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Exhaust Valve Spring on Intake Valve?


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Is there any reason the exhaust valve springs can't (or shouldn't) be used on the intake valves?

 

Reason I ask is because RockAuto has exhaust springs for pretty cheap, but no intake springs, and the other sources I've looked at are asking more for their intake springs.

 

Edit:  By the way, this is for a flathead six (265 in particular, although I think most or all the DPCD flatheads use the same springs 

Edited by Matt Wilson
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Every source I've looked at shows the same PN for everything, 30s-50s 23" and 25", int and ex.  but, I can't find the listing you mentioned at Rock Auto.  Got a PN?

 

edit: example:  https://www.partstech.com/Sealed-Power-Engine-Valve-Spring/details/BDBR-VS-506

 

There may be a different part for ind engines with sodium cooled valves, don't know for sure.

Edited by kencombs
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The only time I have seen a different intake/exhaust spring difference is when a sodium exhaust valve is used with a rotating spring retainer.

Thus requiring a shorter and stronger spring.

I have never seen a exhaust valve rotator used on the 25" engines. Sodium valves yes and some what common.

I have two engines that do have this shorter exhaust spring and rotator set up.... a three tonner 331 DT Hemi and a four tonner 413 flat head six.

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2 hours ago, kencombs said:

Every source I've looked at shows the same PN for everything, 30s-50s 23" and 25", int and ex.  but, I can't find the listing you mentioned at Rock Auto.  Got a PN?

 

edit: example:  https://www.partstech.com/Sealed-Power-Engine-Valve-Spring/details/BDBR-VS-506

 

There may be a different part for ind engines with sodium cooled valves, don't know for sure.

The part number on RockAuto is Sealed Power VS506, which appears to be the same p/n you posted (except your link has BDBR in it).  RockAuto lists it as an exhaust valve spring.  Other websites, such as NAPA, also list it as the exhaust valve spring, and they also list VS304 as the intake valve spring.  Like you, I have noticed that some sites, such as Vintage Power Wagons, show only one p/n for the valve spring, applying to both intake and exhaust.

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4 hours ago, Dodgeb4ya said:

The only time I have seen a different intake/exhaust spring difference is when a sodium exhaust valve is used with a rotating spring retainer.

Thus requiring a shorter and stronger spring.

I have never seen a exhaust valve rotator used on the 25" engines. Sodium valves yes and some what common.

I have two engines that do have this shorter exhaust spring and rotator set up.... a three tonner 331 DT Hemi and a four tonner 413 flat head six.

That's good info, thanks.

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As it turns out, Summit Racing has intake springs (Sealed Power VS304) for $3.99 each, so if I decided to buy intake springs, I could get them for cheaper than the exhaust springs, although I would buy the VS506 springs for the exhaust, just to be on the safe side.

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I looked in three different dodge truck parts books...early 50's thru late 50's.

All use 12 of the same valve springs for intake and exhaust..1/2 thru 2-1/2 ton trucks.

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7 hours ago, Dodgeb4ya said:

I looked in three different dodge truck parts books...early 50's thru late 50's.

All use 12 of the same valve springs for intake and exhaust..1/2 thru 2-1/2 ton trucks.

Hmmm.....interesting.  Sure makes me wonder why Sealed Power makes two different parts (or at least two different part numbers) for the intake and exhaust springs.

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the whys of folks marketing will always raise questions....ask them for the specification of each spring by part number....that will tell the story.....I just ordered door checks for a project....they are identical left and right, if it does not fit, turn it upside down type deal....however...they list them by two different numbers....swap packages and no one would eve know unless they saw you do it....

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I would be very cautious on changing the rate of any spring to one that is stiffer...accelerated cam wear is a possible side effect, there is basically no need to have higher tension springs on a stock cam unless you plan to bust out of the normal operation RPM of the engine as factory springs will properly close and hold shut at X RPM and really, this is the only function of the spring....if you going with a modified cam...it is prudent that it be totally broken in with stock springs long before installation of the higher tension spring.  

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I think I found the difference.  They are not speced as intake or exhaust.  They are with and without rotocaps.  The unit quantity per engine is 12.

 

From the online Sealed Power catalog.

https://www.fme-cat.com/digipubZ/Sealed-Power-Engine-Parts-and-Kits-Volume-1/A39AEBE1696A4CE0658B2CE576745FDB/2008%20SealedPower%20Volume%201%20-%20digipubZ.pdf

 

The higher price is the spring and rotator, lower is simply a longer spring w/o rotator.

 

at least that;s my interpretation of the info

 

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I would check the new springs...especially  new after market springs.for height, wire diameter and pressure ..today's replacement parts for the real old cars sometimes are just close enough and seem to just fit and work....for awhile.

I am going to see if I have a marine or industrial parts book for the 23 or 25" engines to see about this spring issue.

These MoPar flathead industrial engines are quite different from regular car and truck production.

Part numbering is also different.

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I cannot compare part numbers but the Industrial manual I do have quotes the same numbers for both intake and exhaust valves. Does not show any valve rotators.

The interesting thing is the spring pressure when compressed to 1 3/8" is only about 80 lbs compared to the truck or car 115 lbs.    

 

Tony

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26 minutes ago, Tony WestOZ said:

I cannot compare part numbers but the Industrial manual I do have quotes the same numbers for both intake and exhaust valves. Does not show any valve rotators.

The interesting thing is the spring pressure when compressed to 1 3/8" is only about 80 lbs compared to the truck or car 115 lbs.    

 

Tony

What does it list for springs??

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3 hours ago, kencombs said:

Curious, what vehicle application did you input to find those numbers?  I see the PNs, but they don't show application or usage.

The application I entered is a 251 from a 1963 Dodge Power Wagon, since that is the basic engine I'm using to convert to a 265.

Edited by Matt Wilson
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1 hour ago, Matt Wilson said:

The application I entered is a 251 from a 1963 Dodge Power Wagon, since that is the basic engine I'm using to convert to a 265.

Interesting.  I never thought to use a pw input.  The 251s for cars do not show the spring for a rotator, only the 'normal', longer version.  I did see a 251 from a Massey-Ferguson combine that had them.  Missed buying that one by a few hours.

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1 hour ago, kencombs said:

Interesting.  I never thought to use a pw input.  The 251s for cars do not show the spring for a rotator, only the 'normal', longer version.  I did see a 251 from a Massey-Ferguson combine that had them.  Missed buying that one by a few hours.

I don't know that the Power Wagon engine had rotators.   The only thing I recall seeing when I disassembled this engine is the same thing I saw when I was working with my 230, which was the valve spring retainer on each valve.  There wasn't anything I would call a rotator.  I guess I'd better be careful of what I end up purchasing.

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I cannot recall seeing valve rotators listed as being in anything other than trucks over about 31/2 to 4 ton and some industrial units. They were 250 and 265`s.

The 56 PW parts list shows 12 valve springs with the same part number for the 230. Australia fitted the 250 in 58 to 44 units they made using the standard 250. When the US fitted the 250 in 60 (or maybe 61) I am pretty sure they were standard motors.

 

Tony

Edited by Tony WestOZ
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7 hours ago, kencombs said:

I think I found the difference.  They are not speced as intake or exhaust.  They are with and without rotocaps.  The unit quantity per engine is 12.

 

From the online Sealed Power catalog.

https://www.fme-cat.com/digipubZ/Sealed-Power-Engine-Parts-and-Kits-Volume-1/A39AEBE1696A4CE0658B2CE576745FDB/2008%20SealedPower%20Volume%201%20-%20digipubZ.pdf

 

The higher price is the spring and rotator, lower is simply a longer spring w/o rotator.

 

at least that;s my interpretation of the info

 

This is interesting, indeed.  I looked at the catalog at your link. 

 

For Dodge engines (presumably Dodge car), it shows 12 of each spring, either VS-304 (w/o rotocaps) or VS-506 (with rotocaps), making it appear that it's optional to use either kind. 

 

For Desoto and the some Chrysler car engines (through 251 cid), it shows six of each, although it doesn't specify which kind of spring goes on the intake and which goes on the exhaust. 

 

For the 265 Chrysler car engine, it goes back to saying 12 and 12. 

 

For the 218 Dodge and Plymouth marine applications, it only calls out the VS-304 (Qty 12). 

 

Then for the Dodge 230 marine engine, it's back to 12 VS-304 or 12 VS-506, and same for the 236 marine. 

 

But then for the 265 marine, it only lists the VS-304. 

 

For the 218, 230 and 236 Dodge truck engines (light-duty), it calls out 12 VS-304 or 12 VS-506. 

 

Then the 251 light-duty Dodge truck engine calls for six of each spring, and actually specifies that the VS-304 goes on the intake and the VS-506 goes on the exhaust.

 

I have to wonder if they really have everything specified correctly in this catalog??

 

In any case, I wonder if it would be worth it to buy the rotocap type of spring for my exhaust valves.  I suppose they are intended to make the valves last longer?  I don't know if the rotocaps come with these springs, or if the springs will even fit the standard valves that I have.

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11 minutes ago, Tony WestOZ said:

I cannot recall seeing valve rotators listed as being in anything other than trucks over about 31/2 to 4 ton and some industrial units. They were 250 and 265`s.

The 56 PW parts list shows 12 valve springs with the same part number for the 230. Australia fitted the 250 in 58 to 44 units they made using the standard 250. When the US fitted the 250 in 60 (or maybe 61) I am pretty sure they were standard motors.

 

Tony

Thanks for the info.  I'm thinking that even if I were to buy the springs that are meant to be used with rotators, and even if I could find the rotators, I bet they are meant for use with sodium-filled exhaust valves, and wouldn't fit my valves.  It's sounding like I just need to buy (Qty 12) VS-304 springs and call it good, unless someone else knows of a reason not to.

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from the manual,          

"Note.

Special exhaust valve springs are used with the rotators and are not interchangeable with intake valve springs."

 

I am not sure of the difference in spring length with the flat six but the V8`s with spring rotators the exhaust valve springs are about 3/16" shorter than the inlet valves springs. Mixing them up puts lower pressure on one valve and puts too much pressure on the other.

 

Tony

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