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I hear what you're saying and I want to thank you for your thoughts on the subject Daeron! You may recall that when I started testing, I connected my pressure guage to a cold engine, basically because I didn't want to be sprayed with hot coolant as I did my work. But it was an excellent starting point to measure the block coolant pressures with a cold engine and then to witness the changes to the pressure as the engine warmed up and the thermostat eventually open. I recorded the values in another thread. Even when the engine was cold and long before the thermostat was anywhere near open, I saw close to 10 psi pressures @ idle IIRC. Man, to be honest with you, I dont remember seeing any pressure on the guage when the engine was turned off after normal operating temp had been reached and yes, there certainly would be coolant expansion due to heat soaking, the very reason why the radiator has a pressure cap on it! But the real issue is whether an electrically powered water pump can match or be better than the stockers! I mean, I just spent a shitload of cash to find out what the deal was here and I could suggest to you all that it was the best investment since buying my Datsun. I could say that! Am I? (You already know the answer to this one mate .) Maybe like jeffer949 suggests in his post, more work could have been done to the impeller on that CSR unit to at least look more like the stock unit. Its shape is very basic and without being too cruel, appears more like an accountants decision than an engineering one. I remember quite vividly as a young boy, my dad needed a new prop for his Evinrude 70hp outboard. When we went to the boat shop to buy one, there was something like 3 different designs he could have used. Subtle differences with each one with a profound performance effect when put into the water. I could only guess that with some research on the topic, impeller selection could be be based along similar lines. Low speed pressure generator, stock replacement or high speed/rpm combinations could be offered. Hell, they could develop a VATN or centrepital clutched version for those with WAY too much time on their hands. My LD28 water pump arrived this afternoon. Yes, its bigger than the stocker, but not by a lot. I guess the tip speed of the impeller is significant, so with a diameter of 75mm versus 70mm for the standard unit accounts for the greater volume of coolant passed. The length, shape and angle of 'attack' of the individual impeller vanes is the same for both pumps. Get out there and test your block coolant pressure for yourself and don't just take my word for it. That goes for the electric pump boys too. Maybe I'm missing something and my testing procedure just SUCKS.......or is it just that I have WAY too much time on my hands? C'mon, you can do it!

Nice!

Don't hope for too much old boy, 'cause, like the CSR pump, no significant water pressure could be measured on my guage. It seems to me that the electric pumps just don't have enough stonk to do what I'm asking of them. I've read articles where it's quoted that up to 20 hp is needed to turn the mechanical water at 5000rpm. If I read this bit carefully in the first place, I could've saved myself a lot of cash!!!!. How could an electrically driven water pump, regardless of the design, possibly compete with the stock, mechanical pump requiring that much power and give the 30 psi head of coolant pressure seen on my test guage? I'm assuming that when used with a late model engine with ignition and fuel management, timing would be appropriately managed. If knock was to occur due to local hot spots in the head (nucleate boiling), ignition would be retarded. And some engine power would be lost, of course. But the deletion of the mechanical water pump would help to liberate some power so the net effect would be somewhat balanced out. When the ignition timing advances again, power will return and not be hindered by the drag from a mechanical water pump. I'm waiting for the arrival of my LD28 mechanical water pump from Japan. I'm also toying with the idea of setting up the pump with a smaller than stock pulley to increase the rotational speed at lower engine rpm's. Just gotta figure out how to do it! Cheers!

Nah, buggar, the wife stole and hid the tape measure when she saw me looking for it......

Did you just measure it?

:mparty:Oooooooh Tony hits 4k posts! Today!! Got somethin' to say Tony! Cheers.

I just bought a Davies Craig water pump. Its the 115 litres per minute jobbie that looks like a small turbo in design. That 115 litres per minute is almost spot on to what you think the LD28 pump flows, 30 US gallons per minute. One advantage I see is that this volume can flow at any engine speed unlike the LD pump arrangement. Positioning the pump where recommended will perhaps push SOME of the water around the engine bypasses in the opposite way. Davies Craig recommend the lower radiator hose where the pump is to be fitted. I'm curious to see what block coolant pressures I get with this setup. The CSR pump I have ATM produces no coolant pressure. (as far as the guage is concerned) but the 115 lpm unit really pushes out some water when tested on the bench! I will set it up with the CSR unit in situ but turn it off for the tests. I'm expecting that I'm going to be able to adjust the block pressure somewhat by altering the number and size of the lines that connect to the thermostat housing. Until I test this theory, Im really only guessing........but I'm hopeful.

I have read this and experienced it first hand myself, that an oil level that's only half way up the dipstick liberates some power. Less oil windage and drag on the crank it seems. Use some caution and don't underfill it or you'll get oil surge/starvation if you like throwing your car around corners. Try to balance it out, it's not really that hard to do. Cheers.

I can just hear it....."OMG, you bought a what?"

Good job on the dyno! Now, if we can only fix your spelling...........:wink:

A response, finally. Mr. Avramovic, Our pump is designed to be a circulation pump,it will provide very little pressure. The motor turns approximately 2500 rpm at no load conditions unless you have an electrical problem. Be sure your ground is good, (not on a painted or anodized surface). Be sure you have at least a 14ga. wire on the +12 volt side and that it is fused with a 15 amp fuse. Be sure the black wire is ground and blue wire is +12 volt. So the pump is not running backwards. Thank you for choosing CSR Performance Products. Best Regards, Carol Cheesman Customer Service Representative CSR Performance Products 800-226-1274 Visit us on-line today! www.csr-performance.com Answers all my questions.......Oh and BTW, does anyone need a very newish electric water pump for their 'performance' L Series? No longer needed...wrong application! Very cheap. PM me for your best price......I'm not kidding!

I've run Holleys on my l28 for years. The L series engines seem to be quite capable running a number of differently sized carbs. I produced the most power on the dyno with a 600 cfm square bore unit with annular discharge booster venturis fitted. I had good results from a vac sec 650 cfm spreadbore carb too. Those little primaries were great for low rpm throttle response. Hec, I even ran a Nascar #80507 390 cfm square bore "double pumper" at one point. The type of intake manifold you have will also affect the way the engine performs and the way you have to tune up your carb! The Arizona is much more of a torque manifold, especially if the divider is left in place. The Clifford is the power maker but response at low rpms can be a bit soggy, especially with the bigger 600 cfm unit. I'm currently running with a highly modified #4548 450 cfm square bore vac sec on the Arizona ATM. For me and my application, this is the best setup. What works for you will be a matter of choice. For most of the people out there running Holley's, an "outa the box" #8007 seems to be the popular choice along with an Arizona intake manifold. Carter electric, 4-6 psi with 5/16 fuel line with return should do it nicely.

Fantastic stuff Paul! Great photos. Now what do we do?

I sounds like we should be more circumspect in our head gasket choices? I must admit, my last HG may have been some el cheapo that's probably blocking some critical coolant passageway and thus allowing nucleate boiling somewhere. It doesn't overheat, even with the A/C on, but it does rattle with 8.3:1 compression @ 38 degrees total!! (Hmmmm, putting on that Y70 head is a bit closer because we're all a bit wiser.........thanks). Yes Paul, I'm looking forward to seeing your pictures as well. Sticky, anyone?

We were asked years ago in a Science class "Can someone tell me what is the boiling point of water please?" Simple, heaps of kids put up their hands and when asked, all of them said "100 degrees celcius , sir". Of course, he went on to quantify our responses with " at what pressure?" Now we all looked a bit puzzled and didn't really understand the relationship he wanted us to understand at the time. However, it was a good lesson, and one that I've taught my children about!! So yes, yes KTM, I do 'get the gist' By your own statements KTM, you said you haven't solved all of your cooling problems. Have you investigated your block pressure? What size restrictor plate do you use? Do you use a different sized water pump pulley or do you have an alternate sized ie aftermarket harmonic balancer with a differently sized pulley? Is you car pure street or track or somewhere in between? This goes back to what you've said that different situations require different solutions. I hear you loud and clear....mate can you hear me? I re-read Tony's post several times and I think I understand what he's trying to say. Thank you for referring me back to it.

Ben, it's been mentioned by several people, including yourself now, about using a high pressure radiator cap. Firstly, where do you get them from? Secondly, I can't see the point IF you're running a thermostat or a restrictor in the water thermostat housing. I'm thinking that if one were to NOT run either of these, the WHOLE cooling system will run up to 1.5 bar (21 or 22 psi, I think?) Why do this? Just keep the block pressurised, where it's needed, and leave the rest to a more standard pressure of up to 13-14 psi max. Can we save the hoses and radiator from those enormous and perhaps dangerous pressures? People are doing it but do they really understand why they're doing it? Hey, doesn't this just confirm something? Running a higher than stock cap IS an ATTEMPT to increase block coolant pressure???

I can't believe you just did that. Good luck with getting your oil filter on/off unless you clean the threads up first.

Valid points, especially about what you said about taking the advice from someone on the other side of the planet, hell even different hemispheres!! But at the end of the day it's worth giving it a shot, and maybe identify an alternate solution to a pesky problem L engines seem to have. Until the other week when I started this experimentation, my cooling system was working perfectly. A recently overhauled 3 core radiator (2 core stock) with a system flush was the only addition because the old one was starting to weep. I've always used EG as a coolant material and mixed it up per manufacturers recommendations. The fuel issue is an interesting one, I use the best (read highest) 98 RON octane fuel I can get from the bowsers. Unleaded premium of course but I don't add anything to it....maybe I should be adding that lead substitute stuff....I think that has some anti-knock properties IIRC. I don't want to go there if I don't have to though. Otherwise stock N42/N42 L28. CR is 8.3 Timing has been verified by using my lovely Innova fully adjustable timing light. ATM my timing is set at 38 degrees total mechanical advance @ about 3500rpm's.

You can try this.... Get a small angle grinder with a very thin cutting blade on it. Cut two small notches (a couple of mm's will be deep enough) on the end ( think of a Holley fuel jet) and bridge it with a wide piece of flat bar or a cold chisel. Turn anticlockwise carefully and presto! 2 minutes and you're done.

Yeah, I was looking at those as well and was considering using it to change the direction of the coolant flow into the back of the head. I can see that your efforts have worked quite well for you. I've also got the MSD 6BTM, left over from the days when I ran a turbo setup in my Cedric. At the time, I found a similar thing to you, that there was excessive play with the drive spindle causing erratic timing. I solved the problem by pinching the drive slot a little (and very carefully) at the end of the distributor. Then, when replaced, there was some preload applied to the drive spindle and the mesh with the crank was more snug, timing was perfectly stable after that. Cheers for your insights. I'm using the redline water wetter mixed with distilled water....did I notice a difference....nope, couldn't tell any difference at all. The buggar still pings.......it might work for some but where I'm looking for a solution to the problem, clearly this wasn't it.

Hey Pete, yes perhaps changes to the heads were more than skin deep over the years and its more than just chamber shape that contributes to detonation resistance. Gotta get some piccys of that stuff on here, like what you showed me before of your cut up head. Good stuff mate.

This was written by Braap very recently in another thread that was dealing with compression ratios, cylinder heads and ignition advance. Chances are you have already read what he's written. Here it is: Too common for the L-6 to have to back off ignition timing due to the compression ratio. I have been preaching for some time that the power lost due to the retarded ignition timing to keep it from rattling, for greater than the power gained by the bump in compression ratio. Gain of maybe 7-10 HP max for the compression ratio bump over the paltry 8.3:1, but over 20+ HP lost in retarded ignition timing! open chamber L-6 heads, (E88, N42, N47), have their optimum non octane limited spark advance in the 38-42 degree range. "If you can't get 38 degrees total ignition advance above 3500 RPM at WOT, (N/A), with E-88, N42 or N47 head because it is rattling, you are laving HP on the table." I live near Blacktown in Sydney, NSW. The elevation here is 57 metres above sea level. It seems that Braap was able to achieve 38 total advance on an engine build similar to mine many times. His 'concern' was that it was cylinder head cooling and its deficiencies that were limiting ignition advance and power production. My 'journey' is to see for myself if the theory of insufficient coolant pressure around the head contributes to this as well. What I'm concerned about is the CSR pump isn't providing the coolant pressure I thought it would. I don't want to jump to any conclusions too soon without hearing from either CSR or JeffP on this, but I wonder if this was part of their design criteria. Davies Craig have some videos on their website which I found interesting to watch. http://www.daviescraig.com.au/Electric_Water_Pumps-list.aspx

At this point, yes, the thermofan and the water pump work together. There is no temperature dependancy ATM. I could get a water pump controller later on but what for?.......I'm thinking that whatever the stock setup does, (ie come on when the engine starts and turn off when the engine does) I can duplicate that easily enough. I guess for a turbo engine, there'll be more of a reason to avoid heat soak. A turbo timer could be set up to run just the water pump and thermofans after engine shutdown for a period of time......that would be excellent if you had a water cooled turbo.

Ah, what the hell, I bought the Moroso Electric Water Pump Drive Kit (63750) and extra drive cog that can spin the stock L series water pump 28% faster last night......to go with my new LD pump. The electric motor is designed to turn big block water pumps...should be overkill for the L Series water pump then. I'm assuming the LD engine has a redline of about 5000 rpm, so maybe the pump is designed to flow a maximum at a lower rotational speed...can anyone confirm this? Today it's hotter, like 30 degrees and after one good rev and back off, then rev again.......straight into detonation...... .......and I should point out that before testing today, I got sick of seeing that temp needle 3/4 hot, so I put in a 180 degree F (82 degree C) thermostat. (Was 190 deg. F) The needle sits just a fraction over half way now and the temps are stable...the needle doesn't budge. This is all fairly drastic stuff to bump the timing a up a few degrees I know.... Am I asking too much?? Can the stock N42/N42 L28 combo handle 38 degrees total advance? Not as it is, it seems. (..........block pressure man....it's all to do with block pressure........)

Yeah man this is sick......the more I look into this engine cooling caper, the more I like this setup. (Moroso EWP #63750) A) Water pump speed can be varied via either/or electric motor speed or pulley sizes.Totally independant of engine speed. (Electric motor spins @ 2600 rpm.) Can be left on after engine shutdown to combat heat soaking. (Max. 10 amp current draw. Will not flatten battery if left on for 1-2 minutes) C) Cylinderblock/cylinder head can have optimal coolant pressure around the cylinders and head at all times to combat pinging. D) Can use either the stock Nissan water pump or the high flow Diesel unit. E) Easy to revert back to a standard, factory setup if needed if parts fail or need to be replaced at any time. F) The kit is cheap @ US$85.00 (Jan. 2010) CSR @ US$240.00 (Dec.2009) G) May require some minimal bracket/electrical work to make it work on an L engine. H) The thermostat may be eliminated if a "dedicated water pump controller is used" (Some aftermarket ECU's may be able to handle this requirement.) Davies Craig sell water pump controllers that allow for user defined coolant temperature settings for optimal engine performance. The CSR is a good thing, but the jury (anyone with any ideas/thoughts/opinions should mention them!) is still out as to whether it 'cuts the mustard' in all of the above mentioned criteria. Time will tell. I have left messages for JeffP and CSR and I'm waiting for them to get back to me on this.