Timing Belt snapped while going Possible Damage?
Timing Belt snapped while going Possible Damage?
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Discussion

gjones118

Original Poster:

7 posts

83 months

Sunday 28th April 2019
quotequote all
Hey all, so here is my problem.

My girlfriend was driving her car and the timing belt snapped, Towed it home and took off the rocker cover and saw that all the rocker arms were snapped .. not just snapped but in pieces so i replaced all of those. Before refitting i checked the level of all the valves and they were all at the same height, no variations at all so i assumed there was no valve damage. so i refitted a new timing belt with a new water pump,tensioner and idler and of course timed it up as per haynes manual. The car now starts up with no issues but there is a pretty substantial knock. any ideas on what could be the cause of this knock ?

Currently full to the max level with oil, with flushing additive, intention was to run the engine for 20 minutes, drain the oil, change filters (Oil and Fuel). But with this knocking i don't want to run it any more than i need to for diagnosis purposes. On a tight budget and need the car running. kind of don't want to take the cylinder head off due to everything that comes with it, skimming and all the other labour intensive tasks.

i have uploaded a video to youtube : https://www.youtube.com/watch?v=IkGlvV_efIQ&fe...

The car is a 1.6 ford Fiesta Diesel

stevieturbo

17,968 posts

270 months

Sunday 28th April 2019
quotequote all
That engine is not running on all cylinders.

And you're making a big assumption that there has been no other damage....the fact the valves etc had all been hit hard enough to break all the rockers mean there has been substantial piston to valve contact.

You have not dodged a bullet. Do a compression test.

gjones118

Original Poster:

7 posts

83 months

Sunday 28th April 2019
quotequote all
worst fears confirmed

E-bmw

12,328 posts

175 months

Sunday 28th April 2019
quotequote all
100% if the valves have been banged enough by the pistons to break the rockers they have been hit by the pistons & everything needs replacing, as above, no bullet dodged, sorry.

stevieturbo

17,968 posts

270 months

Monday 29th April 2019
quotequote all
Clearly it is running...so not necessarily everything needs replaced.

But certainly it needs a major stripdown and thorough inspection. You might be lucky and all damaged is confined to the cylinder head so repairs wont be horrendous.

it was worth an attempt though at what you did.

gjones118

Original Poster:

7 posts

83 months

Monday 29th April 2019
quotequote all
Yeahh I thought the rocker arms took all of the brunt but clearly the damage is further down.. Might have to throw it into the garage as I don't think I have the time or the tooling required to go further than I already have.. Thanks for all your replies though I'll keep you all posted on what damage has occurred 👌

M_A_S

1,441 posts

208 months

Monday 29th April 2019
quotequote all
Check the camshaft lobes, they have a habit of turning when the belt goes.

gjones118

Original Poster:

7 posts

83 months

Monday 29th April 2019
quotequote all
I've decided I'm going to get hold of a compression test kit before I make a decision on anything.

Camshaft lobe, interesting.. I may take the rocker cover off and have a look to see how everything is there

GreenV8S

30,999 posts

307 months

Monday 29th April 2019
quotequote all
M_A_S said:
they have a habit of turning when the belt goes.
What do you mean by that?

imagineifyeswill

1,245 posts

189 months

Monday 29th April 2019
quotequote all
If its the Peugeot engine then they dont have a conventional camshaft machine from a steel billet, the cam lobes are pressed onto the shaft and can turn on the shaft in extreme circumstances.

normalbloke

8,507 posts

242 months

Monday 29th April 2019
quotequote all
imagineifyeswill said:
If its the Peugeot engine then they dont have a conventional camshaft machine from a steel billet, the cam lobes are pressed onto the shaft and can turn on the shaft in extreme circumstances.
What a great idea...

Megaflow

11,087 posts

248 months

Monday 29th April 2019
quotequote all
GreenV8S said:
M_A_S said:
they have a habit of turning when the belt goes.
What do you mean by that?
Lots of modern cams are made from individual lobes assembled on to a tubular shaft, the fit can be press fit or hyroformed, they are fine when being used as designed. But, loaded incorrectly by something such as a belt failure, it is possible for them to turn on the shaft.

stevieturbo

17,968 posts

270 months

Monday 29th April 2019
quotequote all
imagineifyeswill said:
If its the Peugeot engine then they dont have a conventional camshaft machine from a steel billet, the cam lobes are pressed onto the shaft and can turn on the shaft in extreme circumstances.
That rings a bell actually, have heard of that before.

Can always expect something utterly crap from French designers lol

Megaflow

11,087 posts

248 months

Monday 29th April 2019
quotequote all
stevieturbo said:
imagineifyeswill said:
If its the Peugeot engine then they dont have a conventional camshaft machine from a steel billet, the cam lobes are pressed onto the shaft and can turn on the shaft in extreme circumstances.
That rings a bell actually, have heard of that before.

Can always expect something utterly crap from French designers lol
And one of the biggest users of the technology is BMW.

Stan Weiss

260 posts

171 months

Friday 3rd May 2019
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While a compression test may show up a problem, I think a leak down would be a better test.

Stan

Tyre Smoke

23,018 posts

284 months

Friday 3rd May 2019
quotequote all
I'd bet there are a few bent valves. Not all maybe, because it's obviously running (after a fashion). A compression test will tell you.

I'd also say there is unlikely to be any damage apart from the valves. In my experience, when the lobes shift on the camshaft, it won't start at all. Because the timing pulley moves first, knocking all the timing out.

That sounds like valve damage.

Penelope Stopit

11,209 posts

132 months

Saturday 4th May 2019
quotequote all
M_A_S said:
Check the camshaft lobes, they have a habit of turning when the belt goes.
Amazing, variable valve timing without all the add-ons

gjones118

Original Poster:

7 posts

83 months

Monday 6th May 2019
quotequote all
hello all, i haven't ran away... i'm still here plodding on.

So today i took off the cylinder head images below ;

https://ibb.co/zbJqCtn
https://ibb.co/Lxbw0L9
https://ibb.co/nMH9800
https://ibb.co/9WZpXBL
https://ibb.co/fphBYV2
https://ibb.co/xstH21K
https://ibb.co/yh7tnbp
https://ibb.co/YDFKz67
https://ibb.co/jzyCqBx
https://ibb.co/n69j1MV
https://ibb.co/89cW35P

There were slight indentations on two pistons, but weren't substantial enough for my nail to catch them if you get what i mean, i tried to run a pressure test but i bought the wrong kit.. ended up buying a fuel pressure kit by mistake, so instead of wasting time i took the head off.

My next steps are to clean up the cylinder head with a chemical i'm hoping somebody will suggest for me in order to remove all the carbon deposits to get an indication with feeler gauges to tell me weather the head is warped and to see if it needs skimming.

Another thing to mention, on the last image after removing the rocker cover another rocker arm was snapped on the one that is missing, all others were fine but that one was snapped (all were replaced with new) . Could suggest a bent valve in that position or moved cam lobe? also when the engine was running i removed the oil cap and there was a substantial amount of air blowing out, could this also suggest a bent valve not seating properly?

can anyone suggest any other next moves to carry out?

stevieturbo

17,968 posts

270 months

Monday 6th May 2019
quotequote all
Give the head to a reputable machine shop and get them to check and replace the valves and check it's condition etc.

As to why rockers were broke....only you can see how things went together, and came apart and what might be a cause. A presumption would be incorrect installation, incorrect valve timing again or something along those lines.


gjones118

Original Poster:

7 posts

83 months

Tuesday 7th May 2019
quotequote all
[quote=stevieturbo

As to why rockers were broke....only you can see how things went together, and came apart and what might be a cause. A presumption would be incorrect installation, incorrect valve timing again or something along those lines.


[/quote]

With regards to the incorrect timing, because piston 2 and 3 top out at the same time wouldn't the rocker arms for both cylinders have broken?