Did valve adjustment - now noisy - what's next?

[henko]

Hi -

I just did my first valve adjustment on my '85 Carrera this weekend. I followed the instructions in Wayne's 101 Projects as well as the ones in the Bentley Manual.

I also used the Porsche special tool which seemed to work OK. Despite initial difficulty with determining the TDC (there are two notched on the crank pulley about an inch apart and I decided for the left one) due to the absence of a Z1 mark (or at least I couldn't find it), I got a hang of it and did all the valves to the best of my knowledge.

The car is now running better than before, with more low end pick up, but the valves are pretty noisy.

Should I be concerned that the noise indicates potential harm to the engine?

Also, if I want to do another adjustment, can I reuse the 10 quarts of Mobil1 and the valve gasket kit?

Can the valves be expected to settle in and get more quiet as I put more miles on the car?

And if I redo it, does someone have a good way to express how the feeler gauge should fit? Tight or easily slide in the gap?

thanks,
HB

[berettafan]

You could go back and double check using the 'backside method'. Do a search and you might find it's easier than the traditional method.

See my sig line for my take on valve adjustments!

[lespaul]

Backside is the only way to go. Take off surrounding engine tin before you start.

[ros74911]

henrik, you should have a slight resistance when adjusting valves. not freely or else it would make a lot of noise. tak tak tak sound. that's your valves too loose. as for redoing it and reusing oil. nothing's wrong with it. the more you do it the better you get. it's good practice for me the least. if you decide to reuse oil and gasket you would need to retorque nuts to 8lbs ft torgue instead of 6lbs ft. that's of course if you haven't driven the car a long ways i.e. 30 miles or so. good luck

[henko]

- and if I have driven more than 30 miles? I think I did about 20 yesterday when I took it to work and back.

Henrik

[tjc5911]

Not to worry, I had to re-do three times. Very noisy the first time and got better at it as I went. I've heard that loose is better than tight if you're going to error. Reading the manuals, I initially adjusted too loose. I believe there should be a little more resistance that what you might gather from reading Bentley's.

I bought the red rubber type gaskets from Pelican and am very happy with them. I kept re-using the gaskets and still no leaks! I would use the oil again - just be real careful about contaminents.

[glenncof]

Yea, probably too loose. I used backside as front side I could not get confidence. Too loose first pass, tweeked again 2nd and 3rd pass.

Mine sound perfect, just like before (mine were too tight though).

[ros74911]

Originally posted by henko
- and if I have driven more than 30 miles? I think I did about 20 yesterday when I took it to work and back.

Henrik

henrik, reason i asked - oil might have circulated enough to have picked up something from your engine. so, it make sense not to put same oil back in your engine. better put a fresh oil if you're not sure.

[rusnak]

my $.02 - make sure the engine is stone cold before you start. TDC Z1 is the second of the two timing marks that are close together. You ought to see some faint yellow paint on the pulley mark.

[henko]

Foolish as I am - how could I think I could do this without consulting this website???

Of course all the info I need is on here. Thanks to all of you for your input - it's back to the garage as soon as I return from what I hope to be a snowfilled weekend in Vail.

Take care and happy Porsche motoring.

- Henrik

[SCWDP911]

Sub'd. Getting ready to do thid myself soon... Thanks for the experiential reports!

[Superman]

It is not uncommon for folks with less experience to adjust them a bit too loose. I think the decal (engine compartment, inside the deck lid) says the Porsche spec is .04" plus or minus .002". So....a little snug is okay. Yes, adjusting valves too tight can hurt engines but I have never heard of that happening on a 911. Indeed, I believe I have also heard that this gap increases as the engine comes up to temperature. And....the real danger of adjusting them too tight is that the valve never closes. You'd have to adjust them WAY too tight for that to happen. I think.

[the]

if the valve is too tight, it can overheat and break off, with the head falling into the piston.

pictures of pistons and cylinders that have played ping pong with a broken off valve head are posted all over the internets.

I think the odds of a first timer getting all 12 valves truly within proper spec on the first run are about 5%.

[01sport]

Henko,

I did my first valve adjust about 2 months ago with only the .004" feeler gauge. I read about the "backside method" but I did not have the proper gauges and was itching to give it a try. valve adjustment
My results were like yours. Better running but still noisey. I got my .0025 and .003 and went back in.
The results of my first adjust (measuring the backside) was:
7- loose
2- tight
3- O.K.
The backside method is brilliant. I don't see how you can make a mistake using this method. It took me a full day but my car runs better now than in the 18 years I have owned it.
I found some 12" long individual feeler gauges (as well as short ones) that came in handy. lespaul's tip on removing surrounding engine tin sounds like a great idea.

Good luck,
Jeff

[Early_S_Man]

Guys,

You don't have to drain ANY oil out to do another valve adjustment!

1. Prior to parking before the adjustment, let the engine idle for 2- 3 minutes while sitting on level ground.

2. Cool down ovenight.

3. Jack up one side with rear tire 4" - 6" off ground. Put jack stand under torsion bar tube or extension tube end of trailing arm.

4. Remove valve covers on raised side. It might drip a few drops ...

5. Do the valves again on that side ... replace valve covers, reuse gasket, sealing rings, and Nyloc nuts.

6. Lower that side and raise other side ...

7. Remove valve covers on raised side. It might drip a few drops ...

8. Do the valves again on that side ... replace valve covers, reuse gasket, sealing rings, and Nyloc nuts.

pasted/edited from years ago ... a bit about valve cover Nyloc nut torque:

The specific torque value of 72 in-lb, or 6 lb-ft ... was not specified until the 'late' factory graphited gaskets with the incorporated green bead of silicone rubber came out around 1981. And that 6 lb-ft rating was first published in the '78 thru '81 SC Spec Book, dated 31 March 1981.

Up until that time, no torque value at all was specified in the spec books, and everyone just assumed 'hand-tight' wasn't going to exceed the 'normal' M8 torque value of 18 lb-ft. And, of course ... the original cork gaskets tended to crack or squeeze out in all the wrong places!

If you look at a normal 'combination' wrench of the 10 mm size ... it is no longer than the width of your palm, so, if you do the opposite of 'choking up' on a baseball bat, that is ... snug your four fingers right up next to the box-end of a 13 mm combination wrench, and tighten the valve cover nuts with the wrench held that way, you won't over-torque the nuts, and you don't have to worry about buying a 1/4" drive torque wrench to measure 72 in-lb of torque! Why did I pick an 10 mm wrench? Because a normal DIN 8.8 M6 fastener uses a 7 lb-ft torque specification, that's why!

[dfink]

Really don't have much to add except to add 1+ to the first time too loose club. I thought that I had everything set perfect. I adjusted, rechecked, readjusted and thought I had a pretty good feel for the gauges. When I was done my engine was quieter than before but still had some valve noise. I thought well it is better and I double checked so it must just sound this way.
Well after pulling and rebuilding my engine this winter I used a dial indicator to set them at .004". I will let you know that a properly adjusted engine will not make tap, tap, tap sounds.

I will probably get into hot water cause I know this is an established method. My attempts to do the back side method, though more repeatable than the normal way, did not yeild the results I expected. I wanted to use this instead of the dial as I thought it would be faster. After several attempts my results were always the same.
If I used a go gauge of .0025" and a no go gauge of .003" I always got a .003" lash on the dial indicator. According to math the method should yeild a gap closer to optimal. I don't know if others have tested this in practice but those are the results I found. It would be interesting if anyone currently building could also verify the backside method. I did however get a very consistant .003" measurement.

[axl911]

Hahaha. Valves being VERY noisy after a first time valve adjustment is something I think every one must go through.

I went through the exact same thing! The "drag" they say is more like a "yank to get the feeler blade out".

Always check to make sure you can slightly rock the rocker arm after each adjustment to make sure you did not completely close the valve gap.

[ros74911]

Originally posted by Early_S_Man
Guys,

You don't have to drain ANY oil out to do another valve adjustment!

1. Prior to parking before the adjustment, let the engine idle for 2- 3 minutes while sitting on level ground.

2. Cool down ovenight.

3. Jack up one side with rear tire 4" - 6" off ground. Put jack stand under torsion bar tube or extension tube end of trailing arm.

4. Remove valve covers on raised side. It might drip a few drops ...

5. Do the valves again on that side ... replace valve covers, reuse gasket, sealing rings, and Nyloc nuts.

6. Lower that side and raise other side ...

7. Remove valve covers on raised side. It might drip a few drops ...

8. Do the valves again on that side ... replace valve covers, reuse gasket, sealing rings, and Nyloc nuts.

pasted/edited from years ago ... a bit about valve cover Nyloc nut torque:

The specific torque value of 72 in-lb, or 6 lb-ft ... was not specified until the 'late' factory graphited gaskets with the incorporated green bead of silicone rubber came out around 1981. And that 6 lb-ft rating was first published in the '78 thru '81 SC Spec Book, dated 31 March 1981.

Up until that time, no torque value at all was specified in the spec books, and everyone just assumed 'hand-tight' wasn't going to exceed the 'normal' M8 torque value of 18 lb-ft. And, of course ... the original cork gaskets tended to crack or squeeze out in all the wrong places!

If you look at a normal 'combination' wrench of the 10 mm size ... it is no longer than the width of your palm, so, if you do the opposite of 'choking up' on a baseball bat, that is ... snug your four fingers right up next to the box-end of a 13 mm combination wrench, and tighten the valve cover nuts with the wrench held that way, you won't over-torque the nuts, and you don't have to worry about buying a 1/4" drive torque wrench to measure 72 in-lb of torque! Why did I pick an 10 mm wrench? Because a normal DIN 8.8 M6 fastener uses a 7 lb-ft torque specification, that's why!

warren, thanks for the input. i would've never thought of that. that's amazing. i should've been a member here 5 years ago.

"people of pelican - you guys or gals are awesome."

[rusnak]

I like the idea of rocking the rocker to make sure that you didn't close the valve gap.

I was planning on changing my oil soon, and thought I'd plan on checking the valves and changing my CHT sensor, which I suspect is bad (rough idle).

Some questions before I attempt the backside method:

(1) How long do the feeler gauges have to be? Is the 12" long one the optimal length, because I have no idea where to find those.

(2) Do you still check the cylinders in the 1-6-2-4-3-5 order ( I know, some people use a different order by rotating the engine 240 deg etc etc etc) - the point being that other than checking the valve gap differently everything else is the same?

(3) Let's say you find one of the gaps is off, you don't find it useful to use the traditional crows foot tool at all? Wouldn't you need to put the traditional tool in the gap before turning the adjuster screw in order to adjust the clearance correctly?

(4) In other words, is the backside method a useful adjuct to the traditional method. A quick check, before moving to the next cylinder in other words?

Thanks.

[lespaul]

For what it is worth.

1. I used a standard feeler for my backside adjustment - around 4" long. It worked fine.

2. I checked/adjusted the cylinders in the proper order just because I did not want to mess up. The 240 degree method makes sense however. Bottom line, for the backside method, everything else was the same as the traditional method.

3 & 4. Maybe its just me, but the crow's foot feeler was of no use to me at all. Each time I tried to use it, I could not fit it in or, when I could and I double checked with the backside - the gap was too big. After a while, I just proceeded with the backside technique.

Note - while backside can be done without removing engine tin around the valve covers, I found it much easier to do with the tin off. It only took about 10 minutes to take it off and, for me, it was well worth it.

Good luck!