Hi all,
I have made a study of the markings inside of engine crancase areas and they seem to be some form of Identification for the year manufactured.

These markings seem to have started in 1965 and continued to at least 1980.

The first marking seems to have been two horizintal scratch lines put into the core sand before the block was cast.

I have a few gaps in my record and wonder if anyone has engine apart who can tell me the markings for;

1967, 1968, 1976, 1978, 1981, 1982, 1983 or 1984.

These markings do also have overlaps for some reason that I am not entirely sure about yet.

Any assistance appreciated.

Mike81973



Purpul Police

Hi,
in one word YES,
and to answer your question further, all the blocks were cast in the same location going by the casting identification marks.
Like I have been saying for a little while now, I doubt that any engines were cast outside Holden.
It does not make any sense at all to duplicate an expensive process that is carried out by Holden anyway, I suspect that the engine assembly may have been contracted out for some of the last engines though.

I may be proved wrong yet, so here is the challege for anyone out there!

What are the markings inside the crankcase for a 16 G 3 engine on the 150 list?

I have the markings for 1972 and 1973 and I will share them with everyone when this question is answered.

Mike81973


Purpul Police

Thanks HK 1837,

This is the sort of information I have been looking for a while now, many thanks.

Do you know if this was just a race team thing or not, perhaps they sourced engine blocks from this source when the strikes were restricting Holdens engine production.
I have heard a story that the different blocks also had a rougher surface finish, the 16 G 3, JL and 5 M 3, NP certailally have the rougher finish,
I also have two 27 F 3 heads and a 12 G 3 head that have the rougher finish too.
I have not seen the difference in the JP, NP blocks you refer to but I can tell you that the core sand scratch marks are all the same for a particular year no matter which 202s I have looked at.
There is a huge gap between the 1st 73 Bathurst spec engine change over point and the first 73 spec car recorded on the warranty reporting Vin listing, I suspect that some race cars may fit into this gap as they would not have been covered by a warrenty anyway, so no need to record them in this way.
Do you or any of the readers know anything of this?

Many thanks again,

Mike81973

Purpul Police

Edited by user Sunday, 25 April 2010 1:07:45 AM(UTC)  | Reason: Not specified

hi mike, any pics of these scratches?

i have seen 186 xu1 blocks with X in the same place as photo above
vin

Hi, just today found a bit more.

Paul from Ausie Muscle Car Parts informs me, that Holden had two furnaces supplied from 4 lines of moulds, it now looks like the two different markings may be to indicate which furnace actually cast them.
I don't know if they poured blocks each day or not, still working on that one.

It appears that the rougher castings were just from courser moulding sand, the earliest course finish casting was 12 G 3 so far, and many castings from about this point were rougher to at least December 1973.

As above, looks like the 16 G 3 blocks will be from two seperate sources within Holden, and if Commonwealth Aircaft factory had any role it would probably to carry out machining modifications for some race teams or perhaps, even the valve clearance reliefs for the Bahurst 73 models, work not usually done within Holden.

With the 150 verses 250 Bathurst 73's it could be possible due to rule bending practiced by some teams that; despite 250 sets of special parts being made, that excess of 150 were fitted with these parts, then the remainder simply went into spare parts something like the main rival did with their alloy wheels. ( race teams can't operate without spare parts? )

It could even be that the clerk who was given the task of counting all the Special models simply missed counting some of Bathurst models or simply did not have room on the page for another row of these XU-1's,
we will never know!
It seems that several ( about ten ) of the ealiest Bathurst models were the main ones that were missed out, at least so far anyway.
One thing we know for sure, is that more than 150 bathurst models were produced.

Mike81973

Purpul Police

Not necessarily,
it would have to depend on demand for each size of engine, certainally there were the two different markings for all the early 72 & 73 202's I dont know weather the marks were put in at the moulding area or the casting area, I would have thought the moulding areas, if so this would indicate that both furnaces were casting these supplied from two distinctly different moulding areas.

202 would likely be the higher output quantity of engines and would likely need two moulding areas to keep up with demand.

Mike81973

Purpul Police

mike i just seen this thread on oldholden, i'm not sure if you seen it but is well worth a look

http://oldholden.com/node/83243#comments

now explain those casting marks! lol

Thanks Dave,
I had not seen it, very strange and not one I have had so far.
I have 8 different markings up to date, still need more to get the full picture, hopefully some of the readers will send in more with the block dates?
Thanks also Johno, I too have been busy setting up my shed and getting the GTR Torana painted twice, they buggered it up the first time then had the cheek to say I don' know Toranas, bugger me, I have had one ( actually several ) continusly since 1977, they lost the argument!
Mike81973

Purpul Police

Hi Vin,
1963 and 1983 have no markings but the rest do normally have markings, these are easily overlooked if you are not aware of their significance, many of us have overlooked them for many years.

Don't suppose you took any photos when you rebuilt your bottom end?

Mike81973

Purpul Police