white lightning

The head gaskets on my 1998 Version 5 STi went before Christmas due to a broken radiator & subsequent loss of water & over heating. The heads were quite bad but were saved after skimming nearly 0.5mm off them & they were still within the prescribed tolerances.

Everything was put back together along with a new cambelt tensioner and cambelt. I picked the car up and after approx 15 miles on the M18 at about 70mph I lost all power so I immediately took it out of gear, by which time the engine had stalled, and coasted to the hard shoulder (temperature was normal). The engine sounded like a bag of spanners when trying to start it.

Back at the garage the following day, 4 teeth are missing from the timing belt (unsure at the moment if this was the case before the incident, i.e. fault manufacture) and one of the bakelite cam pulleys has completed collapsed.

What could have caused the above?? Faulty cambelt tensioner, faulty belt, something the garage have done wrong/haven't done??

Thanks in advance for any responses.

V.financially challenged Subaru owner

P20SPD

iTrader: (1)

Who rebuilt it?

The bakelite cam pulleys can get brittle if they have been clamped.

white lightning

A garage in Sheffield.

P20SPD

iTrader: (1)

Do you know which pulley has collapsed, Top left, top right, bottom left or bottome right as you are looking at the engine?

If they have used mole grips whilst putting the cambelt back on, then they could have fatigued the bakelite pulley. This will then shatter once under load etc, if it hasnt already broken when clamped.

It is very tempting to clamp the pulleys when installing the cam belt, but you must not do this.

white lightning

Top left pulley.

Shark Man

The pulleys can be damaged quite easily, they can be chipped if you slip with the spanner and that gives a stress intiation point allowing them to fracture. I found my one pulley in a state, thanks to the heavy handed Subaru dealer who had a habit of breaking stuff on my car before I had chance to remove it out of their hammer fisted hands.

The bearings in the idler pulleys and rollers (including the one on the tensioner) do dry out, and can seize. These should be inspected and replaced (if needed) everytime the cambelt is removed. Geneally I find at least one of them (three in total) needs replacing after five to six years of use.

I presume the belt was replaced with a new one. An old belt should never be re-used.

merlin24

iTrader: (1)

Have known the cams to sieze in the heads before due to sealant/swarf/old gasket stuck in the oil gallerys.
The oil gallerys must be 100% clean before re-assembly especially where the oil restrictor sits adjacent to the main up-feed from the block.