THUNDERZ Posted May 29, 2003 Share Posted May 29, 2003 I have a L28 in a 260z. The motor has been bored, ported and there is a street/racing cam in it. I have an exhaust header(and larger exhaust pipe) and three 40mm dellorto side drafts. Finally , my question. It runs pretty good until it reaches its full temp wich is 3/4 on the temp gauge(a little less). At this point it drops in power and acts like it is vapor locking. I taped up the header to trap the heat, and it helped, but still runs too hot. My cooling system is stock. What do you think is going on? Thanks, Jim [/b] Quote Link to comment Share on other sites More sharing options...
johnc Posted May 29, 2003 Share Posted May 29, 2003 Maybe this should be in the Troubleshooting Forum? Quote Link to comment Share on other sites More sharing options...
j260z Posted May 30, 2003 Share Posted May 30, 2003 are you running the stock fuel rail? Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted May 30, 2003 Share Posted May 30, 2003 moved to Troubleshooting Forum Quote Link to comment Share on other sites More sharing options...
johnc Posted May 30, 2003 Share Posted May 30, 2003 If taping up the headers helped that would indicate that your fuel delivery system in the engine compartment needs better insultation. Try wrapping the fuel lines with some type of heat wrap. If you've got any of the header wrap leftover, try that as an experiment. Also, do you have a heat shield between the carbs and the header? If not, make one. I would also upgrade the radiator, put in a new 180 degree thermostat, check hoses and belts, check the fan clutch and shroud, and/or replace the engine driven fan with a good puller electric fan (Ford Taurus fan coversion is popular and documented on this site). Quote Link to comment Share on other sites More sharing options...
THUNDERZ Posted May 30, 2003 Author Share Posted May 30, 2003 Thanks for the input. I have fuel lines protected with heat shielding sleaves. I want to put a better radiator in. Thanks again. Jim Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted May 31, 2003 Share Posted May 31, 2003 Isn't this part of the reason the I think 78 Z's added hood vents? They sit right above the intake and really let the heat pass. Quote Link to comment Share on other sites More sharing options...
fl327 Posted May 31, 2003 Share Posted May 31, 2003 i like the hood vents, have one problem, is that the one on the passenger side vent is right over the fusible links on a 280z and gets them real wet if the owner has taken the screens out of the bottom of the vent to get more air to pass, besides, the hot side of the engine is on the drivers side! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 13, 2003 Share Posted July 13, 2003 DELETE Quote Link to comment Share on other sites More sharing options...
THUNDERZ Posted July 15, 2003 Author Share Posted July 15, 2003 Childs play huh... Please make me feel stupid! I just had my radiator checked and its fine. I had an emissions check done on the car and took the results to the mechanic who built my engine. He said that it looks like its fine. I know it is not running rich, and the plugs are light light brown/white. So what do you think? Quote Link to comment Share on other sites More sharing options...
Synlubes Posted July 15, 2003 Share Posted July 15, 2003 Jim, do you use this Evan`s coolant ? If so, please give your thoughts on this product . I had not heard of this until now . And one thing I don`t get, on there page it say`s using low or NO pressure systems. " Without pressure (or low pressure, i.e. 2 to 5 psi) in the system, gasket seals, hose connections, and even the radiator core, operate safer and longer. " Quote Link to comment Share on other sites More sharing options...
THUNDERZ Posted July 15, 2003 Author Share Posted July 15, 2003 Doug, Thanks for the advice. I took a look at your pics and at a glance it looks like your set up is similar to mine (engine wise). Do you have your header wrapped or a heat shield under your carbs? Where does your temp gauge ride in normal operating? Are those webbers? What size? I'm sorry for all the questions but I am growing tired of these problems! Want to drive it, not stare at it with my wallet open Jim Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 15, 2003 Share Posted July 15, 2003 The reason we use pressurized cooling systems is to keep the water from boiling. We mix antifreeze and water because water transfers heat a lot better than antifreeze, and antifreeze has a higher boiling point and provides corrosion protection. If you use a liquid that doesn't boil until 370 degrees, then you don't need a pressurized cap to keep it a liquid (pressure raises the boiling point in a conventional system). I question the cost ($25/gallon) and the heat transfer effectiveness of that fluid. I'm not saying it isn't better than what we normally use, but I saw nothing on their site about the heat transfer properties vs. water, only the size of vapor bubbles comparison. I suppose you could just buy 5 gallons or so ($$$) and have some on hand, but it would be expensive when you spring a leak and need to fill the system, or need to remove the radiator for some reason. I also don't know where to get a 4 lb. radiator cap for my Z to take advantage of the longer hose life they offer. Hoses aren't that expensive either, so you could replace a few of them before you actually saved money by spending 10 times the price for coolant - since you don't mix 50/50 you gotta fill the WHOLE SYSTEM at $25/gallon. One thing they say that kinda bugs is that your engine can get up to 250 degrees without the coolant boiling. WOW! Never mind that warped head, I'm gonna run at 250! Now I know that newer Vettes have a 245 degree thermostat, and that increases fuel economy, but I don't think our Datsun equipment is designed for that kind of heat, and I think we can all agree that you don't make the best power at that temp. The whole thing reminds me of the synthetic oil commercials: "Look how regular oil gets all crusty at 450 degrees." Hello??? If your oil is 450 degrees you have some other problems!!! Always a skeptic, Jon Mortensen Quote Link to comment Share on other sites More sharing options...
Synlubes Posted July 15, 2003 Share Posted July 15, 2003 Doug' date='Thanks for the advice. I took a look at your pics and at a glance it looks like your set up is similar to mine (engine wise). Do you have your header wrapped or a heat shield under your carbs? Where does your temp gauge ride in normal operating? Are those webbers? What size? I'm sorry for all the questions but I am growing tired of these problems! Want to drive it, not stare at it with my wallet open Jim[/quote'] I do not have any header wrap . I don`t have a heat shield under carbs YET . I do need one though ! On real hot days the carbs can boil when I shut down . Runs great, as long as you keep your foot in it ! No it really is quite driveable ! Temp gauge at Highway speeds, center the gauge . 180 + / - (stock unit, new sender) . If i play or do a track event, 3/4 the gauge - 195 - 220 ? . 45 mm Weber`s detuned . 32 mm chokes, F11 E tubes, 135 mains / 165 air jets. Quote Link to comment Share on other sites More sharing options...
j260z Posted July 15, 2003 Share Posted July 15, 2003 i just installed infloor heating in my parents new home and the system calls for propylene glycol. i have about 5500 feet of infloor heating lines and the whole system runs at about 15 psi. i think i paid $550 - $600 CDN for 55 gallons of it from my plumbing wholesaler. the stuff tastes awful but they say you can drink it and it won't kill you i'll take the info off of the web and take it into my wholesaler and see if he can confirm that it is the same composition. ( i suspect that it would be) Quote Link to comment Share on other sites More sharing options...
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THUNDERZ Posted July 15, 2003 Author Share Posted July 15, 2003 i just installed infloor heating in my parents new home and the system calls for propylene glycol. i have about 5500 feet of infloor heating lines and the whole system runs at about 15 psi. i think i paid $550 - $600 CDN for 55 gallons of it from my plumbing wholesaler. the stuff tastes awful but they say you can drink it and it won't kill you i'll take the info off of the web and take it into my wholesaler and see if he can confirm that it is the same composition. ( i suspect that it would be) Down the hatch!!! Quote Link to comment Share on other sites More sharing options...
THUNDERZ Posted July 16, 2003 Author Share Posted July 16, 2003 This has been going on for about 4 or 5 hours of total driving time. The car does not get driven because I am trying to get things working corrrectly. It has never "knocked" or "pinged" that I know of, but I have suspected that it may be running a little lean. The car does not over heat, it just runs a little hotter than I think it should. Quote Link to comment Share on other sites More sharing options...
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