and combustion temperatures created/necessitated by the emissions controls on the vehicle. Any experience with deleting some of this stuff? I don't need to run it through emissions anymore and need to do some exhaust work, anyways, so deleting the front catalytic converter is on my consideration list right now. How about the air injection? Any benefits to capping the holes in the head and dumping it? Not familiar with this system too much but I think we have something similar (done a little differently, though) on VWs called secondary air. It's purpose is to add oxygen to the exhaust to heat the cat up quicker, yes? From what I can tell it's not involved in idle control in any way, please correct me if I'm wrong and there's another purpose it serves. Thanks in advance for any help.

Terrible clacking? It sounds like you're already too late. Have you pulled the exhuast side cam cover to inspect? Only takes a few minutes. You know right away if the tappet guide is hitting the cam.






There are a couple different hold down kits. The one that looks like a plate with two fly-cut semi-circles does not require that the cam be lifted. Not sure about other types







Valve adjustment is a serious PITA on these engines. I'd wait till the head was off for other work.







Because the tappet guide problem seems to be primarily a problem with cat converter equipped cars it broadly (and plausibly) accepted that the extra heat causes the problem. I suppose this would be worse if the converter was starting to clog.

The AIR system (which works as you suggest) would increase temp in the exhaust port area which might migrate to the area of the tappet guides. Lost of people dump the air injection on these cars.

The rest of the emission system ...what little there is of it....is non-destructive.

Cheers
DD

Hmmm. When I posted my reply the picture wasn't there! Anyhow, I see you have the cam cover off.

I think those tappet guides have already been hitting the cam and possibly driven back down.

Cheers
DD

Yeah, definitely already hitting on the two exhaust valves closest to the transmission, the rest of them have no marks on them at all. I added a picture of some of the other exhaust tappets for reference. It seems to still run well other than the noise (hell, it even just passed the last emissions test it will ever need) and the noise doesn't seem to happen much until the engine warms up a bit. That leads me to believe that the tappet guides are jumping around and hitting the cam once things expand as they warm. I'm going to go ahead and install the stakedown kit with the cam up and inspect the tops of the valves under the tappets while doing so. If there appears to significant damage to the valve stems themselves I'll stop there and proceed with the head work now, if they look good then I'll roll with the stakedown kit and see what happens. My guess is, based on the way it runs, the valves are still in decent shape and the noise is coming from the guides rattling around against the cam lobe as they loosen up once the engine warms up.

Thanks for confirming on the air injection, I will likely delete that and the cat at some point over the winter. It'll run cooler and maybe find a few extra ponies kicking around in there somewhere. :icon_wink:

forgot the picture

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Well, great success today. Tappet stakedown kit showed up and, as I suspected, was easily installed with camshaft in place in less than half an hour. Death tapping/rattling is now gone. Overall engine is still a little ticky but you can clearly hear the difference. It now simply sounds like an older engine with slightly excessive valve clearance instead of one that sounds like it's about to self machine itself to little bits. The ticking was there before with the tappet guide rattling heard over top of that, particularly as the engine got warmer. I used the plate style stakedown kit from Coventry West, if anyone wants to know. Quite simple job and it's a great feeling to be able to feel comfortable driving it without worrying that a piece of the tappet guide is going to wind up in the timing chain at any time.

As a side question for any of you out there, anyone know of any good sources for exhaust system components? Particularly headers to delete the catalytic converter? I've got a feeling it's something that will have to be fabbed up, haven't had any luck looking around online so I thought I'd put it to you guys and see if anyone's come up with something.

Got a few things done on the car lately. Put some good synthetic gear lube in the diff, replaced the disintegrated shock bushings to correct that clunking noise, fixed the broken wire from fuse 11 of the main box to the aux fan switch (no longer tries to run at 100-110 degrees coolant temp, stays at 95) and cleaned and treated the leather with Lexol, what a difference that made. Having one problem I was hoping for some input on.

A couple days after I bought it it did this thing where the idle stumbled like it was trying to cut out and that was accompanied by the tachometer bouncing around erratically. Drove it a little and it was fine. Attributed it to a weak battery which has since been replaced. Since then it started doing it more, particularly when first started and until you drove it a few miles. Now it's doing it pretty regularly. The odd part is, if you rev it to 1700 or so, even if the tach bounces around wildly, the engine does not seem to miss or hesitate at all. If the car's underway, it doesn't miss at all again even if the tach is going crazy. At idle however it seems like the tach wigging out corresponds to stumbles and occasionally stalling. It's getting to the point where it's stalling out when it stumbles pretty regularly when sitting at a stop in drive or reverse, but it's fine once you get moving.

My first thought was to re-check the tune up parts I installed which seem fine. Cap and rotor are seated properly and show no signs of arcing, nor do the plug wires. I cleaned and put contact enhancer on all connections to the coil and ignition module. Doesn't seem to have made a difference. I suppose it's time to start doing electrical checks at the ignition components to rule out wiring problems to them, just thought I'd see if this is something that's been seen before or is a known problem with one of the ignition systems components.

You might need to check the wires along the top of the intake going to the ignition coil. The white, black, blue wire is the TACH wire and if the insulation is cracked, it could be touching EARTH somewhere causing coil/tach shutdown.

Check the dist shaft for worn bush, reluctor and pickup problems

Could also be the coil, could be the tach, could be.............

bob gauff

Yeah, I hear you, could be almost anything in the ignition system but I'm doubting the tach itself because if the problem was in the actual gauge I don't think it would cause the associated stumbling. I've tried wiggling and pulling on the harnesses for the distributor, amplifier and coil while it's running and it doesn't change anything at all. I'm going to start by checking the coil and amplifier electrically as described in the manual.

Well, that was relatively simple. Using the ignition system check flow chart in the manual checked voltage at the coil. 12.4 at the battery, 12.2 at + and - coil terminals. Moved on to resistance of the distributor pick up, 3.4 K ohm (spec 2.2 - 4.8). Started her up and started wiggling connections and suddenly noticed an ever so slight amount of smoke coming from the coil. Looked closer and noticed it was coming from the resistor on the + coil terminal. Clipped the spade connectors, added ring terminals and re-connected wires to coil sans resistor and viola, problem gone. $2.20 package of ring terminals and it's fixed. In the meantime found the fuel hose in front of the timing cover leaking so replaced that as well.

Hi, would you mind expanding on the technique you used to install the kit? The SIII XJ6 I'm picking up on 8/26 does NOT have the kit installed. I'm trying to get a feel if this is something I can do or I need to have it done by a shop.

Thanks much,

Mark

For tools you will need a drill, a quality drill bit meant for use on metal (5/32nds I think? It will say in the stakedown kit), a flathead screwdriver and an 11mm wrench/socket and ratchet. Deep socket with ratchet would probably be easiest.

Disconnect the air injection valve hose and remove the exhaust cam cover. Stuff rags in the 3 oil holes above the cam to prevent metal shavings from falling in and wipe up the oil collected around the cam.

Mark your drill bit for the depth the self tapping screws stick out past the plate. I marked it with a piece of electrical tape.

Lay the plates in place making sure the lip is fully seated on rims of the tappet guides. The longer of the 3 plates goes between cylinder 3 and 4 tappet guides, the other 2 are identical.

Holding the plates in place fully seated begin drilling the two holes for each plate. It's tough to hold it in place while drilling so just barely get the holes started. You can mark the holes then drill but then you're more likely to deal with the drill bit walking on you and the hole being off center.

Remove the plates and continue drilling the holes to the depth previously marked on the bit. Take care to ensure you're drilling at a perpendicular angle to the cylinder head. Use light pressure on the drill and keep the bit lubricated, let the bit do the work not your force. You do not want to deal with a drill bit tip snapped off inside the head.

Using a shop vac, rag, ect clean out the metal shavings. Take care and times to ensure you get as much of the metal resulting from drilling as possible out of the head, you don't want them to wind up floating around in the oil.

Install the plates with the included self tapping screws. Re-install the cam cover and air injection hose.

That's it, not too big a deal. The main things to keep in your mind are that you make sure the plate is fully and properly seated in place when your start the holes, your drilling is straight and you don't go too deep and that you get all the resulting metal out when you're done. It's something that anyone with a modicum of experience using tools should be able to complete successfully. Just be patient and think it through.

Thanks for the info on the install. Definitely DIY, although I have to admit it will be a bit nerve-wracking drilling into the head....

Thanks again.

was this the clacking you had in your car?
79 xj6 idle - YouTube

Hard to say exactly from the video but it does sound similar. Do you hear it under load, too? On mine you could hear it erratically making a clacking sound under load as well that was clearly separate from the tickiness of the valve operation. Easiest way to tell is to pull the cam cover on the exhaust side (takes 5 minutes, no big deal). If any of the tappet guides look like they do in my first picture in this thread then they've been lifting out and contacting the cam. The later picture shows what they should look like if they haven't been hitting. Either way, you should install the stakedown kit if it hasn't been installed already. Also I would confirm this before driving it much as if a chunk of one of the guides gets knocked off and winds up in the timing chain you're in for a bad day.

Spoke too soon on the jumping tach/stumbling issue. Had idled it for 15 minutes without it happening, took it for a spin later last night and it came right back. Will have to do some more investigating. I had already ordered a used amplifier because I saw a good price on a used one on ebay so I'll try that next.

Do you have any pictures of the kit installed? Where do you install it? right on to the block under the cam shaft? what about replacing the guides?

Replacing the guides is a bitch and probably should be done with the head off. From what I've read new tappet guides need to be ground down to fit, anyways. I wouldn't recommend messing with them unless you're going to take the head off and rebuild it. tipofmonth8 - The What & Why of Stakedown Kits There's a link to another install writeup that has pictures of them installed, I forgot to take pics before I buttoned it back up. The half circle cutouts in the plates half lips on them, the lip sits on the rim of the tappet guide.

you are awesome to my cause vwtech....thank you. Just ordered my kits from coventry west, i assume it will come with instructions...

vwtech,

Sounds like you are getting the kinks out of your car. It takes some time and patience, but once done right the car should be reliable. I use mine near daily (swapping around with my other 2 cars to make sure everyone has a chance to stretch their legs).

Couple of notes, I had an issue with stumbling after the engine heated up and it turned out to be a leaking coil. I saw some moisture under the coil and the oil (which keeps things cool in there apparently) had been seeping out. Replaced the coil and all has been good.

On the cat delete option, search for Jagbits. i believe they had straight pipes specifically for the 2 different cat sections of the exhaust and they weren't too pricy.

Post some pics of your car. Always good to see another one. Best looking 4 door sedan, IMHO.

Eric

Ronin, thanks for the encouragement. I have no doubt it can be made into a reliable car, it's all about staying in tune with how it's running and keeping up on things. I posted some pics in the welcome section. Definitely agreed it's one of, if not the, best looking sedans out there.

Was playing with it last night and realized I had overlooked the plug wires, they look fine and aren't brittle or anything but a quick test with soapy water revealed arcing in several spots on multiple wires. I'm going to put new wires on it tonight and see what happens, if not I'll probably move onto the coil. I have a feeling the wires will take care of everything....everything except my ego which will be a little bruised for having overlooked something so simple and obvious, lol. The tach bouncing around threw me off and had me ignoring them looking for electrical issues.