rb25det timing belt snapped

[DRIFTER]

has anyone heard of a timing belt tensioner bolt braking before or was this just human error?

[sproosy]

ny mates VL had that happen to him, bent valves and all the good stuff that comes with snapping a timing belt. Hope its not too costly to fix dude! im not sure if its human error or just the age of the tensioner.....

[Cubes]

Its happened on both RB20DET's and RB25DET's that I know of.

I'm not sure if the RB25DET bent valves but I know for sure the RB20DET actually snapped them off.

[ylwgtr2]

RB25's are an interferance engine....sorry!And yes i have seen it happen no one's fault...they just break!

[Alf]

I've always changed the studs when i've changed the belt.

It's cheap insurance. :flamed:

[R31Nismoid]

Its happened on both RB20DET's and RB25DET's that I know of.

 

RB20DET actually snapped them off.

yeah, i snapped 3 off my old RB20, and bent 5 more.

The rest were shagged... had to get a wohle new head :Oops:

turns out the bearing wasnt changed with the belt change... so previous owner cost me a dime and a half!

[Cubes]

The interference theory is an interesting one.

Reason being as turning the motor over by hand you don't get contact.

Once the motor is running you do and break valves.

My guess is its a combination of a couple of things once the motor is running.

Hydraulic lifters are completely pumped up, possibly piston rock and everything is hot so everything has expanded... Not sure on that last one but.

[jnr32r]

So it is recommended the tensioner be changed with the timming belt change?

[R31Nismoid]

yes. for sure.

they cost a few hundred. But worth it

[Jordan]

My Tensioner snapped a few months ago, nothing caused it, it just died.

Valves were bent and needed new valveguides. Didnt do anything else but I got the whole thing rebuilt again anyways.

[benl1981]

Hey Jordan - Did the bearing sieze which caused the stud to take more load and then snap off? Or did the belt snap?

[dnb]

i just buy the bearings and rebuild my own tensioners. costs about $20

[nv033]

if the tensioner bolt ever comes off change it....its not worth saving $20

[Dragster33]

does the new tensioner come with a bolt aswell? and is there anywhere that does high tensile bolts for the tensioner?

[Jordan]

Hey Jordan - Did the bearing sieze which caused the stud to take more load and then snap off?  Or did the belt snap?

dont know for sure, I was just told the cause.