350 Chevy Valve Rotators?

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Model T Ford Forum: Forum 2015: 350 Chevy Valve Rotators?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Pat Kelly Montana on Sunday, December 06, 2015 - 03:35 pm:

Anybody use valve rotator type spring retainers with 350 chevy valves?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erik Barrett in Auburn Ca. on Sunday, December 06, 2015 - 05:29 pm:

I think they are too large in diameter and will hang up on the cylinder wall of the block casting. I don't think a T engine needs rotators anyway. They were for high compression engines with heavy valve spring pressure. I always use the 350 Chevy intake retainers and keepers with 350 Chevy valves or 351 Windsor Ford valves. Don't over complicate a model T valve train. Of course, opinions will vary.


Top of pagePrevious messageNext messageBottom of page Link to this message  By joe bell on Sunday, December 06, 2015 - 07:28 pm:

Jeep has a smaller rotator that fits well with the smaller springs?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gene Carrothers Huntington Beach on Monday, December 07, 2015 - 03:53 pm:

Joe, any more info on those Jeep rotators?


Top of pagePrevious messageNext messageBottom of page Link to this message  By joe bell on Monday, December 07, 2015 - 05:04 pm:

Gene, The ones I had used came off of a 67 jeep 4 cylinder with the over head intakes and exhaust was still in the block. They where smaller diameter and the T spring fit well with them, I had the old head lying around from an older engine job years ago.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Pat Kelly Montana on Monday, December 07, 2015 - 05:33 pm:

What stem/guide clearance do I need with the 350 valves? PK


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erik Barrett in Auburn Ca. on Monday, December 07, 2015 - 05:35 pm:

11/32". Reamers are available from the T parts vendors.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Pat Kelly Montana on Monday, December 07, 2015 - 06:18 pm:

Thanks, PK


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roar Sand on Monday, December 07, 2015 - 09:21 pm:

May be more than you ever wanted to know about valve rotators.
Valve rotators come in two types; Rotocaps and Rotocoils, the latter rotate at about 1/10th the speed of the Rotocap. The rotators have internally a conical washer that is calibrated to collapse at the valve open spring load and spring back at vale closed load. It is therefore doubtful that any of them will work with the low spring loads of a T.
Inside a Rotocap there are a series of pockets with ramps with a ball in each pocket. When the conical washer collapses, it loads the ball, which then rolls down the ramp. That causes the upper and the lower part of the assembly to move relative to each other. When unloaded a small coil spring in each pocket pushes the ball back up the ramp. The Rotocoil is simpler, in that it just has a coil spring in a round trough, and when the conical washer collapses, it presses down on the coil spring, which then flops over and makes the upper and lower part of the assembly move in opposite directions.
Rotators were used primarily in overhead valve applications where temperatures around the exhaust seat were uneven. It would prevent one spot of the valve head to sit at the hot spot continuously and cause a burnt valve.


Top of pagePrevious messageNext messageBottom of page Link to this message  By bob middleton on Tuesday, December 08, 2015 - 12:38 am:

Erik set me up using 350 chevy valve train only issue was getting the keepers in had to use old school C clamp compressor with some tacky grease .
I agree rotators wouldn't do much good in a T


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