Are "Top-Hat" shims the correct type?
3 posts
• Page 1 of 1
Thanks Brian, this helps greatly.
Just wonderig if top-hat shims are what are supposed to be in there?
A couple of mine have these types of shims but no one around here has
seen this type and we thought that they were somehow not correct.
What should I be using?
Regards.
David
--- In ***@***.***, "Brian Goodison" <bgoodison777@h...>
wrote:
Just wonderig if top-hat shims are what are supposed to be in there?
A couple of mine have these types of shims but no one around here has
seen this type and we thought that they were somehow not correct.
What should I be using?
Regards.
David
--- In ***@***.***, "Brian Goodison" <bgoodison777@h...>
wrote:
- davidwinegar
- Second Gear
- Posts: 149
- Joined: 23 May 2004
--- In ***@***.***, "david_c_w" <david_c_w@y...> wrote:
David,
I have never used them myself although I have seen them, they are not
used under normal circumstances in a T.C.
As far as I know they are used in racing applications and when the
base circle of the cams have been modified.
Maybe one of the racers can add something.
Brian
64Elan/72Sprint/J.P.S.Europa/Birkin T.C.Seven
David,
I have never used them myself although I have seen them, they are not
used under normal circumstances in a T.C.
As far as I know they are used in racing applications and when the
base circle of the cams have been modified.
Maybe one of the racers can add something.
Brian
64Elan/72Sprint/J.P.S.Europa/Birkin T.C.Seven
-
types26/36 - Coveted Fifth Gear
- Posts: 3877
- Joined: 11 Sep 2003
Brian,
I think you are on the right track. I have had heads with both "disc" and "top hat" shims. Which type are used seems to depend on the cam/valve/valve spring/retainer/spring seat combination. Normally the disc type is retained laterally by sitting in the cup in the valve spring retainer. If a combination is used where the valve stem is level with, or protrudes above the top of the retainer cup, a "top hat" shim is used which sits on the valve stem. The shim is now retained laterally by the cup in its underside . David Bean lists 9 different valve stem lengths, 3 different retainer types, and 4 different thickness spring seats, and 3 different cam follower thicknesses, That's 324 combinations !
Sean Murray (Not really a racer !)
----- Original Message -----
From: Brian Goodison
To: ***@***.***
Sent: Tuesday, June 28, 2005 9:02 PM
Subject: [LotusElan.net] Re: Are "Top-Hat" shims the correct type?
--- In ***@***.***, "david_c_w" <david_c_w@y...> wrote:
David,
I have never used them myself although I have seen them, they are not
used under normal circumstances in a T.C.
As far as I know they are used in racing applications and when the
base circle of the cams have been modified.
Maybe one of the racers can add something.
Brian
64Elan/72Sprint/J.P.S.Europa/Birkin T.C.Seven
I think you are on the right track. I have had heads with both "disc" and "top hat" shims. Which type are used seems to depend on the cam/valve/valve spring/retainer/spring seat combination. Normally the disc type is retained laterally by sitting in the cup in the valve spring retainer. If a combination is used where the valve stem is level with, or protrudes above the top of the retainer cup, a "top hat" shim is used which sits on the valve stem. The shim is now retained laterally by the cup in its underside . David Bean lists 9 different valve stem lengths, 3 different retainer types, and 4 different thickness spring seats, and 3 different cam follower thicknesses, That's 324 combinations !
Sean Murray (Not really a racer !)
----- Original Message -----
From: Brian Goodison
To: ***@***.***
Sent: Tuesday, June 28, 2005 9:02 PM
Subject: [LotusElan.net] Re: Are "Top-Hat" shims the correct type?
--- In ***@***.***, "david_c_w" <david_c_w@y...> wrote:
David,
I have never used them myself although I have seen them, they are not
used under normal circumstances in a T.C.
As far as I know they are used in racing applications and when the
base circle of the cams have been modified.
Maybe one of the racers can add something.
Brian
64Elan/72Sprint/J.P.S.Europa/Birkin T.C.Seven
-
Foxie - Coveted Fifth Gear
- Posts: 1632
- Joined: 20 Sep 2003
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