P & G Valve Gapper

Crankster

Crankster

Well-known member
Here is an interesting tool that used to be advertised when solid lifter engines were commonplace. Y block engines are spec'd for .019" cold .018" hot. Have always used a feeler gauge, or the "Walt Nuckels" quarter turn method, after taking up the clearance. The principle on the latter is based on thread pitch, similar to how a micrometer works. It is handy and quick. I experimented with both, the last time with using a feeler gauge. Tried setting them a "little" on the tight side at one point, but manifold vacuum dropped off a cliff. Valve hanging open. That'll never do. Loose isn't any good either, it beats the hell out of the valve train.

The feeler gauge method works fine, except high mileage engines can have a pocket worn on the rocker arms that makes setting a consistent gap with a feeler gauge problematic. I surmised the correct valve lash is important, but so is a consistent valve lash. When I (finally) found one of these tools at a decent price I bought it. This is the 111-F series 2, suitable for Y blocks. It is designed to be used while engine is idling, and would be very fast in the hands of an experienced user.

I opted to first use a remote starter on a cold engine just to see how close and consistent the valve lash were across all cylinders. Turns out, not very. I expected to see maybe .001" or .002" error. I was surprised to see more than that. Most cylinders consistently showed valve lash at .023", though there were two "fliers" at .025 and .027". Way too loose! There must be more wear on the rocker arms than I thought. This surprised me as there is no obvious clattering or valvetrain noise. So I went through all the valves and set them to .019" cold with this handy tool.

After buttoning up the valve covers took it for a spin. It idles smoother and has good low end grunt power in high gear and cruises noticeably smoother and quieter. This has me puzzled a little bit, for the camshaft gurus allow that valve lash can be varied slightly for more low end power. A looser valve lash within reason should allow for better low end.

A rebuilt engine with fresh rocker faces may not benefit from this tool but for consistent, right on the money valve lash across all cylinders on well loved motors this is just the ticket. Will you notice .001" or two one way or another - maybe not, but it's sure nice to know they are all correct without any guess or by golly.
 

Attachments

  • IMG_0010.jpg
    IMG_0010.jpg
    50.6 KB · Views: 103
  • IMG_0024.jpg
    IMG_0024.jpg
    62.2 KB · Views: 86
Years ago I was trying to find one of these. I always thought this was the most accurate way to adjust the valves. I do remember Walt's many contributions in the past. The quarter turn is also a good way to set the valves. I am hoping that someone re-pops the P&G tool
 
Well there are plenty of them out there, but they seem to want $150+ for them. They are nicely made and weren't exactly cheap when new. But the demand today is next to nothing.
 
Looking at ebay there are different models. How do I know what fits a Y block and are they complete?
 
They did make several different models. It's difficult to find much information on them. Gil Baumgartner has a page on them at the classic thunderbird site:

https://www.ctci.org/gilsgarage/ValveGapperInstructions.php

The model 111 is correct for Ford Y blocks. 111-F series 2 etc. He mentions looking for "1B" on the barrel, this must be an earlier iteration. I've never seen one. The other barrel and included parts aren't necessary or used for Y blocks anyway, afaik. The 300 series was a universal set with many different barrels for different applications. Maybe that's what the 1B references, I don't know.


"More than likely the best tool ever for adjusting the valves on the 292/312 engine was the P&G valve gapper. It is a dial indicator type tool designed to adjust the valve lash on several types of engines with solid lifters. This tool allows the gap to be adjusted precisely to the desired amount. A feeler gage does not compensate for wear because it bridges the gap and is almost impossible to get a perfect adjustment.

With the P&G gapper and patience the valve lash can be perfectly adjusted. The P&G valve gapper was made in the 50's and 60's and is obsolete, but they keep turning up at swap meets and usually in perfect condition."
Gil
 
Last edited:
I owned a P&G valve gapper and they are the most accurate way of adjusting valves.
If you adjust valves with a feeler gauge and I adjust with a feeler gauge we both feel two different clearance but the P&G was always the best way ,I just never understood what happened to the company.


Sent from my iPad using Tapatalk
 
True hydraulic lifters don’t need a P&G but there is still tons of solid lifter guys out there or roller cams that need a gap and even go no go feeler gauges don’t do what a P&G does!!


Sent from my iPad using Tapatalk
 
I don't have a price sheet, but it looks like they were around $40 to $45 in 1960, that was some serious coin for a fairly specialized tool that wouldn't be used all that much by an individual. Fleet owners and garages would have wanted them though, I think.
 
Pete F said:
If you adjust valves with a feeler gauge and I adjust with a feeler gauge we both feel two different clearance.
Click to expand...

I experimented a little with "tight" lash and "loose" within a certain range of feel. I wondered about that too, so I took a micrometer and set it to .019" on the feeler gauge blade and felt how much clearance there was. It's pretty tight actually. I think the key is that this device compensates for all the wear and variance, not just in the rocker arm wear but maybe slight difference in the cam lobes and whatnot. It's simply going to be more consistent across every cylinder.

What I noticed with the P&G was how much more solid the idle sounded. Definitely less vibration, not ready to balance a Nickle on the valve cover just yet but it crossed my mind at the time. And I had it tuned pretty well to begin with. Need to check manifold vacuum, and readjust the idle mixture on the carb probably.
 
The quarter turn past zero lash is for hydraulics, never on a solid lifter. The valve will not be seated
 
craig said:
The quarter turn past zero lash is for hydraulics, never on a solid lifter. The valve will not be seated
Click to expand...

Yes, it causes some concern when brought up. Here is the article that I referenced. It seems to work better than a feeler gauge, though not as well as the P&G valve gapper - assuming we're talking well used motors here, with significant rocker arm wear. When digging around trying to find info on the websites, I found a couple folks who posted their accounts, who were around when the P&G was new. The story goes that P&G wanted to get Ed Iskenderian to offer the gapper in his catalog. Ed had his mechanic adjust every valve + or - .002" from spec on an engine and they did a dyno pull, and then readjusted using the P&G gapper. No difference. Ed didn't put their product in his catalog. I think the issue is old rocker arms wear a pocket, new engines will adjust consistently with a feeler gauge. Most people won't care, and a thousandth here and there isn't the end of the world. But they do result in a smooth tune. I've found tuning is not any single thing but a whole bunch of things together, get all the tolerances stacked up as close as possible doesn't hurt anything.


------------------


Valve Lash

Y-Block enthusiast, let’s talk valve lash. As y-blocks have no hydraulic lifters, it is necessary to adjust the tappets quite often. Unfortunately, the use of a feeler gauge is satisfactory only if the rocker faces are in good condition. If the rocker faces have wear pockets, from contacting the valve stem, the use of a feeler gauge will provide results which are little better than calculated guessing, as the gap will always be greater than the thickness of the feeler gauge due to said condition.

About fifty years ago when solid lifters were most common, a tool was developed for adjusting valve lash, utilizing a dial indicator, called a P&G Valve Gapper. These tools were supplied with specific adapters for different makes of engines, including y-block Fords, by P&G manufacturing co. of Portland, Or., but to the best of my knowledge they no longer exist. Can anyone expand on the existence of this company or a source of this tool, or parts thereof? I have found a few at swap meets but not in the last decade. This is the finest tool ever developed for adjusting solid lifter equipped overhead tappets as anyone who owns one would testify.

For those of you without the luxury of such a precision tool, may I suggest a very satisfactory method alternative to feeler gauges anyone can perform without special tools.

The tappet adjust screw is 20 threads per inch thus 1 full turn
represents .050” of linear travel. It works just like a micrometer. Multiply 1 turn turn of travel times existing rocker ratio. Example, .050 ” X 1.54 = .077 ”. As you can deduct, one full turn of the adjust screw used in a 1.54 ratio rocker will represent .077” of tappet clearance. Now divide one turn of tappet clearance i.e, .077” by 60 as in the 60 minutes of a clock face. This number
is .001283” = 1 minute of clock face rotation. Thus 15 minutes of rotation will =.0192” Very close to .019” which is the specification for valve tappet clearance on 292 and 312 engines. 15 minutes clock rotation = 90 degrees rotation, an increment most auto enthusiast can easily estimate quite closely.

Get into the engine, with the lifter all the way down obtain some tappet clearance then carefully rotate the adjust screw clockwise to obtain .000’ valve lash. Just touching but not depressing the valve. Now rotate the adjust screw counterclockwise 90 degrees. The resulting clearance should be very, very close to .019” regardless of rocker arm face wear.

If adjusting 1.43 ratio rockers rotate the adjust screw 16 min. of rotation ccw. To obtain .01906” clearance. Very, very ,very close.

In order to determine the ratio of said rocker, observe the # on the side. 1.54 rockers are marked ECG 6564-B2 or –B1. I am led to believe any rocker with a B1 or B2 suffix will be a 1.54 ratio rocker and all those without suffixes will be 1.43 ratio.

Walt Nuckels 12/31/00
 
Last edited:
Today kind of messed with it to see how different methods of measurement work and whether there is any discrepancy in the indicated lash between them. With a given cylinder at TDC compression, both valve lifters should be on the heel of the cam lobe. This is how the clearance is measured with a feeler gauge, basically. This is a valid way to measure.

The 300 series "universal" gapper included a hook, so as to exert upward pressure on the rocker arm and take up the clearance. Then the dial is set to "Zero". The total lash is then displayed accurately. I also tried setting the lash at a slow idle. This didn't work as well as I thought it might. It's tough to read, and adjusting the rocker arms while they are moving is a pain in the ***. Overall it seems like using a remote starter makes the most sense. It would be easier on the starter, battery and solenoid to remove spark plugs.
 
Wouldn't a dial indicator placed on the valve end of the rocker arm and mounted on a magnetic base attached to the engine accomplish the same thing? I've always used feeler gauges, never had any issues that I'm aware of. Never heard of the p&g gapper until I read this and talked to some of my gearhead buddies that have been twisting wrenches on cars since the 60s and they were not aware of the gapper also.
 
Yes, if you can rig something up to be consistent that would work fine. If the rocker arms have been refaced or are new/in good condition a feeler gauge is all that is necessary.

Put a vacuum gauge on it today and it seemed slightly low from where it should be. I checked valve lash without using the remote starter or spinning the motor. I set them strictly using the unit as a dial indicator, without cranking or at idle. The key is getting a good zero. So I made sure on that, and just lifted the rocker arm and adjusted nut till the dial indicator pegged .019" cold. A few were definitely not where they should be. It takes a little skill to observe the oscillating needle when spinning the motor, and it might overshoot a bit. Have to play around with it to get a feel how it works. The 300 series included a camera cable to stop the needle on the high side for this reason. Will check engine vacuum and another test drive and see how this feels by the seat of the pants.
 
So after re-re-adjustment manifold vacuum came back up from kinda sorta 18" if I tweaked everything just so, to 20" steady at 600-650 rpm. Just one or two misadjusted valves will mess up manifold vacuum quite a bit. This is something to check after a valve lash adjustment no matter what the method. Runs smooth with a nice idle.
 
I have owned one for a very long time and couldn't bring myself to part with it, so now I use the dial gauge for my lathe and milling machine. I am not going to buy a mechanical cam just to use the gapper. I found it to be an excellent time saving too. In the early 60s, I first saw one used by a high profile super stock racer, and he was actually checking the lash between runs. He also took home the trophy. After seeing that, I had to have one.
Bob
 
When I started my first job in a garage back in about 59 or 60, we worked on so many of those old greasy pig engines, (mostly all there was) y-blocks were inclusive. My boss loved those things, but I always got stuck with working on them, and I hated them. Dirty oil smeared everywhere, all you had to do was open the hood, and you were dirty. Stupid spark plug wires, Stupid timing chain marks, stupid wheezy starters, stupid rocker arm oiling, stupid distributor ALWAYS seized in, stupid rear main leaks, etc. and all of this compounded by that filthy black 30w no detergent oil that was everywhere. Nice sound out the back tho, when they ran good. I could never bring myself to own one, even tho I liked the car itself. Several of my friends owned them, and would grenade the engines on purpose so they could install FE engines. Whatever. Anyway (whew!) we used the PandG valve gapper exclusively on all the solid lifter engines. Our tool was in a large kit box, and there were adapters to fit the different springs to the same tool. It worked great, and any shop at that time that was worth a ****, had one. Yeah they were expensive at the time. If you could get one for a couple hundred bucks, it wold be a good investment. They broke easily, so if you bought a broken one, I would think it would be the majority of them out there for sale, as I'm sure the good ones are few and far between. I broke ours several times, and the boss would get so POed at me, as it had to be sent in to be fixed. What usually happened, I didn't get the spring loaded part of it on the valve retainer good enough, and the thing would fly off, and that would be the show. They were kind of delicate, and it didn't take much to mess one up
 
I can see the idea is that the unit is installed on each valve assembly while engine is idling, adjust valve, and move on to the next one. Both quick, and accurate. But I had a hell of a time trying to read that thing while it's bouncing up and down. Maybe I should have tried turning the idle RPM down super low, to the point of almost stalling. I think it was about 600

There's also two ways to set the barrel in the unit, by means of a pin. This decreases the spring tension quite a bit by extending it longer. I think the heavier tension setting seems to work a little better, but the unit also seems to want to rotate when engine is idling.
 
You must log in or register to reply here.
Back
Top