small cracks betwwen the valves....

just pulled the head off my '86 cab, as i overheated it pritty badly and i think ive warped the head, ive put a straight edge on it and its low in the middle of the head, so i was gonna get it skimmed, but now ive noticed little a crack between the inlet and exhaust valve seats, on each clyinder!

  i know they shouldnt be there, im just wondering wether to find a new head, or just skim this one and live with the little cracks….? as im un-sure whats behind the cracked area etc…???

anyone see cracks in this place before?

any help would be great

cheers
alex.

Yep, seen it many times before must be a common issue.

A mate of mine who ran a garage used to just skim the head and refit but I would try to source a new one personally as the cracks must have some effect on reliability & performance.

Skimming the head alone may be just a waste of your time and money.

Good luck with it anyway,

C.

yeah 'normally' i would get another, and check/get that skimmed, but times not on my side, i shoudl be at work, using the car, right now!! lol


gonna see what my head man says, he needs to do a quick turn-a-round on skimming it too…

if he saids its scrap then i need a run-about quicksharp…..

cheers
alex.

Text book answer is: "Cylinder heads with small, fine cracks between valve seats and plug threads are useable provided the cracks are not more than 0.5mm (.02in.) wide, and do not extend into more than the first few spark plug threads." As stated, that is the book answer. I also would not use the head and find another one but not because I believe it is no longer any good, I just would feel better. If it's being used for normal driving and you're in a pinch then use it. If the gap between the head and straight edge is 0.1mm (.004 in.) or less, the books also say that's OK to put back on and use.

well ive pulled the head apart ready for skimmin, just pulled all the rocker studs and the cam studs etc, labeled and removed the followers/hydrolic tappets etc..

thought id investigate these cracks a little more, so i removed the valves from no.4 and the crack itself is only 2/3mm long going from one valve seat to the other, now this aint great as if it drops a valve seat ill know about it, other than that i cant see any reason not to use it, its not close to any water jackets/oil ways etc… so im gonna get it skimmed and chuck it back on….

hopefully it'll be fine… if not it'll trach the engine and its 16v time!

cheers
alex.

My TSR Donnington has cracks between the valves when i had the head off last year, put it back together and do you know how many sleepless nights ive had worried about them cracks ?????


























NONE

all the diesel heads crack there,just reuse be ok  :wink:
Bert

Same problem on mine which I've got apart atm they're just expansion cracks and won't do any harm I was told by guy who pressuretested my head yesterday and all was well.

Same issue on the 10 valve audi heads, cracks between the seats.

Had to scrap the turbo head i had because the cracks were about 1mm wide and 15mm deep so was beyond reasonable repair.

If theyre just as grimyfingers stated then youll be ok.