1975 TX Big Valve Head

Sparrow · tinkerer Joined: 08 Oct 2001 Posts: 171

Ok here is my 'research and development' from measuring the head off my 1975 TX sedan 1600.

Stamp Number on head = 1
Inlet Valve = 42mm dia
Exhaust Valve = 34mm dia
Inlet port (standard) = 35mm dia
Exhust port (standard) = 31mm x 34mm bore.

*Combustion chamber
depth: measured from
spark plug recess = 21mm +/- 0.5mm
(vertically to the
top of the chamber)

Inlet valve is stamped with '00742'.
Exhaust valve has no stamp.

Measurements taken with vernier caliper.
Hope this helps.

NUT161 · tinkerer Joined: 30 Dec 2001 Posts: 225

they also have no isuzu emblem near the front hose connection and have stamps 7, 14, 21 also

flatchatcharlie · rice boy Joined: 08 Nov 2002 Posts: 38

Another post dealing with big valve heads states that the number on the big valve heads located under the mounting point for the mech fuel pump is 7,14,or 21 the head you messured has a 1 so is it a big valve head or not?

TXcoupe · petrol head Joined: 05 Oct 2001 Posts: 1675

um that casting number is crap
i have had many big valve heads with different stamps. but the correct one is that the izusu symbol is a small valve head

tx1975 · tinkerer Joined: 21 May 2002 Posts: 321

G180 heads also have no izusu symbol on the front of them but have pipes coming off near the spark plugs for the pollution gear , just thought it might be usful info

TXcoupe · petrol head Joined: 05 Oct 2001 Posts: 1675

yeah thats for later model pollution gear heads. i have had the pollution gear heads and they have big valves in them. pity i cant find a g180 head

NUT161 · tinkerer Joined: 30 Dec 2001 Posts: 225

that's because there aren't any g180 heads they just have a 1600 head and have different shape pistons

Stock TE · backyard mechanic Joined: 12 Mar 2002 Posts: 853

The only way to tell a big valve head is there is no Isuzu Symbol I have seen both big and small valve head with the number 4 cast under where the fuel pump goes.