Valve Seats

Discuss all things Model T related.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules

Topic author
GG Gregory
Posts: 295
Joined: Sat Jul 20, 2019 3:05 pm
First Name: GG
Last Name: Gregory
* REQUIRED* Type and Year of Model Ts owned: 27 Roadster
Location: Maryville Tn

Valve Seats

Post by GG Gregory » Tue Aug 09, 2022 6:46 am

Which angle of cutter is used to just clean up valve seats ?

User avatar

Tim Rogers
Posts: 387
Joined: Sun Jan 06, 2019 11:04 am
First Name: Tim
Last Name: Rogers
* REQUIRED* Type and Year of Model Ts owned: 1925 Coupe & 1923 Runabout
Location: South of the Adirondacks
Board Member Since: 2013

Re: Valve Seats

Post by Tim Rogers » Tue Aug 09, 2022 7:19 am

Original Model T valves are at a 45 degree angle which means the seats get cut at 44 or 44.5 degrees. Hope this helps!


seat.jpg
seat.jpg (9.5 KiB) Viewed 1413 times
<o><o><o><o> Tim Rogers - South of the Adirondacks - Forum member since 2013 <o><o><o><o>


Topic author
GG Gregory
Posts: 295
Joined: Sat Jul 20, 2019 3:05 pm
First Name: GG
Last Name: Gregory
* REQUIRED* Type and Year of Model Ts owned: 27 Roadster
Location: Maryville Tn

Re: Valve Seats

Post by GG Gregory » Tue Aug 09, 2022 7:34 am

Thanks Tim, where would a guy find the tool? I don’t think the Vendors sell things like that


Kerry
Posts: 1297
Joined: Mon Jan 07, 2019 2:42 pm
First Name: Frank
Last Name: van Ekeren
* REQUIRED* Type and Year of Model Ts owned: 1916 touring, 1916 pick-up, 1924 coupe, 1926 touring, 1927 touring
Location: Rosedale Vic Australia

Re: Valve Seats

Post by Kerry » Tue Aug 09, 2022 7:44 am

With out spending a fortune, Ebay has sets made in India, work OK on cast iron but not to flash on hardened seats.


Topic author
GG Gregory
Posts: 295
Joined: Sat Jul 20, 2019 3:05 pm
First Name: GG
Last Name: Gregory
* REQUIRED* Type and Year of Model Ts owned: 27 Roadster
Location: Maryville Tn

Re: Valve Seats

Post by GG Gregory » Tue Aug 09, 2022 7:53 am

Thanks Kerry

User avatar

BRENT in 10-uh-C
Posts: 226
Joined: Mon Jan 07, 2019 11:21 am
First Name: Brent
Last Name: Terry
* REQUIRED* Type and Year of Model Ts owned: 1909 Tourabout, 1914 Runabout, 1915 Touring, 1916 Speedster, 1925 Speedster, 1926 Hack
Location: Eastern Tennessee
MTFCA Number: 32295
Board Member Since: 1999
Contact:

Re: Valve Seats

Post by BRENT in 10-uh-C » Tue Aug 09, 2022 8:24 am

GG Gregory wrote:
Tue Aug 09, 2022 7:34 am
Thanks Tim, where would a guy find the tool? I don’t think the Vendors sell things like that
It really is not that easy IMO. I say this coming to you as a professional engine rebuilder near you however this tool that is referred to requires other things IMO. To begin with, I am unsure if you are touching up seat faces or whether you are cutting seats to remove damage. Cutting a seat face requires a carbide cutter that has rigidity. You really do not get that with a cheap-style cutter, and what you often get using these is a seat that has chatter marks that often leads to the valve's face not sealing well to the seat. More on that below.

If you are only touching-up a seat, then using a rock to stone the seat is the quickest way to a nice finish however you must also have a mandrel to pilot from. These pilots use the valve guide area of the block to center with, and I feel you need mandrels in multiple sizes (+/- around 0.001" - 0.0005" in oversize) to find the best fit. Then you really need a gauge to verify the concentricity of the valve seat so you will know how the valve's face will seal. This is especially important if new or refurbished valves are being installed. My suggestion is to see if you can find a professional shop in the Knoxville area that can do the seats for you. Valve seating is an area that is often overlooked. Model-T engines need a good sealing valve to make power, and one that is even leaking slightly quickly causes a power loss,


speedytinc
Posts: 3814
Joined: Fri Feb 12, 2021 12:24 pm
First Name: john
Last Name: karvaly
* REQUIRED* Type and Year of Model Ts owned: 14/15 wide track roadster. 23 touring, 27 roadster pickup, 20ish rajo touring
Location: orange, ca
MTFCA Number: 14383
Board Member Since: 2020

Re: Valve Seats

Post by speedytinc » Tue Aug 09, 2022 8:40 am

A single 45 degree cut makes for a wide seat which is not optimal for long life. Done properly, the seats need to be narrowed to around .060" & positioned above the center line of the valve face. This is done with 30 & 60 degree cutters/stones then lapped & seal confirmed. If the seat is getting too deep, then new seats are needed. This takes expensive equipment. Best done by an experienced person.


Topic author
GG Gregory
Posts: 295
Joined: Sat Jul 20, 2019 3:05 pm
First Name: GG
Last Name: Gregory
* REQUIRED* Type and Year of Model Ts owned: 27 Roadster
Location: Maryville Tn

Re: Valve Seats

Post by GG Gregory » Tue Aug 09, 2022 8:54 am

Thanks Brent. Yes we’re not that far away from each other. I think you know a friend of mine, Jim Eubanks. Sounds like this valve job is more involved than I have the talent or tools.


Art M
Posts: 830
Joined: Wed Jun 19, 2019 12:57 pm
First Name: Art
Last Name: Mirtes
* REQUIRED* Type and Year of Model Ts owned: 1923 Touring
Location: Huron, Ohio
MTFCA Number: 32489
MTFCI Number: 24068
Board Member Since: 2016

Re: Valve Seats

Post by Art M » Tue Aug 09, 2022 11:12 am

I totally agree with speedy except I shoot for about 080 to
0 90 inch width of contact. Lapping is important in my opinion.


Cordes_jeff
Posts: 61
Joined: Wed Jan 09, 2019 8:45 pm
First Name: jeff
Last Name: cordes
* REQUIRED* Type and Year of Model Ts owned: 25
Location: houston

Re: Valve Seats

Post by Cordes_jeff » Mon Aug 15, 2022 9:42 am

I've put many a seat in and have never lapped any but it takes experience to know what to look for. .060 width is good for gas motors. You could put a larger valve in to deal with the worn seat but it requires more seat grinding of various angles to get the seat width and diameter right. You also don't want a valve seating on the outside edge of a valve where it can burn.

Post Reply Previous topicNext topic