Connor280ZX Posted August 14, 2014 Share Posted August 14, 2014 So. New engine, new radiator. After my old engine blew due to overheating i picked up an L28 (F54/N47) to put in my 240Z. First couple drives out, the car ran great. Temp stayed down around 140-150F and all. Recently though, my temp has been starting to hike. Installed a brand new radiator (Aluminum 2-row) due to a rock hitting the old one. Hollowed out thermostat, and 50/50 coolant mix. Also an MSD Blaster 2 coil with ACdelco wires, and BP6ES plugs. It's not running cool anymore. The temperature will hike to about 200-220F and stay around there, no matter if im stopped at a light, crusing at highway speeds, or going WOT. Popped my radiator cap to make sure i wasnt running low on coolant and noticed a very thin layer of white foam on top of the coolant... Don't know what thats all about. At this point, my only guess would be that the blaster coil is making my car run hotter some how... I have a set of colder plugs i'm going to try, and maybe ill revert back to my old coil to see if that helps. Any ideas? Quote Link to comment Share on other sites More sharing options...
lazlo Posted August 14, 2014 Share Posted August 14, 2014 White foam, also called milkshake, in your coolant is a sign of a blown head gasket. Any white smoke coming out of the exhaust? That would be coolant being burned in the combustion chamber. After you get that sorted out, and hopefully confirm that your headgasket is intact, then you can return to the original question of why it is running hot. A compression tester could come in handy here. Blockage somewhere in the system not letting the coolant circulate? Have you tried flushing it per the FSM? There is a plug on the drivers side of the block. I had a motor that had a nasty rust and crud booger behind the plug that I had to excavate. Everything was good after getting that cleaned up and properly flushed. However, I did have to go back a couple of thousand miles later and re-flush as all kinds of other schtuff got picked up in the coolant after I got it all flowing again. Water pump OK? Where is the timing? Someone may jump in and call me an idiot, but I don't think it is your coil or plugs. Why did you hollow out your T-Stat? Quote Link to comment Share on other sites More sharing options...
johnc Posted August 14, 2014 Share Posted August 14, 2014 You also should run a thermostat or a flow restrictor in the thermostat housing. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 14, 2014 Share Posted August 14, 2014 Popped my radiator cap to make sure i wasnt running low on coolant and noticed a very thin layer of white foam on top of the coolant.. You popped the cap after it was hot? I can't do that on my car, coolant will overflow. And the temperature gauges and senders on these cars aren't known for accuracy. I would get an accurate measurement before going crazy. The steady temperature would be a good thing if it's in the right range. Quote Link to comment Share on other sites More sharing options...
Connor280ZX Posted August 14, 2014 Author Share Posted August 14, 2014 Lazlo, the only smoke that comes out of the exhaust is a bit of blue smoke on decel, which this engine has always done. Probably needs valve seals. I haven't done a compression test yet, but its on my to do list. The previous engine and radiator had a quart of sand and rocks in it from sabotage, which caused it to blow. I have only reverse flushed the engine, havent used that plug behind the exhaust yet, but that's probably a good idea to do so. Water pump seems fine, no leaks or bearing noise. I cut the internals out of the thermostat just to see if it would run any cooler or not. Not sure if its just me, but it did seem to start to run hot right after i upgraded the ignition. NewZed, yes, when i popped the cap the car was running around 180-190F. Just a Pssshhh of air escaping, and a bit of gurgling. Of course i had to open it slowly though. The sender seemed to me to be reading accurately, but i guess i could try another method if measuring the temp just to make sure. Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 14, 2014 Share Posted August 14, 2014 How are you coming up with these numbers? 140/150...180/190... 200-220? Do NOT use the dashboard gauge. Quote Link to comment Share on other sites More sharing options...
Xnke Posted August 15, 2014 Share Posted August 15, 2014 Check your ignition timing... The OEM dash gauge will lie to you. Without fail, it will lie to you. Replace it with a quality aftermarket gauge, and replace the clock with a quality oil pressure gauge, if you are at all concerned about those two data sources. Otherwise just temporary in some to get good numbers. Quote Link to comment Share on other sites More sharing options...
DaneZ Posted August 15, 2014 Share Posted August 15, 2014 Running a thermostat again would be a good idea. Without a thermostat or restrictor the coolant runs through the radiator so fast it doesn't have time to cool. Quote Link to comment Share on other sites More sharing options...
Connor280ZX Posted August 15, 2014 Author Share Posted August 15, 2014 Yes, Tony, i have been trusting the gauge... I'm going to pick up one of those laser temp readers to point at the thermostat to see how accurate that gauge really is. Xnke, I have guessed on my IGN timing for this reason: The little white mark on the pulley that lights up with the timing gun is missing... No idea why but it's just not showing up. With and without vac advance hooked up. I think my timing is around 2BTDC. The thernostat is still in place, i just removed the valve assemble, so its basically just a disk with a small hole in it... I guess i could try putting in a new one to see if it makes a difference. Quote Link to comment Share on other sites More sharing options...
Zipper Posted August 15, 2014 Share Posted August 15, 2014 You don't mention a fan here? Useful cooling device! I had overheating at idle/stops with my L28 due to a fan clutch, spinning too freely. Changed it out and problem completely solved. What was the fan on your old engine? But if you have a blown head gasket, you need to tackle that first. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 15, 2014 Share Posted August 15, 2014 You can get a digital thermometer with a small fast-acting probe for about $12 at Bed Bath and Beyond. Stick it in the coolant and see what it says. Overall, you're doing way too much guessing, with the temperature and the timing, and coil and the plugs (both of those guesses are way off). Quote Link to comment Share on other sites More sharing options...
Connor280ZX Posted August 15, 2014 Author Share Posted August 15, 2014 Zipper, It has a brand new fan clutch that i installed to try and correct this issue. Zed, going to try what you are suggesting today, as well as another flush, this time from the bolt in the back of the block. Quote Link to comment Share on other sites More sharing options...
Connor280ZX Posted August 15, 2014 Author Share Posted August 15, 2014 Ok. I just went to unscrew the bolt on the back of the engine under the exhaust manifold, and nothing... Not even a drip. I stuck my finger in the hole and it felt like i was touching a flat peice of metal, like the hole doesnt go all the way though the block... I don't get this. Quote Link to comment Share on other sites More sharing options...
lazlo Posted August 15, 2014 Share Posted August 15, 2014 Now you are on to something. If your are actually getting your finger all of the way into the passage, you have a blockage somewhere and the coolant isn't circulating properly. Like I said, mine had a rust plug under the bolt and I had to scale it out with a pick. Quote Link to comment Share on other sites More sharing options...
lazlo Posted August 15, 2014 Share Posted August 15, 2014 I'm having an ID10T error and can't edit my previous post. Did you try running it with the plug out to see if you are getting any flow out of the hole? Quote Link to comment Share on other sites More sharing options...
Connor280ZX Posted August 15, 2014 Author Share Posted August 15, 2014 (edited) Upon further inspection, it seems like the previous owner tried this method because part of the bolt has snapped off in the block. Jesus... I can't Believe this. On the bright side, I did a compression test and i think my results are alright. Dry: 175 - 174 - 174 - 178 - 177 - 176Wet: 189 - 195 - 195 - 183 - 190 - 187 Edited August 15, 2014 by Connor280ZX Quote Link to comment Share on other sites More sharing options...
Xnke Posted August 16, 2014 Share Posted August 16, 2014 uhhh...2BTDC??? Yeah, that's going to run hot. Not enough ignition timing will make the engine and exhaust run very hot. You absolutely need to know where the ignition timing is. If you can't set the timing, then you need to stop and correct that before you try anything else. BASIC TUNE UP FIRST! Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 16, 2014 Share Posted August 16, 2014 Xnke, I have guessed on my IGN timing for this reason: The little white mark on the pulley that lights up with the timing gun is missing... No idea why but it's just not showing up. With and without vac advance hooked up. I think my timing is around 2BTDC. I was just going to mention the same thing as Xnke. What do you mean by "the timing mark isn't showing up"? Is the mark still on the pulley but isn't there when you use the timing light? Is the timing light not firing? Is the paint just worn off of the pulley so it's hard to see? Bring your engine back around to TDC (Google "finding tdc with heads on") and locate the indentation where the mark should be and put a dot of white touch-up paint on it. If the timing mark isn't lining up with the 0 deg mark on the front cover, then your crank pulley is likely shot. If it does line up but is nowhere to be seen when the engine is running and you use the timing light then your timing is WAY off. Quote Link to comment Share on other sites More sharing options...
Connor280ZX Posted August 16, 2014 Author Share Posted August 16, 2014 (edited) Oh damn. I didn't think that the timing being a few degrees retarded would make such a difference in engine temp. What i mean is basically that little white tally mark on the pulley that points to the degree on the timing scale isn't visible for some reason. Dizzy advance unplugged, or not i can't see the mark. The timing light is definately firing. I assume the paint is worn off, i tried cleaning the pulley with no luck. I guess i could take the plugs out, turn the engine to CYL 1 TDC and make a timing mark, but i will read up on that so i know exactly how to do it right the first time. I'm going to try to advance the timing all the way to see if that makes a difference first. It initially was all the way advanced before it started heating up. Edited August 16, 2014 by Connor280ZX Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 16, 2014 Share Posted August 16, 2014 One way to get close to zero is to set the camshaft sprocket notch on the groove on the compression stroke (lobes up). The damper pulley notch should be close to the zero line on the marker, visible for sure. If it's not, you might have damper problems. Also, if you get the marks all lined up, pop the distributor cap and make sure that you're rotor is pointing at the correct #1 plug wire, and that it's the one your light is on. Maybe you have some firing order weirdness. Quote Link to comment Share on other sites More sharing options...
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