Water flow through the L series heads

Engine, Transmission and related drivetrain.
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Byron510
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Water flow through the L series heads

Post by Byron510 » 16 Feb 2018 17:12

OK, this post is just a bit of a question regarding water flow in our old L series head - for those of you who haven't stepped up a few decades in engine design.

I was browsing on a Z forum, and came across this;

https://www.facebook.com/godzillaracewo ... ater&ifg=1

Does this mod simply follow the FIA L4 head design where the water had a similar flow pattern? Is there water cycling issues in these heads generally? Is it worse on the L24-28 motors than on the L13-20B? Just curious as these motors have been raced here in NA since 1970 and I haven't seen this mod done in the past. So why the need now?

Thoughts?

Byron
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zKars
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Re: Water flow through the L series heads

Post by zKars » 16 Feb 2018 17:43

L6's definitely suffer from overheating in #5 and #6, but it's restricted to very high output engines. There is a very extensive thread on hybridZ.org that goes on and on and on about it. i'll see if I can find the link. One of the early L20A's (I think) used an external water manifold like what GodZilla is duplicating above, so the problem has been around a long time. No issue at 150 BHP.

No surprise that L4's don't have the same issue. Less thermal mass and less length to the return path with esseentially same cooling capacity (water pump flow rate).

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Re: Water flow through the L series heads

Post by zKars » 16 Feb 2018 17:48

This is it I think. Grab a coffee and get comfortable

http://forums.hybridz.org/topic/59029-h ... solutions/

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Re: Water flow through the L series heads

Post by icehouse » 16 Feb 2018 21:42

I wonder if they flow the water top to bottom? It would be nice to send the cool water through the head first the help prevent detonation. I've thought about that with my SR's. I'm not much of a motor guy though.
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Re: Water flow through the L series heads

Post by 510rob » 17 Feb 2018 00:55

Byron, look at Jamie Mitchell's motor.

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Re: Water flow through the L series heads

Post by Byron510 » 17 Feb 2018 08:02

I’ll assume there is a similar mod there Rob, Jamie’s car hardly sees the light of day any more, but next time I get the chance...

I would assume there is some relavence to this mod. As the FIA head also addressed the issue. Jim thanks for you input on the L-6 engines. The only issue I see with the mod above is that the water ‘manifold’ has the same outlet size as all the inlet sizes. One would have thought that the manifold itself would need to be collectively larger and it’s outlet much bigger. And it feeds back into the thermostat housing after the thermostat; effectively bypassing it.

But that aside, it’s an interesting mod to come up some 50 years after the introduction of the motor.
Interesting discussion, thanks guys.

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Re: Water flow through the L series heads

Post by datzenmike » 17 Feb 2018 20:47

Image

Why are the outlet drains so high up when the combustion chambers are so much lower down? Why not copy the L16/18/L20B???



First thing that comes to mind on the L4 is the two openings for the warming/cooling of the intake manifold. I bet these move a lot of water from near the combustion chambers. Only the U67 head did not have these holes in them. That would be '75-'77 L20B engines. I have one, and put a later coolant passage intake on it and drilled out the holes.

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Re: Water flow through the L series heads

Post by Chickenman » 02 Mar 2018 14:43

1It's definitely an issue on the L6's. Doesn't take all that much HP either for the detonation problems in #5 and #6 to raise it's ugly head.

I've been tuning quite a few Turbo L28's with MS2 and MS3 lately. The cooling Mod greatly reduces detonation. More evident in areas with constant high ambient temps like Florida and Texas. But Cali has big issues with their Goat P**ss fuel.

Even the NA engines benefit from the #5 cooling port Mod. Particularly with N42 and N47 heads. I'll be doing the #5 cooling Mod to my N47 head this Summer. I have to be pretty conservative with my timing on my N47 L28 ( 10.3 + CR )

With the P90 head, there seems to be a casting issue problem. So on the Turbo Motors you can really benefit from the external cooling Mod on Cylinders #5 and #6. It's a simple fix and it really works well.

FYI. Don Devondorf was plumbing external cooling lines on the Electromotive 280ZX GTP car way back in the early 80's. Tony D and I were at the same race in Portland back in those days and we both had some interesting conversions with the Electromotive guys on the cooling system. They spent a ton of time getting it right.

And yes, the L6 does have a bigger problem than the L4 due to the length of the block and head.

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Re: Water flow through the L series heads

Post by Byron510 » 03 Mar 2018 07:30

Thanks Richard for your input. It’s good to know.
My own 289 ZXT doesn’t have any mods planned, bit if it did I’ll keep this in mind.

Regarding the mod as done above with the manifolding and size of lines, do you feel the design is correct or could use some different engineering?

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Re: Water flow through the L series heads

Post by bertvorgon » 03 Mar 2018 07:38

That would be this motor, Andy and I looked at this also.
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Re: Water flow through the L series heads

Post by Chickenman » 03 Mar 2018 09:17

^ yes, that is a picture I've been looking for.

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Re: Water flow through the L series heads

Post by bertvorgon » 03 Mar 2018 09:58

That was at Portland of course, we went down to watch the IMSA race. Andy and I were blown away as to how far over that motor was leaning.

Those things just EXPLODED down the straight with acceleration!!!!
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Re: Water flow through the L series heads

Post by Byron510 » 03 Mar 2018 10:09

Ok, so I think the photo answers my engineering based question - along with the need for such improve circulation. Thank Bert and Rich.

Note that the fittings on this the GTP car pictured here run into a manifold of much larger capacity and the outlet is much larger again. Where the package being offered at the top of the thread has the same size line heading out of the manifold as the lines going into said manifold.

In any case, it's been enlightening guys - thanks.
Electromotive 280ZX GTP Motor water lines.jpg
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I always loved this GTP car - and the radical angle the motor was placed in order to get the low hood line. The starter must have been grinding on the grand with the engine at this angle! But the work on the intake manifold and the amount of sensors on the engine control system was unreal. No wonder this car was a rocket as Bert noted, it was engineering by rocket scientists.

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Re: Water flow through the L series heads

Post by Chickenman » 03 Mar 2018 10:44

As far as the stock L28 goes, a single -6 hose at the casting pad between #5 and #6 is usually sufficient on N42 and N47 heads. P90's usually need 2 hoses for both #5 and #6 cylinders. This is due to a big casting flash on the P90 heads. The Hybrid Z article explains it all.

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Re: Water flow through the L series heads

Post by Chickenman » 03 Mar 2018 10:46

It's basically a steam vent for a stagnant area of water flow

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