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LC GTR 2850s camshaft

2850s CF GTR LC

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#1 gtr_161

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Posted 19 February 2021 - 06:27 PM

Hi all,
Have any members with factory original 2850s LC GTR removed an original camshaft from their engine?
Looking to confirm if they all had the XH camshaft fitted like the documentation states?
Thanks

#2 S pack

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Posted 19 February 2021 - 10:52 PM

What documentation? The LC Torana Parts Catalogue?

The 2850S engine was factory fitted with the same camshaft as the 2600S engine.



#3 crabba67

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Posted 19 February 2021 - 11:39 PM

Hi all,
Have any members with factory original 2850s LC GTR removed an original camshaft from their engine?
Looking to confirm if they all had the XH camshaft fitted like the documentation states?
Thanks

LOOKS TO BE XH CAMSHAFT FOR 2850S  CF

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#4 S pack

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Posted 19 February 2021 - 11:48 PM

Can't believe everything you read in a parts catalogue. Not always a true account of what was originally fitted on the assembly line.



#5 gtr_161

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Posted 20 February 2021 - 07:09 AM

What were the cam specs for 161s?

This is from the August 71 service letter.

#6 yel327

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Posted 20 February 2021 - 07:24 AM

Same as that^^ for 2600S engine. 23/53 256 58/18 256.



#7 S pack

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Posted 20 February 2021 - 07:28 AM

Same as that^^ for 2600S engine. 23/53 256 58/18 256.

Spot on, exactly the same.
 



#8 gtr_161

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Posted 20 February 2021 - 07:36 AM

Ok,
I have also spoken to Clive Cams that profiled the cams for these engines and they stated that they had XH camshaft fitted.
Makes it difficult to know what really was fitted.

#9 S pack

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Posted 20 February 2021 - 07:38 AM

The specifications that GMH published are correct.



#10 gtr_161

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Posted 20 February 2021 - 07:39 AM

This is why I asked the first question as I did in my post...

#11 yel327

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Posted 20 February 2021 - 07:50 AM

It isn’t difficult, just have to believe what GMH published in their Engineering Documents and Dealer Service letters. Always best to find two sources as well which you have for this: what you posted above plus it is replicated in the 1600 and 173 supplement to the LJ Features Manual (also known as Engineering Technical Specifications). Parts Catalogues are probably the least reliable sources of GMH documentation.

#12 yel327

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Posted 20 February 2021 - 08:22 AM

LC not LJ^^, my bad.

#13 S pack

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Posted 20 February 2021 - 08:31 AM

Ok,
I have also spoken to Clive Cams that profiled the cams for these engines and they stated that they had XH camshaft fitted.
Makes it difficult to know what really was fitted.

AFAIK it was Wade Camshafts Pty Ltd that ground the camshafts for GMH.  Clive Cams (the business) didn't exist at that time.

Clive was just an employee of Wade Camshafts.
 



#14 gtr_161

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Posted 20 February 2021 - 08:32 AM

Have either of you both dismantled a genuine untouched 2850s engine?

#15 crabba67

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Posted 20 February 2021 - 09:30 AM

gtr_161 They were fitted with a xh cam series 1.....the parts book is correct still have my old cam from body 362#A.
Clive at Clive cams knows his cams he learnt of the master

#16 yel327

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Posted 20 February 2021 - 09:40 AM

Have either of you both dismantled a genuine untouched 2850s engine?


In my experience Engineering Technical manuals do not have errors like that. Parts Catalogues are full of them. Consider the source.

#17 gtr_161

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Posted 20 February 2021 - 09:47 AM

Thanks for your help Crabba,
Yel327 and S pac I guess you both have not owned or stripped down an original c.f. engine?
I'm interested in info from owners or members that have owned them. Cheers.

#18 Ice

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Posted 20 February 2021 - 09:59 AM

Lol 



#19 S pack

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Posted 20 February 2021 - 10:23 AM

I have a friend I have not seen in decades. He had a Phantom Metallic 7/71 Brisbane built CF GTR that he owned from new. The camshaft was not an XH and it had the fibre/resin cam gear.

 

It would not surprise me though if some Holden dealers had fitted XH cams to 2850S engines at the owners request.

 

The FIA  LC GTR Recognition documents also back up the Holden engineering specifications that the 2850S was fitted with the same camshaft as the 2600S engine.


Edited by S pack, 20 February 2021 - 10:26 AM.


#20 gtr_161

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Posted 20 February 2021 - 10:38 AM

Are you willing to share these docs?

#21 yel327

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Posted 20 February 2021 - 11:03 AM

I'll give you another example. All the docs for L34 show a standard V8 M21 transmission. Yet when you look in LH Parts Catalogues they list a different input shaft and cluster gear for L34. It doesn't tell the whole story. The parts catalogue amendment issued with L34 shows the extra bits, and whomever amended the later edition has made a mistake and written it so it looks as if all L34 had the different gearbox. The truth is is was really only fitted when a 3.08 rear axle was fitted. If you found one L34 and pulled its gearbox apart and it had the close ratio components you might jump to the wrong conclusion that the Parts Catalogue was correct. If I had to guess I'd say this is a similar situation, where something has been added to an amendment for some purpose and gets wrongly added to the amended Parts Catalogue so it looks like all 173S engines had that camshaft. This sort of stuff is all through Parts Catalogues. If it isn't an error, there will be a document somewhere that tells you why the XH camshaft is listed against late LC GTR, but it doesn't mean they all had it, which cannot be the case or the Engineering Technical Specs would have an amendment. I have all the amendments for them as far as I am aware. Even if I don't it means at least the earlier build 2850S engines had the 2600S camshaft.

 

Here is the relevant page from the 1600 and 173 supplement to the LC Engineering Technical Specifications. It backs up your Dealer Service Letter information. The two combined are far more reliable than any other sources, but doesn't mean they all had the 2600S camshaft either.

 

Attached File  LC.jpg   119.48K   10 downloads



#22 S pack

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Posted 21 February 2021 - 09:29 AM

GMH internal documentation states the LC GTR 2600S cars are to be identified as Stage 1 and the 2850S cars classified as Stage 2.



#23 gtr_161

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Posted 21 February 2021 - 10:56 AM

Can you share this documentation?

#24 gtr_161

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Posted 23 February 2021 - 12:07 PM

This is why people don't like to use this forum these days. These cars are too valuable to build from peoples memories of what the cars were. If members won't share their hard copy proof / documents they have what's the point?
My original question was directed at members that have owned these cars so I can fit the correct camshaft back into my gtr and help others do the same. We have identified an early car with a 161s cam and 2 later cars with the XH so far.

#25 S pack

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Posted 23 February 2021 - 01:04 PM

You have 2 pieces of GMH documentation that tell you what the valve timing figures are for the 2850S engine. A copy of the dealer service letter from August 1971 and Byron has put up a copy of the LC 1600 and 173 Engineering Technical Specifications. What more official GMH documentation do you need to prove the 2850S was factory fitted with the same camshaft as the 2600S engine?

The last piece of GMH information I mentioned does not discern anything about camshafts, only that info which I have already stated about Stage 1 and Stage 2.

 

The Engineering Technical Specifications define the build of the model. If GMH had factory fitted the XH camshaft to the 2850S engine there would be a revision in the Engineering Specifications and another Dealer Service letter would have been issued to inform the servicing Dealers about the change. No documentation exists, or has been found to exist, to support the XH camshaft claims.






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