Ian Vincent Posted September 4, 2011 Report Share Posted September 4, 2011 As I said a week or so ago, I have recently started the engine on my TR3a for the first time. Today, having fixed a couple of coolant leaks and thoroughly cleaned the wrapping on the exhaust manifold, I started it up again and let it run at 2 to 3 thousand rpm for about 15 to 20 minutes. Its a Phoenix tubular manifold and I noticed that down in the down in the middle where all the pipes come together and where it is impossible to wrap, the manifold was glowing cherry red. is this normal? Presumably the rest of the manifold is equally hot but because it is wrapped, it isn't visible? This apart, everything seems OK. Once I had run in the camshaft, I balanced the carbs, set the idle to about 900 rpm - much below that it was a bit lumpy - and checked the dynamic timing which seemed pretty much spot on. I have a bit of a brake problem which I'll cover in another post, but I would appreciate some re-assurance that its normal for a tubular manifold to get red hot when the engine is running at a fast idle. PS what sort of oil pressure should I be looking for? Mine seems to be just over 50 psi whatever the revs, even when the oil has warmed through. I assume that is the point at which the pressure relief is operating, I didn't touch it when i rebuilt the engine, is that about the right figure? Rgds Ian Quote Link to post Share on other sites
Ashley James Posted September 4, 2011 Report Share Posted September 4, 2011 Mine's got a cast iron manifold, but I was surprised at the way paint burnt off the down pipe when I started it. Like you I did a quick check of everything but it's running fine, just getting the exhaust very hot. I have a lot more oil pressure than you. Mine is up mat around 70-80 psi. Ash Quote Link to post Share on other sites
BrianC Posted September 5, 2011 Report Share Posted September 5, 2011 (edited) I've had a SAH/TriumphTune mild steel (not stainless) system for many years and it's never glowed red. Maybe wrapping only part of the system is causing local hot spots. Doesn't sound right to me (but then I wouldn't have wrapped any of it in the first place!). Oil pressure on rebuilt engine is 70psi hot (50-60 at idle) using Penrite HPR30 (20W/60) after 13000 miles. But how accurate are the oil pressure gauges now? Don't worry unless it drops any lower or starts making noises or burning oil. Edited September 5, 2011 by BrianC Quote Link to post Share on other sites
john.r.davies Posted September 5, 2011 Report Share Posted September 5, 2011 Manifolds get very hot, but cherry red=too hot! Suggest timing retarded too far, so gases still burning as they exit the chambers. John Quote Link to post Share on other sites
67_gt6 Posted September 5, 2011 Report Share Posted September 5, 2011 You could possibly adjust your pressure release valve to get a bit more pressure at 2000 RPM (about 70). Tubular manifolds do get very hot, although when I had them on my GT6 I only saw them cherry red hot when thge timing was a bit off. I have always wondered with exhaust wraps whether they would create a very hot spot at the first unwrapped section. Andy Quote Link to post Share on other sites
Ashley James Posted September 5, 2011 Report Share Posted September 5, 2011 Retarded timing most likely so make sure it's spot on. Ash Quote Link to post Share on other sites
RogerH Posted September 5, 2011 Report Share Posted September 5, 2011 Hi Ian, Tubular manifolds are thin. The hot gas coming out of each port heats its associated tube and then cools for a moment - roughly 4:1 ratio cold/hot. However at the point where it all joins you have continuous hot gases. Normally the gases are less hot than where they exit the port, but!!, you have lagged the only place they can cool. Therefore you have very hot gases at the joining of the four pipes. = red glow. Keeping the heat in is very good. But it appears that you are too hot to start with. Roger Quote Link to post Share on other sites
Menno van Rij Posted September 5, 2011 Report Share Posted September 5, 2011 I'm with John and Ashley. Last winter, after rebuilding my engine (camshaft faillure), the first start up suffered from a to far retarded ignition. Point is, with retarded ignition, the car will start and run pretty decent as long as it's in the workshop. And it sounds pretty normal too! The only give away on my car: fumes and smoke bellowing out of the exhaust, setting off the fire alarm inside the workshop! Menno Quote Link to post Share on other sites
Ian Vincent Posted September 5, 2011 Author Report Share Posted September 5, 2011 Thanks All, So the general consensus is that I need to retard the ignition. No problem but just so I don't do it wrong, the distributor rotor arm is rotating anti-clockwise so I need to rotate the body of the dizzy clockwise to advance the ignition - correct? Rgds Ian Quote Link to post Share on other sites
Ashley James Posted September 5, 2011 Report Share Posted September 5, 2011 Ian You don't need to retard the ignition, if there is anything wrong, it's that the engine is already too retarded. The best thing to do is use the timing marks to set it by the book. Guessing desnt work. Ash Quote Link to post Share on other sites
Menno van Rij Posted September 5, 2011 Report Share Posted September 5, 2011 (edited) Try setting the static timing first with a light bulb, by the book. That's your first step. The overall idea is, that it's best to advance the timing even a little more due to the modern fuels. There's a lot of info on the forum about that. Menno EDIT: here's some useful info: http://www.vtr.org/maintain-index.shtml, about 1/3 down, under Electricals > Ignition System > Setting the Ignition Timing on a TR. M. Edited September 5, 2011 by Menno van Rij Quote Link to post Share on other sites
Ian Vincent Posted September 6, 2011 Author Report Share Posted September 6, 2011 Ian You don't need to retard the ignition, if there is anything wrong, it's that the engine is already too retarded. The best thing to do is use the timing marks to set it by the book. Guessing desnt work. Ash My mistake, I meant advance! I have set it by the book and checked it with a strobe against the timing marks I made on the (new) pulley when I re-assembled the engine. It is currently at TDC when the engine is running at about 900 rpm. Rgds Ian Quote Link to post Share on other sites
Ashley James Posted September 6, 2011 Report Share Posted September 6, 2011 From memory I think they should have about 7 degrees of static advance, but it doesn't sound as though it's far enough out to overheat the manifold. Ash Quote Link to post Share on other sites
stuart Posted September 6, 2011 Report Share Posted September 6, 2011 I would check your mixture settings as too weak will get the manifolds red hot as well. Stuart. Quote Link to post Share on other sites
Ashley James Posted September 6, 2011 Report Share Posted September 6, 2011 Good advice Stuart, I've just checked my SUs and found the jets at 29 & 32 thou, shifted them to 40 and it's running like a dream. Wiith the high axle 70 is 2750 and very relaxing. Ash Quote Link to post Share on other sites
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