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Snapped A Rocker Arm And Dont Know Why Help!


CRAZYDAVE
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As per title just got my gte coupe on the road a week ago and its snapped a rocker arm. Was running fine then all of a sudden a bad misfire. Running on 3 cylinders. I took the the rocker cover off to discover the rocker arm in 2 pieces sitting on top of the head but no other visible damage. Any idea what could cause this and anyone help with a replacement? Strangest thing was there was no noise when it happened!! Pics of the car will be up soon when i get the finger out and start a projects thread! :lol:

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Random fatigue.

or overtightened

or timing chain slipped.

Check the rest carefully.

Engine still running just on 3 cylinders. Reckon i've got away without other damage? Theres no knocks or rattles off her shes just running lumpy as hell!

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Allegedly this is a problem with the CIH engines. Don't know whether its age or bad manufacture. The material the rocker is made from is very hard so can probably become brittle. one of the recommendations on Opelgt forum is to get them shot peened to getbrid of any surface imperfections. Personally i've revved my engineto over 7000 with no problems but this is where the rockers are likely to give up. The only real solution is roller rockers but at the moment the only sets available are through cat cams at around 300 quid BUT the geometry is not that good and problems have been encountered. A second alternative is being worked on at the moment, in sweden i think, but these are likely to cost 6-700 euros.

HTH

Chris

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Cheers for everyones help. Does anyone know where i can obtain a replacement? Also what is the torque figure this should be tightened to? Is there a sequence they have to be done in same as torqueing down a head? Thanks for all the help ^_^

You do not torque them down. You have to set them to give the correct clearence for the valves.

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I had a rocker snap in half, the engine suddenly went down on power and made a rattling noise. as it was still running i limped the fifthteen miles home (didn't want to swithch it off then not be able to start it again and leave myself stranded)

When i took the rocker cover off i found the snapped rocker, replaced it with one 'pinched' from another head and the engine ran fine again. Unless the broken rocker halfs get jammed into some other moving parts no damage will be done,all that happens is one valve doesn't open and one cyliner doesn't work.

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I had this happen to me in my cavalier sports hatch, a couple of months back. its the 2.0 l CIH and there was no other damage. the more people i spoke to, the more common it seems.

Anyway, just wanted to say that i got a brand new one from ULTRA PARTS LTD, they're on the web, and it was under a tenner including vat and postage! I didn't think that was bad considering how many other people had laughed at me and said 'best of luck', including the local gm dealership.

They said they had all sorts of engine parts for older cars, so they could be worth trying for other problems too.

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