Jeffrey Smith Posted June 15, 2020 Report Share Posted June 15, 2020 I have a '67 TR4a with the factory fitted vacuum oil vent valve on top of the rocker cover.This connects to the intake manifold,the idea being to draw the oil fumes into the engine.Fine. But where can I connect my new aftermarket brake servo ? I'm wary of merely fitting a T peice to the manifold vacuum connection because this is designed to suck in oily fumes from the rocker cover and therefore it won't provide the full vacuum effect for the servo (and might contaminate the servo diaphragm ?).Help please ! Quote Link to post Share on other sites
Lebro Posted June 15, 2020 Report Share Posted June 15, 2020 Drill & tap the manifold to take a screw in connection ? Bob. Quote Link to post Share on other sites
Andy303 Posted June 17, 2020 Report Share Posted June 17, 2020 (edited) On 6/15/2020 at 10:50 AM, Lebro said: Drill & tap the manifold to take a screw in connection ? Bob. You can get a clue from how Triumph designed the TR250 intake manifold. The PCV screwed into the top of a lump on the manifold with another port for the brake servo in close proximity. That would imply they were not too worried about mingling the vacuum sources with regard to contamination. The servo works by vacuum at the manifold - the servo is not doing any of the "sucking" per se. But then they did use two separate ports and not a common tee. They did however use a tee-like banjo fitting for the servo take-off and a funky distributor retard mechanism. That might serve but they can only be found as used parts. Edited June 17, 2020 by Andy303 Quote Link to post Share on other sites
ChrisR-4A Posted June 17, 2020 Report Share Posted June 17, 2020 Hi Jeff, do yourself a favour and whilst adding further complication to your set up, ie.the brake servo, remove a totally unnecessary item, ie, the PCV valve. Let the rocker cover breathe with a plain rubber pipe taken down to a point just lower than the sump in the airstream. Then you can use the PCV take off for the servo. One other point, a decent set of front disc pads, Hawke for example will give more gain than a servo, the currently available "standard" brake pads are pretty hopeless. Lots of info on this, just search the forum. Chris Quote Link to post Share on other sites
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