G'day,

I adjusted the rocker clearances on my 998 last night, I followed the instructions in the "do-it-yourself workshop manual" (SP manuals). And it was actually quite a lot easier than i thought it would be.

However, today i thought i might do a search on here to see how others did their, this is when i noticed all the posts said the clearance should be .012", i did mine at .019" as per what i read in book??

So ive just got home and checked the book again, it says :

Rocker working clearance .... 0.012
Rocker clearance for Valve timing ....0.019 (which i used)

Obviously i'll change to 0.012 as this seems to be the correct one, but could anyone tell me the difference between the two? (and no smart arses saying 0.007)

Cheers

Normal rocker clearance installed (stock cam) is .012" cold or .011" hot.
The .019" is used when checking cams for comparison with others. Some BMC race cams are .021". BUT it's not a running setting.

However, many sports cams run more than .012". eg a Cooper S uses .015" for competition, Kent cams are usually .016", so are Graham Russell's RE13 cams.

These figures are for the stock rockers. If Hi-lift 1.5:1 rockers are used, add .003" to these numbers.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks for the response, I'll adjust to .012 on the weekend,



I'm just a little curious what you mean by above (i'm still pretty much a noob when playing with engines), so how does adjusting to .019 check/compare the cam?

Cheers

Kuross,
I believe that you use the 0.019 when checking cam profiles, i.e. duration, lift etc. This is a standard clearance to minimise the initial 'ramp' on differing profiles, particularly when dealing with reground and racier profiles.

You would not actually run the car with this gap, just measure!

Am I right kev?

_________________
Sir Alec! we are not worthy!

righto thanks for that, i think i get it now.