73 240z engine rebuild questions

[rem1313]

I'm using new 73 style pistons and want to upgrade cam to Comp Cams 280S-110 grind. The head has been surfaced at -.012. My main concern is valve clearance, I do plan to use cam tower shims but I'm unsure how many it might take to make this combination work.

Thanks for your help.

Specs for stock v. Comp Cams:

Comp Cams

Advertised Intake Duration: 280

Advertised Exhaust Duration: 280

Intake Valve Lift: 0.460

Exhaust Valve Lift: 0.460

Stock Cam L24

Intake Duration:   248

Exhaust Duration:  248

Intake Valve Lift:  0.413

Exhaust Valve Lift:    0:413

 

 

 

Edited May 6, 2021 by rem1313
incorrect information

[jonbill]

Is your question about clearance between valve and rocker or valve and pistons? 

[rem1313]

The valve and pistons

[jonbill]

are '73 style' pistons flat top? If so, it'll be pretty close I think.

I'd mock it up with plasticine and check how much clearance there is. 

[rem1313]

Thanks jonbill, The pistons are stock 73 style with the eyebrow cutouts.

[Diseazd]

rem1313.....If you are using a 73 E88 head and only shaved .012 inches, you shouldn’t have any problems IMO. Those pistons are fly cut. If you use a cam with any more lift than .460,  you would need to use a shorter valve seal. 

[rem1313]

Thank you Diseazd, appreciate the feedback