Please see my enclosed pictures and advise me as to whether or not I'm going about this right...
I assume that the bored holes right at the top deck of the engine, that the valve chamfer goes into, are a datum that the guides are referenced off of (or vice versa), so I used them for my "centering" feature on the base. The base to my pilot piece is .0002 TIR and lapped to each other and are a firm hand press fit to each other, and perfectly perpendicular to the base's bottom or "face".
My test "skritch" with the reamer shows a nice clean diameter being cut in the old worn guide area.
The question arises, that the forward 4 valves have a counterbore of 1.312 as I recall, and the rear 4 have a counterbore of 1.320... 0.008" larger. I therefor made two bases, to fit each counterbore. I'm wondering if this is the way to go or to have my bases be a little loose and allow the reamer to float a bit.
My new shop has no 220v yet or I'd do this on my mill and indicate everything, so this is my backup plan.
And I'll add that I used pictures of the Steven's valve reamer guide as my "guess" that the bore at the valve face was what they were using for a datum...While my engine does not look like it's been hacked on, I've seen goofy valve seats on other engines and am leery of using the 45 degree seat as a datum...
Eric B and others have posed good pictures and words that I have used to make my tool...but pictures and guesses are the best I have. I was particularly surprised to see that the original counterbores varied by as much as they did...and did it as batches, to boot.
Your set-up is very similar to a Stevens Oversize Valve Guide Reamer Kit - somewhere I have the Stevens number - nice job there !
Where did you obtain the information regarding the #'s 3 & 4 being a larger size ? I would consider that you would prefer minimal "float" which could be verified after re-cutting the valve seat then bluing in the new valve.
thank you for the picture and info...I actually measured each counterbore and found Cyl #1 & 2 to have one value for the counterbore and Cyl 3 & 4 were all definitely larger by .008". I was really surprised by that and drove me to make a separate base to account for that.
From the good picture you posted it really looks like the guide centers on the same feature mine does. Your original reamer has nice short edges and a nice long body...the reamer I bought has the opposite and that drove the long pilot that I made...I would have preferred it to be shorter but so much of the flutes stuck up past the deck, I had to counterbore the guide a bit for clearance for when you first start off. Could I trouble you to measure your base's pilot diameter and post that value? That would tell me if I should have very little or a little bit of float at the base to the guide datum. Right now, I have .002 clearance between the guide pilot and the counterbores in the block. Thank you.
Oh, and this is all a precursor to recutting the valve seats for a concentric and consistent seat face.
Unfortunately, that is not my Stevens kit (T-245) Scott ! A fellow on the Forum posted it a while back inquiring as to just what it's purpose was - he wasn't aware that it was even a Model T tool. Unfortunately for me, he would not let me purchase it !
I do a considerable amount of T valve work and would love to have that set but I'm utilizing the current Neway set up with expandable pilot reamers - just finished a block for Chev. S.S. exhaust valves and they blued perfect !
I love my Neway valve seat cutters...fast, easy, accurate!
I've found that T's either have worn out seats or butchered seats and the fastest easiest boost to performance is putting them right.
This is a little project for myself.
I have used our clubs Stevens tool as shown above. I don't at this point recall having any issues with different size holes, it fit them all. I made a similar tool a couple of weeks ago, mine is sure not that nice but I hope it works.
Guess what you could do is take of piece of rod the same diameter of the old hole(s) and use it for a guide to center the plug when installed in the head. Checking to make sure it's at a right angle to the deck. I have also just used the piloted reamer without a guide back in the days when I did not know better and the holes come out ok.
was the fit a loose or close fit on the holes?
thank you for your info.
I made a tool similar to yours Scott, I've done two engines and had no issues with the valves.
Good to hear, Philip
Scott, It has been more then a few years, sorry don't remember.
I like to use a knurling tool and then ream the guides. That way the knurler makes the hole smaller and leaves a spiral groove for the oil so it can lubricate the stem better.
But how are you "centering" the knurling tool, Frank ?
If the the valve rotate as they should from the action of the cam then in reality the holes should worn round. The movement of the valves is straight up and down. Of course things like a spring that is putting more pressure on one side, end of the stem not ground flat, the spring retainer cocked to one side sitting on the little pin or a small bend in the stem can change that. How many valves have you pulled and seen one side of the stem more worn, I am sure more then a few. Could be the holes are worn hour glass shaped but still on center. Maybe as coming from the factory the wide seats were less of and issue them how some like to do it now with the narrow seat.
Well, it's an unqualified success! Tooling has been heat-blued for rust prevention and placed into service.
After use, new valves drop in and print with bluing on the old valve seats (which still look darn good), so my suspicion of the counter-bore and the valve guides being dimensioned off each other was right on (or not far off).
Now for a light kiss with a Neway cutter to put the proper angles and seat width and I'm off to the next project.
Thank you to the respondents for your advice and pictures. It was well appreciated.
Knurling arbors and reamers both follow the existing hole. There is no "centering" them. They center themselves. If you lean a bunch one way or the other with whatever you are driving them with, of course you will have problems, mostly broken tools and oversized holes. I just chuck them in a drill at low speed and let them do the job. No oil for reaming cast iron, and special lube available for knurling.
I used the self centering reamer and had good luck with the results. Perhaps if the guides were very very worn, results could be less reliable?
Here is a link to photos of my valve project. Made a big difference having valves that fit well. Took the opportunity to use all new springs and keepers as well as stainless valves, adjustable lifters.
You can see how the oil had leaked by the intake valves and caked all over the intake chambers and valves, combustion chambers, etc. Was nice to get to clean all that out. Also used a Stipe 280 cam. After all the work I had a sore back and Lizzy ran much better.
Thank you guys. I do realize that the piloted reamers are made to follow the hole, but having had to recut valve seats in the past due to very poorly executed valve reaming in prior years, on other cars, I was concerned about doing the same to my car, or at least ending up with slightly oversize beyond 1/64 over is the reamer was allowed to wobble freehand. Perhaps I am into "overkill" land, but must say I am very happy with my results. As found, the engine had new standard valves, unworn, in worn out guides. Now the new (my purchase) 1/64 oversize valves are a dead drop in the newly reamed guides and all print very well on the original valve faces. I am still not convinced that doing it freehand would have resulted in that accurate of a location, but I am not here trying to pick an argument, either. Just not sure, and wasn't inclined to find out!
Glad it worked for you. Results are what matters. Anything you can do for greater accuracy can only help.
Very interesting subject - I'm in Scott's "camp" concerning accuracy - I've been in a situation where the previous "mechanic" obviously free-handed the reaming of the valve guides and failed to remedy the "missing" issue !!!
Scott, thanks for the report. Seems I am on the right track making the plug to fit the hole so the ream would track straight.
Mark - anyway to access and get an accurate measurement off your Club's Stevens centering plug ?
What Scott did certainly won't hurt. In the case of non-piloted reamers, they will still follow a hole that isn't true. That is why in toolmaking a drilled and reamed hole is not as well done as one drilled and bored with a single-point tool, but that level of work isn't usually called for with engines. The hole will be round and to the size of the reamer, but not necessarily straight. Piloted reamers are mostly an automotive machine thing and they do help to a degree with the tolerances called for in that line of work, but I think largely the pilot is to help the operator keep the reamer square with the hole when operating freehand or to quickly line it up when using a press (e.g., not indicating in each hole). Also think about this -- most of the time when we're doing this stuff, we're oversizing valve guides because the guide is worn out, so the pilot on the reamer tip is of little relevance as far as making the reamer track straight depending on the amount of wear. It's going to go where it wants until the pilot hits the side of the hole.
Scott's set-up is good because the reamer would have to "bend" at his guide rather than at the chuck, so if the feed is light enough, it probably does help keep it true to the deck to a better degree and would even if his reamer were not piloted on the tip.
Well said Walter. We're on the same page. Your submission is much clearer than mine on the details.
Thanks. I see your earlier post now. Didn't mean to step on your toes, I was kind of skimming things over quickly. You already covered it.
that is how I made my counter-bore seat and the pilot that goes into it. Drill, bore, ream the last few thousanths.
I additionally lapped the reamed holes to get rid of the .0002" taper that the reamer left in my base...I think my turret is a little off. I ended up with a .5630 - .5632 tapered hole where I was desiring .5625 from the reamer. That got lapped straight and round and the pilot OD was turned and lapped to be a dead fit with a gentle hand push...sort of like a firm wrist pin in a piston. If not for the fact that I made 2 bases (with different OD), I wouldn't have been so fussy with lapping everything to identical sizes...I'd just have matched the pilot to the base and been done with it. It was a nice project with good results. Great to be retired now and spend time doing things no one else in their right mind would spend the time on...
Please understand, in no way am I criticizing your work. Most things can be drilled and reamed and come out fine so long as care is exercised. I was speaking more of how reamers behave. If you're really working in "tenths", that is well beyond most specs for engine work and the rigidity of your set-up is where it really shines. Like Erik said, results are what matters.
no offense was taken. I just decided to expound on how I made my tool based off what you had written. It was all about making the pilot and the base act as "one" assembly as though it was turned from one piece. No way was the final job done to tenths...I got what the reamer gave me...
I appreciate your and everyone else's comments
Wanted to add these findings regarding a bare block waiting for me to learn how to pour bearings - I checked each valve opening I.D. with my telescoping gauge & micrometer and this is what I came up with: #1 - 1.308, #2 - 1.313, #3 - 1.320, #4 - 1.313, #5 - 1.317, #6 - 1.315, #7 - 1.318 & # 8 - 1.316 ! How's that for a small amount of variation ? Comments ?
The more the wear, do you find them to be more hourglass shaped top-to-bottom or are they pretty consistent along their length?
They all seemed to be pretty consistent around & down the length of the opening, Walter - the area below the "seat" really not an area susceptible to wear that I can determine.
Been my experience the valve guides wear in an hourglass shape
I'm referring to the circular area just below the valve seat - not the guide itself. The tool Scott machined & the Stevens tool is to "center" the reamer to insure accuracy for the most part.
Yep, I goofed in reading those as guide dimensions. My eyes blocked out the 1. part and only saw the numbers after it. Amazing how the brain can screw with you like that!
Scott, how much larger, if any, is the finish size of the guide as compared to the diameter of the reamer? Is the guide tapered at all?
Steve, if there is that degree of difference in the diameter of the seats, seems like using the centering guide is a lot of work for questionable results. I am thinking that the slop in the fit would allow wobble of the reamer, especially if you are using a drill or mill to power the reamer.
The guide ID is .001 larger than the shank of the reamer. The pilot length is about 5/8 - 3/4" long at the top of the guide (the lower portion of the guide is opened up for clearance of the reamer's flutes). The guide is not tapered. I reamed by hand with a tap wrench. I ended up with 7 valve guides that are very close fits with little side play when checked by hand. Valves plop down and bounce in their seats. One exhaust valve is in my opinion too tight as there is no detectable side play when extended. I have not ball gauged them but to answer you completely, I will and will post.
I can tell you that there is NO excessive clearance of installed valves. This is not surprising, particularly when I expected the o/s reamer to be 21/64 (.3281) when in fact after the job, I saw printed on the side of the reamer ".327". It will be very interesting to see what the ball gauges tell me.
Knowing now the wide variation of counter-bores based on my measurements, and particularly in light of Steve T's findings, I believe that my dimensioning the base to be a close fit is not a good plan for a useful tool across the range of T's to be found. My guess is the Stevens tool is well undersize and the user simply "feels" for the hole with the reamer's chamfer. The pilot of the reamer will find the hole, and the chamfer on the leading edge of the flutes should do a good job of finding the geometric center of the worn hole. Regardless, I am pleased with the results that I got.
I was also quite surprised of the counter-bores variations and I also hand ream my guides as I have no mill.
I have several more bare blocks and am going to check the counter bores to see where they stand. I find this a very interesting subject as Stevens is known for producing very accurate and useful tools for Model T's and then some.
I have yet to see or find any instructions to correctly operate the T-245 tool kit but one might surmise that one simply sets the mandrel into the valve counter bore, installs the reamer to evidently "self-center" then tighten down the collar clamp ????????
I believe not all Model T owners "in the day" brought their T's into the Ford Dealer for service or the market for DIY tools wouldn't have been so enormous - granted we expect a great deal more out of our engines than they did partly because of the road conditions and we seem to have a tendency to run them a bit faster & higher R.P.M. !
To make a tool to account for the variation in the counterbore, the piece that goes into the counterbore could be made with a very slight taper to account for the variation you have found, then make a ring that goes around the o.d. of the tool that is a slip fit and it would sit flush on the deck. The taper would center in the bore and the ring would hold the bushing square to the block, the ring purely being necessary because working with a taper you would have a constantly varying depth with a fixed shoulder tool.
Has anyone verified that the counterbore that's being used for reference is even 100% concentric to the guide? Part of the reason we have to expect more out of our work now is we're undoing old repairs incorrectly made. If you have an engine with several valve jobs on it the seat and/or valve center-line can get moved around quite a bit. Modern engine shops aren't as concerned about these things because they are almost 100% dealing with replaceable guides now, so they have a constant datum point to reference when they punch out the old one, press in a new one, and they are reaming something that's already in the center. We don't have that luxury.
If you really wanted to get down to it, the correct way to renew badly worn guides in the right location would be to get a print of the block, find the datum point, locate the first guide, bore it with a single point tool, and go down the line with each of them with the block indicated in. How many blocks have we seen where the seat is way off when cutting it or the valve stems hit all the lifters differently? That said, for what a Model T delivers, basic valve work is usually good enough.
I have some copies of pages from a Stevens catalog. Bummer, I think the page that shows the tool is missing. I do however have a reprint of the 1926 KR Wilson catalog. It does have the page for their reamer and guide. It is a flat plate that bolts to the block using the head bolt holes with a longer cast guide. The instructions say; The pilot(reamer pilot) automatically locates the reamer in position before permanent guide is fastened. The spiral flutes cut freely with a very smooth finish.
My best guess is, both units had some float and once the pilot was centered in the hole they were locked down and the hole reamed.
Thanks a bunch for your input Walter - clearly, you have mechanical engineering or machining background.
Looking at the photo of the Stevens tool above, one can see a taper on the centering mandrel (for lack of the proper term) but I have never seen this tools installed on a block for reference.
Anyone else have a bare block laying around and the tools to measure the counter-bores for a general consensus ?
that taper is just a fancy turning job to get down to some smaller diameter...it appears to have no useful mechanical function
If you will look at the picture, also, you'll see the reamer is already doing it's work, so to fully withdraw the reamer to start the work, the guide must be relieved on the ID at the bottom to clear the flutes, so the actual "guide" ID of the tool must be quite short.
Thanks for showing that page. It is one that I am missing. My copies of pages ends at 39!
Did you get a hold of Keith?
Thanks for the kind words Steve. I just say that I'm a recovering machinist and leave it at that. Checking a clean 1918 block that I have here, just doing it quick with calipers, the counterbores range from 1.311 - 1.319, about the same range as yours and most with the same median size as what you found. Apparently something they didn't put too much effort into and I'm sure they had some sort of gang machine cutting them all at once, so maybe they used reground cutters without worrying about holding a specific size. There's probably a photo of the machine out there somewhere.
A 0.312 gauge pin fits these guides very nicely, so this engine must be fairly low mileage. I put a gauge pin in each guide and it's about 0.500 from the pin to the counterbore, so I took a 0.500 gauge pin and swept around the 0.312 pin and on all of them, on one side it's tight and the other it's loose. Checking more carefully against the pin with a small hole gauge, it measures different from the counterbore by about 0.005 to 0.010 going around the pin (note: that doesn't tell us whether the guide isn't square or the hole is off-center, more likely the latter, which would mean 0.0025 - 0.005 off the center). When you consider the kinds of production speeds they were running and the fact that the valve allows for a couple thou clearance itself, that's pretty decent. Obviously, it worked! If you can get a rebuild closer, all the better. At least in a case of badly worn guides, that gives the rebuilder some kind of tolerance to shoot for.
Lifter bores aren't usually as bad as the guides. Most of this tooling was made to ream guides with the rest of the engine still assembled. If you have the block disassembled and worked up a special purpose reamer, it would also be possible to attack it from the bottom by making a bushing to use the lifter bore as a pilot. It would be neat to take some measurements that way and see how well aligned the whole works are, but my engine here still has the bottom end in it.
Appreciate all of the input, fellas ! Nice to hear other opinions about this subject - I for one am quite a "stickler" for getting the best & most out of my valve work !
Yes Mark - I spoke with Keith - thanks !
And finally, I think somewhere I said I'd post the actual diameter of the reamed hole, so here it is: Reamer diameter is .3270, the hole it made is .3275 (consistently across all eight holes)
Since the question was asked earlier, I figured I would put my $.02 in.
When I started making solid copper head gaskets years ago, I plotted several T blocks. You have to remember that these valve pockets were machined using an "all on one" form tool... Or rather, 8 of them mounted on a gang drill. This gang tool would have drilled the valve guides, roughed in the valve pockets, and possibly finished the seats too. And I'm sure this operation was completed in just a couple minutes or less. Not much time was spent worrying about achieving the "nominal values", but rather "within tolerances".
I don't have my numbers from 10 years ago in front of me, but I do remember very clearly being amazed at how far out of position all of the valves were. There were no 2 valves in line with one another... Cylinder bores either! Or head bolt locations...!
These were not intended to be machines of excellence... They were machines of utilitarianism and functionality. The technology of the day restricted potential quality. In all reality, the machine work was as good as it needed to be, in order to be predictable and reliable (relative term of course ;) ).
"These were not intended to be machines of excellence... They were machines of utilitarianism and functionality. The technology of the day restricted potential quality. In all reality, the machine work was as good as it needed to be, in order to be predictable and reliable (relative term of course ;) )."
Iím pretty sure that valve & tappet guides were broached at the factory. Not reamed.
In order to broach the hole it would have to be drilled first almost to size. ?
Modern engine rebuilders don't like to throw any old parts away. They grind the valve stems down until they are perfectly round with no taper. Then they take a new Bronze valve guide and drill a hole right through the old valve stem hole and thus enlarge it enough to set the bronze valve guide into the hole. Then they use an internal hammer to swage the new bronze insert in to the hole and lock it in place. Then they ream the valve guide to the proper clearance which usually about .0015" fit on the stem. Now they have a true smaller valve guide made of bronze. They then put a guide post into the hole and fit a valve grinding stone and tune up the valve seat. They insert the valve, Spring, and keeper. These were overhead valve heads and I suppose that a flat head would have been more expensive.
These bronze valve guides are at times knurled and then reamed to size in order to provide better lubrication on the valve stems. The valve guides can also be fitted with oil proof rubber nipples which wipe excess oil off of the valve stems. I don't know the current price of the process but in the late 1980's it was $2.75 to purchase and install the bronze guide, ream it and resize the valve stem. Those were wholesale prices that I paid in those days so I used to pay $44.00 for a V 8 valve job and an extra $10.00 to clean up the mating surfaces of the heads I took the heads in clean and got them back assembled. The builder friend of mine did 400 engines a month and I had to wait until they did the set up for my particular engine model. It would have been far more expensive if I had needed a quick turn around.
I had a four cylinder Mercedes Benz and it accidentally got filled up with no-lead gasoline by the full service Shell station attendant. All of the valve seats and valve faces burned within 20 miles and had to be refinished and the shop did it for me while I was at work teaching a Technical Writing class and charged me $1.75 a hole on that little 1900 CC four cylinder engine.
It pays to have connections or a box of tools like the ones that I acquired later on for $100.I also had a valve grinder for the seats but not the stems.