These retainers raise the installed height of your t3 valvetrain by .080".
What does this do and why do we need these for our Turbo III engine?
Long story short: the 2.2 Turbo III Lotus cylinder head was originally designed for an 11,000rpm rev limit. As such, they engineered the installed height to a point where there is so much tension on the valve springs and the closed pressure (on the seat) is so high that it's very hard on the valve train. This is why you see so many t3 heads with cam lobes wiped out, and why so many Lotus heads have timing belt issues. There are a couple of things we can do to alleviate this engineering blunder. The main thing is to raise the installed height. The best (and easiest) way to achieve this, is to modify the factory retainers - which is what we have done here.
RDI championed this engineering modification back in the mid 90's and we continue to make improvements to the Turbo III platform to this day.
What will I receive?
You will receive a full set of 16 retainers (enough to do 1 cylinder head).
Do I need to send in my old factory valve spring retainers?
You can if you want. There is a $100 core fee included in the cost of these. If you send us your factory retainers, you will receive a $100 credit from us once we receive your old retainers. ***RDI must receive your old retainers within 30 calendar days of the date of purchase of these modified retainers in order to issue you a credit. If we receive your retainers after 30 days, no credit will be issued.
Do I need to pull the cylinder head off the car in order to remove my old retainers and install these modified ones?
No. However, if you choose to do them "on the car", you will need a special tool to depress the springs. Otherwise, you can pull the head, bring it to a machine shop and they can install the new retainers for you.
What does RDI recommend?
We recommend you pull the head, bring it to a machine shop, let them do a full service on it (i.e. give it a fresh cut - minimum to make it flat - typically .003", install new valve stem seals, polish your cams, and install these new retainers. And we highly recommend you install a brand new fresh timing belt). This is what we do on every Turbo III engine that comes into our facility.