Xantia HDi timing belt snapped WHAT HEADGASKET????

HDI · Post by **HDI** » 15 Nov 2009, 00:36

There are also so called no contact engines , the belt can snap but valves don't hit pistons , the Toyota MR2 engine is one of these.

citroenxm · Post by **citroenxm** » 15 Nov 2009, 09:36

Mazdas OWN engines in their Nineties models, the 323F, MX 3, MX 5 and MX 6 and of course 1992 to 1998 626, these engines are also Clearence engines! Surely the BEST way to go really!

Im not sure what the later engines of theres are like, I know they arent Ford units.. in fact, up untill VERY recently, they have ALWAYS used their own engines, except the 121 Fiesta COPY...

Paul

scoles · Post by **scoles** » 15 Nov 2009, 10:28

i know i have worked on a few vauxhall engines that are supposed to be non contact,

how hard are the fuel pumps to set up on these? they still run off the timing belt?

are there any How To's floating about on doing the headgasket and such?

Cheers
Stuart

HDI · Post by **HDI** » 15 Nov 2009, 11:07

If u mean HDI's the pumps are not timed , just run off the ancillary belt.

citroenxm · Post by **citroenxm** » 15 Nov 2009, 13:38

NO They ARE NOT, the High pressure PUMPS Run off the CAM BELT, But you are correct, they ARE NOT timed, all you nee to do is Pin up the Cam shaft through the cam sprocket, and pin up the Crank at TDC through the timing hole on the block behind the starter motor. The two items will be easyest to time while in two pieces...

Paul

HDI · Post by **HDI** » 15 Nov 2009, 14:29

Ooooop's , excuse me there , my brain was AWOL !!! Was thinking of the hydraulic pump

citroenxm · Post by **citroenxm** » 15 Nov 2009, 18:07

Excused!

It can be a bit confusing really, HP Hydraulic Pump... HP Fuel Pump... me must specify more clearly, your not the first to confuse the HP Pump term.. 8)

Paul

Kowalski · Post by **Kowalski** » 16 Nov 2009, 10:02

Sadly the days of non-interference engines are behind us.

Diesels are pretty universally interference engines, its rather hard to make a high compression ratio diesel engine non-interfering. The vast majority of petrol engines are 16 valve now, and again 16 valve engines tend to be interference engines and when they have inclined valves, (i.e. valves that are not vertical but at an angle) if the piston hits the valves they bend, jam and can break instead of being able to be pushed upwards so that they break a cam follower or rocker arm.

scoles · Post by **scoles** » 16 Nov 2009, 10:22

One thing i did notice when looking at the bottom end of this HDi engine is that the pistons had pretty big pockets in them almost like holes,

Take it this is normal? nothing looked like new metal as in it had been broken everything was covered in carbon.

Stuart

HDI · Post by **HDI** » 16 Nov 2009, 10:46

Kowalski wrote:Sadly the days of non-interference engines are behind us.

Diesels are pretty universally interference engines, its rather hard to make a high compression ratio diesel engine non-interfering. The vast majority of petrol engines are 16 valve now, and again 16 valve engines tend to be interference engines and when they have inclined valves, (i.e. valves that are not vertical but at an angle) if the piston hits the valves they bend, jam and can break instead of being able to be pushed upwards so that they break a cam follower or rocker arm.

Thats what I've never been able to understand with engines like that from the MR2 , it's 16 valve , high compression , how do they manage to make it non contact with such tight clearances ?!

Diesels obviously can never be non contact with such high compression , but the clever thinking with the HDI seems to overcome that restriction.

Roll on pneumatic , electromechanical valve operation or spherical rotary valves , no cam to worry about !

wheeler · Post by **wheeler** » 16 Nov 2009, 17:50

scoles wrote:One thing i did notice when looking at the bottom end of this HDi engine is that the pistons had pretty big pockets in them almost like holes,

Take it this is normal? nothing looked like new metal as in it had been broken everything was covered in carbon.

Stuart

The big pockets are the combustion chambers, completely normal.

scoles · Post by **scoles** » 20 Nov 2009, 14:12

well finally managed to get a proper look at the head today,

all 8 rockers are broken right enough, but all valves are seating fine and i can push them out with a fair bit shouve and they spring back and seat ok.

Tops of pistons arent marked and the faces of the valves dont look to be marked neither.

checked the cam and all looks fine there as well.

i am still unsure though if it will be ok to rebuild this head with new rockers and build it up.

Any opinions on this?

Cheers
stuart

Toby_HDi · Post by **Toby_HDi** » 20 Nov 2009, 14:29

Will be fine, My belt slipped on my HDi and took out a rocker. Bought a new one, fitted it, and all was fine.

Be aware though they are around £16 each from Citroen. If you need 8 thats a fair whack, however, I'm not sure where else you can get them from.

scoles · Post by **scoles** » 20 Nov 2009, 14:33

i have priced them from places like dingbro GSF and euro car parts and they all come in at £14 each, so £16 from main dealer aint bad, your right though does add up when you need more than one ie 8.

stuart

Toby_HDi · Post by **Toby_HDi** » 20 Nov 2009, 14:46

Indeed, as said though. Once fitted and new belt on (make sure it's tensioned properly

) all should be fine.

Good luck with the rebuild!