Hi all

I have the opportunity to buy (at a good price) a good 2nd hand Isky Z-322 cam for my 144 - plus a set of Isky lifters, pushrods & 625/626 double valve springs.

Anybody had any experience with this cam ? For reference, it's advertised specs are :

Intake 32/68
Exhaust 68/32
Lift 0.480
Adv. Duration 280

My car is running a B20 with slightly modified "E" head (basically just ports matched to manifold, & a little unshrouding of the valves ... no major port work) with a D cam. Standard integrated manifold (no secondary butterflies here in Australia !) with HS6 carbs & twin downpipes to 2.25" exhaust. Bottom end has been balanced. 5-speed Celica gearbox.

The engine is coming out for a freshen up in the next couple of months anyway (hopefully just a set of rings & valve stem seals - bottom end should be OK) so I was thinking it would be a good opportunity for a cam change if it was worthwhile.

Car is a combination daily driver / hobby car (I do a bit of rallying & dirt autocross in it). Not really chasing outright top-end hp, but a little more "urge" is always a good thing :o)

Ideally I would like the car to rev cleanly to 5500-6500rpm - which it won't do at present without "running out of steam" around 4500-5000 (although that may be largely to do with the fact that it is a bit down on compression in a couple of cylinders).

Also - regarding the valve springs ..... would I really need to use the double springs with this cam ? Given that the head would need to be modified to fit them, it would save a lot of hassle if I could keep the existing springs.

The valve springs in the car currently are not standard (although they are single coil). The are a "D51888" spring from Performance Springs here in Oz. Specs (from the companies website) are :

OD 1.080
ID 0.755
Seat pressure 1.530:65
Open pressure 1.130:190
Coil bind 1.101

Are these likely to be adequate for the Z322 cam ? Not sure how they relate to the specs of standard springs.

just as a side note, according to various receipts I got with the car when I bought it, it is running Datsun L20 valves - which at 44mm/35mm are the same size as late B20 ones !)

Interested in the thoughts/experiences of people with more knowledge on this subject than me !

cheers

Dave
Victoria, Australia