Rb26 Head And Cam Question

[den001]

im just curious to know if i can drop a set of hks 272 duration with 10.2 mm lift into a standard head casting????

im not entirely sure if there is a set that requires machining for clearence but thought id ask the question....

ive heard that some high lift cams require relifes to be machined out of the head for the increased lobe size...

does anybody know whats the max on a standard rb26 head casting???

thanks

denis

[Duncan]

no, you will need to relieve the head for sure.

[Risking]

depends on the base circle of the lobe.

If its a 31mm lobe then no they wont fit without machining out the head, If they are 30mm base circles then chances are they will clear the head but require new shims or bucket/shims to accomodate.

Honestly get them anyways and machine out the head, its so worth the extra effort.

Edited January 17, 2008 by Risking

[den001]

no problems, thanks both of you for the good info... i will get them anyways, just heard that there may be clearence issues so i thought id ask..

cheers

[rockabilly]

if it helps i have jun 264/in and 272/ex 9.7mm lift. these are the biggest cams for lift in a std rb26 head. bernie

[2BNVS]

im the same as rockabily

[rev210]

You need to re-shim with the Juns, different base circle.

[Swiper the Fox]

You need to re-shim with the Juns, different base circle.

not 9.7's as they have a 31mm base circle...same as stock

[2BNVS]

yep didnt reshim mine

[special_agent]

i have just installed JUN 266 9.7mm inlet and exhaust, the base circle is smaller on these cams and needs to be re shimmed, they clear without machining.

[den001]

ok, took the cams and valvesprings to my engine builder and he has to relive teh head and reshim it... this is for 272, 10.2mm lift in and out.

thanks for the help guys