Hello All, After much dicking around my new Works 72 cam arrived the other day. Now for the install, but before some questions need answering.

1: Just to confirm the camshaft needs to be carefully slid out though the front of the motor, not lifted out like you would with say a CA18 or 3SGTE. Because of how the cam bearings are made removing them looks like it'd cause major problems.

2: In order to achieve the above you need remove the rocker arms,
-> Thus the question: in order to do this do you simply remove the spring clips, and wind out all the adjustment? Or do you need to compress the valve springs somehow? Eg: wedge a screwdriver underneath the cam and press on the spring? <-- Seems dodgy

Now here comes some tricky stuff: I've got a thoroughly unimpressive "C-Spec" Yo camshaft, which has an amazing 7.25mm of lobe lift.

As mentioned previously the new cam is a Works 72 Grind which has 8.46mm of lobe lift, but the thing here to remember is that all L-Series cams are effectively regrinds whereby lobe lift is increased by reducing the base circle, not by adding material to the lobe tip (I'm sure there's a good reason for this but I just can't think of it.) Therefore I've lost a minimum of 1.21mm from the base circle of the camshaft. Now as we're aware, these engines are sensitive to lash pad thickness so here comes the math:

Knowns
Rocker ratio: 1.5165
Reduction in base circle Radius: 1.21mm (min)
Head has been recently rebuilt and wear makes on wear pads are central:)

Unknowns
Lash pad thickness

Now if I multiply the radius difference by the rocker ratio I get: 1.8323mm (or 0.0721")

Would I be correct in getting a lash pad from the supplier (Precision Shims) that is 1.8323mm thicker than the existing lash pads (seems a lot?) or at least would this be a good starting point. Or better yet, can the Works 72 cam be installed and simply adjusted by using the screw adjusters with little consequence?

Thanks in advance for your replies. Also as I've looked everywhere for a step by step guide on how to do this and came up short (the workshop manuals are rather vague...) I'll be posing a how to once done.

Regards
Jordan.

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Past rides: 86 Hilux, 3x ke55 rollas's (2coupes,) 2x ST185 GT4's, RA28, TA22, KE10, P610 datto, RT40 corona x3, RT132, MX13.

Current Rolling stock: 2000 model ST215 Caldina, CAA22 celica (race,) RT40 corona (cruiser)

You lost me at "Hello"
What does the cam supplier recommend?
Removing the existing cam can be done by backing off all the adjusters and removing the rockers.
The cam towers can be removed for head machining but there is a trick when re-installing them.

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Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

The lash pad thickness will vary radically depending how the seats on the valves are cut or if the valves have sunk over time. The only way to get the right thickness is to mock the head up with the new cam and old lash pads. Then check cam wipe on rocker using a bit of black texta and then add small washers under the lash pad until the wipe pattern is centered.
Then check the thickness of the washers and add it to the thickness of the original lash pad and then order the correct lash pads.

Backing off the rocker pivots and then levering out the rocker is the best way.

Cam towers can be removed, but there is a simple procedure of re-assembly.
Tapping the cam towers with a mallet while torquing and rotating the cam to check for smoothness and no binding

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Circuit Race 1600 in the build

1. yes, comes out the front

2. Yes, wind out all adjustment and remove rockers

Tricky stuff :

What Lampy said .

Here's some pics that may help. NOTE: I've never done this with the head on the engine, I've always set it up with the head on the bench before re-assembling engine . I would assume you need to install ALL rockers and timing chain setup, then turn the engine. Install one rocker with texta, work on it till you're done, then move on and remove the next rocker to work on it. This should avoid piston to valve contact ? Someone may be able to confirm / deny this.

And don't forget to check cam timing, mine was off after installing a 72 degree cam, even though I already had a 72 degree cam installed previously (the old one was damaged, and repaced with new one).


Texta on rocker






Set it up and turn cam





This is what you want






This isn't.






Keep mucking about with altering the thicknes of the lash pad and the rocker adjustment at the pivot (I do it by inserting little bits of chopped up feeler guage between the tip of the rocker and the existing lash pad, but anything eill do). Once you get the wipe pattern correct, measure the thickness of the existing lash pad, the thickness of the washers / feeler guage / whatever you use, add the two together and order new lash pads to suit.

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

Thanks for the great information lads. If Clive form live cams wasn't so useless he'd have sent my cam to Chris Miltons on time and I wouldn't have to do it in the car, but as it is I'm not pulling the head again unless I absolutely have to.

Will be getting stuck into it when I get back from my Ski trip to NZ

Regards
Jordan

_________________
Past rides: 86 Hilux, 3x ke55 rollas's (2coupes,) 2x ST185 GT4's, RA28, TA22, KE10, P610 datto, RT40 corona x3, RT132, MX13.

Current Rolling stock: 2000 model ST215 Caldina, CAA22 celica (race,) RT40 corona (cruiser)

great info.
http://www.spannerfodder.com/the_works_ ... ratios.gif

if a perfect cut head seats, valve stems ecgt.. then you would use only 1 size lash pads. also if head shimmed sometimes cam tower shills are installed to make up the difference which also affects lash size.


Best to get head off and do this right and get the chain nice and tight with tensioner al.lthe way in. Meaning put thead on then the chain ,guides ectt..... Not work from the bottom up.

with head off and rockers out just slide it ou the back

don't know where you get the rocker ratio. its about 1.48 on Nissan rockers guess it can change abit

.

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