Jump to content
SAU Community

Recommended Posts

I changed a timing belt on an RB25DET for a family member and unknown to me, a spacer or collar (what ever it was) found it's way where it didn't belong :D .

This caused the inlet cam to become retarded by 2 teeth and the exhaust cam to advance 2 teeth.

Resetting the cam timing and the engine to runs like a bought 1 (it wouldn't start befor).

The obvious question is, was there any potential to have damaged valves/pistons?

My main concern is that the boost gauge is showing about 11" mercury when idling. This seems low to me but I never paid any attention to the gauge pre busted cam timing.........

Other than that, engine is smooth as silk with a rock solid idle speed.

Link to comment
https://www.sau.com.au/forums/topic/191413-chance-of-valve-damage/
Share on other sites

i would say no... several teeth out wouldnt be enough to do any major damage, trust me you'd hear the valves touching the pistons when you first crank it over :D

Cheers. Like I said it's only the low idle vacuum that bothers me, but that could be a dud gauge or crap hose.

Cant really comment on the 2 teeth you picked up but ide say if the changes were made from TDC then you should be ok (considering how much *safe* adjustment you can get out of adjustable gears)

What exactly did you do to cause the problem? I only ask because I have a 25 and a 20 here both awaiting a new belt so I dont want to make the same mistake

Cant really comment on the 2 teeth you picked up but ide say if the changes were made from TDC then you should be ok (considering how much *safe* adjustment you can get out of adjustable gears)

What exactly did you do to cause the problem? I only ask because I have a 25 and a 20 here both awaiting a new belt so I dont want to make the same mistake

Somehow a steel spacer that I can only guess was from the timing belt cover got in behind the timing cover. I found it sitting between the cover and the tensioner roller. I think we (I) were very lucky, and propably the only thing that prevented major engine damage was because the owner was (suppose to be :rofl: ) taking it easy due to a dud fuel pump.

Belt replacement is quite straight forward, just leave out any and all small and large belt wrecking items and it will all be sweet :D

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • I have a 6 boost manifold and it has loads of bends etc. turbo has a cover however manifold doesn’t so I started to wrap what I could without taking turbo off. Very restricted area   are you stating wrapping could lead to cracking weld? Is that because heat is retained?    i have a exhaust gas temp right after turbo and it hits 700degree or 800 at times.   there are areas which is impossible to reach with fibre glass cloth. Is there anything I could apply such as the photo shared earlier which would formulate around exhaust pipe in difficult to reach areas, sort of like aluminium foil flexible to shape it in place?   i think from earlier reply you mentioned acl? Is this what you meant?   https://www.nstparts.com/product/acl-heat-shield-700x275     photo of my engine bay   https://ibb.co/9grHsMN https://ibb.co/bXC8KRM https://ibb.co/KV3kGZc   I am trying to cover bottom of the exhaust manifold which joins the turbo. Only way is to take turbo and possible manifold out as it also touches the engine mount which I don’t fancy doing
    • So....I managed to fix the belt coming off problem, but unfortunately i destroyed my oil pump. While testing and hitting my rev limiter a bunch, my oil pump took a shit. I actually heard it break. In my great wisdom i decided to hit redline 5 times (original plan). Lowered it to 7500 for the soft limiter. Normally it would come off on the first go. The 6th time I hit the limiter the pump broke and as i began accelerating again and hit it the 7th time, oil pressure dropped and the protection kicked in. It actually made a "tink" as if i dropped something hollow.   The motor is pulled and should be rebuilt and put back in 3 weeks. No bearings were spun and i could have gotten away with simply replacing the pump, but since i had to pull the motor....might as well build it   I made a billet tensioner and the belt stayed on without getting frayed. I also made one for a friends R33, but I was thinking of using a hydraulic unit to keep constant pressure on it when the belt stretches.
    • Yeah 98 for me, and 6.7/100 was my actual usage. On the downside the bloody thing still isn't running properly but at least they hybrid system is happy now. It starts but missfires like a bastard, and isn't throwing any code except "missfire". Thanks scoop. I did notice the AFMs are reading quite different at idle 1.33v and 1.67v so 25% variance (and have both changed and swapped them, the issue stays on the driver's side afm) so I'm looking for exhaust restriction (mouse nest?), compression issue or (hopefully not, no physical damage seen) wiring issue. Throttle might also be an issue but that is harder because you can't swap them side to side and not cheap to fire the parts cannon at.
    • I hope you're right and it somehow justifies it's existence!
×
×
  • Create New...