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Discussion Starter #1
Hi,

I'm wondering if putting 164 S cams in a 2.5 is worth the trouble. I've read some posts where they say that the S cams don't do much and then in Jim K's book, he seems to think they're pretty nice cams.

Anyways, I have a chance to get some and just wondering if I should do it or save my money. Any info on what I should expect or from someone who has used these cams on a 2.5 would be appreciated. Also, are there any fitment issues using these cams since they originally are from a 3.0?

Thanks and I'm off to the French and Italian car show now....
 

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I have done it. They give an honest 5 peak horsepower on a 2.5 and allow it pull pretty well to 7000, while the stock cams start to fall off around 6300. Are they worth it? I don't know.

I have only installed them using the factory timing marks, which seem to work fine. I recall RJR saying the factory marks are a little off for this cam swap, so it's possible they could give a little more if dialed in just right.

Greg,
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But Mad North-Northwest
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I put 'em in my 2.5 when the original cams needed replacing. They're decent cams and make a noticeable difference at the high end. Slightly rougher at idle but nothing troublesome. Not cheap so its a tough call on whether they're worth it or not.

Since you're in CA, smog testing is a consideration. S cams will pass smog unlike many hotter cams. So they may be the best you're gonna get around here.
 

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Discussion Starter #4
thanks guys. and when i said "worth it," i meant worth the trouble of installing them. i know they're probably not worth the normal aftermarket price. but i think i might give them a try.
 

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Richard Jemison
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S cams

If the S cams are free then they are worth putting in.
Any 2.5 timing marks are for closer LSAs As a general rule the GTV6 marks are for 102 LCs and Late (85 up GTV6 and Milano 2.5s are 108 LCs on the intake.
The S cams should be set at 110 or close to it as by design info they are 110.5 LC on the intake and 108.5 exh. This results in a wider LSA of 109.5 compared to the 104LCs of early GTV6 ans 108 of later Milano`s etc.
The wider LSA is to function with the overly long runners of the 164 designed for lower RPM torque to deal with higher gearing/fuel economy etc.
You can`t change the LSAs on these stock cams so best to set them at the proper LC and use them as they were designed as better torque producers, as they are in no way a "performance" cam.

When you set these cams at the original 2.5 timing marks technically you are "ADVANCING the cams which only makes the higher/mid range weaker. A S cam set at a 102 LC mark means that the exhaust LC is at114.5 so your power stroke (valve events) are truly mis-timed. (similarly a 108LC motor would have a exh LC of 110.5)

As a shot at getting the cam timing better set the S cam`s timing mark just before the cam cap mark(retarded) so that the timing mark`s edges are just begining to make a strait line, for later motors (108 LC versions). And for early motors separate the two marks by a distance of 1/2 the width of the marks themselves.

Remember these cams have the very same exh profile as other V6 12V cams. Only the intake has .5mm more lift and very little more duration (a result of lift, not better lobe design)
 

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Discussion Starter #6
Thanks, Richard for the cam timing info but looks like i'm not getting the cams. They were in a 164S at the pick a part but i got there too late; someone grabbed the whole engine which i admit is much better than me just grabbing the cams. hopefully it finds its way into a nice milano or GTV6 and lives to rev another day.
 

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Thanks, Richard for the cam timing info but looks like i'm not getting the cams. They were in a 164S at the pick a part but i got there too late; someone grabbed the whole engine which i admit is much better than me just grabbing the cams. hopefully it finds its way into a nice milano or GTV6 and lives to rev another day.
You should have just bought the whole engine!!! Anyway...
 
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