Tr4aJim Posted June 12, 2016 Report Share Posted June 12, 2016 Hi folks, I just found this forum. I just bought a 65 Tr4a. It's a good "driver" car, and looks pretty good from 20 feet!???? I will probably go down the restoration path some day, but for now I'm just going to enjoy it. Although the previous owner(s) did some "creative" mods to it (mostly electrical), for now I'm going through all the items to make it safe and comfortable to drive. However I do have two questions: - the PO removed the Tr4a PCV plumbing and replaced it with the Tr4 vent tube and added a small breather element on the valve cover fitting. Is this venting sufficient, or should I source a Tr4a system? - the car has a fiberglass bonnet. From what I can tell, new metal bonnets are unavailable, and the used ones I've seen online look pretty rough. For now it's fine, but when I restore it I want to go back to metal. Does anyone know of a good supplier that might have a metal bonnet? I might want to score one now and store it until needed. Thanks Jim Quote Link to post Share on other sites
ChrisR-4A Posted June 12, 2016 Report Share Posted June 12, 2016 Hi Jim, I assume you mean the 1 ins bore vent tube from the crankcase below the fuel pump. Together with a plain vent from the rocker cover this is a far superior set up to the PCV which was only brough in to appease emission regulations. Mine has been running like this for 18 years, better performance and less to go wrong. Quote Link to post Share on other sites
Allan Westbury Posted June 13, 2016 Report Share Posted June 13, 2016 Hi Jim, When I fitted a fast road cam I was advised by a reputable TR specialist that the first thing you do after buying a 4A is remove this valve & put it in the bin. It was fitted for emission control reasons and just screws up the performance. I have the inlet manifold take off point blocked off & feed the outlet on the rocker cover to an oil trap on the bulkhead. many people just fit a length of suitable tube to the rocker outlet & drop it down by the side of the engine to vent under the car (as I did or the first few years). Not quite so environmentally correct but just as effective! I was tempted to use the inlet manifold take off to provide a vacuum for an after market brake servo but was advised that as this is offset towards the left carb it would b*gger up the fuel balance. I had a hole drilled & tapped in the centre & this works just fine. cheers. Quote Link to post Share on other sites
TR4A1965 Posted June 13, 2016 Report Share Posted June 13, 2016 http://www.ebay.co.uk/itm/Triumph-TR4-TR4A-Bonnet-/262476354469?&_trksid=p2056016.m2518.l4276 Bonnet here. Also, Walter Petchy http://tr4a.weebly.com/walter-petchy.html Best Paul. Quote Link to post Share on other sites
peejay4A Posted June 13, 2016 Report Share Posted June 13, 2016 (edited) Hi Jim, When I fitted a fast road cam I was advised by a reputable TR specialist that the first thing you do after buying a 4A is remove this valve & put it in the bin. It was fitted for emission control reasons and just screws up the performance. I have the inlet manifold take off point blocked off & feed the outlet on the rocker cover to an oil trap on the bulkhead. many people just fit a length of suitable tube to the rocker outlet & drop it down by the side of the engine to vent under the car (as I did or the first few years). Not quite so environmentally correct but just as effective! I was tempted to use the inlet manifold take off to provide a vacuum for an after market brake servo but was advised that as this is offset towards the left carb it would b*gger up the fuel balance. I had a hole drilled & tapped in the centre & this works just fine. cheers. This got me thinking. Can anyone corroborate that the PCV affects performance? Also how would the connection of a servo to the offset vacuum take off affect balance as there shouldn't be any flow? Edited June 13, 2016 by peejay4A Quote Link to post Share on other sites
stuart Posted June 13, 2016 Report Share Posted June 13, 2016 TBH as long as the engine isnt breathing lots of oil through the PCV then it shouldnt make that much difference and there wouldnt really be any difference in the angling of the take off as the balance tube is just that "Balancing" the two. Stuart. Quote Link to post Share on other sites
mike3md Posted June 13, 2016 Report Share Posted June 13, 2016 AFAIK, as with the vacuum advance, a servo take off from the inlet manifold does not have any air passing through it. The servo/advance use the difference in pressure between atmospheric and the manifold, by way of a diaphragm. Mike Quote Link to post Share on other sites
Tr4aJim Posted June 13, 2016 Author Report Share Posted June 13, 2016 Thanks for the responses. Regarding the PCV, I do have the Tr4 style tube vent that attaches near the fuel pump. The manifold inlet is capped. On the valve cover tube, the PO attached a small aftermarket breather element that looks like a tiny air cleaner. From your descriptions above, it sounds like this should work fine. BTW- I looked at this small breather and do not see any evidence of it being wet with oil. Is that good or bad? Based on some descriptions above, I was expecting to see at least some oil on the element. Jim Quote Link to post Share on other sites
peejay4A Posted June 13, 2016 Report Share Posted June 13, 2016 If the small filter is dry I'd say all is fine. Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.