92 replies to this topic

[TerrA LX]

^ I have spoken to "someone from around this time" and they tell me that a part only had to be "available" thru Holden to be listed as a part etc... it did not necessarily have to be on the shelf...

[yel327]

Same with 12 bolt axles for HK-HT. By special order only.

[REDA9X]

There is certainly a lot of speculation and guessing going on here with this one. Lets look at it logically. It's been covered a lot of times now over and over. Australian Muscle car magazine has just released a compilation of the V8 Torana stories that should help along the way though.

Firstly, what were the A9X and L34 before it built to do? They were built to homologate the parts required to put a race car together within the rules, but in such a way Holden only had to develop the parts that were not free to change.

With the L34 they put all the good bits in the engine but didn't worry about all the parts that were free to change. A good example is the exhaust past the first break.

With the A9X, it was an evolution from the L34, so all they needed to do was fix the problems they encountered with the L34.

So, why does the A9X have a different crank to any other 308 of the same period while the L34 had the same crank as any other 308 of its period? Logic would suggest the crank was improved with the release of the A9X. Holden only had to do just enough to comply with the rules, and to save money they only fitted it to the cars they had to.

Holden also produced a list of parts required for race teams that were converting their L34's to A9X spec, this had updated part numbers for cranks and blocks.

As for the cam, why is it different to the cams in any other 308 of the period, while the L34 shared the same cam as any other 308 of its period? Why bother changing it when the cam was free to change for race teams?

I was told two reasons many years ago, the first being the flogging Holden had copped in the press over the 308 with ADR27A, and secondly the journals had been made bigger to allow larger journal cams to be used in race cars.

If it was made to fix ADR27A issues, then why not extend it to the rest of the range? The timing on the A9X was slightly different too, so perhaps it was a matched set for their so called performance car? Maybe they wanted it to stand out a little? All press reports of the day suggested the engine felt much stronger than other 308's with ADR 27A they had driven. Was it designed to make the most of the 2.6 diff? Perhaps, that makes sense too, maybe it just so happens it was a good match and they inadvertantly fixed the issues with ADR27A with the same stone? The fact is though, it is different to the standard 308 cam of the period.

[yel327]

So the crank on an A9X is a rope or neoprene rear main seal? AFAIK L34 were neoprene.

[REDA9X]

From my memory it was rope in mine, and mine hadn't been out before. My 253 SS of the same build date was rope also.

[A9X]

I like your thinking Red.

 

Many times we miss the 'big picture' when trying to work out the factory intentions.

[a9x868]

rope seal for mine too!
original block

[S pack]

GM Parts & Accessories News 7th November 1979.

 

L34 High Performance parts serviced for LX Torana Performance Equipment Package Option A9X.

 

GMP&A have released the following L34 high performance parts for fitment to LX Torana vehicles equipped with the A9X option package.

 

92005960  Crankshaft

92011190   Pistons & Rings with Pins

etc etc etc

 

The high performance parts will enable owners of LX Torana models equipped with the A9X option, to increase performance of their vehicle for trial, rallying and other competitive sports. So let prospective customers know that the above L34 option parts can be supplied.

 

Just on a side note. Another GMP&A News from 1980 lists the L34 replacement block (lip seal type, presume that's a neoprene type seal) fitted with pistons as currently available.

Nice summation a few post back there Red, however it still leaves me wondering why GMH would send out the above info to the Dealers with the crankshaft mentioned as being an L34 part and advising that it can be fitted to LX A9X as a performance upgrade if the A9X L31 engine already incorporates said crankshaft?  Admittedly this advice was sent to the Dealers in November 79 and the A9X's mainstream racing career was near it's end, so I'm thinking maybe GMH just wanted to move their remaining stocks of L34/A9X performance parts from the shelves.

[REDA9X]

You'd need to know every meeting, results and causes of DNF's for that. I would suggest Harry and perhaps other teams were finding cracks or other issues when they were pulling engines down after race meeting. They wouldn't just change it for the sake of changing it.

[WhiteA9XS]

  Reda9x is on the money ..

 

 
 

[yel327]

Oldish thread I know, has anyone found anymore info about the A9X camshaft part number 9933211?

 

I note it was removed from parts history as early as July 1978.

 

The camshaft having a bigger nose makes a lot of sense. Note that from HJ onwards the 308/304 all used the same camshaft timed at 0deg (prior to HJ the 308 used the same cam as a 253 but it was advanced 5deg) right through to the end of VL 5.0 with carby. The only GMH produced engines to get a bigger cam were the A9L engines, the rest all got the same camshaft which incidentally has the identical grind to the HK-HQ 350 camshaft - the GM general performance camshaft. This cam grind was good enough for the L48 350/300 engine with Fuellie heads so is a pretty decent cam spec for a 308 with smaller valves and smaller ports and 42ci less than the L48. I can't imagine the A9X needing anything different timing wise, unless it was bigger as mentioned a few posts up or maybe it had extra advance ground into it rather than using a different cam sprocket?

 

Funnily enough too the part number of the post HJ 308 camshaft 2825882 sits smack bang amongst other parts from early HG which is when Harry was first playing with the 308 engine for a lightweight Bathurst HG GTS, this is when he first developed his wish list for the 308 much of which became the L34 engine. Thinking "Harry-like" for a minute, imagine the discussions about a better cam for the 308? "The cam in the HT 350's works well, let's try that grind". Maybe.....