39 replies to this topic

[V-SLR5000-P]

Genuine NOS impeller, curved blades

 

[Shiney005]

this is the rear of an original Holden V8 pump with the cast impellor

Just getting back to RED's photo for a moment, at which model was the second heater hose outlet no longer required? ie. One is blocked off in the picture.

[MustardGTR]

Genuine NOS impeller, curved blades

 

 

Looks like the genuine 253/ 308 replacement impeller is very similar to the GMB I have.

Only notable differences between the two is GMH - 6 blades  and GMB - 8 blades. And also the GMH blades are laid back at a larger angle and the curve in the blade is more subtle.

[Dr Terry]

Just getting back to RED's photo for a moment, at which model was the second heater hose outlet no longer required? ie. One is blocked off in the picture.

The second 'heater outlet' was added for ADR27A in July 76, but it was't actually for a heater hose. Because the 'pollution' motors ran about 10 degrees hotter than earlier engines the cooling systems were altered, for both 6 & V8 engines. A by-pass hose was added which ran from the water pump up to the thermostat housing.

 

All replacement pumps have the 2 outlets, so they supply a screw-in plug so that will fit early V8s, which have no by-pass hose.

 

Dr Terry

[Shiney005]

Do you know when the steel plate was added? I only ask because the pump pictured below is a factory fitted post ADR27A LX Torana pump and it doesn't have it.

 308 factory lx.jpg   105.84K   8 downloads

[Dr Terry]

The change to the cooling system was that the inlet manifold was no longer heated with the water, it was now heated with the exhaust via the EGR system.
The Early engines still ran a thermostat bypass, but via the manifold, with the 3 way tap at the heater.
The engines have always had, and require, a thermostat bypass.

It is true that the inlet was no longer water heated, which was one of the reasons that the plumbing was changed. However on early cars HT & HG (& export cars) which had no heater, the hose fittings were blocked off & there was no thermostat by-pass, very similar to EH & HD 6-cyl red motors.

 

Dr Terry

[TerrA LX]

Maybe there is confusion as the "by pass" as such was part of the heater plumbing?

[Dr Terry]

Pardon my saying this, as I do bow to your knowledge, (much respect).
But they still ran a bypass through the manifold..
The systems MUST have a bypass,if you do not run a bypass hose, when the thermostat is closed, you get no water flow, which will:

A: Prevent the hot water being circulated to the thermostat to open it on time.
B: Create Hot spots via not having the water circulating, and
C: Cavitate the water pump as it is trying to pump water, that cannot go anywhere.
I have a Pic of the first 253, showing the manifold heated via the thermostat outlet, with no heater, but bypassing the thermostat, and returning to the water pump..
Again, much respect, but the system MUST run a bypass..

 

 

While it is true that it is more desirable to have a by-pass, especially for the reasons that you have posted, there are many engines which do not have one. 

 

The original Holden Grey does not, nor do the 149 & 179 Red motors. HR onwards do have a water heated manifold, so they do get a by-pass. LJ XU1s miss out as well. 6-cyl Falcons up to & including the 4.1 Alloy head were the same, however all V8s back to the mid-60s did get one.

 

Dr Terry

[Dr Terry]

Eh Holden 149/179 had no heated intake.

Yes they do, it's just not water heated. Both Grey motors & the early Reds (149/179) have their intake manifold heated by heat from the exhaust manifold.

 

HR to HJ Reds & HT to HJ Holden V8s have water heated intakes & then they reverted to exhaust heating for HX onwards (ADR27A) motors.

 

Dr Terry