Humber FV1600

[fv1620]

That does seem to be a common problem I have seen several over here with that. As you know the Y-piece is different & longer on armoured Humbers & don't think I have ever seen occur on those. Although on the Hornet I did have the front manifold crack.

Ferrets seem to get round the problem by having a gap & once heat expansion takes place a sort of 'seal' is formed.

Rather than shims I use copper covered asbestos gaskets. I found that gaskets for a Vanguard car will do. Although the 4 holes are not quite centred because the holes are larger they fit the studs fine. As the 'square' gaskets are not flat-sided but elliptical I have trim a small section where they are next to each other.

I note there were two types of Y-piece fitted to the GS

FV175019 from chassis 20,000 to 20,681
FV228288 from chassis 20,682 onwards

So I don't whether that was to address the cracking problem or indeed how they differ.

Interesting the official recognition that the 'Commers' are proper Humbers after all

[Richard Coutts-Smith]

Hi There Clive.
Did not know that the Pig had a different "Y", or indeed that there was a choice depending on chassis number. Aust. delivered chassis were in the 11 000 to 14000 range so all had what I assume is the short "Y".
Ferret does seem to have a way better design to allow for the expansion.
We use the Copper/asbestos gaskets on the Champ, thought they were genuine for the B40, either way, they do work well
Any idea as to why I have one engine with a heat shield casting, and one not?
Rich.

[fv1620]

Originally Posted by Richard Coutts-Smith

Any idea as to why I have one engine with a heat shield casting, and one not? Rich.

Rich I think it is because supporting the heat shield from the two manifolds meant there had to be two different components, a forward one & a rear one.

Supporting the heat shield independently meant one manifold could be used in either position. Another factor might have been the difficulty of removing the retaining stud if it had become too encrusted with the effects of heat, rust & time.

[fv1620]

Here is a Pig Y on the left & a GS Y on the right. I have no idea whether it is early or late type.



The parts book for the Hornet gives the same Y piece as for the Pig. But the book is wrong the entire Hornet exhaust system is quite different. The book was based on the prototypes using the Pig system.

But that meant you had a heat source directly under one of the spare missiles in the rear. It also meant loaders were tempted to stand on the end of the tailpipe, although this was later protected by a small armoured cowl.

The production Hornet had quite a different silencer mounted below the radiator accommodated by an enlarged belly plate with the tail pipe exiting in front of the front wheel on the driver's side, sometimes causing hypoxia for the driver.

Hornet Y on the left, Pig Y on the right.



You can see the gaskets I have fashioned from the Standard Vanguard gaskets.

[fv1620]

The GS one looks to be the later type FV228288 although to me the casting looks to read FV228287

[Richard Coutts-Smith]

The Aussy one appears to be the same as FV228288. see attached.
Spare book shows castings for chassis no. 20 000 and above, where does that put the Aussy chassis at 13 000 + 14000?
Can't quite believe the differences in one casting for a short production run of vehicles. I assume these would have been ripped off, when the armoured bodies where fitted, as the inherent design flaw would have been quite obvious by that time. Which would also mean that you should have bucket loads of these castings lying around over there.
Maybe one of the designers had shares in a casting plant?
Obviously the longer legs on the "Y" are able to absorb the manifold movement.
That is the first uncraked short "Y" I have seen.

Not sure if your gasket fitting hammer is quite large enough.
Rich.

[lynx42]

How interesting is that. Thanks fellas for such an insight into the problems of manifolds. I still have to look forward to that problem as my manifolds are still OK. (Hope I haven't spoken too soon.)
Rick.