Snapped cambelt??

handyman · Post by **handyman** » 05 Apr 2005, 23:45

Driving my Activa Turbo yesterday, after a long journey, I noticed it was down on power and lacked its usual acceleration. I put it down to a duff spark plug and went to change them today.
Out of curiosity, I attempted to start the engine, which refused to fire and sounded like a bag of nails. I presume that the cambelt is at fault and has given up the ghost.
The previous owner said he had the cambelt changed, but in view of the other things I have found wrong with the car, I treat this comment with caution.
If the cambelt has slipped or snapped, what is the likely damage? As it was not running or under power, will the valves and pistons have touched? If the answer is yes, I know it is a head off job. Will the head need to be skimmed once removed, as this seems to be the norm with modern alloy heads? Any likelyhood of a bent conrod?
I had this problem many years ago with a Pinto engined Transit, just changed the cambelt and all was well. Will I be so lucky?
I will undertake the work myself, as garages I have used locally to me have given less than satisfactory performance. Are there any wrinkles or dodges to help with the job?
My first task will be to remove the cambelt cover to confirm my fears!

Stinkwheel · Post by **Stinkwheel** » 06 Apr 2005, 00:03

I've heard of cambelts, breaking/strippping etc when not running and just turned on starter and doing no damage. You may be lucky you may not.
Only way to find out is fit one and see if you have got away with it. Not really lost anything but the price of nother belt if it doesnt work. Will have to strip it to fix it properly anyway then.

Richard Gallagher · Post by **Richard Gallagher** » 06 Apr 2005, 00:09

If the engine has been turned over with a broken belt then the valves will almost certainly been bent. I've just done this job on a 2.0 16v and the damage was just bent valves, clean up the surfaces of the block/head then put together after examination and replacement of bent valves and checking that the other valves haven't got a build up of of carbon on their back.
Normally when the belt has broken the engine will turn over much quicker than normal as the camshaft takes quite a lot of power to turn.
Changing the belt on a the Activa 8 valve turbo engine is relatively easy, but removing/replacing the head will be a two man job due to the weight of the turbo and the location of the engine at the back of the engine bay.

ActivaV6uk · Post by **ActivaV6uk** » 06 Apr 2005, 00:34

its not taht bad you can do it on your own as its possible to get the turbo off the engine with the engine still bolted in, you have to retract the drivers side drive shaft to do it thoguh other whise you cant get to the bolts.
If the valves are bent I have a complete good head from an activa here that is up for £150 plus delivery I also have an ecu if that turns out to be the problem.
i have access to the engine pin out and electrical diagram and info on the head job and setings if you need any help eather email me or post here for help.
If you deside to write the car off let me know I may have people who are interested in suspension parts.
Andy

handyman · Post by **handyman** » 06 Apr 2005, 01:03

Hi Andy, I am a bit mystified by your comment about the ecu. As far as I am aware, the fault lies within the top end of the engine. I would be extremely surprised if both the ecu and the cambelt were faulty.
As regards a secondhand head, I will replace any bent valves and rework the head myself so I know it is right. I get a little p****d off at the general standard of bad workmanship in garages nowadays. I used to run a number of garages a few years ago and all my mechanics & fitters knew the job and were honest and conscientious.
The car is not available for breaking, your comment about wanting to purchase it is a little "vulturesque", if you get my meaning.
Thanks for the offer of information, though.

jeremy · Post by **jeremy** » 06 Apr 2005, 01:38

I don't know much about the intimate workings of the petrol turbo engine but do the valves actually touch the pistons when it turns without a cambelt?
The reason I say this is that it is SOHC with direct acting valves (no rockers) so the valves are nearly vertical and in a straight line. As a Turbo the compression is probably lowered from the non-turbo engine so?
If you're sure the belt has gone why not turn the engine with a spanner and see if you can hear or feel anything and if all feels ok why not remove the rocker cover, turn the camshaft so that the Inlet is open when the piston descends, then turn it again and test the compression. At that speed and under those circumstances if there is any valve damage you will get no compression at all.
Jeremy

handyman · Post by **handyman** » 06 Apr 2005, 01:48

Hi Jeremy, I had been thinking along those lines. I am still in the throws of removing the cambelt cover to check the condition of it and the other assorted gubbins. Next question, how to get a spanner onto the end of the crankshaft to turn over the lump? From a quick visual, not a lot of room down there.

jeremy · Post by **jeremy** » 06 Apr 2005, 01:58

You could always jack it up and carefully turn one front wheel with it in 5th.
Jeremy

ActivaV6uk · Post by **ActivaV6uk** » 06 Apr 2005, 03:16

My apologys if my comments came across wrong. The forum at www.activanet.co.uk has a lot of activa members and with these cars only being worth about £600 at the moment people tend to write them off and track down another one. Its better that the cars that people do give up on end up saving other activa's than being lost compleatly.
I'm glad to see you want to resurect it, with powerloss there are numerouse sensors that can cause this that have a directe efect on the turbo and injector systems, the bag of nails sounds as you sau is lighly to show a cam belt issue (check the tensioner if the belt looks ok it may have let the belt jump a tooth). changing a cambelt for this car is the same as with any XU there are alot of induction pipes in the way and the turbo is almost impossible to get to with out eather taking the enigine out or the driver side drive shaft out. the bolts are 10mm and of a star shape fitment which is the same as a ring spanner.
some of the guys on activanet who dont read this forum have done a lot of work on there activa's it may be worht posting on there too if you run into trouble.
Andy

alan s · Post by **alan s** » 06 Apr 2005, 03:57

I'd suggest the first thing to do might be to whip the top cover off and find out for sure if the belt is broken. It could just be that a tensioner has collapsed or a water pump bearing fallen to pieces both of which would cause strange noises and possibly screw up the performance in the process. If it is something like this, chances are that you may be lucky enough that no reasonably major damage has yet occurred but this could all change real quickly if you keep turning the engine over and the belt does snap or drop off.
From what I've seen and heard, it is normal for the damage to be limited to the top end so you'd have to be a bit stiff to have con rod or any other problems.
I'd suggest possibly getting a price from an engine rebuilder to replace valves, cut seats and face valves and true off the head surface as well as checking valve stem seals and guides to do a proper job on it.
I agree with you as to the standard of far too many tradesmen these days; it's bloody woeful, and I say that as an ex-tradesman myself.
I recently did some maintenance on a '92 BX TZi that was specialist serviced and when I canged the cambelt, it was obvious it was the original. I subsequently did a job on a family friends BX that had done 45,000 since she bought it and found an oil filter that was also just as obvious that had never been changed whilst she owned it but she's been charged for a few, so if they tell me when I buy a car that their "specialist" has done any particular job, I usually make that first port of call of jobs to be done as usually it either hasn't been done, or they done a short cut on the job.
I think these days, too many (not all mind you) want to write up the bill first and then do as little as possible to convince the customer they've got their moneys worth. They could save us all a lot of time and aggro if they just asked for you to empty your wallet on the counter and just walk out; at least then you know what you've got.
Alan S

handyman · Post by **handyman** » 06 Apr 2005, 10:06

Hello AlanS, I have not run the engine, as soon as I heard the rather strange noises, I knew it could be terminal. Luckily, the engine did not fire up when I tried to start it so I am assuming any damage will be minimal.
If I need to remove the head to replace the valves, I will probably rebuild the head myself. I have had a number of years building and moding bike racing engines, so I think I might be up to it. Might even try and blueprint it whilst it's in bits. Anybody got any tuning mod data?

ActivaV6uk · Post by **ActivaV6uk** » 06 Apr 2005, 19:05

you will need to go to www.205gtidrivers.com and there forum. almost every member drives a car with one of these heads on it and a lot have tuned them. its a technical forum at hart so your should find the info you want.
FYI the C/R on these engines is pretty low and as such there is quite a lot of room for the pistons and the valves to share the same space you will with luck find that any damage is minimal.
Andy