[shepp]

hi guys been a while just got head rebuilt went to put it on and noticed some marks on pistions would this have damaged bottom end? i also have spare block wich pot no 3 is rusty hows best way to clean this without damageing the pot any advise thanx

 

[Lagdti]

The valves will mark the piston tops as they touch when the belt breaks,but it's unusual for the piston to actually be damaged unless the belt breaks at high engine rpm or a valve head snaps off and embeds it's self into the piston crown.

Without looking at it I can't be certain,but I would strongly suspect the pistons will be fine.

 

[shepp]

hi there lagdti thanks for reply so u think bottom end will be ok i was doin 75 ish on motorway wen belt snapped all valves are intact and looks like there all bent to some extent! my doner engine i bought has rust in pot 3 but not sure how to clean that with out damageing it so mite aswell go with my original block then thanks again lagdti

 

[Recycled Scenic]

I would strongly suspect the pistons will be fine.

I would agree that is usually the case if it's timing belt failure or guide rollers collapse.


The 2.0 F4R does have valve clearance cut outs in the piston crowns which the valves do collide into when the timing belt / guide rollers collapse and can give the impression that more damage has been done than is actually the case in my experience. Here are some photos of a 2.0 F4R that has suffered a guide roller collapse which was successfully repaired.

it's unusual for the piston to actually be damaged unless the belt breaks at high engine rpm or a valve head snaps off and embeds it's self into the piston crown.

Like this you mean

 

[shepp]

hi thanks recycled scenic looking at your pictures thats bad on my block theres no sighn of valve impact on top off pots just a slight mark on 2 of the pistons so yeah im going to use same block as the engine has only done 86000 wich i consider low mileage for a 2001 model so thanks again guys for your input much needed:d. of i go then put it bck together:d

 

[danthevan]

Check for movement in the pistons, and that they're all coming up and down nicely with no sideways movement.
When mine went, i had some horrible movement in no1 piston, which i guess was a broken ring