The Kirk Valve Lash Tool; a Good Sort of Story

Give me a minute or two at the start of this post to introduce this topic; this isn't so much a technical story as it is a human interest tale, and it's an agreeable one. It's almost a tutorial on how to use this tool, but not quite. Carry on.

Kirk Engines, Inc., is a business run by J. David Kirk, of Fond du Lac, Wisconsin, U.S. of A. It's a small business that offers special parts and tools for certain engines, and among these products is a valve lash adjusting tool for use on vintage air-cooled Porsche engines. Mr. Kirk owns a 1988 911, and he works on it himself, so I imagine that this valve adjusting tool came into being as a product of his direct experiences with his own car.

For correct operation of the engine, a valve adjustment is a periodic, necessary task for older Porsches, and when it is done with the engine in the car, which is to say most of the time, it can be challenging because of the shear awkwardness of the process. Getting your head, and hands, and tools, and a light, and a sandwich, and your cat into the small space of the engine compartment - a contortion that requires that you have at least two elbows in each arm while it simultaneously gives you a good kink in your back - can be off-putting for some, and disastrous for others who royally foul up the job in the process, making their car run worse. I'll skip why you need a gap in the first place, as that's not the focus of this story.

A blue handled feeler gauge in action.

Anyway, the proper gap between the top of the valve's stem and the 'foot' under the adjusting screw is 0.10mm, and the routine method of measuring this gap is to use a feeler gauge having a thickness of 0.10mm that is inserted into the gap being measured. It has to be a firm, but not too tight fit, and this involves an accurate 'feel', which can be subjective.

However, the valve adjusting screw on a 911 engine, possibly all of them that had them, moves in or out one millimeter per revolution. Therefore, to establish the correct gap the adjusting screw may be turned 36° from a no-gap position to a 0.10mm gap. Ten percent of a revolution, never mind the feeler gauge unless you have OCD.

Measuring small gaps and thicknesses by this means uses the principle of the micrometer, an instrument whose job it is to measure small dimension items by turning a precise screw in or out, comparable to a Porsche valve adjusting screw. So, David Kirk decided to contrive a tool that would make the valve adjustment process more consistent, quicker, easier, and likely more accurate. The tool is, by a certain extension of things, a form of micrometer needing a new name.

Obviously, every part of the tool has to fit precisely, because if it does not the measurement will be off, or the tool won't fit the engine, whatever. This is what Mr. Kirk set out to build, and the resulting tool is beautifully made and is on offer to DIY Porsche owners who want to make their lives easier in the valve adjustment domain.

It's a nice looking little (minuscule) tool, well engineered, and still evolving. This last part is good, of course. So, I bought one.

OK, my hands are large.

It didn't work.

You have to install the tool onto a valve adjusting screw, and then fine-tune the 'tool post' in order that it keep the tool correctly oriented. I couldn't get it to fit onto the adjusting screws of my engine. It seemed that the driver bit was too fat, or misaligned, or my car is weird - I didn't know what, but it just refused to install on any valve and would not perform.

It's supposed to attach like this. Thumb is on the tool post.

Okay, I bought this thing from Pelican Parts, a California supplier of parts and tools for European automobiles, perhaps mainly Porsche cars. I will not pass judgement on Pelican here, but I will directly quote from my correspondence with them. To P.P. I wrote:

"I recently purchased the Kirk valve lash tool for air-cooled Porsche 911s.

". . . It is important that the tool's driver bit fit snugly onto the valve adjuster screw, however, I was unable to get the driver bit securely into [any] screw's slot. It seemed that the driver bit is too fat for the screw's slot.

"Since the tool is miniature, and work has to be done in an awkward environment when the engine is in the car, the difficulty I experienced is magnified and I have wasted a great deal of time with no good result.

"Please comment on this situation. Is there a problem with the tool's compatibility with certain valve adjuster screws? Is there some 'trick' to use the tool that has not occurred to me (I tried everything I could imagine)? . . ."

It took slightly over a day to receive a reply from Pelican, and P.P. said:

"Thank you for your enquiry (sic) and after review, we have several technical articles on our website regarding valve adjustmet (sic) for 911 vehicles. We would recommend that you please review these for resolution . . ."

Duh. What?!  Sorry, I said that I would not pass judgement here.

However, David Kirk's email address is on the instructions that came with the tool. As a result, I wrote to him, too, voicing the same lament as above. Here is where the human interest component of this post begins.

David responded in 19 minutes. In part he wrote:

". . . This is the first complaint I have received on this tool and I take it very seriously.  I want to produce a quality tool that is easy to use and is durable.  Please know that I will do everything that I can to make this right for you.

"I apologize for the problems and thank you for your understanding."

Later he wrote, " . . . Having the tool back in my hands to inspect will verify what's defective and will help me make sure that this never happens again.  Please know that I'll also refund your shipping costs if you elect to return the tool to me for servicing.  You should not have to pay for anything extra because of defective parts . . ."

He concernedly recommended that I send the tool to him for a complete examination.  He would test it, and if there were any manufacturing flaws, he would correct them, or refund my money (even though I did not buy the tool directly from him, but rather from Pelican). Basically he was prepared to do whatever it took to make me a happy customer.

In the 18 emails that have gone back and forth between Mr. Kirk and myself, I reported a number of measurements from my car that I was asked to make, David did tests of the tool, and he diagnosed that there was an invisible burr from the manufacturing process on the screw driver bit. He was embarrassed that this flawed tool was shipped by mistake. Corrections were made (with jeweler's tools, which says something), and tolerances were adjusted in the tool to within 0.001in (0.0254mm), which is a very fine fit for any mechanical tool. Splendid.

Installed on an intake valve adjuster in my car and fitting properly. The wrench is there to tighten the lock nut.

 
I learned that Dave Kirk is a decent and honest guy who is concerned with excellent quality, and he fully stands behind his work and his product. This is not anything like buying a cheaper tool that is made in a distant factory on the other end of the planet.

Yes, the Kirk tool is pricey. And, yes, I am disappointed that time was wasted while the issue was resolved, but it was resolved, and very properly. This is the kind of result that is only possible when dealing with a small, relatively local, specialty maker of precision products. And it helps a great deal that David Kirk is principled and conscientious. I enjoyed my exchanges with him, even though they arose as the result of a problem.

I very much doubt that any such manufacturing irregularity will occur again with the Kirk valve adjustment tool, therefore, I recommend it with no reservation, and I suggest that you buy one directly from him. A good tool from a good guy is hard to beat. 

I have no affiliation with David Kirk or his business. This might sound like a commercial, but it's just my honest story. You'll have to contact him to get info on this tool, because it is not listed on his main website.

His card, sent with the adjusted tool.

    

ADDENDUM  The tool in actual normal use - impressions.

Becoming familiar with the tool takes patience and determination, because the tool is not that easy to use immediately. You already know that it is tiny - and, therefore, just hard to hold onto, especially with oily fingers when doing the exhaust valves where you are upside down. Even with the intakes you must hold it firmly in place, because it will not work while simply sitting there as I show in one of my pictures. I discussed this with David Kirk, and he said that he is working on some evolutions of the tool, such as a very strong magnet built into the tool to hold it in place, but that has not happened yet. In the end it is usable, once you learn.

The last time I adjusted my valves I had the engine out of the car. It doesn't get easier than this when adjusting valves, especially if you have a rotating engine stand. Never mind, I got some of them wrong. I even borrowed a dial gauge from a friend, which showed me that I was adjusting to exactly .004" (.1mm). I found that gauge way too tedious and slow to use, so I reverted to using a feeler gauge. I thought I had them all perfect. This was not the case. There weren't any really loud valves while the engine ran, but still you could hear some of them too much. What I worried about were the ones I could not hear, because some might have been too tight and that's worse lest you burn those valves.

This means that my sense of 'feel' with the feeler gauge didn't cut it, or that for some mysterious reason gaps change after you have adjusted them. I don't know which, so I bought the Kirk tool in order to make my adjustments consistent, and I hope more accurate. Using a feeler gauge to check the gap after adjusting with the Kirk tool seemed to suggest that the 'feel' was the same, one valve to the next. That, and once learned, the process is faster. Plus, the valves at the front top of the engine, the ones that you can't see properly, were so much easier to do. I find it near impossible to get the miserable feeler gauge into the gaps of those valves, mainly cylinders 3, and 6 - with the Kirk tool you don't have to use a feeler gauge at all once you have gained confidence with the Kirk tool after doing the 'easy' valves elsewhere.

That said, I would be disingenuous if I were to say that I now trust the Kirk tool 100%, because my engine is still not running, since now I'm fooling with my transmission and other things. When I hear it run I'll know more. It will take a while, as it has been snowing heavily for the past two days and more might be on the way.

In the end, the tool isn't magic (what is?). It takes finesse, it still is somewhat subjective in use, but it is clearly faster, and it allows for adjustment of those valves that are impossible to do for an amateur who seldom does this type of work. If I were to immediately check them all again I would probably find some that are 'off', which would mainly be my fault. I am also convinced that if I were to check the valve lash clearances, and then go back and check them again without doing any adjusting at all, I would still get different results. Remember, Porsche's tolerance for error is +/- .02mm. I think I have those numbers correct, so maybe we fuss too much over this.

If you get one and have difficulty, talk to Dave Kirk. He communicates quickly and well.

ANOTHER ADDENDUM:  May 8.  Finally I got my car on the road today.  It runs and shifts okay, but after the careful valve adjustment I did, it sounds as if I have one or two loose valves!!  They are really clacking, so this means getting new valve cover gaskets, again, and going through the whole exercise, again. Damn. I thought I did a perfect job, double and triple checking, and there you are, noisy valves anyway. Likely this is my fault, but it's really frustrating. 

Later - Okay, so it's not all my fault, entirely. At least one of the valve adjuster screws evidently has a flaw, or damage, and this makes the lock nut stick on it at various places. Of course the damaged thread on the screw is right in the region where the nut resides as I attempt to critically adjust the valve, so getting a correct result to begin with is frustrating. And, then trying to hold an exact adjustment is the issue when the nut will not turn properly when snugging it up. Naturally, this is on the challenging to reach cylinder #6 intake valve which is awkward to begin with. Next time that the engine comes out I will inspect and change a few of my adjusting screws (which reasonably means changing the whole rocker arm in each case).

And, I just filled the engine with fresh oil and I didn't want it to go to waste if I had to drain it out to remove the lower valve covers to check adjustments.

First one side.

So I didn't drain it, I just tipped the car over, somewhat, so that the oil would run to the opposite side, and this allowed me to adjust on one side at a time without the oil coming out.

It's a simple trick, but try it if you need to get rid of a clacking valve and have brand new oil in your car. Make sure that your car is redundantly supported while on a tilt.

Probably my cylinder number 6 intake is the one that still makes noise. I must have done it over a dozen times.


For other valves, the Kirk tool does its job.

And then the other.

 

YET ANOTHER ADDENDUM:  An additional reason for noisy valves is worn valve guides. Yikes. It's not impossible that this is happening on a couple of valves in my car, so I'll have to check into it, and do something about this if necessary.  A P.P.S. at a later date:  A leak-down test showed 5 of the cylinders at a 2.5 to 3% leak-down, with the sixth a few percent more but still very good.  Therefore, the valve guides are fine.  It turned out to be a bad adjusting screw after all.

This video gives a simple preview, but it shows the process using the valve that is easiest to access: 

https://youtube.com/watch?v=o1H9WNRC_Yc