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Hugh

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GT6 Mk2 / Vitesse Mk2 / Mk1+ Early Mk2 PI 132 bhp has the number "308778" etched on it.  Also has a 1 wide groove machined in the diameter behind the sprocket mount face. It is a better cam than the Mk3 GT6 one.  It is not the limiting factor in the mk 2 engine - I think Steve Attenborough holds the record with upper 140s bhp with that cam in a 2L......

The TR5 / Early TR6 cam has p/no. 307689.  I've never seen one so I'm not sure if they also have the number etched on them.  They should have two slim rings machined in the diameter behind the sprocket mount face.  You'll be lucky to find a real one - Newman do something similar (though not identical apparently) if asked.

Some info here http://www.chriswitor.co.uk/cw_technical/camshaft_applications.pdf

Nick

Too slow...... Roy beat me.....

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I would go TR5 - perfect for a 2.5 lump in a GT6 - might be a bit peakier in a 2 litre but in 2.5 should have bags of torque - assume you are still going Lucas PI - K Raven Smith can calibrate a MU for 100 quid.

Worth checking the cam hasn't been reground - I bought a SH TR5 cam and some goon had ground a late 125 profile on it :-(

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lagerzok wrote:
I would go TR5 - perfect for a 2.5 lump in a GT6 - might be a bit peakier in a 2 litre but in 2.5 should have bags of torque - assume you are still going Lucas PI - K Raven Smith can calibrate a MU for 100 quid.

Worth checking the cam hasn't been reground - I bought a SH TR5 cam and some goon had ground a late 125 profile on it :-(


Thanks Andy profile is original and is going in 2.5 lump still going Lucas  PI
Cheers Hugh ;)

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908 wrote:
Okay I can lay my hands on a GT6 MKII camshaft for £60 or an original TR5 for £150 which is the best one to go for price/performance wise any ideas welcomed  :)


Hugh
You can buy a new cast blank TR5 profile cam for less than £150.  I wouldn't bother with used unless it's cheap!!

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339 wrote:


Hugh
You can buy a new cast blank TR5 profile cam for less than £150.  I wouldn't bother with used unless it's cheap!!


And do'nt forget you will need a NEW set of GOOD QUALITY followers. unless the used cam comes with matching individually numbered ones in top condition.

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Don't think even matched, numbered followers will really work unless it's all going back in the same block...... No reason they'll sit in the same relative positions.

Just been pondering this on mine, tried lapping the followers but some turned out to be fairly dished anyway although they looked ok.

Nick

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Nick_Jones wrote:
Don't think even matched, numbered followers will really work unless it's all going back in the same block...... No reason they'll sit in the same relative positions.

Just been pondering this on mine, tried lapping the followers but some turned out to be fairly dished anyway although they looked ok.

Nick


Correct just testing. not to say I have not done that.


It's okay I remember being wrong once before.

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Gt6s wrote:


TH7 !

You are planing to fit a race cam to an otherwise stock 2.5 ?


Well I thought if I started with this one I could upgrade the engine bit by bit or is this cam too much for a stock engine if so why do you think so.

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I know little about cams really, this is a subject area I need extensive research into, however...........

Am I right in thinking it is possible to alter the cam timing (retard?) in order to gain extra torques at the expense of peak horsepower?? And if so, if Hugh went for this cam could he do this whilst waiting for other stuff to be done and so gain a drivable engine?

A wee caveat to that, I am assuming compression will have to be increased before this is possible?? Stock compression not being enough?

Cheers,

Phil

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908 wrote:
Okay how about a Kentcam  KCTH7 would this be a good one to use  :)


Hugh

If going for PI, get a cam designed for PI.

MikeyB has a Kent TH something in his PI.

The fuel ecconomy is so poor he has retired it temporarily. They don't generate enough vacuum I think.

Now if you are going for EFI, then yes, as you can program it to allow for the fuelling.

Also a TH7 may give you a rev-band above the sane levels for a 2.5.

Cheers

Colin

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