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Trying To Identify An Rb30 Modified Head And Cam

R31 Patrol!

By R31 Patrol!,
in Engines & Forced Induction

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R31 Patrol!

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Hi Folks,

I've got a modified RB30 head to go on my patrol which I am currently re-conditioning. It was removed from an R31 skyline some time ago. It is fitted with a different camshaft, vlave springs and cam gear when compared to an un-modified head. Both the inlet and exhaust ports have been enlarged. I hoping someone might recognise the markings I found on various parts in order to help me identify the thing and it's potential.

The head itself has the name John Chard 1999 or John Charo 1999 engraved by hand along the back rocker cover sealing surface.

The outer valve springs have been 'upgraded'. I note that the 1, 2 and 3 exhaust valves do not have the reverse wound springs fitted as indicated in the patrol handbook. I am unsure why nissan would have specified reverse wound springs for the 1, 2 and 3 exhaust valves only, and I wonder what effect - if any - is likely to occur by not having them.

The camshaft is stamped with 2 codes at the front (under the cam gear) KLJ and H14. It measures different to the stnadard patrol (RB30S) cam in overall lobe height. It would be nice to know what brand/grind it is to make sure I have it dialled in correctly when re-assembling the motor. I have searched around the 'net for a few days now with no real success.

The cam gear appears to be a custom modified unit to allow vernier style adjustment of the cam timing.

For what it's worth, the patrol runs Motec EFI - so being able to tune it effectively poses no real problem once installed. Any help in identifying the origin of the mods and parts would be greatly appreciated.

PS any enlightenment on the valve spring specs for 1, 2 and 3 exhaust also appreciated.

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