ACMOC
Login
ACMOC
D7 Intake/Exhaust Valve Interchangeability

D7 Intake/Exhaust Valve Interchangeability

Showing 1 to 8 of 8 results
KansasD7
Topic Author
Offline
Send a private message to KansasD7
Posts: 32
Thank you received: 0
The service manual for my 3T1 D7 (3T14387) says that intake valves have a small groove around the top of the valve stem to distinguish them from exhaust valves.

The used head I removed from a 3T1 in a salvage has the intake/exhaust valves reversed.

The valves appear to be the same size and physically interchangeable. Does anyone know if there is indeed a difference in these valves besides the small groove around the stem?
Please log in or create an account to join the conversation.
Sun, Aug 10, 2008 8:22 PM
SJ
Offline
Send a private message to SJ
Posts: 1,890
Thank you received: 0
I never thought about it but I,m guessing they are both made out of different material or tempered different to withstand the heat as with the ex. valve.I can,t remember the size of the valves on the D7 but most times the in. valve has a larger diameter head than the ex.does.
Please log in or create an account to join the conversation.
Sun, Aug 10, 2008 11:26 PM
Jack
Offline
Member
Send a private message to Jack
Posts: 817
Thank you received: 0
Reply to SJ:
I never thought about it but I,m guessing they are both made out of different material or tempered different to withstand the heat as with the ex. valve.I can,t remember the size of the valves on the D7 but most times the in. valve has a larger diameter head than the ex.does.
I recently found an intake valve that had run in the exhaust port of a D2. The valves look the same but are stamped on the top exh. or int. somebody just screwed up.

Anyway, that intake valve showed some serious heat treatment--bluing way down the stem. I'd say the steel is different on that basis. I was afraid to reinstall it, bought another intake valve and used the exhaust valve that had been running in the intake port for exhaust. I've no idea whether it would be soft, or brittle, or heat checked, or OK. I could just see that it was changed.
Please log in or create an account to join the conversation.
Mon, Aug 11, 2008 8:43 AM
Old Magnet
Offline
Send a private message to Old Magnet
Posts: 16,685
Thank you received: 14
Reply to Jack:
I recently found an intake valve that had run in the exhaust port of a D2. The valves look the same but are stamped on the top exh. or int. somebody just screwed up.

Anyway, that intake valve showed some serious heat treatment--bluing way down the stem. I'd say the steel is different on that basis. I was afraid to reinstall it, bought another intake valve and used the exhaust valve that had been running in the intake port for exhaust. I've no idea whether it would be soft, or brittle, or heat checked, or OK. I could just see that it was changed.
They are definitely a different part number for intake and exhaust valves so I think it would be safe to assume they are of a different metallurgy and not to be interchanged.
Please log in or create an account to join the conversation.
Mon, Aug 11, 2008 10:55 AM
Soapy
Offline
Send a private message to Soapy
Posts: 399
Thank you received: 0
Reply to Old Magnet:
They are definitely a different part number for intake and exhaust valves so I think it would be safe to assume they are of a different metallurgy and not to be interchanged.
Go to your web browser, and type in Stellite. This is the alloy that is normally used in the manufacture of exhaust valves.
Please log in or create an account to join the conversation.
Mon, Aug 11, 2008 12:04 PM
tctractors
Offline
Chapter Leader
Chapter Two
Send a private message to tctractors
Posts: 627
Thank you received: 0
Reply to Soapy:
Go to your web browser, and type in Stellite. This is the alloy that is normally used in the manufacture of exhaust valves.
Although the valves are just about identical with the 1/2 stem and same angle to the seat area, CAT did make an effort to make it near fool proof with the location, marking the face and also the stem, the price of the exhaust valve is often about 1/3 more expensive than the inlet so something must be made of better metal, but I am pleased to see you spotted the snag and put up a querry,

tctractors
Please log in or create an account to join the conversation.
Tue, Aug 12, 2008 2:07 AM
KansasD7
Topic Author
Offline
Send a private message to KansasD7
Posts: 32
Thank you received: 0
Reply to tctractors:
Although the valves are just about identical with the 1/2 stem and same angle to the seat area, CAT did make an effort to make it near fool proof with the location, marking the face and also the stem, the price of the exhaust valve is often about 1/3 more expensive than the inlet so something must be made of better metal, but I am pleased to see you spotted the snag and put up a querry,

tctractors
Sounds like it was just a mistake. I decided to correct the mistake, touch up the valve seats and re-grind and insert some other used valves that I had.

Unfortunately, I found a crack on one of the exhaust valve seats after touching it up. The fun just never ends..... Now I have to learn how to replace a valve seat. I started by TIG welding a bead around the inside of the seat to shrink the seat. Next, I will press out the valve guide and see if I can reach through the valve guide hole and drive the seat out.
Attachment
Please log in or create an account to join the conversation.
Tue, Aug 12, 2008 8:35 AM
tctractors
Offline
Chapter Leader
Chapter Two
Send a private message to tctractors
Posts: 627
Thank you received: 0
Reply to KansasD7:
Sounds like it was just a mistake. I decided to correct the mistake, touch up the valve seats and re-grind and insert some other used valves that I had.

Unfortunately, I found a crack on one of the exhaust valve seats after touching it up. The fun just never ends..... Now I have to learn how to replace a valve seat. I started by TIG welding a bead around the inside of the seat to shrink the seat. Next, I will press out the valve guide and see if I can reach through the valve guide hole and drive the seat out.
Attachment
An easy way of getting those seats out if you are going to fit new valves is to grind down the outer dia' of a scrap valve head and weld it into the the seat, let it cool then a few taps and it falls out, to insert the new seat, I press in any new valve guides first then get the seats out of the freezer and press them in also, I have made myself press tools on a lathe to make this job very simple and easy,

tctractors
Please log in or create an account to join the conversation.
Wed, Aug 13, 2008 2:40 AM
KansasD7
Topic Author
Offline
Send a private message to KansasD7
Posts: 32
Thank you received: 0
Reply to tctractors:
An easy way of getting those seats out if you are going to fit new valves is to grind down the outer dia' of a scrap valve head and weld it into the the seat, let it cool then a few taps and it falls out, to insert the new seat, I press in any new valve guides first then get the seats out of the freezer and press them in also, I have made myself press tools on a lathe to make this job very simple and easy,

tctractors
tctractors, you make that sound easy.

Do you need to heat up the head before pressing in the new valve seat or does putting the valve seat in the freezer shrink it enough to allow it to be pressed in at room temperature?
Please log in or create an account to join the conversation.
Wed, Aug 13, 2008 8:03 AM
Showing 1 to 8 of 8 results
YouTube Video Placeholder

Follow Us on Social Media

Our channel highlights machines from the earliest Holt and Best track-type tractors, equipment from the start of Caterpillar in 1925, up to units built in the mid-1960s.

Upcoming Events

CAFES 2025 TULARE, CALIFORNIA

Chapter Fifteen

| Tulare, California

Wheatlands Warracknabeal Easter Rally

Chapter Nineteen

| 34 Henty Hwy, Warracknabeal

Veerkamp Open House 2025

Chapter Fifteen

| Placerville, CA

Stradsett Park Vintage Rally

Chapter Two

| Stradsett, Nr Downham Market. Norfolk PE33 9HA UK
View Calendar
ACMOC

Antique Caterpillar
Machinery Owners Club

1115 Madison St NE # 1117
Salem, OR 97301

[email protected]

Terms & Privacy
Website developed by AdCo

Testimonials

"I became a member recently because the wealth of knowledge here is priceless." 
-Chris R

Join Today!