Lessons learned from my first valve adjustment

[jwakil]

Just thought I would share some pointers...I did my first valve adjustment on my 83SC (with 77 CIS 3.0 engine) while I had the engine partially dropped for an internal thermostat replacement. I thought this would make the job much easier (and yes it does). Luckily I had read the 'backside adjustment method' technical article on this site which saved my life.

1. I can't image doing it the conventional way (as described in Bentley and Waynes 101 book) where you measure the gap between the valve stem and the rocker arm foot. Even having the luxury of looking straight at the piston as I did, I could not get the feeler guage in the gap without significant trial and error and effort. I would say it would be impossible if you couldn't look at it straight on. The only way would be to back way off on the adjustment screw, put the gauge in, then tighten down. Which means that if the gap was correct to begin with, you just did a lot of work for nothing. Once you take the guage out, you can't really double check the gap easily the second go-round.

2. Getting the right feel of how tight the gauge is in is also very tough the conventional way. Again, it would be an order of magnitude harder if you couldn't see what you were doing, without dropping the engine.

3. The net is, if you do it the conventional way with the engine in the car, I think there is a high probability you will end up with a worse adjustment than you started with after a lot of effort.

4. That's why I'm surprised I haven't seen more people talk about the backside method. This was in my opinion at least an order of magnitude easier and also the go/no go guage insertion method takes away the guessing game of whether you have the right adjustment. I would highly recommend doing a partial drop (easy to do) and using the backside method.

[tobluforu]

I just checked out this back-side article and this seems like such an easier way of doing it. I have probably adjusted the valves on my 72 at least 10 times and what a pain in the ass it is doing it the conventional way.
Thanks

[d.a.autry]

I tried the backside method the other day on my 2.7. I was meaning to update the site here but forgot about it until now. I'm still out on this one, being that with the engine in and all tin around one has to go from top to bottom (and vise-versa) repeatedly when a valve is found needing adjusting.

I'm thinking use this as a good check, but if a valve is found to need adjustment, use the old standard on that one. . . then go back and do the go/nogo for a final.

[kodioneill]

Partial engine drop and go no go are the only way to go. That's the only way to do it and how all my valve adjustments are done.

[LUFTMAN]

Never dropped engine down after 35 years of adjusting valves you get used to it. C2 and turbo models are the worst. Standard 911 models with a/c air pumps etc.. Is a 3 and a half hour labor operation and engine must be at room temperature it is a feel thing the more you do the easier it is. Practice practice practice regards tom

[Dixie]

If I was running a shop, I'd do it the conventional way. I'm sure it's faster *if* you've done a bunch.

Being my own mechanic, I use the back side method. I willingly trade my time to assure I'm being accurate. I only adjust the valves once every decade or so.

[James Brown]

Get one of these things and make your life easer.

Quick, easy, cheap.

[tobluforu]

Originally Posted by James Brown

Get one of these things and make your life easer.

Quick, easy, cheap.

Ok, what the hell is that?
So, in order to this back side method on say a 72 without ac, one has to drop the motor some?

[James Brown]

no motor drop on ANY 911 valve adjustment!!! Might have to take things out of your way but don't have to drop the engine, who told you that?

[snbush67]

No matter what method, tool, etc. you use, the final check is always a "tug" on the adjustment screw to feel the gap. If it don't feel right you'll do it again even if the gauge went in tight.

A good way to learn the feel is before you start your adjustments, rotate the engine to each valve and "tug" each one, some are looser, some are tighter. They all might be wrong depending on how they were last adjusted.

Then using your gauge adjust a single valve to where you think it should be, compare it by using the "tug" to the other valves. You will probably be amazed at how a good sensitive tug can help get you a better gap.

Since I have learned to do the tug its all I do, so put the gauge away and get in the garage and tug one out today!

I guess if you aren't good at tugging a gap you could use the backside!


Shane

[scotricker]

I need one of those dealie-bobber gizmos that James pictured. Where do I get it, and then...of course.. what do I do with it?

[SP2]

I would guess that homemade tool is to visually aid you when you turn the screw i.e. a quarter turn, and help you keep the screw in the same position when you counter turn/tighten the corresponding bolt. But not necessary IMO.

[Trackrash]

The one thing that caused me problems over the years is when the oil is at room temperature it is difficult to properly feel the gap. A thick film of oil on the feeler gage, in the elephant foot, and in the rocker shaft all added up to noisy lifters when the motor was warmed up. I even tried using a dial indicator.

The last time I adjusted my valves I did so when the motor was still somewhat warm. I waited until I could touch the motor without discomfort. When I used the feeler gauge I could easily feel when the gap was correct. An guess what, quiet valves!

I know the book says adjust when cold. But when using 20-50w oil I could never get it right when adjusting cold.

[Zeke]

I'd like to hear more about just what a "tug" is. I don't think that is in my Bentley or 101 Projects.

[sc_rufctr]

Our host has these. I use it as a check for the conventional method.

[runfaster]

That screwdriver looks cool...I found a demo on how to use it on youtube.

YouTube - VAS Video

[snbush67]

The screwdriver pictured takes into account thread spacing, so if you close the screw all the way in, you then back it out using the arms as a measure (I think it is 30 degs) it will back the screw out exactly .004".

You could easily make your own with a small bit, some nails and a donor stubby flat tip.

You still have to tug the screw to check it.

Milt, It is good to have you back.

Shane

[James Brown]

I have some thing for you to tug!!!(badda-bing). I got this thing off rennlist, not sure but do a search for it. Around $15.00

[tobluforu]

Originally Posted by James Brown

no motor drop on ANY 911 valve adjustment!!! Might have to take things out of your way but don't have to drop the engine, who told you that?

Read above where a few state that a partial drop is required for the back side method?

[GothingNC]

Congratulations !
I think perfroming the valve adjustment helps bond a relationship with the car.

I just performed my first valve adjustment with my brother the other week using the traditional method.

Took us about an hour after the covers were off. It was probably his 200th time he did a valve adjustment so he had no problem with the "feel" getting the feeler gauge in to verify the gap.

Much easier then the job he did on a co-workers 964 the day before.

One exhaust was a hair loose and #4 & 6 intake were just a little tight, could have been a false reading but we readjusted just to be sure.

Back-dated heat, no AC and SSI's help create lots of working room.