Backside method valve adjustment question

[bsimonson]

Hi all,

Today I attempted to check my valve adjustment with a 0.07 mm (0,0026") feeler as a GO feeler. Unfortunately I was not able to get it between the rocker arm and the cam so I tried the smallest one available, 0,04 mm (0,0016"). Could not get that one between either.

I had to abort before trying another cylinder than nr 1 so that will be my next step before jumping any conclusions as this might of course be due to my inability to get the feeler in the correct position to slide into place.

But I'd like to hear from anyone who has done this. How hard is it usually is to get the feeler in place when the valves are correctly adjusted, or near correct?

Cheers, Björn

[kach22i]

1. Make sure you are not 180 degree out of phase, the rotor contact should be pointing towards #1 cylinder (contact). If you go past your pulley tick mark, you must turn the engine twice around as going only once will put those valves 180 degree out of phase. To get back in phase go only once around.

2. I had the same problem my first time and on my first cylinder, could not fit anything in there and had no idea what was going on. The reason an engine can sound more smooth and less noisy when in need of a valve adjustment is because the clearances can close up tight (doing some wear damage). You need to loosen the adjustment nut and reset. Alternately you could skip that first cylinder and do it last, on the chance the second one in firing sequence is not so tight and easier to get your method down.

3. I would re-torque the head studs first, I choose to do it a few pounds less than spec so I would not snap any by accident.

4. My first time took 2-1/2 days with a good day of that just cleaning off the gunk and carbon with cleaners. Take your time, pretend you are getting paid by the hour and not the job.

[kodioneill]

I do a partial engine drop. It helps because you don't have to raise and lower the car or get up and down from a sitting position. Well worth it considering how easy it is to drop the engine.

[bsimonson]

Originally Posted by kach22i

1. Make sure you are not 180 degree out of phase, the rotor contact should be pointing towards #1 cylinder. If you go past your pulley tick mark, you must turn the engine twice around as going only once will put those valves 180 degree out of phase. To get back in phase go only once around.

2. I had the same problem my first time and on my first cylinder, could not fit anything in there and had no idea what was going on. The reason an engine can sound more smooth and less noisy when in need of a valve adjustment is because the clearances can close up tight (doing some wear damage). You need to loosen the adjustment nut and reset. Alternately you could skip that first cylinder and do it last, on the chance the second one in firing sequence is not so tight and easier to get your method down.

3. I would re-torque the head studs first, I choose to do it a few pounds less than spec so I would not snap any by accident.

4. My first time took 2-1/2 days with a good day of that just cleaning off the gunk and carbon with cleaners. Take your time, pretend you are getting paid by the hour and not the job.

Thanks for your input, I'll try a couple of other cylinders and see if anyone is easier. Like you mentioned, it would be nice to build some confidence before tackling a full reset

I left my Bentley manual in the garage so I can't check right now, but can the head-studs be re-torqued without dropping the engine?

2 days sounds reasonable and I'm in no hurry really. I'm just getting a bit worried that the valves might have been burned, only bought the car this summer so I don't know the last time the valves were adjusted. But there is nothing I can do about that now so...

Originally Posted by kodioneill

I do a partial engine drop. It helps because you don't have to raise and lower the car or get up and down from a sitting position. Well worth it considering how easy it is to drop the engine.

Unfortunately I don't really have that possibility due to the garage I'm in and lack of some important tools.

Cheers, Björn

[Gunter]

Björn,

Yes, you can check the torque on the headstuds by using a LONG 10 mm Allen socket on a calibrated 3/8"-drive click-type torque wrench set to 23-24 ft-lbs. I recommend you do it now while the valve covers are off, very easy to do. You can make a tool by cutting off the short end of a long L-type 10 mm Allen wrench and stick it into a regular 10 mm socket.

For the valves, make it easy on yourself and use the standard Porsche P213 tool like this:

Turn the engine so the pulley shows Z1 and make sure the rotor in the distributor points to the notch in the housing. If Cyl. # 1 is at compression stroke, both intake and exhaust valves should be loose. Wiggle the #1 intake & exhaust valves. If they're loose, you're o.k. If not, turn the engine 180 degrees.
You can turn the engine by putting a large socket on the large fan nut and squeeze the belt when turning; it works.
Start with the intake valve. Make sure it's slightly loose. Open the counter nut on the adjuster and back off the adjuster a little. Insert the P213 feeler gauge. Snug up the adjuster on the blade and tighten the counter nut. If the clearance is right, the feeler blade should have a tight slide when removing. Repeat as needed until you have the right clearance.

I have tried the backside method and found it too complicated in part because the long feelers are so thin that they bend too much.

The regular adjust with the P213 works well if you do the above; much less fuss, effort and frustration.

Cheers.

[john walker's workshop]

get the proper tool and learn to do it the normal way before attempting the go/no go method that leaves you somewhere +/- of the proper .004, unless you get lucky.

[bsimonson]

Ok, building a head stud tool should not be a problem as I have everything but an expendable 10mm Allen key. Seems to be a typical "while I'm in there" job.

I'll give the backside method a few more tries on the other cylinders before I give up on it and get the P213 - from what I have gathered here it seems that some like one better, others the other one.

I'm pretty sure I had everything lined up correctly today but I could not wiggle either valve anything, which might indicate that they are indeed to tight and thus making the feelers impossible to slide in. I'll report back when I have had another go at it.

Thanks for helping out!

/b

[Gunter]

Couple things:

Allen keys are hardened, so, you'll need to clamp it in a vice and use what is called a zip-cutter blade on a hand-held grinder. Watch your eyes.

Get a long, LONG 10 mm L-type because the headstuds are deep inside. You really want to do this to see if some studs are getting soft meaning: starting to pull out from the case.

Typical no-problem tightening would be just a little turning with the torque wrench clicking at 23-24 ft-lbs. Keep a log on how much turning it takes per stud for future reference. Also, when you do this, go cross-wise (Diagonal) from one stud to the other to ensure that the head sits square on the cylinder.

To see if the rocker is loose, you grab the rocker by the adjuster end and wiggle sideways and up/down. Expect that leftover oil under the elephant foot sometimes fools you; wiggling brakes the suction.

People that do this often will go with the P213, IMHO.

BTW: I glanced over your blog and it looks to me that the oil filter wrench is on the filter the wrong way? Oil filters go on cw (Right-hand thread) and open ccw. If the wrench broke, something is wrong.
If all fails, another way to get it off is to place a rag under and then hammer a big long screwdriver right through the filter so it comes out the other side and then pull up on the handle.

Engine oil: Diesel 15W40 mineral is what I use for the 911, not Synthetic.
Plugs: Copper, not Platinum.
1980 US SC's have a specific CIS, later '81-'83 CIS systems are the same.

Call on Greta's spirit to help you.

[bsimonson]

Hi Gunter

Yeah, I was thinking about how to cut the key since I don't have a grinder, but I'll figure it out, maybe I can pick up a straight one somewhere. How long is long LONG? Like 5" or more? I'm thinking I'll have problems getting it in place if it is too long.

Actually, if I remember correctly I could wiggle the rocker arm a little bit sideways, but not up/down which I thought was the important motion. Might have been because of suction then.

The tool only locks if used correctly and I did apply the force ccw, but this is a $6 tool so I guess it was bound to happen. I've seen stories on here of other people with stuck filters and broken tools so at least I'm not the first one but the screwdriver approach is getting nearer.

Like I wrote on the blog I've been fretting over what oil to choose for a while but decided to try my luck with a synthetic after all, I hope I won't regret it. The plugs are the ones that were recommended on here, I know close to nothing about plugs so I just went with that.

"Gretas spirit to help me" - does it look that bad?

Cheers, Björn

[bsimonson]

I've found a product but I don't know if it is suitable for this job. It's available with a 10mm head and it's 100mm long. Is that long enough, or if it is not, is there any room to use 1/2" or 3/8" extenders or are they too big (diameter wise)?

This picture shows a smaller version but you get the point.


http://www.jula.se/mediaarchive/5184762/zoom/170412-jpg.jpg

[Gunter]

Not even close; It's too short and there is no room in the hole for anything other than the 10 mm long tool.

The actual Porsche Allen key for the heads is way too expensive; make your own tool.

Now that I think about it more, I made up 2 straight Allen keys: 1 about 4" long and the other more like 5.5".
I suggest you get a LONG L-type Allen key; stick the long side into the abyss and mark where you need to cut; you'll see how deep the hole is. Get a small inspection mirror as well.

To cut: Buy a cheap small hand grinder with a thin blade on it. Clamp the Allen in a vice and carefully grind away. (Forget about a bolt-cutter!)

Grinder, Mirror, Allen key, Torque wrenches are a must for a DIY working on a Porsche: 1/2"-drive for the Lug nuts (96 ft-lbs) and 3/8"-drive for other stuff.
And of course, the Bentley SC Repair Manual.

[kidrock]

cut it with a bolt cutter and grind the tip until it's flat.

[Canada Kev]

If you want a dedicated long 10mm allen socket, most of the 3/8 inch drive types have removable allen keys. There's usually a small screw on the side of the socket. Loosen the screw, remove the short allen and substitute your shiny new one you made from a cut down long L-type key. It's a bit more elegant than using a 10mm socket on the end of your cut off allen key, though both will work.

[kach22i]

I did not have to make any tool to tighten down the head studs. I did have to make several stops to my favorite hardware store which carries everything though.

I purchased the tools for adjusting the valves the traditional way, but tried the backside method first. As a newbie (several years ago) to both methods I found the backside method better, never got the hang of the traditional method and gave up on it quickly - after one try.

Cleaning the outside of the engine first really helps. Last thing you want is to have any road grime or sand make it's way into your engine.

[911pcars]

Here's a cross section of a typical cam lobe:



If the rocker arm contacts any part of the heel of the cam, that valve is closed and can be adjusted. Thus, exact TDC is not required. As in most things mechanical, it's always better to understand the concept rather than to "paint by the numbers".

If it's difficult to insert the feeler blade, the existing clearance is either tight or a typical issue measuring a gap of 0.004" (1mm). Loosen the adjuster far enough to open the gap, insert the feeler blade, then adjust to spec.

The torque required to retighten or loosen a threaded fastener is much higher than the torque spec which is established as the fastener rotates in the threads. I would just check it's not loose (torque spec) and call it a day.

Hope this helps,
Sherwood

[bsimonson]

Originally Posted by Gunter

Grinder, Mirror, Allen key, Torque wrenches are a must for a DIY working on a Porsche: 1/2"-drive for the Lug nuts (96 ft-lbs) and 3/8"-drive for other stuff.
And of course, the Bentley SC Repair Manual.

Well, I got the book, mirror, a lot of Allen keys and a torque wrench so I'm almost there. =) I think I'll start with another trip to my car (it's in a garage ~15 min on bike from me so every little thing take its time) and measure exactly how long it needs to be and to get a feel for how it's all looking IRL - take the guesswork out of it a bit.

Originally Posted by kach22i

I did not have to make any tool to tighten down the head studs. I did have to make several stops to my favorite hardware store which carries everything though.

That sounds promising, I've have not yet seen anyone that carries straight Allen keys but I guess they should exist. Or did you use any other combination of tools?

Originally Posted by 911pcars

Here's a cross section of a typical cam lobe:

...

Hope this helps,
Sherwood

It does, very interesting! Wow, this is really half of the joy of owning this car - learning all the stuff, both the theory and how to wrench it.

Thanks guys (and gals?)!

/b

[kach22i]

Originally Posted by bsimonson

That sounds promising, I've have not yet seen anyone that carries straight Allen keys but I guess they should exist. Or did you use any other combination of tools?

My allen socket fits right on the end of my torque wrench, various extentions can be used. I bought from a local retail store, may have came in a three pack all 3/8" drivers. I have a 8 mm, 10 mm and a 3/8" Allen socket - I think many many sizes are available. Not very different from the posted image.

[bsimonson]

Just got back from the garage where I have checked all the cylinder head studs. None of them were in need of tightening and more importantly, none of them were broke.

Since it was only a $7 part I decided to try the socket extension I posted above (or rather its bigger brother) which turned out to be almost perfect. With a swiwel, a long extension, about 4", and a 3/8 to 1/2 adapter to fit it to my torque wrench it was a 30 min job.

Many thanks to all of you, now on to the valve adjustment!

[mtndawg]

Keep the updates coming. I'm going to adjust my valves for the first time in the coming days (just ordered the pelican feeler gauge and head cover gaskets). Now I know to check my head bolt torque.

[lindy 911]

You won't get accurate torque if you use a swivel in the combination.

Lindy