Total mystery : sheared off cambelt but valves ok!?

[Grifter]

I just can't figure out if my cylinder head & valves are defo ok.
I was driving down at raking 40-50 mph & the engine quietly died. Tried restarting but nothing I got home by recovery & realised my cambelt had sheared but never split, wear n tear caused it to shear around the teeth. A
It basically had a second belt running from the inside.
So I took off the head expecting the valves to be bent but to my surprise the valves r all good
Pistons clean not a mark in em to suggest they'd been hit by the valves
I bought a second head for that reason but the original one looks perfectly fine. Headgasket is real good too only about 8 months old

Can anyone tell me if I'd be ok to reuse the HG & if its possible the head valves would survive a belt/chain slip cause in at lost here I'm looking to reinstall the head I took off,
Chain on my r6 slipped & that caused havoc in my engine probsbly cause I kept on restarting it despite it sounding like a bag of spanners
But with my s13 I tried to restart but nothing continuous drill noise (whizzzzz)
Any help is good help
Thanks

[float_6969]

HG's can't be reused. I would be hard pressed to believe it survived without bent valves. Often they're not bent is such a way that is obviously visible. I would at least pull the cams, set the head upside down on a bench with the spark plugs in, and fill all of the combustion chambers with some rubbing alcohol. Watch the ports closely to see if any of the alcohol leaks through.

[Grifter]

Hi
Thanks for that float... Tell me about it I was amazed when I took off the head to see all ok, il do the leak test to confirm if their leaking & get a new HG
Pistons would have a mark if valves hit right ?

[themadscientist]

I've seen a CA and an RB survive a belt break. It's like playing Russian Roulette with just one empty chamber, but it is possible to get lucky. I wish you hadn't pulled the head. You could have done a compression check. Try shining a strong flashlight down the ports in a dark room and see if you see any light sneaking past the valves. That's not as accurate as Float's test, but you may see a problem at the crude level which will make the more accurate test unnecessary.

[PapaSmurf2k3]

Yeah its possible that it fails in a position that doesn't ruin everything.
I'd say just try slapping a fresh belt on and see if it runs well.

[Grifter]

Hey papasmurf!! Good to hear from you matey, thx fir that yeah I think il give it a belt & hopefully all shall be good will get done pics if I can .

[Grifter]

Yeah I did do w compression test but think I had a faulty tester, thanks for the tip about the flashlight think that'll be straight forward at night il do that asap

[float_6969]

Well keep us updated. I'd like to know how it turns out.

[Grifter]

Ok, so I've done the leak test you mentioned float & it was all good no leaks or anything like that, but il do it again just to be sure.
whilst taking off the head I've lost one if the engine dowels omg
Could I put it back on with just one dowel & what about these head bolts would I be ok to reuse em with some thread locker or would I need to get new ones?
I've ordered a new HG should have it next 2/3 days to install the head back on. I'll try & get some pics added

[Grifter]

Any one know how to add pics if it can be done, cause I've tried to put it through as image but won't work

[float_6969]

You need both dowels. They also hold the HG in position. You'll never get it to line up properly without them. The dowels aren't hard to get. I've never seen anything in the FSM about the head bolts being TTY, meaning they have to be replaced, by they're not that expensive either, so we always recommend replacing them. As for the images. You have to upload them somewhere, then get a link from that site, and place the "img" tags around the links. If you use the full editor, you can simply click the IMG button at the top of the editor and a box will pop up. Then paste your link in the box and the editor will do it for you.

[Grifter]

Thanks float. I'm on it & get some pics or a video clip added asap,

[Grifter]

Ok so I've been checking the head bolts & they were most likely replaced last year done the leak test again with good seals & no drastic leaks taken a few photos & will put this link to route it there & hopefully you'll see the pics https://imageshack.com/i/iqYRv6Fmj

[PapaSmurf2k3]

I'd take a close look at the intake valves on this cylinder, right at the outer edge (at the top of this picture), it looks like they may be discolored, possibly via contacting the piston.

[Grifter]

Ah, ok il get to it asap, when doing a leak down it didn't loose any liquid I think the alcohol has probably cleaned the valve caps. I'll get a pic of the pistons/block next

[PapaSmurf2k3]

Yeah it could be nothing... it just caught my eye in the pic.

[float_6969]

I think something must have rubbed on that after you took the head off. There are two other pictures in that series and that "shine" isn't there. Maybe it's just the camera angle. Regardless, he's right and I would inspect those valves extra closely.

[Grifter]

I've been checking the valves again & they sure look ok the "shine" on the two valves was the rubbing if the liquid I used to do the leak down & it sort of cleaned them up.
I've just got my HG & going to the nissan dealers to pick up a engine dowel so i can work on putting the top end back together
Taken more pics of the pistons etc

[Grifter]

[Grifter]

[float_6969]

Well it looks like you're the luckiest man alive, LOL

[Grifter]

I've just pulled the turbo off & it does have some shaft play . The turbine wheel has enough movement to rub against the inside of the housing!
Would that be ok ? or if not I've got another unit somewhere which haven't used for over 12 months could put that on.
It's not like the original turbo on is shaking madly but does have play which'll rub the inside.

[float_6969]

If there is enough play that it will make contact with the housings, it's done and needs replaced

[Grifter]

Thanks float have to replace it then with.the one ive got stored up that's a bit dry should I soak it with oil for few days to lubricate the bearings

[Grifter]

Just trying to put the head on now but have two figures for the torque?? Anyone know what the exact torque n-m would be ?
Should I put on the camshafts first or after the head installation.
Will get some pics loaded soon as I've got it on to try & set timing

[PapaSmurf2k3]

The 2 figures for torque are because it should be a multi-stage torque down. First torque them to the lower torque, then the higher one in the sequence shown.

[Grifter]

Ok that's made it much easier thanks papasmurf. Trying to get this installed asap to add some pics

[Grifter]

Ok I've been trying to get the head on & nearly there it's getting stick somewhere & getting rid of the obstructing bits. I've had to take the turbo off with all the pipes & stuff & there's two small pipes that run along the back of the engine to the turbo.
Now I can't figure out to where they connect to? Would they go down the cooling system or the intake from the back
I've also got this spare turbo which looks much bigger than a t28 currently on the car. When I bought it I was told it was an upgraded t28 pumping 20psi try n get that put on soon as

[float_6969]

There are two lines, but only one is a coolant line. One end should connect to the intake manifold, and the other end should connect to the turbo.

[Grifter]

Ok float thanks. I'm in a bit of a muddle here cause I have this t28 turbo which was dry stored for a few months & now the turbine is very stiff to turn I've put some oil through it from the inlet overnight & turned it with a electric drill bit its still very hard to turn by hand!! Could I put it in & after its had some oil in it'll free up