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?Aftermarket Cam Identification


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Hi all, this is a bit of a long shot. I'm awaiting delivery of a cam [that has been removed from a Gt6 for what it's worth].I came across it while buying a distributor over the phone, asked if the guy had any other bits and yes he had, an engine in bits. I've been looking for a 308778 cam for a while so asked him for the numbers/number of rings on the end.

The cam has one wide ring, looks more like a channel really, there are no familiar numbers or stampings on the cam. All there is is what looks like "okn" with possibly two digits/letters after it, also 2X stamped quite clearly on the vertical axis.

I decided to have a go at it but can't find any reference to anything resembling these markings. When I get it I can sort out measuring its lift etc but wondered if anyone could throw any light on it?

 

Many thanks.

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On Triumph cams I don't think any numbers that are cast into the cam identify it. Had trouble locating any ID on a some cams I removed from  a couple of 2.5 engine. Found a number engraved on a filled flat eventually.

Mark

IMG_4024.jpg

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As above.  The factory cams have the part number etched into a rough flat.  If it is (or was when it left the factory) a 308778, it will be marked like that.  They do get reprofiled though - some to restore them as they were, some to spice them up a bit.  As yours has some other marks on it, it may have seen further attention.  The height of the heel above the shaft of the cam gives a crude indication of whether its been reprofiled.  The lower it is the more likely.  Pics don't help much I'm afraid.....

What GT6 was it removed from?  the 308778 was found in Mk2 GT6s, Mk2 Vitesses plus Mk1 and early Mk2 2.5PIs.

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Hi, he knows nothimg more about the history, apparently it was a spare engine he had for his Vitesse which he was told came from a GT6, that's as much as I know for now. I've only got a couple of factory cams for mine which are clearly marked [both 399's from my Mk3 Gt6], which is why this one threw me a little.

I took a chance on it having what I thought was the one ring at the end hence a 778. I wondred if the 2X was significant and realted to a regring spec froma particular source but it doesn't relate to any I can find.

 As said I'll have to measure it all when i get it and see what the figures are! I don't want to put anythuing in that's going to be overly peaky etc [hence my search for the 778].

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Chris Witor does a repro 308778 and also a version with more lift on the inlet which apparently works well.  Newman do their mild PH1 (which works very nicely in an injected 2.5) with slightly shorter timing than the 778 but more lift.  There is also the PH2 which might be just a bit too far for standard Strombergs.

The 2X is a foundry mark only I think.  When you have it in your hand you may well find the etched number, they are quite faint sometimes.

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A while ago, OTU and I had a thread here on cam ID, showing how to measure a knobby stick on the bench.

See: http://sideways-technologies.co.uk/forums/index.php?/topic/8106-how-to-measure-a-cam-in-the-hand/page/2/&tab=comments#comment-109205

He did it on his lathe,  mine is too small, but it can be done, like this:

P1040330.JPG

So if you're in any doubt, give it a whirl, as it were.

If you can, compare with Alan's data for a 308778:

308778Cam.thumb.jpg.d09382697b7641ae713a9342e5129382.jpg

Edited by JohnD
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For comparison, and I apologise for the slightly different format, here's the profile of the Crane Cam I've just fitted to a new engine.  Mesured with the rig above, two V-blocks,a dial gauge on the cam and a dial gauge stand to support the pointer on the protractor.

image.png.6c099bfd4afe3508a442e97f3045075b.png

Lift is 8.15mm or 320 thou.

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16 hours ago, yorkshire_spam said:

Got me thinking about 2 cheap hacked digital calipers and a rotation sensor connected to an arduino as a data logger:

There's precedence for this : https://shamwerks.com/CamWerks-DIY 

It's got me thinking too, because I have a box of cams that I've accumulated over the years and (soon) a new garage/workshop but also 1,000 other projects constantly on the go.. Still might get round to it one day :)  It's definitely piqued my interest though..

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