cam specs

[mbarjbar]

Can anyone supply the stock 1970 cam specs? Lift, duration, etc.

Mike

[Diseazd]

I believe that the stock 240Z had an advertised duration of 270 degrees and a lift of .410 inches.

[ChrisZ]

I believe that the stock 240Z had an advertised duration of 270 degrees and a lift of .410 inches.

Oh no Guy, the stock cam is much smaller, IIRC 270 is a stage II.

Mike, have a look here, there should be a letter stamped in your cam as you see on the page, witch will refer to the "cam mark" on the spec. sheet.

Chris

[Diseazd]

Chris.....Isky lists it's Stage I cams at 270 degrees advertised and 222 degrees at .050 inches (same as stock).See link below.

http://www.iskycams.com/onlinecatalog.html

[ChrisZ]

So Guy, what youi are saying is that the duration listed in the Nissan L serie spec sheet, is at .050 inches?

Chris

[Diseazd]

Isky didn't know what valve lift the factory uses........Isky uses .050 valve lift. Advertised duration at Isky is at .020 valve lift. They show an advertised duration of 270 degrees (at .020 inch valve lift) and 222 degrees (at .050 inch) for the stock 240z camshaft.

[ChrisZ]

Sorry if i get a little confused about all this, but what you are saying is that Nissan A cam (248) is the same as Isky stage I, i run a Nissan C cam (256) what would that be at .050 inch lift?

Chris

[Diseazd]

http://www.iskycams.com/onlinecatalog.html

The Isky Stage I is a stock 240Z camshaft reground to a higher lift (.475 vs .413), but with the same duration as stock. Click on the above link, on the left, click on Datsun,then on L24 page 176. For the Stage I regrind they list duration at .050 lift at 222 degrees and indicate that that is the same duration as stock.

.

[ChrisZ]

I did look at the link, but didn't see the comparison (10 inch netbook), so the stage II is the same as the C cam with a little higher lift, that is very interesting to know.

Guy, did you take a look at the link i provided above?

[Diseazd]

Chris.....Yes, duration can be confusing because manufacturers may select any lift to advertise duration. It would be interesting to see what Nissan used to come up with 248 degrees duration. If .020 lift is 270 and .050 is 222, it must be somewhere in between. Guy

[ChrisZ]

270 + 222 / 2 = 246 at .060 witch is just about 1.5 millimeter, it might not be that simple, but it make sense.

Chris