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Head cooling on cylinder #5 - solutions?


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the radiator is made by a company called Meziere http://www.meziere.com/index.php?pgName=rad

 

Interesting idea about tapping only one of the cylinders above the exhaust port Tim. I will take some pictures tomorrow of a cross sectioned head at #5.

Have you ever noticed that the cooling inlet size and hole positions on the head where it mates to the block has changed over the years. Some holes have been added and some omitted as well as there size. It would be interesting to check the differences between your N-42 and a P-90. I have both of those heads at work, I will check it out as well, maybe Nissan found the same thing out when they went to the P-90 head from the N-42.

I was also thinking about the flow. You know how they say on an intercooler with the inlet and the outlet on the same side causes a recirculation of the air inside the intercooler, and that baffling helps this. I wonder if the water could be seeing this same type of effect. Here is a really bad illustration of what I am talking about. On the left is what it should probably work like and on the left is a possibility of what could be happening?

Now if we only had a clear plastic head and block to watch the water flow:

 

 

flow.JPG

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  I assume you did try to source the LD pump in Australia, I saw a thread and you mentioned you got it from Japan (?)

My thoughts on the Summary:   - The path of coolant through the L engines results in the rear of the head receiving the hottest coolant having stagnated water flow, insufficient for the he

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Then again...like GM found out in the 50's, but didn't take the $$$ to implement till the recent SBC Generation...who says the coolat needs to enter the block? Kind of stupid, no? Putting the coldest water in the coolest portion of the block---totally opposite of any other heat exchanger!

 

I reverse flowed a 6.6 Pontiac a long time ago, after reading some articles about it, and having it make sense to me: Coolest Water entering the hottest portion of the engine, and then pulling that heat down to the block where it aids in keeping cylinders round from equal heat top to bottom... Really cools down the heads as well.

 

I just cause all sorts of problems making statements like this, huh? LOL

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Personally, I'm kind of leaning towards the Evans NPG solution, but they require elimination of all water from the system, which isn't that easy without pulling the block.

 

Easy as pie, run your engine till warm, shut down, drain coolant.

 

(This sounds wierd...)

 

Refill with the best technical grade Isopropyl Alcohol you can get your hands on, I can get 99% from the hardware store.

 

Let it have some residence time to assimilate the water left over, then drain and leave it open to evaporate.

 

Alcohol Flushing is very efficient at removing trace amounts of water in any oil system. I have pumped 100 gallons at a time through large Centrifugal Compressor gearboxes and sumps after an oil cooler had broken some tubes and then contaminated the system with water. Those high quality pinions and thrust collars don't take long in water to corrode to the point of uselessness!

 

I cuirculate with a diaphragm pump.

 

For the Block you can probably get away with a gallon in through the thermostat housing, and drain it into a bucket through the lower hose.

 

Heater Core, if you have one could be done separately.

 

Alcohol works really well for soaking up water from just about anything! Cleans up grease and oil as well---and usually won't kill rubber seals so it shouldn't have any affect on the water pump seals or stuff like that.

 

Good Luck!

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Guys,

 

I was looking for my 3 Z manuals but can not find any of them, so here is a thought. If you pull water from the back of the head from the boss for the water to the heater core could this help out some?? Also on the P90 head you have a coolant sensor boss behind the #5 cylinder, maybe you can make this bigger and pull coolant from there?

 

Not sure how you would pull coolant from these, maybe a small pump of some type???

 

HB280ZT

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Thanks Tony - great advice. Since I already have the head pulled, I think I should be able to come up with a plan for flushing the block, and the heater core and rad separately.

 

On the reverse flow thing, I have had thoughts about that as well, but haven't figured out how to plumb things without a ton of changes...

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Then again...like GM found out in the 50's, but didn't take the $$$ to implement till the recent SBC Generation...who says the coolat needs to enter the block? Kind of stupid, no? Putting the coldest water in the coolest portion of the block---totally opposite of any other heat exchanger!

 

I reverse flowed a 6.6 Pontiac a long time ago, after reading some articles about it, and having it make sense to me: Coolest Water entering the hottest portion of the engine, and then pulling that heat down to the block where it aids in keeping cylinders round from equal heat top to bottom... Really cools down the heads as well.

 

I just cause all sorts of problems making statements like this, huh? LOL

 

 

I was waiting for someone to bring this up, Tony the trouble maker HAHAH. Now there is even more to think about...

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Then again...like GM found out in the 50's, but didn't take the $$$ to implement till the recent SBC Generation...who says the coolant needs to enter the block? Kind of stupid, no? Putting the coldest water in the coolest portion of the block---totally opposite of any other heat exchanger!

 

I reverse flowed a 6.6 Pontiac a long time ago, after reading some articles about it, and having it make sense to me: Coolest Water entering the hottest portion of the engine, and then pulling that heat down to the block where it aids in keeping cylinders round from equal heat top to bottom... Really cools down the heads as well.

 

I just cause all sorts of problems making statements like this, huh? LOL

 

I am thinking that there are arguments for circulating coolant both ways, depending on application and observed results in a specific application. I believe I read somewhere that for some applications the most efficient path is for the coolant (either air or fluid) to enter in the cooler region, cooling it to the limits of the temp differential as allowed by flow speed, and then move on to the hotter region, where it will still cool, because of the remaining temp differential.

As Tony D points out, apparently reducing the temperature differential between the top and bottom of the block can be as important as maximizing the amount of heat pulled out by the coolant.

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Yeah, it's one of the reasons JeffP always regrets calling me and discussing anything! "Every time I talk with you it costs me $2000!" LOL

 

If you are considering an electric pump, the plumbing is secondary, really.

I believe if you take a look at how the Electramotive People vented their heads, reverse flowing will be a snap, though the bypass circuitry may need to be rethought.

 

And electric pump pumping into the head, and out the stock waterpump location would not be the most difficult to do, especially if you use a nice aluminium plate to replace the water pump and use that as your 'outlet housing' for the thermostat.

 

With the Pontiac we did for a class project, we reverse flowed a 6.6L Trans Am (great to have GM drop off flood vehicles every year!) and ended up using a much smaller radiator---I want to say Toyota Corona or something like that. Granted the external pump design of the Pontiac and SBC is easier to alter than on our Datsuns, the electric pump option makes for an interesting alternative.

 

Really, pushing it in there cold to the head (130F maybe...), and under pressure will really halt any kind of spot-boiling issues in my mind at least. The problem is the coolant already heated when it hits those head pockets, well over 100 degrees in any case, and with the way Aluminum wants to transfer heat...oooh, bad!

 

I have been convinced that when the Bonneville Car goes Turbo, I will figure out the plumbing issue and do it that way. From the way the Pontiac acted during our winter testing, the reverse flow really made for a better, more behaved vehicle. With a high specific output L, I think the reverse flowing of the system would reap many benefits if from nothing else, the decreased water temperature being introduced to the head.

 

I can't think of any high-efficiency water transfer system that does not put counterflow cooling at the head of the list: coolest water at hottest point of heat generation. Heat exchangers, refrigerant systems, etc... the only possible downfall is the formation of steam bubbles and having the pocket go to the head...proper venting and bypass lines should eliminate most of this danger as it does in industrial applications everywhere.

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Refill with the best technical grade Isopropyl Alcohol you can get your hands on, I can get 99% from the hardware store.

 

I don't know how many of my fellow HybridZ'ers out there will be able to appreciate this sentiment, but its a cool feeling when you hear somebody whose word and knowledge you HIGHLY respect passing along a trick that you have known about for a LONG time to someone else....

 

Usually 91% Isopropyl is the strength readily available, (I have never seen 99%; 91 is literally at the corner drugstore and wal-mart. Then again, I cannot say that I have LOOKED for 99% in a hardware store.) I know 91% is plenty strong enough for use as a solvent in most cases to be considered "pure alcohol." It IS a fantastic dryer, and its one of my three big solvents: 91% Iso; WD-40 (about all its any good for anymore, now that we have PB B'Laster AND Sea Foam Deep Creep; ) and Naptha. Of these, the alcohol (or a multi-stage process terminating with an alcohol rinse) is the only way to go for any sort of "drying" application; WD-40 is best in applications where a certain amount of "hydrophobia" is involved, and naptha is the all around safety net: if the other two didn't work, a little naptha cant hurt anything.

 

If those guys fail, its time to break out bigger guns like goo gone, and the whole gamut of industrial-type solvent products. Its surprising how rarely I need that stuff, though. This is ALL irrelevant to the current discussion, though, so I'll drop it.:rolleyesg

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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.

 

The other pictures show a large casting flash rib blocking probably 50% of the water passage from the bottom of the head to the top. This web was going from the #6 to the #5 cylinder. It appears that these flash webs are through the whole head. There are also some large casting bumps from the exhaust studs that would appear to restrict flow.

 

The final pics show the nice open cavity that flows above the exhaust ports. We talked about taping into the head above the exhaust ports, this looks like an ideal place.

 

Sorry about the big pics, but wanted to show the details. Click the pics to enlarge them from my gallery

 

Enjoy, Jeff

 

blockedbygasket.JPG

 

notopeninhead.JPG

 

castingweb.JPG

 

close-upweb.JPG

 

bump.JPG

 

middle.JPG

 

tap.JPG

 

tap34.JPG

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I would posit many people who run 1/4 mile at a time probably won't encounter this issue with cooling, but people who are really hammering on it for full load dyno sessions, track events, and high speed contests where the engine is running WOT for minutes at a time will benefit from addressing this issue.

 

Those are some nice cutaways, people can really see what is going on in there. I would say that with a -4 NPT or -6 NPT hole at the indicated point you would have access to the interior of the head to attack some of that flash with a carbide burr and knock some holes in it to allow steam entrapped below the flash to escape...

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Tim, I can cut up more of the head, but it looks as if the "flash web" runs the length of it. I would say it is a casting error. You can really see the difference in the quality of the casting between a N-42 and the P-90. On the outside near the port openings a N-42 is very nice and smooth. On a P-90 that same area is very inconsistent and rough. I wonder if this reflects on the inside.

Tony D, it looks like you could access some of the flash through some of the openings in the gasket surface, and also by removing the plugs in the rocker valley.

Sorry I cant cut up the N-42, its in great shape and going to be used on one of my projects. I did compare the water ports on the P-90 and the N-42 and they were the same. I think it was the E-31 that was different.

 

Jeff

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Awesomeness on a Stick!!!

 

Thanks for the photos, if you ask me those pics alone qualify this thread for sticky status, but I am trying to stockpile as many head images as possible to try to a comprehensive photo essay as a companion for the great links we have for the text write ups on the various heads. Once I compile enough high quality pictures (I am striving to save each photo in a folder with the original poster's name attached) it will be posted as a thread here.

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Tim, I can cut up more of the head, but it looks as if the "flash web" runs the length of it. I would say it is a casting error. You can really see the difference in the quality of the casting between a N-42 and the P-90. On the outside near the port openings a N-42 is very nice and smooth. On a P-90 that same area is very inconsistent and rough. I wonder if this reflects on the inside.

Interesting. If the web runs the length of the head, then I'm not sure that it would account for the anecdotal evidence of #5 being a problem area, especially not if the N42 doesn't have the flash. However, it does sound like removing the flash would at least change the flow characteristics - hopefully it wasn't "added" in an effort to address the "#5 issue" :mrgreen:.

 

Also - sorry - I didn't realize that you didn't have the whole thing cut up already. What you've shown is extremely helpful, I didn't intend to ask for more free work.

 

Sorry I cant cut up the N-42, its in great shape and going to be used on one of my projects. I did compare the water ports on the P-90 and the N-42 and they were the same. I think it was the E-31 that was different.

AWWWW, COME ON - you can always JB Weld it back together...

 

Again, sorry - it sounded like you had a scrap N42.

 

hell, let's go DEVAS on the valves, and then we can use those threaded holes for the upper water gallery! LOL

:mrgreen:

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I have an E31 head that blew the water jacket though the exhaust port in number 3. I had the head checked to see if it could be welded and the technician found that there were more thin spots in the exhaust ports throughout the head. This particular head had not been ported but the damage may have been due to corrosion over the years.

 

My current track L24 with an E88 gets progressively hotter at WOT. I put a higher pressure cap on it and I used a higher temperature thermostat. The condition improved but it is not fixed.

 

I am considering a "constant purge" water system with a swirl tank for my new track V8 327SBC. I have only begun to consider the plumbing and tank requirements. The Idea behind the system is to constantly purge air from the system using a bypass restriction and a swirl tank.

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totally awesome thread guys.

 

i may be off base with this, and i may be foolish for asking, but in regards to the coolest cooling medium and which places it should go to: how about the coolant entering in more than one place? like it splits from the radiator (or electrical pump) and goes to 2 inputs: one to the head and one to the block? i realize that it might be a bear ensuring that one doesn't counteract the other and it may cause eddies, but with enough fabrication it might work....

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