Removing the cooling lines (intake manifolds)

[Pop's Z]

Hi all,

I've been considering removing the coolant hoses and fittings from the intake manifold, and just running the heater line direct to the water pump.. I have a

'73 with a F54/N42( shaved w/ a Delta Cams Stage 2 cam, and header) combo with Z Therapy 4 screw carbs(no coolant through them), and a ZX dizzy. I would love to hear a discussion as to pros and cons. Bruce, Arne, Dave? Has anyone done this? What was the result as far as driveability, etc.? Any problems? I have to admit that I would be doing it for cosmetic reasons to clean up the appearance of the engine compartment. I do live at 5,000' and most of my driving takes place at even higher altitudes if that is a factor. Thanks in advance.

Cheers, Mike

[Z train]

First-those are "heating lines".Like a exhaust X-over on a V-8.Starting and cold operation will be your only issues.Here in Az. there is no need for them-so they are long gone on my truck

[Zedyone_kenobi]

When I had put my Ztherapy carbs on I had them removed as well. You can use the stock fitting on the oil filter side of the engine, but just block off the port that connected to the intake heater line.

[Bruce Palmer]

To my way of thinking, for the average guy driving mainly summer time, I look at this as one of those ancient systems designed to leave you standing beside the road when the whole thing decides to pop a leak. An awful lot of the steel fittings on manifolds we disassemble are pretty severly corroded away from the inside to the point of being really thin. Remove the fittings and glue in some little freeze plugs to finish the holes.

Every shakey system on these old pots that can be taken out of the equation, the better. Return everything else to square one and enjoy good long term driiving fun.

[Pop's Z]

Thank you all. I was thinking along the same lines, but wanted my hand held. This car has a mish-mash of '72/'73 stuff as the P.O. had done the dump the flat tops thing, and I just transferred everything to the F 54/N 42. Those extraneous parts will be sent to the storage unit where I have put all the original parts I have taken off.

Cheers, Mike

[ozconnection]

I kept my coolant lines.

I used a cheap water valve from the hardware store to set up a system where coolant could pass through the manifold, if required.

I don't drive regularly in truely cold weather but I have. If I do in the future, I don't need to worry about letting the thing idle to warm up properly before I drive off or things like throttle plates icing up. I like the idea of having an 'option'.

As far as performance goes, volumetric efficiency is improved in summer when the ambient temps are already high, the setup can be turned off. In winter, as I mentioned, there is some benefit to retaining something!

[dimitri_zee]

I don't run carbs on my L24 but I still have a similar water path to that one that runs through the Hitatchi's. My setup though runs from under the thermostat housing across the front and down to where the heater hose runs under the spark plugs. I should take a pic, it will explain it a lot better than text! And where the heater hose connection is at the back of the cylinder head, I have a piece with 2 hose connections rather than one. Joins to the "Y" pipe fitting again where the plugs are. In case the heater is in the off position, coolant will still flow through to the back of the head. I have noticed with this system, the engine does heat up a few minutes quicker than without that plumbing; temp needle starts moving sooner than before.

[beandip]

Mike, I am running almost the same engine as you in my '73 . I have kept my hoses intact but only running coolent through the intake . Not into the SUs. What I found last year at my Clubs Show-N-Shine . We have it at Forged Performance and they offer a super deal on the use of the

Dino , several of the 240 driver took advantage . I had no problem at all but several of the other cars had detonation problems after the first pull. The ones that had the problem had disconnected the coolant hoses from the intake manifold. So this is just from my own experience. I realize that running on a Dino is not the same as on the road as far as air flow through the engine compartment. But just the same in warm weather .....

Gary

[Mikez73]

My manifold doesn't even have fittings for water lines. From my z31 turbo days...everybody's goal was to eliminate hot water percolating near the intake to whatever degree possible. Water lines to the TB and plenum were eliminated. Guys with completely custom intakes eliminated coolant from the intake completely. They had the fastest cars. Of course this is EFI turbocharged cars so completely different animal. I would still think keeping the air and fuel as cool as possible would have benefits performance wise even on a carbed car.

I wonder if anyone here uses water/alcohol injection?

[ozconnection]

EFI cars are much more precicely managed fuel wise than any car running carbs.

The idea of heating the induction tract for carbs is necessary with a wet manifold design.

Latent heat of vaporization. No heat, no vaporization.....that's why carbed cars take a while to "warm up"...the manifold has to do its thing evening up afr's between cylinders and minimize WOT mixture fallout...these things collectively called 'driveability'. Designed from the factory that way so granny doesn't get the shits when trying to drive the car to the shops, sells the car and vows never to buy another one of 'those' ever again. Damn carbies.

We can put up with the rough running issues until it warms up...isnt that part of the appeal of owning a old skool,modified car?

My car is modified too, but I do understand what the engineers were trying to achieve in the first place so kept the setup in modified form. It costs to put all that junk on a production car.....they would've junked it all if it wasn't necessary on some level.

At the other end of the spectrum, water through the manifold can prevent runaway manifold temperatures as mentioned by Beandip. Dyno's can be a bit of a odd enviroment for cars but if you're seeking out the best possible driveability versus best possible horsepower, then you have your answer.

The first few pulls may have more power (cooler induction temperatures) but power may eventually fall off as manifold temps goes rocketing skywards....get a laser heat gun onto it and see for yourself. I have!

[Bonzi Lon]

I replaced my 73 balance tube with an early polished shaved euro one. The small water line that runs from the thermostat to the balance tube, through it and to the line behind the block was found to be plugged with radiator mud, all the way through. So I wonder if the manifold tube is plugged also. Will find out this winter when I replace or ceramic coat the header and polish the N36 intakes, without cooling lines between them, among other improvements.

Bonzi Lon

[Z train]

The idea of heating the induction tract for carbs is necessary with a wet manifold design.

Only during start-up.Once the engine is up to temp,the water in the manifold is completely redundant.Where you live and how much cold weather driving should be a factor in the "removal equation".