How to identify Holbay engine

[mackem]

Does anyone know how to identify a Holbay engine without taking it to bits. I know that the alloy cover can easy be swapped as can fitting twin 40's, but how do you know it's a genuine Holbay?

 

[RootesRacer]

Does anyone know how to identify a Holbay engine without taking it to bits. I know that the alloy cover can easy be swapped as can fitting twin 40's, but how do you know it's a genuine Holbay?

One good tell tale is true holbay heads have smallish ports compared to a series alpine head.

If you have access to a bore scope, you should be able to detect if the pistons are also flat tops.

A holbay engine can be made after the fact, using some non-holbay identifiable parts, so visual inspection is next to impossible.

 

[RootesRich]

IIRC, the only way to tell if a cylinder head was a true Holbay is to look at the casting number.

I can't remember if Holbay stamped any blocks, but I can look at my info this evening if no one posts more on this topic.

 

[Rootes 66]

There are others but an engine number beginning B391000001 is always good.
Visually there should be a set of 40's, a named rocker cover and alloy sump, genuine Holbay heads have production number stamped on the front L/H side and generally there should be no vacuum advance on distributor.
These still only give you an indication, strip down is the only sure fire way of finding out what you've got!
Pete

 

[mackem]

Thanks for your replies, it looks like i'll have to take my chances.

 

[SIVAllan]

There are others but an engine number beginning B391000001 is always good.
Visually there should be a set of 40's, a named rocker cover and alloy sump, genuine Holbay heads have production number stamped on the front L/H side and generally there should be no vacuum advance on distributor.
These still only give you an indication, strip down is the only sure fire way of finding out what you've got!
Pete

Great picture - thanks .

At some point I hope to go the Holbay route and will need a distributor.

Is there a model number on the Holbay distributur that you could post ??

Thank you.

Allan

 

[Rootes 66]

Allan
I Believe there were as many as 6 different distributors used at various times, from W/S manual some of the numbers are as follows;
Lucas 23D4 41239. Lucas 43D4 41454 & 41556. Lucas 45D4 41604.
Pete

 

[RootesRacer]

Allan
I Believe there were as many as 6 different distributors used at various times, from W/S manual some of the numbers are as follows;
Lucas 23D4 41239. Lucas 43D4 41454 & 41556. Lucas 45D4 41604.
Pete

The model number is just a case, the magic is with the application number which sets the springs and advance weights and adv stop position.

 

[Rootes 66]

Allan
Just to be perfectly correct, the later Holbay distributor 41604 (45D4 type) does have Vacuum Retard.

Pete

 

[SIVAllan]

Guys - thanks!

Allan