Post Number: 28
|Posted on Friday, 11 June, 2010 - 03:12 pm: |
Can anyone advise me if there is an easy way to tell the difference between a cylinder head for a 4 1/4 and a cylinder head for a 4 1/2 . The reason for asking is that I have a spare cylinder head and I am unsure as to what engine this will fit.
Post Number: 81
|Posted on Friday, 11 June, 2010 - 10:08 pm: |
The studs on the cylinder block are in slightly different positions. At one time your father had some difficulty with several cylinder heads which failed on pressure test. The spare that you have may be OK or it may be one of the failed ones. Your car will have 3/8" studs. Some of the earlier 4 1/4 blocks had 5/16" studs.
Post Number: 29
|Posted on Saturday, 12 June, 2010 - 12:19 pm: |
Thank you for the information.
I am not sure of the condition of this head, it looks OK,but it has not been reconditioned so it is a bit of an unknown quantity.
Posted From: 220.127.116.11
|Posted on Friday, 18 June, 2010 - 11:51 pm: |
There are indeed some easy ways to tell the difference between the various 4.25 ltr and 4.5 ltr cylinder heads. You will not find these descriptions detailed anywhere else, quite why I really do not know.
The 4.5 ltr rocker cover gasket is longer than the 4.25 ltr. To accommodate the gasket length the 4.5 ltr cylinder head is longer at the rear end. This extra length takes the form of a very noticable curvature at the top of the cylinder head rear wall.
Place your fingers on the very rear face of the head about 3 inch (75 mm) below the rocker cover gasket line, then draw your fingers upwards.If your fingers meet an overhung curvature protruding about 3/8th ( 8 to 10 mm) the head is 4.5 ltr.
On the other hand, if your fingers detect a flat rear cylinder head wall, no real protrusion, then the head is 4.25 ltr.
Failing those tests, a 4.5 head is MORE THAN 8 inches wide, about 8.25 inch from memory.
A 4.25 ltr head is LESS THAN 8 iches wide, around 7.8 inches.
(Message approved by david_gore)
Post Number: 32
|Posted on Thursday, 01 July, 2010 - 08:58 pm: |
Many thanks Norman
I will check the head when I am next home