RB26 very noisey up top....

[Guest shano2]

A mate of mine was playing with his newly fitted HKS adjustable cam gears on an otherwise stock R32 GTR (90mm HKS exhaust, filters & boost restricter removal is the limit of the modifications) and after making some very mild (suggested) adjustments and restarting the engine a VERY loud top end "clatter" appeared.

The settings he was aiming for was :

INLET : 2 deg advanced

EXHAUST : 4 deg retarded

BUT he went the wrong way on both cams and ended up with

INLET : 2 deg retarded

EXHAUST : 4 deg advanced

Once the engine was restarted the idle was very rough, the aforementioned noise appeared and the was significantly less vacuum present on the boost gauge.

This is where my involvement began

Pulled the covers off again and I pointed out the cams were set in the wrong positions. We reset them to where they should have gone in the first place :

INLET : 2 deg advanced

EXHAUST : 4 deg retarded

Idle still poor, noise unchanged and vacuum the same.

We then reverted the cams back to standard position (0 deg IN, 0 deg EX) and while the idle improved it's still rough the vacuum and noise stayed the same.

Each time the ignition timing was reset appropriately.

Given the lower level of vacuum we suspected 1 or more dropped inlet valves so checked each cylinder by removing the injector plugs one by one and found that the engine revs dropped when every one of the plugs was removed and picked up again when each plug was replaced, so that would APPEAR to rule out inlet valves.

The rocker cover will come off tomorrow for a better look but until then does anyone have any other suggestions to mull over? Exhaust valves?? Camshaft??? Other????

Also is the RB26 a "non-interferance" engine?

[MattyB]

from a bit of pure guess here.

Maybe with the place the boost guage is connected to the true vacume isnt shown.

[Emre]

Yes, the RB 26 is a non-interference engine, in stock form.

Did you make sure to put the spacer washer between the engine and the crank angle sensor back on...? This is a common overlook if you want to expose your new cam gears and decide not to put the cover back on. If you slide the CAS without the spacer washer, it will chew the rear of the CAS out and make the noise you are describing.