Slipped the belt...

[Leeboo]

Engine in question is made up from a c14nz block, 1200 nova carb head, 16sv cam, and a pierburg 1B carb off 1200. The engine has run well and has covered around 500 (or bit more) miles since being put together.

However it made a strange clattering sound randomly at around 3-4000 rpm today (cannot remember actual rpm but it wasn't high) and I turned it off immediately. Upon inspection it had slipped the belt by a large amount (with crank pulley in correct position, the cam pulley was half a turn out, therefore completely opposite to the correct position :wtf: ). To my knowledge the belt had the right tension.

With nothing to lose I set them back to where they should be and tried turning the engine over, it won't turn over properly and made an odd sound (internally).

Whats the likely damage? Bottom end would be fine wouldn't it? Likely to have bent valves or something along those lines?

Any replies very appreciated!

[garyc]

Take the rocker cover off and see if owt is broken. If so its head off job. Prob bent a valve and cracked guides I would think.

[Leeboo]

Thanks, I will do that tomorrow... somethings defo not right, somethings touched something else that it shouldn't have lol

[AlexW]

Depends tbh, Some snap the valves and they end up ****ing the pistons and head up.

But that is worst case, Most likly its bent a few, couple of wrecked valve guides and a bit of shineyness on the piston tops. As said tho, take the rocker cover off, if a valve is bent your see the spring still down of course.

[Rich]

Are you sure you dont just need to turn the crank another turn?
Not looking at it 180deg out?

[andy22sri]

do a cyclinder leak test before taking the head off. you could have only broken the rocker fingers.

[craig green]

Are you sure you dont just need to turn the crank another turn?
Not looking at it 180deg out?


crank turns twice per 1 revolution of the cam. :thumb:

[Leeboo]

Thanks for all the replies.

Rich - I'm not sure what you mean.. I have the little notch on the crank pulley lined up to where it should be, and same with the cam pulley. Theres nothing else to it is there?

[AlexW]

Im too thick to think about it now, but try turning it another 180 degrees, do the timing marks match up?

[MattBrown]

The Crank pulley is half the size of the vernier pulley on the cam.

2.1 ratio, hence you can run the dizzy off the end of the cam, as the dizzy also turns at half the speed, so no wasted spark!

Pistons may be dented, I smashed a hole in one, but that was when a valve snapped, and lodged itsself in the head, so it was obviously going to do this.

Valves will be bent, rocker arms maybe snapped, and the guides may be mashed.

Just take it off, 20 minute job, pics when its off:thumb:

[Spudly]

Umm why would there be valve damage, 8v engines are 'valve safe' you cant have it lined up correctly, burgos cambelt failed the other week on the motorway so he got another one brought out to him, refitted it and drove home!

[Leeboo]

Thanks again for replies, I'm goin to go and take the head off now soon, I'll take pics if I see anything.

Spudly - Yeah 1200 8v engines are valve safe i think... not sure on this one as its a 1200 head on 1400 block. Something definately made contact as it made a noise

[mowgli]

probably took a rocker out & wedged it somewhere.

[Leeboo]

http://i222.photobucket.com/albums/dd139/leeberto/SP_A2634.jpg

You can just see where the valves have contacted the top of the pistons... pistons seem ok though. New head then so!

[General Baxter]

bah that will be fine lol

[garyc]

I've got some 1300 heads if you need one! PM me

[burgo]

might be worth fettling the pistons so it cant contact in future

[Leeboo]

garyc -

hopefully getting one local but if not I will contact you thanks.

burgo -

Theres an idea.... should I just dremmel out a small amount of material around where the shinyness is? (where the valves hit the piston?) It won't fcuk anything up by taking a little bit of material out? Thanks

[burgo]

exactly that. you want to do it with the piston at the top of the bore and put grease around the outside of the piston to stop any swarf going down the side of the piston