MTFCA Forum

My T sat for a while, and at least one of the valve seats got rusty and pitted. I have all new valves coming, and i'd like to clean up the seats also. I see various valve seat cutters on eBay used for under $100, but I'm leery. I don't want to spend $350 on a Neway tool that I'll probably never use again. Who can help me out?

Without knowing how much other work you plan on doing, my suggestion, if the motor is out, take to machine shop with one of the new valves and have the 3 angle seats done there. The 3 angle will give better sealing and flow.

The engine is not coming out. I'm just doing a ring and valve job.

I would still do a 3 angle grind. Find someone in your area that can come to you. Last 2 valves cant be done well without removing the firewall or pulling the motor forward about 5". Do the job right the 1st time.

I have lots of used valve seat cutters. They all have one thing in common: they're dull and very hard to get a good result. My advice, either pay to have someone do it right, or buy a new, high quality cutter and do it yourself. If you plan to only use it once, then resell it when you're done. How much is your time & frustration worth when you've spent $100 and the job doesn't last long or work well.

And, BTW, you've got lots of reaming to do in order to clean those seats up! A used, dull reamer will be something like torture by the time you're done.

I had forgotten that I acquired this machine last year from a friend. Do I need three angles, or is 45 sufficient?

Make sure the valve guides are not severely worn. I learned the hard way after grinding the valves and reassembling.
Grinding one angle will work, three angles are better for long life. If removing the engine, I suggest installing hardened seats.

Your grinder will do the 3 angles. I see a diamond dresser unit in the box. 3 angles will give you a defined width which has a concentric (top and bottom) seating area. So if the valve turns it will still be seating on a clean seat. The width and location of the seat is important too. Cast iron grinds fast, so short bursts and check often. Dress the wheels often as well.

I think the only way you'll be happy with a single angle job with the outfit you have is if you have extremely low expectations.

You will have a seat which will be 2-4 times wider than you want. Carbon chips will very likely keep the exhaust valve from seating occasionally, resulting in misfiring and eventually burnt exhaust valve(s). Even with the correct equipment you may find the valves so sunken into the block that it won't have been worth it...that is a lot of material to remove from those seats. With very low valve spring pressure, there is always a balance between having a seat narrow enough to enough pressure on it to cut through the crap that will inevitably end up there, and having a wide enough seat to cool the valve properly.

Suggestions to measure and maybe ream the guides is in my opinion a mandatory step. Then order the correct sized valves, send them to be "kissed" on the seat to remove any travel damage and finally a 3 angle seat with an interference seat (block cut with 1 degree tighter angle than the valve). This will give a good seal.

What you're about to undertake is no small task, as you'll need some sort of tooling to keep the reamer straight and concentric to the valve seat (they're piloted, but a lot of damage can be done if it's just free-handed).

Best of Luck.

When reaming valve guides i use tooling that controls the location of the reamer at a point about 2 inches above deck height. This point is established by using the grinding arbor.
The arbor is replaced with a bushing matching the reamer diameter.. The leading end of the reamer has a pilot. Consequently, the two points provide the alignment.
Art Mirtes

A tool like this is very helpful for reaming valve guides:

My grinder only has 45 and 30 degree stones, so a two angle valve job it is.

Your set has a stone resurfacer. It can be set for 60 degrees. Seat shown looks good, but is way to wide for reasons already mentioned.
You are 90% to doing the job right.

Need to see what the contact on the valve looks like. You have plenty of stones that can be dressed to the desired angle. The current contact width is too wide .

I'll keep working on it. I'll get it right.

GREAT. You have restored my faith.
Here's a bit more. Just kiss with the 60. Fine lap Valve & seat. Note lap line on valve. Should be too wide. Contact should be higher than center. On the upper half of valve, but not to top edge.
Intake contact area should be .060". Exhaust .080-.090".
You move(narrow) the contact area by grinding with the 30 or 60 degree stone.
If contact area extends low, narrow with the 60 degree. If high, narrow by 30 degree stone.
Remove very little at a time. Especially with the 60 degree stone, removes a lot of material quickley.
You can mute the lap line on the valve with a light touch of a fine wire wheel.
Do your finish lap. looking for consistent(even) contact & proper contact width on seat & valve.

If you want to check the quality of the job. Test with vacuum with valve spring installed.
Commercially expensive. I made one from a 1 1/2 pvc pipe cap. Cut o ring groove in the edge & hook up to a vacuum brake bleeder.
This was a hint from one of them montana racers. I have found a few that needed more lapping this way.
Good luck.

Thank you Speedytinc. I have the tools and basic skills to do this job. Your detailed tips are exactly what I needed, not people telling me to take it to a machine shop. I will dress a stone to 60 degrees, and do it right. I will post more pics soon.

sdbraverman wrote: ↑

Tue Mar 30, 2021 7:44 pm

Thank you Speedytinc. I have the tools and basic skills to do this job. Your detailed tips are exactly what I needed, not people telling me to take it to a machine shop. I will dress a stone to 60 degrees, and do it right. I will post more pics soon.

The only two post I see are mine and one other suggesting taking it to a machine shop or having someone doing it and that was before you posting you found the tooling that you forgot you had to do the job. Your first post indicated you did not have the tools to do the job and was trying to save some green.
I think it is great you are able to do the seats yourself. Great job!

Mark Gregush wrote: ↑

Wed Mar 31, 2021 10:12 am

The only two post I see are mine and one other suggesting taking it to a machine shop or having someone doing it and that was before you posting you found the tooling that you forgot you had to do the job.

Sorry, you are right. I originally asked this question on the HCCA facebook page, and was told by more than one person, that if I didn't know what I was doing, to take it to somebody that does. When I pressed that I wanted to learn how to do the job myself, I was told that early cars are very rare, and I shouldn't risk damaging it.

I am a shop teacher by trade, and I was a mechanic before that. I hate the attitude that a job is somehow so difficult that only "professionals" can do it. There are very few jobs on my cars that I won't tackle, but grinding valve seats is a job I have never done before. Now I am learning a new skill, and how to use a machine that was being thrown away.

Cool and thanks.

speedytinc wrote: ↑

Tue Mar 30, 2021 12:20 pm

GREAT. You have restored my faith.
Here's a bit more. Just kiss with the 60. Fine lap Valve & seat. Note lap line on valve. Should be too wide. Contact should be higher than center. On the upper half of valve, but not to top edge.
Intake contact area should be .060". Exhaust .080-.090".
You move(narrow) the contact area by grinding with the 30 or 60 degree stone.
If contact area extends low, narrow with the 60 degree. If high, narrow by 30 degree stone.
Remove very little at a time. Especially with the 60 degree stone, removes a lot of material quickley.
You can mute the lap line on the valve with a light touch of a fine wire wheel.
Do your finish lap. looking for consistent(even) contact & proper contact width on seat & valve.

If you want to check the quality of the job. Test with vacuum with valve spring installed.
Commercially expensive. I made one from a 1 1/2 pvc pipe cap. Cut o ring groove in the edge & hook up to a vacuum brake bleeder.
This was a hint from one of them montana racers. I have found a few that needed more lapping this way.
Good luck.

I realize that this is an old thread, but I am about to cut valve seats and I'm doing research. I bought a guide reamer, Neway 30, 45 & 60 degree cutters, solid pilots and I am in the process of making a reaming guide block to hold the reamer in proper alignment. I was having difficulty determining what is a preferred valve seat width.

J&M Machine recommends a width of .070" for all seats. Above, John says .060" intake and .080"-.090" for exhaust. I assume the wider exhaust seat is for better cooling. Is there a consensus that these are in about right? Wider seats for cooling seems logical. But a wider seat means more surface area for carbon debris to cause problems.

A valves ability to seal properly is a direct result of pounds per square inch of seat pressure. Since our T’s have very little spring pressure, the seat widths must be narrow to ensure a good seal. I usually go for about .060” on both, and am not bothered if they’re a little thinner

Suxty five years ago, i was taught by a truck and farm tractor mechanics how to grind valves and seats. They recommended .070 to .090 in. contact width. The contact should fall oi the middle of the valve surface. The valves were then lapped to the swat.
This was in the days when the engines were gasokine and hard working.

The common modern procedure is to grind the contact surfaces at one degree different. This is a lot quicker and is apparently adequate with hardened seats. I prefer to use the lapping procedure.

Others will have other thoughts, but that ok. The forum needs the discussion.

Art Mirtes

A plain cast iron seat might be expected to "wear in" a little and give a slightly wider seat after a few hundred miles. A hardened insert seat probably wouldn't.

Most modern “hard seats” are basically cast iron. The true culprit of the dreaded valve seat recession is insufficient valve material selection for the expected valve operating temperatures. A small amount of seat distortion/wear is to be expected on any new engine break in. The 1 degree valve to seat angle difference is to maximize valve sealing potential during start up

What you don't want is an excessively wide seat contact. Also, modern cam with a more aggressive profile might call for stiffer springs.

45* or 46* will clean the seat for the valve to seal, 60* will make it larger, 30* will make it smaller. the objective is to
put the valve seat in the middle of the valve face & thin enough to seal & make enough contact to cool when closed.
Hardened seats are not cast iron, replacement seats are, hardened seats are not serviceable with most hand cutting
tools ( stones are needed ) If you have to ream the valve guides you will find the small block Chevy valves are a little
more robust than ford valves and may help with deep valve seats. When it comes to valve springs stock T springs
installed height is not correct with Chevy valves but valve keepers are available to compensate. If you think you will
turn your T engine more than 3000 rpm model A springs are much stiffer than T springs are. And only a couple of
dollars more.
Craig.

Stellite 1234567890

Some engines have 30 degree intake valves Do these breathe better?

There are some diagrams and observations that you might find relevant in my video here https://youtu.be/WLcaqM89iQE

I use the Newark tools to make the seats right.
They are easy to use and make the job right.

Three angles : 45° for te seat; 15° for the top and 60° to finish the job.
Good luck
Andre
Belgium

Actually,....NEWAY,....jus' try'n ta' help,...

HI ; do one of you us this Ford Tool # 20-Z-340 .
Toon

ABoer wrote: ↑

Sun Nov 26, 2023 5:44 am

HI ; do one of you us this Ford Tool # 20-Z-340 .
Toon100.JPG200.JPG300.JPG004.JPG

Rounded valve seat cutter! First one I have seen. Really neat.