The Ford Barn

fordwife · 03-30-2017, 10:41 PM

In about all of the V8s I have worked on the intake and exhaust valves are different. Usually the intakes have a ford script and the exahusts are plain. Does anyone know why? my ford parts book has the same part no. for both.

Brian · 03-30-2017, 11:12 PM

The exhaust valve operates under harsher conditions/higher temperatures than an inlet which is cooled by the incoming charge. Therefore, the exhaust valve is made out of a different material than the inlet. However, because it's made of a superior steel, an exhaust valve can be used as an inlet. however, using an inlet valve in the exhaust would rapidly cause the valve to burn. This describes it as simply as I can.

fordwife · 03-31-2017, 07:19 AM

If this is the case, then why does Ford show only one part no. for intake and exhaust valves?

DavidG · 03-31-2017, 07:41 AM

Because they stopped supplying the unique intake valves and all service part valves could be used as either intake or exhaust.

51 MERC-CT · 03-31-2017, 07:47 AM

Quote:

Originally Posted by fordwife

If this is the case, then why does Ford show only one part no. for intake and exhaust valves?

Parts manual shows pn.-6507 as original factory installed intake valve.
When replacing intake valve, pn.-6505 exhaust to be used.
Suppose that Ford discovered it did not have to make two different valves thus saving on production cost.

fordwife · 03-31-2017, 07:59 AM

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Thanks, guys, that makes sense.

DavidG · 03-31-2017, 08:24 AM

With respect, pennies, nickels, and dimes mount up to big money when multiplied by eight and then by tens and hundreds of thousands. It would not be a production cost savings to eliminate the use of unique intake valves in production, but not supply them for service, rather it would a cost penalty. Cost reductions such as this are basic task of automotive engineers then and now.

03-30-2017, 10:41 PM	#1
fordwife Senior Member Join Date: Dec 2015 Posts: 287	v8 valves In about all of the V8s I have worked on the intake and exhaust valves are different. Usually the intakes have a ford script and the exahusts are plain. Does anyone know why? my ford parts book has the same part no. for both.

03-30-2017, 11:12 PM	#2
Brian Senior Member Join Date: May 2010 Location: Masterton, New Zealand Posts: 3,832	Re: v8 valves The exhaust valve operates under harsher conditions/higher temperatures than an inlet which is cooled by the incoming charge. Therefore, the exhaust valve is made out of a different material than the inlet. However, because it's made of a superior steel, an exhaust valve can be used as an inlet. however, using an inlet valve in the exhaust would rapidly cause the valve to burn. This describes it as simply as I can. __________________ Unfortunately, two half wits don't make a whole wit!

03-31-2017, 07:19 AM	#3
fordwife Senior Member Join Date: Dec 2015 Posts: 287	Re: v8 valves If this is the case, then why does Ford show only one part no. for intake and exhaust valves?

03-31-2017, 07:41 AM	#4
DavidG Senior Member Join Date: May 2010 Location: southeastern Michigan Posts: 10,101	Re: v8 valves Because they stopped supplying the unique intake valves and all service part valves could be used as either intake or exhaust.

03-31-2017, 07:59 AM	#6
fordwife Senior Member Join Date: Dec 2015 Posts: 287	Re: v8 valves Sponsored Links (Register now to hide all advertisements) Thanks, guys, that makes sense.

03-31-2017, 08:24 AM	#7
DavidG Senior Member Join Date: May 2010 Location: southeastern Michigan Posts: 10,101	Re: v8 valves With respect, pennies, nickels, and dimes mount up to big money when multiplied by eight and then by tens and hundreds of thousands. It would not be a production cost savings to eliminate the use of unique intake valves in production, but not supply them for service, rather it would a cost penalty. Cost reductions such as this are basic task of automotive engineers then and now.