Z22SE Big back fire from inlet, need help!

[jnaisby]

Well my cars has been rebuild, bottom end checked with new piston rings changed and full recon + port and polish head, its not even done 1000miles yet!

but the problem is when tried starting the car a loud bang came from the engine bay from the inlet manifold, after the engine was just turning over at normal speed but no start just starter motor pulling it round. this come out the blue when from a hour or so before it started no problem :/. when I removed the rocker cover I seen one of the cam followers off and looked undamaged on inlet valves cyl 3, after checking the rest were fine apart from cyl 1 cam followers and the other one on cyl 3 just push off and I could take them out which I didn't think should happen :/. chain is soild and don't look like its jumped.

I've left it for the time been and don't know what to do next I don't wanna just put it back together without knewing what happened in the first place, and of course save any more damage. any tests I can do with the way its acting now?

any help would be great thanks jnaisby

 

[jnaisby]

Few photos before putting the head in

 

[evocarlos]

bent valve and backfiring into the the inlet

 

[jnaisby]

how did it bend with the timing still fine? its started great before hand and the other day was putting out 170hp

 

[evocarlos]

was the tensioner activated ?
ive only seen the cam rollers come out after the valve has been bumped by the piston
you can see the valve height is not the same as the one next to it this was broken chain and bent valves yours must have jumped

 

[jnaisby]

I'll have to double check tomorrow after work the cars at my friends garage, they looked fine from first look i'll take a photo tomorrow , but even tho can you say why the other cam followers just come off on cyl 1 and 3? and there was a squeaking noise at turn over before removing the rocker cover.

 

[evocarlos]

i put the cams back in my b207 head today and when the cams are in the correct timing location the followers on #2 and #4 exhaust cam move but not much the gap between the cam and the roller was less than 0.10mm checked with a feeler gauge

 

[Daz]

was the tensioner activated ?
ive only seen the cam rollers come out after the valve has been bumped by the piston
you can see the valve height is not the same as the one next to it this was broken chain and bent valves yours must have jumped
View attachment 43084

I'll 2nd that carl..... rollers can only be removed when s**t has happened..... unless the cams are out too..

 

[evocarlos]

I'll 2nd that carl..... rollers can only be removed when s**t has happened..... unless the cams are out too..

even if the were out you cant get them out 0.10mm is not a lot of room

 

[corsaZ22se]

with the power you have I take it your using uprated cams? have you changed the springs? are they cheep regrinds? there are some very poor cams out there, I know from bad experience. not always cheep ones either.
you may have had valve bounce chucked a follower and timing still spot on?