Question on New Modern Valve kit's

[Jim Cten]

There are alot of supplier's offering the new Modern Valve kits. At all differant price's Are they all selling the same kits? I'm building a new Burtz block and want to make sure I'm buying quality parts. Any suggestion?

Thanks
Jim

[Ernie Vitucci]

Good Evening...If you deal with one of the major Model A Suppliers, you should be fine. Brattons, Snyders and Burts come to mind at the moment...stay away from 'Low Bid Louis' that fellow has ruined many a good engine...Ernie in Arizona

[alexiskai]

The main difference is the valve guides. Snyder's sells a set that uses a one-piece replacement for the original guides, which have a shoulder that the spring rests on. Bert's sells a set with straight guides. The spring tension will differ between the two. The Burtz builder's guide should specify which guide shape is preferred, I don't remember offhand what it says.

[nkaminar]

If you have questions call or email Terry. Here is what the engine builder's guide says about valves:

Valves

Two-piece original, one-piece with shoulder, or press-in valve guides
with appropriate valves can be used. We recommend that the valves be
lapped using Permatex 80036 Valve Grinding Compound.

Oversize intake valves can be used; however, your warrantee does not
cover poor machine work. The thickness of the upper surface of the new
cylinder block and an original cylinder block are identical at .375 inch.
The ports can be smoothed, but the walls are only 5/32 inch thick, and
the removal of material is not warranted.

To verify that the valve seat is concentric with the valve guide, make
sure that the cylinder block is vertical and then drop a valve through the
guide. If it bounces, everything is concentric. If it doesn't bounce,
something is not concentric.

[alexiskai]

Remember too that the cam you use may work better with a particular spring pressure. Here's an older thread about the best spring pressure for different cams, and some ways to get the pressure you want:
https://www.fordbarn.com/forum/showt...7816&showall=1

The press-in guides will give the lowest spring pressure, and then the one-piece with shoulder, and then the shoulder guide with a spacer installed will give the highest. After that you're looking at aftermarket springs.

[Jim Brierley]

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I prefer the 1- piece with the shoulder, this insures the guide will stay in place, and you don't loose spring pressure as you will with straight guides.

[BRENT in 10-uh-C]

I almost hate to get involved in this because Terry took offense to my comments in a previous post, but this is the very reason why I feel I would want to do the machine work from 'A-Z', -and not rely on Terry's machining. However, against my better judgment I will begin with some thoughts on the above.


I buy my valves from the same supplier that many vendors get theirs from. These are production grade, offshore-manufactured valves that have tolerances that I have found to be all over the place. In other words, my experiences are the concentricity of the valve's face can have runouts of up to 0.005"+ difference between each of the valves in the set. The face angle also can be off by a few tenths also. (-this is not uncommon with replacement valves for modern engines too!) Therefore, a good engine rebuilder with good equipment will always reface new valves he is using to ensure concentricity using the stem as the baseline. My valve grinding machine will hold a tolerance of about 0.0007", -and although my machine is good, it is not as good as some of the machines out there that can produce numbers below 0.0005". So my point is, you honestly do not know whether your brand new valves will be concentric with the stem, -and/or concentric with the seat.

Next, we get into dead pilots vs. live pilots ...and machining with 'no pilots'. I have no doubt that Terry's machining center can produce a valve seat that is indeed concentric with the valve guide bore, -however, knowledgeable engine machinists will tell you that at minimum you must have the valve guide installed which will be used for that valve before the seat concentricity can be established. Folks, it really does not matter who's guide is being installed because, the one-piece guides are installed with an interference fitment, and most two-piece guides are way off. Therefore, because the way these guides are installed, the hole in the guide will generally never be concentric with the seat in the block. Additionally, when these one-piece guide are installed into the bore of the block, it generally always distorts the bore of the guide. A good machinist will check this and then hone the bores to around 0.0015" clearance from the stem measurement. If this operation is not done, the likelihood of the valve's face being concentric to the seat is not very good. And, ...just so we are clear, the industry standard for the maximum amount of runout allowance (-lack of concentricity) of a valve to its' seat is less than 0.002". This maximum number is about the same thickness as what a human hair is!! Good engine machinists target (-and achieve) concentricity numbers of less than 0.001".

So you may ask, what does concentricity matter, ...and that is a fair question. Before valve seating tolerances became something that had close attention paid to, the valves would land all over the place in a seat. As such, higher valve spring pressures were used to slam the taper of the valve face down into the seat in order to get a seal. These higher spring pressures are not needed as long as the valve does not 'float' without control, which on a L-head engine with a vertical valve, gravity is on your side with regard to closure. Also, the sloppy valve fits allowed the valves to have poor seal which then caused a term that many called a "burnt valve". For the past few decades, engines that rarely see a 'burned valve' and the serviceability of engines valves going 150k miles is considered normal. This is solely due to concentric valves to their respective seats. One final thought on this, the bounce test can be fooling as a rough seat or valve face will bounce yet will not seat. Again, this is where a knowledgeable engine machinist that has the proper method of checking concentricity with a gauge, and uses a vacuum pump and port flange to get a good leakdown reading is invaluable for having a long-lasting seal.

[Jim Cten]

Thank you all for replying. I have one of Terry's camshafts on order, so I will wait and see if they come out with a recommendation

Thanks again
Jim

[nkaminar]

Neway makes a set of tools for cutting the seats. It is worthwhile to visit their site as it has some good advice. I have used their tools for cutting the seats on a Model T and it worked well. The Neway cutter indexes on the installed valve guide. As Brent said, the valves can be ground concentric by a qualified machine shop.

See https://www.newaymfg.com/cutters.

[KR500]

Brent, for many years I got used to using Hall Toledo seat grinders. In the tool maker trade I am in a jig grinder was generally always used to finish precision holes using an eccentric spinning abrasive stone. It was better at keeping the stone sharp, not loading up and creating less heat. I have done valve jobs using both a 19/32 solid tapered pilot and a 5/16 taper pilot directly in the installed guide and reinstalling the 2 piece guide in as close to the same position I finished the seat in. What are your thoughts?

[Terry Burtz, Calif]

Brent,

Thanks for your comments.

We have supplied hundreds of "New Engine Kits" to our customers and nobody has reported a problem with valves.

For credibility, we had the engineering evaluation engine assembled evaluated by an independent 3rd party. The 3rd party was Bert's in Englewood, CO.

We supplied the "New Engine Kit" (Cylinder Block, Crankshaft, and Connecting rods). All other parts were either new and "off the shelf" or they were "good used parts" that were cleaned up and painted.

When we arrived in Englewood, CO to observe and assist in the assembly, Steve Becker's mechanic Dan had already chosen to use the AER valve kit with solid press-in guides, and the guides were already installed.

We were curious as to seat width and where the seat was located on the face of the valve, so we applied permanent marker ink to the valve faces and had Dan use some lapping compound and lightly lap the valves. The time spent lapping each valve was about 5 seconds.

The marks on the valves were centered on the valve faces, the seat widths were consistent at about 0.077 inches wide, and there was a continious 360 degrees of contact.

I was concerned about valve spring tension with a valve guide that didn't have a shoulder. A call to AER assured us that the valve was cut to the proper length and the keeper groove was moved upwards to compensate for the lack of a shoulder on the valve guide, so valve spring tension is the same as the original.

The first machine cut on the "New Engine" cylinder block casting is to machine the bottom surface (where the oil pan attaches) and 2 dowel pin indexing holes.

The bottom surface and 2 dowel pins are used to locate the cylinder block as it progresses through several CNC machines and line boring.

The accuracy of all machines that machine the "New Engine" Cylinder Block is guaranteed to be +/- 0.01 mm (+/- < 0.0004 inch).

If they were quality, I would like to use the split guides or the one-piece guides with a shoulder that you like.

Why are you buying guides and valves that have so many problems? The valve kit from AER had no problems.

Our guarantee does not cover modifications to the cylinder block to accommodate valves and guides that are not concentric.

[denniskliesen]

All above as stated by Terry Burtz I have found the same results with AER valve kits. They fit well with the seat being concentric with the face. The guides go in with no problems as long as you have the correct tools to install. The easy way to install the spring is using a C clamp type valve spring compressor. I fold a heavy piece of cardboard on top of the block so the spring compressor doesn’t mar the top of the block.

[alexiskai]

What tools are needed for the press-in guides?