Rb30 Ring Gap?

[carl h]

anyone know what the service manual ring gap specs for the 1st and 2nd ring are for the e/et engines?

looked everywhere for a standard bore, standard ring setup with no avail.

[jarrod83]

i think this is what your after...

piston ring end gap

top compression ring 0.24 to 0.31mm (0.4mm limit)

second compression ring 0.18mm to 0.28mm (0.4mm limit)

piston ring side clearance

top compression ring 0.040 to 0.073mm (0.1mm limit)

second compression ring 0.030 to 0.063mm (0.1mm limit)

oil control ring 0.015 to 0.0190mm

Jarrod

[carl h]

exactly what i was after but the second ring gap is questionable...all of the other rb engines have a rather large range for the second ring gap.

using a set of NPR std size rb30 rings with a light hone to clean the walls up...top ring came in around .33mm and second at .55 or so all around...a bit worrysome but the rb20/26 has a large gap as well.

wish i could find a service manual for this engine.

Edited June 21, 2010 by carl h

[Trozzle]

I have a full workshop manual for the '86 VL at home, reckon this would have what you're after in it?

[jarrod83]

that was from the haynes vl manual

yeh the top and second ring gaps for the gtr are pretty large... .24-.34 and .42-.57

but the rb25 only has .21-.38 and .18 to .44

when i built my rb25 with cp forged pistons and rings.. all the ring gaps ended up pretty huge.. all 20 thou plus.. and all a fair few thou bigger than the ones i calculated it required based on the bore size, blows a bit of steam out the breather on the dyno ( while it did at the 1200km).. but doesnt seem to burn any oil.. might of sealed up a bit better now but i havent had any problems. Compression came up 160 cold for all pistons cold aswell.

Hope it works out for you

Jarrod