johnc Posted July 11, 2008 Share Posted July 11, 2008 I am also using more of the push-lock hose fittings as replacements for braided lines. I don't rely on just the push lock connection though. I usually add a oetiker clamp. http://www.hydraulic-supply.com/html/productline/mfgprod/oetiker.htm Link to comment Share on other sites More sharing options...
ktm Posted July 11, 2008 Share Posted July 11, 2008 I am simply using braided in this case for appearance given my engine bay. I like pushlock as well and run some of the fittings for my vacuum lines. Goodridge has a nylon-esque type of braided product that is much easier to work with than braided SS. You get the same benefits without the chaffing issue. Link to comment Share on other sites More sharing options...
ktm Posted July 11, 2008 Share Posted July 11, 2008 Slow Old Car, clearance for one. try welding a NPT bung on there and see if it will fit. Link to comment Share on other sites More sharing options...
X64v Posted July 12, 2008 Share Posted July 12, 2008 Well, I'm glad to see some support for the push-on hose. John, that's why I've assembled all my hoses with the included crimp collar. They're not crimped right now, but if I have a problem (or if I just feel like it) I'm going to get the right size crimper and lock them all down. I tapped mine because I don't have a tig, but ktm makes a good point about room. There is room, but it'll be a tighter fit for sure. Other than that, I don't see a reason not to weld on a -6 fitting if you feel like it. Edit: You may have a problem if you ever want to get your manifold mating surface machined flat. Link to comment Share on other sites More sharing options...
hughdogz Posted July 14, 2008 Share Posted July 14, 2008 I'm thinking of going with a fuel rail blank and AN fittings to solve any hose heat issues (like Alan Osborn did on the Bonneville S130). If anyone asks what it is, I'll say it is staged direct fuel injection. He suggested that I also plug the "bypass" hole (in the block at the head gasket interface) that allows the coolant to travel directly from the water pump outlet into the head. The caveat is that the lower radiator hose may collapse due to negative pressue this might cause. I think TonyD mentioned something about this too... For the return, I was thinking of going into the upper thermostat housing. He went directly into the radiator inlet. Link to comment Share on other sites More sharing options...
TimZ Posted July 14, 2008 Author Share Posted July 14, 2008 He suggested that I also plug the "bypass" hole (in the block at the head gasket interface) that allows the coolant to travel directly from the water pump outlet into the head. The caveat is that the lower radiator hose may collapse due to negative pressue this might cause. I think TonyD mentioned something about this too... He did, in the context that it was a bad idea to block the bypass hole. Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 21, 2008 Share Posted July 21, 2008 Hey Guys,Here are the pics of the cut-up P-90 showing the inside water passages. The first two pictures show the inlet points in the gasket surface. You will notice that there are holes in the head that are blocked off by the HKS steel gasket. These could flow water if the gasket was opened up. In the second picture you will see holes in the head gasket that do not have holes going into the head. This makes me wonder if this was for a reason, or just a manufacturing convenience, so that 1 head gasket design would fit many application of the different years. I wonder if an improvement could be had by opening the gasket up to the holes in the head, and the head up to the gasket. Hmmm. So should holes be cut into the head gasket when it is blocking head ports? I suppose the answer is to leave it alone as long as the year-range of the gasket matches the year of the head. Link to comment Share on other sites More sharing options...
jgkurz Posted July 23, 2008 Share Posted July 23, 2008 He did, in the context that it was a bad idea to block the bypass hole. My bypass hole is blocked and I can't say there has been a notable cooling benefit. Link to comment Share on other sites More sharing options...
Tony D Posted July 27, 2008 Share Posted July 27, 2008 My comment on blocking the bypass hole in the block being 'bad' is directly related to the ammount of flow the waterpump will produce when the engine is revved off-idle BEFORE the thermostat is cracked. There has to be enough flow through the engine's bypass circuits to allow the pump flowing freely without cavitation. This is roughly 2 10mm holes flowing directly back to the inlet of the pump. In later cars like the 73 and 74 Z's the second bypass line around the back of the engine was closed off as the engine neared 170-177F...about the time the thermostat was cracking to flow to the radiator. Note the thermostat has a spring relief function---put enough pressure on it and it WILL pop open somewhat, allowing flow. But it's likely the pump is experiencing cavitation from low-flow before that point. Put a water pressure gauge on the block and watch what happens. It's interesting, you can see when the pump is cavitating if you have a good resolution gauge with a fluid damped movement. It will start twitching, moving around, etc...and right about that time, if you have a good temperature gauge, you will see the temps start to do strange things: cool off....then rise suddenly, the rise some more... Link to comment Share on other sites More sharing options...
dapiper Posted July 29, 2008 Share Posted July 29, 2008 I am building a N42 head and am considering recirc lines on cyl 5 & 6 as posted here. Any caveats? I will recirc both to Tstat hsg. How thick is head? Do I need to weld boss to provide sufficient thread engagement? AN6 big enough? Link to comment Share on other sites More sharing options...
HowlerMonkey Posted July 29, 2008 Share Posted July 29, 2008 Did the later head gaskets start that block some holes happen to show up at about the same time as the cylinder head exhaust port liners? If so, would one believe the holes were blocked because the liners keep some heat from the exhaust port from conducting into the head? Link to comment Share on other sites More sharing options...
WizardBlack Posted August 20, 2008 Share Posted August 20, 2008 So for someone with all the heater core stuff removed and plugged and running a non-water cooled turbo on an EFI car, the #5 and #6 taps can be routed directly to the bottom of the thermostat housing? EDIT: Another comment/question here. Based on a previous poster's hand-drawn image of the various routes the coolant can take, it seems that as soon as the coolant is pushed in to the block, it has about seven routes it can take. It can immediately go up through the head gasket to the head and out of the thermostat housing, or it can flow through the motor and between any two cylinders and then up through to the head and then back forward to the thermostat housing, etc. Would it not make sense in this parallel flow scheme (if you thought of it like a parallel electrical circuit) that the longest path (namely cylinders 5 and 6) would get the least amount of coolant because they have the longest path? Additionally, 5 is hotter than 6 because 6 gets more air cooling for being on the end of the engine whereas 5 is more insulated with another cylinder on each side of it? That would also explain why simply adding an additional exit point at 5 and at 6 effectively shortens the route for these two to help them pick up more coolant flow. Link to comment Share on other sites More sharing options...
Tony D Posted August 20, 2008 Share Posted August 20, 2008 That is correct. Electramotive put these cooling holes above every cylinder and ran a paralell cooing header that fed into their radiator or upper radiator hose (I forget which). The later FIA heads had a similar cooling flow with separate manifold. The LY Crossflow heads had another manifold entirely separate in the intake manifold (like the L4 Engines) with three large holes letting coolant out between each pair of combustion chambers. Nissan fixed this on the FIA heads and the LY, but did nothing on the L-Head as they didn't see it as a problem at the horsepower levels they had in mind for it. The LY head motors were all 320 HP L24's in Rally Use, same as the FIA head, dedicated high-specific output (compared to stock) engines. Personally, I think many street driven Z's will benefit from the modifications done here to #4,5,6, not just 5&6 alone. My 260 right now is spark knocking (on 91 octane) to beat the band on partial throttle hillclimbing running SU's. Dropping that temperature will help with that issue, without having to retard my spark. I have a problem retarding my spark running premium fuel on a stock setup which is already tuned rich to begin with! As for the heater being blocked off---that is irrelevant to the discussion. Routing the cylinders to the bottom of the theromstat doesn't do anything different than what is already internal to the head---it just gives it an independent flow channel with less restrictions allowing more flow through an area with stagnant water relative to the front two cylinders. The Water Cooled Turbos will benefit from these mods as well. When your heater is on, it is NOT giving more flow to that area above the combustion chambers, and it is recycling to the inlet water that has already passed through a radiator (the heater core) so that recycle is not a big issue. Don't cool that water flow and you run into heating issues recycling back to the inlet. The hot water that can be recycled is basically limited to what will flow through an 8 or 10mm line along with a mirrored 8 ot 10mm internal passage. And that is more a function of letting the pump flow during warmup when the thermostat is closed. After that cracks open, ideally those bypass lines would close altogether to allow all pump capacity to go through the coolant system, with no recycle. In an ideal world, the turbo would be fed water from the cold side of the pump during operation, instead of where it gets it. But after a shutdown, the coldest water available is on the inlet to the water pump, and that goes directly to the hot turbo...and then to the thermostat housing---meaning the hot turbo can act as a thermal siphon heating the water and letting it rise to the water outlet neck...it will get more from the radiator! Follow? Link to comment Share on other sites More sharing options...
Xnke Posted August 21, 2008 Share Posted August 21, 2008 I'm working on a 260 Spec E88 head right now, and am interested in the spark knocking that you are experiencing. Are you planning to do the coolant mod soon Tony D, or just speculating? I'm going to be adding external flow lines to cylinders 5+6, do I need to go ahead and run one to #4 as well? I'm hoping to run my work-in-progress L29 to power levels of 200-220 horses eventually, so if this is gonna be any kind of issue at all, I want to catch it now. Link to comment Share on other sites More sharing options...
Tony D Posted August 21, 2008 Share Posted August 21, 2008 It wouldn't hurt. The head I have on there now is an L24E N47, changed some time in the past. I have another E88 of proper vintage for it...but 'vintage' is the key. The car is numbers-matching, and my wife will eventually return to driving it so she wants everything looking stock. I will probably not do the mod to this car, but my 73ZT will get it on the new engine, as well as the 71 "Rally" vehicle. They aren't 'stock' by any stretch of the imagination and I'm not constrained by that requirement on them. Actually, now that I think about it, screw it! The N47 is going to be a throwaway anyway. I think I just might do this just to see how it helps the spark knocking. I got some 1/2" tubing and swagelocks a-lying around the yard. Hell, I need to change the coolant to stuff with water-wetter in it anyway. What the hell. Why not? I'll repost when it's done. I got to do it while it's still hot or we will have to wait a year to see the results! LOL It's my 'daily driver' now so that is in the mix... It has to be 'back up' before any weekend is complete. Link to comment Share on other sites More sharing options...
ktm Posted August 21, 2008 Share Posted August 21, 2008 Don't forget I've been running this setup for a couple months now and I can atest that my engine is running cooler. Link to comment Share on other sites More sharing options...
WizardBlack Posted August 22, 2008 Share Posted August 22, 2008 That is correct. Electramotive put these cooling holes above every cylinder and ran a paralell cooing header that fed into their radiator or upper radiator hose (I forget which). The later FIA heads had a similar cooling flow with separate manifold. The LY Crossflow heads had another manifold entirely separate in the intake manifold (like the L4 Engines) with three large holes letting coolant out between each pair of combustion chambers. Nissan fixed this on the FIA heads and the LY, but did nothing on the L-Head as they didn't see it as a problem at the horsepower levels they had in mind for it. The LY head motors were all 320 HP L24's in Rally Use, same as the FIA head, dedicated high-specific output (compared to stock) engines. Personally, I think many street driven Z's will benefit from the modifications done here to #4,5,6, not just 5&6 alone. My 260 right now is spark knocking (on 91 octane) to beat the band on partial throttle hillclimbing running SU's. Dropping that temperature will help with that issue, without having to retard my spark. I have a problem retarding my spark running premium fuel on a stock setup which is already tuned rich to begin with! As for the heater being blocked off---that is irrelevant to the discussion. Routing the cylinders to the bottom of the theromstat doesn't do anything different than what is already internal to the head---it just gives it an independent flow channel with less restrictions allowing more flow through an area with stagnant water relative to the front two cylinders. The Water Cooled Turbos will benefit from these mods as well. When your heater is on, it is NOT giving more flow to that area above the combustion chambers, and it is recycling to the inlet water that has already passed through a radiator (the heater core) so that recycle is not a big issue. Don't cool that water flow and you run into heating issues recycling back to the inlet. The hot water that can be recycled is basically limited to what will flow through an 8 or 10mm line along with a mirrored 8 ot 10mm internal passage. And that is more a function of letting the pump flow during warmup when the thermostat is closed. After that cracks open, ideally those bypass lines would close altogether to allow all pump capacity to go through the coolant system, with no recycle. In an ideal world, the turbo would be fed water from the cold side of the pump during operation, instead of where it gets it. But after a shutdown, the coldest water available is on the inlet to the water pump, and that goes directly to the hot turbo...and then to the thermostat housing---meaning the hot turbo can act as a thermal siphon heating the water and letting it rise to the water outlet neck...it will get more from the radiator! Follow? Yep, I follow. I apologize for misleading about the turbo and heater stuff. I just wanted to stress that my cooling system is about as simplified as you can get. It sounds like a decent plan with 4/5/6. What of blocking the thermostat housing off altogether and running, say -4 AN lines from 1/2/3 and -6 AN lines from 4/5/6? Route them together in a remote t-stat housing, etc.? Is this to say that, due to the recent results from the bypass lines, many think that the theory of poor casting flaws, etc. doesn't contribute that much to the issue? Link to comment Share on other sites More sharing options...
ktm Posted August 22, 2008 Share Posted August 22, 2008 There is no reason to go overboard. I've blown three head gaskets. Every single gasket showed detonation on 5 and 6; cylinders 1, 2 and 3 were perfectly fine. Read the thread again through it's entirety. The real issue is #5 and #6. To answer your question, you could do exactly what you described, but why do it unless you are running a setup that is going to be turning lots of revs all the time. For a street setup, making sure your coolant system is holding pressure, running distilled water with Water Wetter, keeping the coolant topped up, keeping air out of your system, etc. will be fine. Link to comment Share on other sites More sharing options...
Tony D Posted August 22, 2008 Share Posted August 22, 2008 I would agree with KTM on this point. Elecramotive ran a whole separate manifold, but they still kept the thermostat housing. I know some L-Engines in Boats blocked off the uppoer thermostat housing, but let's not even go down that route---they are turning like 9500 rpms continuous and have 70 degree water supplied directly... no I'm not even going to do it.... No! "I agree with KTM, let's not go overboard, fix the issue that is present and don't overengineer a solution to something that won't exist in your situation." Link to comment Share on other sites More sharing options...
WizardBlack Posted August 23, 2008 Share Posted August 23, 2008 Gotcha. No worries. 5&6 it is, then. Link to comment Share on other sites More sharing options...
Recommended Posts