sheared off front cam chain guide bolt, inside inspection hole

markm7

Hi all and thanks for your greetings,
I was wondering if anyone has experience with dealing with this problem. I have owned this astra 2.2 for the last 2 years and have covered 15k with it now at 97k. Basically i would get a diesel start up noise intermittently for a few seconds which would go after a rev upto about 2500rpm from immediate start up. This i got use to and lived over time, within the last 2 weeks however this stuck and it rattles constantly, at first i thought maybe this could be low oil and checked it was at middle on the dipstick but topped up anyway with a litre. This didn't solve it so i decided to buy a socket set and inspect the cam chain using a haynes manual. After removing the cam cover it is all nicely oiled and there is no sludge or crap in the head. I removed the top chain guide and there is a little slack in the chain, i then spotted the slack gets worse around the front inlet sprocket and could see that the front side guide rail bolt was protruding outwards and the guide rail was very loose. I then noticed that there was a inspection hole so removed the plug and tried to tighten the bolt, this didn't work it was just spinning so i removed the bolt and found it was snapped with around 15mm of thread still on and could see the rest of it through the hole. The head of the bolt was all worn where it had obviously been rattling against the back of the inspection plug which was also worn. Any advice on how to remove the bolt and what slack in the chain is allowable plus where to get a single bolt would be appreciated, thanks.

evocarlos

normal process would require drilling and EZ-out of the pin left in the block if there was no head damage
if the head thread is damaged it will need drilling and tapping to fit a helicoil
is the front guide broken ?

if you know someone with a lathe you can get an inspection plug guide fix plug made
like so i dont have a die big enuff to put a thread on :s but i'm sure i could get some made

any nasty noises during startup or running should be dealt with even out of paranoia 🙂

there should be no slack in the chain if there is the tensioner is not taking up the slack and maybe the front guide rail is broken

im sure i can find a bolt out 🙂 plenty of spares about unless you want the part number for 2 new ones
GM #11588522

flatbeat

If you have a few mm of bolt stuck out you should be able to get some vice grips on it and undo it
Or at worst replace the chain cover

IDI_AMIN

Sounds like it is time for a new timing chain. try and grip the remaining thread with pliers or mold grips if they fit.Go in from the top

evocarlos

flatbeat said:
If you have a few mm of bolt stuck out you should be able to get some vice grips on it and undo it
Or at worst replace the chain cover

i wouldn't risk mashing up the end of the broken pin if there is any sticking out would mess up the chances of getting the drill down the center line, but there won't be its a flush fit the the block
the denzil noise at start up is the slack in the chain smashing against the front guide causing the bolt to get sheard there are worst cases where the hole in the block get opened up to 10mm like a funnel

markm7

flatbeat said:
If you have a few mm of bolt stuck out you should be able to get some vice grips on it and undo it
Or at worst replace the chain cover

There's no room plus the snapped pin is inside the cam head, when i was saying about bolt length left i meant on the bolt itself.

evocarlos

markm7 said:
There's no room plus the snapped pin is inside the cam head, when i was saying about bolt length left i meant on the bolt itself.

so the thread in the head is stripped ??

helicoil

markm7

evocarlos said:
normal process would require drilling and EZ-out of the pin left in the block if there was no head damage
if the head thread is damaged it will need drilling and tapping to fit a helicoil
is the front guide broken ?

if you know someone with a lathe you can get an inspection plug guide fix plug made
like so i dont have a die big enuff to put a thread on :s but i'm sure i could get some made
[ATTACH]38626[/ATTACH]

any nasty noises during startup or running should be dealt with even out of paranoia 🙂

there should be no slack in the chain if there is the tensioner is not taking up the slack and maybe the front guide rail is broken

im sure i can find a bolt out 🙂 plenty of spares about unless you want the part number for 2 new ones
GM #11588522

I think i'll try the ez out method, the guide is still ok although it is worn around the plastic hole but intact enough, want to avoid replacement at the moment

markm7

evocarlos said:
so the thread in the head is stripped ??

helicoil

i don't think it's damaged, will need to look properly evo. as i said tried to put the remaining bolt back but not enough length left on it really to start to bite

evocarlos

you could always get a plug made like my pic 🙂
keep us informed 🙂

markm7

hi evo, it's gonna be so awkward to ez out the pin left in the block. How do i go about making a plug, or did you say you could do it?

evocarlos

markm7 said:
hi evo, it's gonna be so awkward to ez out the pin left in the block. How do i go about making a plug, or did you say you could do it?

helicoil is the next quickest option drill it out to m8 then fit a m6 helicoil you would need to catch the swarf
http://www.ebay.co.uk/itm/25-Piece-Helicoil-Thread-Repair-Kit-M6-x-1-0-x-8-0mm-/310678382294

if i were to get a plug made up i would need to go buy a plug and get it replicated with the bolt part on it and test fit it sort of thing

markm7

evocarlos said:
helicoil is the next quickest option drill it out to m8 then fit a m6 helicoil you would need to catch the swarf
http://www.ebay.co.uk/itm/25-Piece-Helicoil-Thread-Repair-Kit-M6-x-1-0-x-8-0mm-/310678382294

if i were to get a plug made up i would need to go buy a plug and get it replicated with the bolt part on it and test fit it sort of thing

I'm gonna leave it until weekend as weather is bad and no time, i think i am just gonna do what you suggested in the first place and try and ez it out, borrow a trolley jack and romove the engine mount for better access. i think i can borrow a magnetic bar for the swarf, thank you again for the advice and i'll keep you informed

markm7

Just an update, i used a 5mm drill bit and managed to remove all of the bolt, then luckily there was remaining thread in the cam casing and i easily managed to put a new bolt in with the help of evocarlos's part number. Then like a stupid t$$$ i knocked the top elevated guides bolt down into the cam/balance chain mechanisms on rebuild. Is it ok to leave or am i going to have to remove the side panel and get it out?, if so i might just aswell replace the camchain and all the bits while ive got it open

evocarlos

you will need to get them out if there stuck in the chain area it could cause more trouble than removing the cover to fish them out unless they dropped right thru to the sump
if you can see them from the top get a magnetic arial and try and fish them out

nice work getting the hole clear 🙂

markm7

evocarlos said:
you will need to get them out if there stuck in the chain area it could cause more trouble than removing the cover to fish them out unless they dropped right thru to the sump
if you can see them from the top get a magnetic arial and try and fish them out

nice work getting the hole clear 🙂

hi evo, another update. I managed to dismantle everything needed to get the chain cover open, with the main time taken trying to remove the crankshaft bolt. I ended up using the starter method with ratchet and bar tied to subframe, quick turn off key and it was free!. On inspection i found the bolt in the sump entry tray at the bottom and also 2 snapped drill bits. I also noticed a small metal block around 8mm x 6mm with a stepped tooth cut down 1 long side. It looked to me like it's out of the balancer chain tensioner which looked to be operating properly. I couldn't find anything else down there but i think the block possibly acted as a self adjuster?. I checked everything else and all looks good. Lastly i unbolted the cam chain tensioner and found the pin was seized with black coloured burnt gunk on the pin. I scrapped this off and gave a good clean. I have put it all together and sadly run out off light with just 10mins off work to do. I am up now early eager to see the results, will update if hopefully news is good

markm7

Completed, initially a little noisy then silence, guess thats cos i haven't run it for around 3 weeks. Wow i thought it had cut out and it's quieter than when i first got the car 2 years ago. topped oil up after loosing alot removing the chain cover plate. I'm so glad that guide bolt is sorted, and i bet regarding the tensioner it must of been partially siezed for along time and then given up when it got very rattly and wouldn't shift with a high rev of the engine. buzzing now (y), thanks evo for your help.

evocarlos

no problem mate im here to help if i can 🙂
glad you got it sorted finally