and yes they will be utilized to stabilize 'spring walk" in which case I am presuming I will need +0.050" retainers to offset the 0.062" thickness (I'm guessing) of a spring cup.
Should I be concerned about spring walk with these springs and 0.567" lift and are cups even required with a cast iron head?
Again, I hope to have answers directly from Crane.
Thanks all who replied
The valve train of the 351 Boss engine had spring cups. Same iron heads. Less over the nose force, less lift than your engine. The idea is to stabilize the location of the spring where it mates with the head, to prevent it from squirming around, for a more stable valve train.
You'll need to fly-cut the spring seat area to accommodate the spring cup, and to make everything fit. Remember the installed height of the Crane spring is 0.020" less than the standard 351C installed height.
You'll need to fly-cut the spring seat area to accommodate the spring cup, and to make everything fit. Remember the installed height of the Crane spring is 0.020" less than the standard 351C installed height.
Called PAC racing springs as an alternative and they recommended the following
PAC-1900 spring - identical to Crane #99839
PAC-R405 10 deg titanium retainer +0.050"
PAC-L8025 steel lock
PAC-S112 spring seat 0.060" thick
If required I can swap out for PAC-L8027 +0.050" locks and use shims to fine tune installed height once everything is mocked up.
PAC-1900 spring - identical to Crane #99839
PAC-R405 10 deg titanium retainer +0.050"
PAC-L8025 steel lock
PAC-S112 spring seat 0.060" thick
If required I can swap out for PAC-L8027 +0.050" locks and use shims to fine tune installed height once everything is mocked up.
I finally found some time to take a look at the PAC Racing valve spring. Its not identical to the Crane spring, but yeah its close.
I have one concern with that spring, at PAC's rated 1.88" installed height the spring has only 98 pounds seated force. If you install the spring at the standard Cleveland height (1.82") the seated force is great (120 lbs) but the maximum lift is reduced to 0.540".
If it were me I would juggle the installed height to give me just enough maximum lift for the cam lobes & rocker arms you are using, while maximizing seated force as well.
I have one concern with that spring, at PAC's rated 1.88" installed height the spring has only 98 pounds seated force. If you install the spring at the standard Cleveland height (1.82") the seated force is great (120 lbs) but the maximum lift is reduced to 0.540".
If it were me I would juggle the installed height to give me just enough maximum lift for the cam lobes & rocker arms you are using, while maximizing seated force as well.
I guess this is why people leave this stuff up to their engine builder to sort out but that would take all of the fun out of it.
Obviously more questions need to be asked especially since the spring loads and height charts for PAC and Crane are nearly the same.
The chart for PAC #1900 shows 90#@1.900"and 372#@1.115".
The chart for Crane #99839 shows 86#@1.900" and 359#@1.115".
Inside and outside diameters of 1.500" and 1.086" are identical and spring rates are 376#/in. and 354#/in.
PAC show a max lift of 0.600" in their catalogue and Crane shows 0.660" in theirs
If someone has installed the Pence Cobrajet cam and used a Crane (or other) spring package on iron 4V CC heads then please stop me from trying to reinvent this wheel.
Eternally grateful
Monty
Obviously more questions need to be asked especially since the spring loads and height charts for PAC and Crane are nearly the same.
The chart for PAC #1900 shows 90#@1.900"and 372#@1.115".
The chart for Crane #99839 shows 86#@1.900" and 359#@1.115".
Inside and outside diameters of 1.500" and 1.086" are identical and spring rates are 376#/in. and 354#/in.
PAC show a max lift of 0.600" in their catalogue and Crane shows 0.660" in theirs
If someone has installed the Pence Cobrajet cam and used a Crane (or other) spring package on iron 4V CC heads then please stop me from trying to reinvent this wheel.
Eternally grateful
Monty
I contacted PAC with the following:
"The lift of the hydraulic flat tappet cam I am using will be 0.568".
If my math is correct, using the 0.060"seats and +0.050" retainers that you recommend would put my valve closed (installed height) at 1.810" and the valve open at 1.242".
The chart on page 32 of your catalogue shows valve closed 98@1.880", valve open 315@1.300" max coil bind at 1.115" and a max lift of 0.600"
My question is: What is the maximum amount of spring compression before running the risk of coil bind? ie. If coil bind happens at 1.115" then is it safe to run the spring with a clearance of 0.060" or valve open at 1.175" or is it in fact 1.300" as stated on the chart.
This spring is a little week for my application at an installed height of 1.880" but is right on target at around 1.820". the open load at 1.242" is on target as well but if coil bind occurs at 1.280" (1.880"-0.600") or 1.300" then I am going to have big problem.
My thinking is that if coil bind happens at 1.115" and I require at least 0.060" clearance then I should be safe with the valve opening to 1.175".Is more clearance required?"
They responded with:
"You are correct. The spring does CB at 1.115" and you can run .06-.08" off of that number. You do not have to have open at 1.300"
Also You may want to look at a PAC-1218 beehive spring. This will go in at 1.800" with 130 seat and 310 open. Being that the chrome moly retainer for this spring is only 10g you would be saving a ton of weight."
Hope this helps
"The lift of the hydraulic flat tappet cam I am using will be 0.568".
If my math is correct, using the 0.060"seats and +0.050" retainers that you recommend would put my valve closed (installed height) at 1.810" and the valve open at 1.242".
The chart on page 32 of your catalogue shows valve closed 98@1.880", valve open 315@1.300" max coil bind at 1.115" and a max lift of 0.600"
My question is: What is the maximum amount of spring compression before running the risk of coil bind? ie. If coil bind happens at 1.115" then is it safe to run the spring with a clearance of 0.060" or valve open at 1.175" or is it in fact 1.300" as stated on the chart.
This spring is a little week for my application at an installed height of 1.880" but is right on target at around 1.820". the open load at 1.242" is on target as well but if coil bind occurs at 1.280" (1.880"-0.600") or 1.300" then I am going to have big problem.
My thinking is that if coil bind happens at 1.115" and I require at least 0.060" clearance then I should be safe with the valve opening to 1.175".Is more clearance required?"
They responded with:
"You are correct. The spring does CB at 1.115" and you can run .06-.08" off of that number. You do not have to have open at 1.300"
Also You may want to look at a PAC-1218 beehive spring. This will go in at 1.800" with 130 seat and 310 open. Being that the chrome moly retainer for this spring is only 10g you would be saving a ton of weight."
Hope this helps
Thanks for sharing the update Monty. So how do you plan to proceed?
By the way, I do have part numbers for Crane spring cups designed for 1.5" OD springs. #99465 has 0.570" ID, #99455 has 0.637" ID.
I played with the lift numbers & coil bind numbers last night and came to the conclusion that with an installed height of 1.82" either spring should be good for up to 0.600" lift. Its cool that PAC's reply validates that. I believe Crane's rating of 0.660" max lift is based on an installed height of 1.88. At 1.82" installed height the Crane spring will have 114 pounds seated force, the PAC spring will have 120 pounds seated force.
I will be needing to update the valve train section of sticky #3 after I figure out how to make room for additional text.
By the way, I do have part numbers for Crane spring cups designed for 1.5" OD springs. #99465 has 0.570" ID, #99455 has 0.637" ID.
I played with the lift numbers & coil bind numbers last night and came to the conclusion that with an installed height of 1.82" either spring should be good for up to 0.600" lift. Its cool that PAC's reply validates that. I believe Crane's rating of 0.660" max lift is based on an installed height of 1.88. At 1.82" installed height the Crane spring will have 114 pounds seated force, the PAC spring will have 120 pounds seated force.
I will be needing to update the valve train section of sticky #3 after I figure out how to make room for additional text.
1218X Beehive. Lighter weight and comparable cost. PAC was very helpful with suggestions.