i've been told that if your timing belt breaks it'll immediately destroy your valves and would need to full rebuild your head 2 get it running again. Is this true? if not what are the risks if it happens, this is kinda worrying me cos my timing belt has done around 80,000

well if your worried about it get a new timing belt they dont cost much at all and get your mechanic to fit it for you...

For the sake of few bucks, change the belt. Not sure if the RB30 is "free running" or not. I do know my RB30 with RB25 head is free running though so fair chance the RB30 SOHC is too. The engine will just stall if it's a free running engine and the belt snaps. The CAS is driven by the cam i think so with no signal, it wont have spark or try to inject fuel.

The belt snaps Valves go down, pistons go up... bent and dinted. I dont believe the rb30 is "free running" as you put it

it is.the valves do NOT hit the pistons

Yeah I always thought there was clearance- Still can't be too healthy, avoid it if you want

I've always been told Holden won't fit an engine to their cars (commodore atleast) unless they are a non-interferance design. i.e. valves dont hit pistons. So i would say the RB30 would be the same if Holden allowed it in the VL... Can anyone confirm if all Holden motors are a non-interferance design? Mick

im not worrying about it, mostly just wondering if it were true, so now i know it happens with sum engines, would b good 2 know if mine is one of them monstas4 i like your assumptions that the 2 heads would work roughly the same but they r totally different, apart from size i guess, but if it was ever to snap and wreck my head, it'll b a gr8 excuse to put an rb25 head in

Quote: Originally Posted by RB30-POWER I've always been told Holden won't fit an engine to their cars (commodore atleast) unless they are a non-interferance design. i.e. valves dont hit pistons. So i would say the RB30 would be the same if Holden allowed it in the VL... Can anyone confirm if all Holden motors are a non-interferance design? Mick The VL is the only commo with a belt. the rest have chains which ya never touch but they reckon change every 300. theyre all pretty much ****ed by then anyway

chains stretch with age too.

Quote: Originally Posted by RB30-POWER I've always been told Holden won't fit an engine to their cars (commodore atleast) unless they are a non-interferance design. i.e. valves dont hit pistons. I was told the same thing by a ex Holden Dealer mechanic......Can anybody confirm this?

I can confirm that a mate of mine bent a valve in his rb30. He put the cam timming way out when replacing the belt. But as for a belt breaking it would depend on where the cam was when belt broke, but they are not a non interferance engine. cheers

my mate broke a timing belt.i was in the car. no damage was done at all and the engine must have done about 300 revs i reckon with the valves stationary. the pistons have recesses in them so they will not hit if that happens. vl calais. if your mates bent a *rod*(TYPO, i meant VALVE) i reckon his pistons were installed back to front as the exhaust valve recess is smaller than the inlet valve recess.if you done this the inlet valve would hit.not the exhaust. i bet he bent the inlet!

perhaps the dished turbo-spec pistons are non-interference design but the domed n/a pistons DO hit the valves if free-running occurs. that would account for the variability in people's experiences with the RB30.

There are still valve recesses in the N/A pistons, I don't think it should happen with either RB30 engine.

I broke the timing belt on my n/a bent the valves

try it and see hahah. I need to replace my timing belt too, NFI how old it is.

Quote: Originally Posted by VL_Nick chains stretch with age too. yes chains do stretch thats why the good old guys at the factory put tensionors in them rg hydraulic. early holden sixes were gear drive witha nylon gear that would strip out

wel i found 2 old timing belts from my car in the garage and the car has only done 200,000km so i dont think its that old, on that note im gonna leave it another year and change it then. thanx guyz 4 help Some original photos have not been recovered yet.

ok im gonna test it.