I have a Datsun 240z 1973, when I bought the car I was informed the previous owner may have added a "hopped up cam". Since owning the car I have had issues with rough idle and pinging and I am curious if this some of this could be related to the valve timing. I have not checked the Valve timing but I am not sure that stock numbers will work if the cam was changed from Stock. Curious advice for a Zcar novice.

 

Thank you for your time,

If there's a cam there might be higher CR.  You'll want to check things carefully.  These engines are prone to detonation (pinging/knocking) and can get damaged.

My Schneider. 460 lift which is considered a "stage 3" on MSA's website has the same cold adjustment numbers as factory specs, intake .008 and exhaust. 010.

I agree with Zed

You also need to run premium fuel if you are unsure of the compression ratio. Maybe retard the ignition some until you figure out compression ratios

The grinder and their number should be on the front of the cam where the chain sprocket is.

Edited September 28, 20213 yr by siteunseen

Thank you for that info. I did not get a card when I bought the car. So can I take that number and name, and google it to find the specifications? If the cam is stock- will it have Nissan printed in the same place?

Thank you

On 9/28/2021 at 3:43 PM, paulreverex said:

the previous owner may have added a "hopped up cam".

 

23 hours ago, paulreverex said:

If the cam is stock- will it have Nissan printed in the same place?

As it happens i have a reserve 1973 240z engine laying apart at the moment and looked at the cam.. it has a big A on the BACK (!!) nothing else.. 

Another new old stock cam i have is a so called slalom-cam and has big lobes.. that one has Datsun and a partnumber on it and the word: brown.  it was in the 70's a original datsun special cam. (new in box.. what's left of it.. cam is as new..)

EDIT:  the letter is on the back ofcourse.. not on the front of the camshaft... silly me...

Edited September 30, 20213 yr by dutchzcarguy

Nissan stamped letters in to the backs of their cams.  You might need a mirror to see it.  Here's an F cam.  Some companies regrind factory cams so yours might have the Nissan stamp and the marks that siteunseen/Cliff showed.  Check both ends.  

You can also tell by the height of the base circle.  take pictures of the cam and post it.