Euromagination

Hi all. Some of you may know that I just recently bought my 964 about 3 weeks ago. According to the records from last May ('04) it's been 8500 miles since its last 15k service. During that service however, I just noticed that the lower plugs had not been replaced. They were bought, but not replaced. The uppers were though. I was wondering why there were six Bosch Supers on the bottom of a box of things the PO gave me.

When he serviced it, the car got a new distributor belt, vent kit, caps, rotors, fuel filter, all accessory belts but one--the power steering, which the PO gave me, but he just never installed it.

Anyway, I am changing the oil and filter in it this weekend at my friend's shop; using his lift. I was wondering what the consensus is on changing the lower plugs since they're way overdue. Is it really hard to change these or something? I've been searching for a week now and haven't found an answer. Adrian's book says nothing about changing plugs either so I'm wondering if it's something that is a relatively easy DIY like changing the plugs in my A6 or my old Passat. (I know it wouldn't be that easy, but still.)

Obviously, I'm really wanting to at the very least be able to perform the 15k service on my 964 myself. That's why I bought it...to have fun with it, drive it, and work on it a little bit to pass the time. This is just another thing I need to know if I can do or if I should just take it to a local independent porsche shop and have them do it for me.

Any other suggestions?

Thanks,
Harry

Smokin

Harry... You should be able to do it... Especially with a lift. (Geez... Some people are lucky!) The passenger side just needs to have the heat shield removed and then you have access to the bottom row. I believe on the driver's side you need to take part of the muffler off. It should be easy to do... Especially if you have the convenience of the lift!

Good Luck!

Euromagination

Thnx Rick! Do you (or anyone else) have any access to a write-up on how to do the change? Like I said, I tried searching around here a million times, but came up empty-handed.

bhensarl

You're actually pretty lucky. I've never done it myself, but from looking at the engine bay I would think the upper plugs would be much more difficult to replace than the lower ones. You searched all over for a DIY for spark plug replacement and couldn't find one? Hmmm. Did you check the DIY forum? (Okay, I know there isn't one there, but I just wanted to make sure you know it exists.) Sounds like a great opportunity to write one up yourself! Don't forget to bring your digital camera over to your friend's shop!
Brian

Smokin

Harry,

Check Pelican parts and P-car.com... One or both has tutorials on sparkplug changes along with sparkplug wire changes.

Check it out!

Euromagination

Yeah, maybe I'll have to step up and do that.

As far as the search goes... yeah, I found nothing! It's not necessarily that nothing came up, but nothing answered my question. Also, the search function sometimes like to reset itself when I use it. When I click "search", it tries to load a new page for a while, then just take me back to the search page. Really weird.

That said, if I'm gonna step up and do a write-up, I would at least like to have a cheat sheet (or equiv.) to go by!

-Harry

Dave R.

Do a search on "valve adjustment".

To change the lower plugs you have to first get access by removing the catalytic converter (drivers side) and the secondary muffler (passenger side) and then the heat shields, and that is most of the preparatory work to do a valve adjustment - the only extra work from there to do a valve adjustment is remove the valve covers and adjust the valves. You might consider adjusting the valves at the same time, or holding off until it is time to do a valve adjustment. That said, did the PO tell you the valves were adjusted at the 15k service? If yes, then there is a possibility that only the intake (upper) valves were adjusted - it seems odd to adjust the lower valves and not replace the lower plugs.

If you drop the cat and secondary muffler you will likely need new bolts (cat bolts and clamp bolt connecting the secondary) since the existing ones are probably corroded due to heat. The valve adjustment kit from Porsche is about $50 and has them (plus valve cover gaskets, nuts & cat seal).

Wachuko

yes, what he said... might as well get the feeler gauge with a few blades and do the valve adjustments...

Here is a link to a post I did on changing the plug wires (spark plug cables)... you can see that once you remove the shields there is easy access to the sparkplugs. Buy some cable clips from your Porsche dealer ahead of time because you will break the ones in the car when you remove the cables (the heat makes them brittle...) Besides the heat shields there are two metal covers that gives you access to the top plugs. You will need an extension to get to the plugs and depending on the sparkplug socket you have you may need to modify the rubber insert in the socket or you will find that the socket stays with the new plug and you are left only with the rachet and extension in your hands.

Let me look for the other write up I had on this... (older, I hope the photos are still there...)

Sparkplug wires replacement

springer3

Replace the plugs. Even though the engine runs great, the voltage required to fire the lower plugs has undoubtedly increased due to erosion and contamination. The stress on your coil. electronics, and insulation is higher when the plugs are worn.

Dave R.

Duct tape works well to hold the spark plug socket to the extension - snap together, then wrap a layer of duct tape around the junction.

Euromagination

Thanks. One more question though... Considering my average mechanical ability, about how long should it take to do all of what you said above plus the oil change (of course)? I would just like a very loose estimate so I can tell my friend how long I'll be using his alignment lift at his shop. I don't want to keep him there all night on a Saturday evening.

Euromagination

Also, I was just reading Adrian's book and saw that it says to make sure the car is cold (i.e. leaving it overnight) when adjusting the valves. This makes sense to me because of the expansion and properties of metal, but then the oil change has to be done when the motor is at operating temp.

Sounds sort of contradictory to me. How do I get around this? Is it okay to change the oil out if the car is cold when doing a valve adjustment? I don't know if I can do the valve adjustment this time anyway since I have to drive the car there right before I start working on it. It will still be warm for quite a while. I need some direction.

Thanks in advance!
-Harry

springer3

You will lose exactly 138.3 miles of engine life if you change the oil cold instead of hot. You can compensate for this by changing the oil 0.3 miles earlier every time you do it cold, or add 10 minutes extra drip time to get the cold oil out.

The engine does need to be cold to get the valves exactly right. I don't know what happens, or how far off you will be, but the factory said do it cold for a reason. Perhaps you can leave the car overnight, and then push it onto the life. Better still, do it like the rest of us poor slobs and do it on your back with the car on the ground.

Good luck with it. Read RedRS's posts about stripping the valve cover stud before you get started.

Dave R.

On second thought, just replace the lower plugs this time and treat it as a partial dry run for a later valve adjustment. About 4 hrs should do it, you might take a lot less.

The secondary muffler will come out pretty easily (2 bolts up front and one corroded bolt at the band clamp), don't drop it on your head it will hurt, the multi-part metal shield between the cat and the road can be a bit ungainly (not complicated but remember the configuration as you take it out), the forward 4 bolts on the cat are probably the hardest part and might take some wrestling and at least one is in somewhat tight quarters, the band clamp bolt at the back of the cat will probably be corroded, the heat shields between the cat/secondary and the valve covers are straight forward with about 8 small nuts each.

You will also need to unplug the oxygen sensor cable inside the engine bay and push its rubber grommet through since you will be removing the cat and the O2sensor is bolted into the cat. The plug connection is on the left side in the back (nearest the driver). I don't recall if you have to remove the blower motor from the left side of the engine to get back there, if you are agile maybe not, if you do then note: if you stand at the left rear wheel and look across the engine bay toward the right rear wheel, the two bolts holding the blower to the intake manifold are located at the 3 O'clock and 6 O'clock positions and the front end of the blower has a prong that locates in a hole in a bracket mounted to the engine bay.

Takes me all day to adjust valves (open, adjust, clean the valve covers, replace plugs, peer at things for a while, put things back together, doublechecking periodically) after draining the oil night before. I take my time though.